Hazardous Waste Management System; Identification and Listing of Hazardous Waste; Chlorinated Aliphatics Production Wastes; Land Disposal Restrictions for Newly Identified Wastes; and CERCLA Hazardous Substance Designation and Reportable Quantities

Note: EPA no longer updates this information, but it may be useful as a reference or resource.

[Federal Register: November 8, 2000 (Volume 65, Number 217)]
[Rules and Regulations]
[Page 67067-67133]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr08no00-9]

[[Page 67067]]

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Part III

Environmental Protection Agency

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40 CFR Part 148, et al.

Hazardous Waste Management System; Identification and Listing of
Hazardous Waste; Chlorinated Aliphatics Production Wastes; Land
Disposal Restrictions for Newly Identified Wastes; CERCLA Hazardous
Substance Designation and Reportable Quantities; Final Rule

[[Page 67068]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 148, 261, 268, 271, and 302

[SWH-FRL-6882-6]
RIN 2050-AD85

Hazardous Waste Management System; Identification and Listing of
Hazardous Waste; Chlorinated Aliphatics Production Wastes; Land
Disposal Restrictions for Newly Identified Wastes; and CERCLA Hazardous
Substance Designation and Reportable Quantities

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is listing as
hazardous two wastes generated by the chlorinated aliphatics industry.
EPA is finalizing these regulations under the Resource Conservation and
Recovery Act (RCRA), which directs EPA to determine whether certain
wastes from the chlorinated aliphatics industry may present a
substantial hazard to human health or the environment. The effect of
listing these two wastes is to subject them to stringent management and
treatment standards under RCRA and to subject them to emergency
notification requirements for releases of hazardous substances to the
environment. EPA is finalizing a contingent-management listing approach
for one of these wastes. Under the contingent management listing
determination, the waste will not be a listed hazardous waste, if it is
sent to a specific type of management facility. EPA also is finalizing
determinations not to list as hazardous four wastes generated by the
chlorinated aliphatics industry.

EFFECTIVE DATE: This final rule is effective May 7, 2001.

ADDRESSES: Supporting materials are available for viewing in the RCRA
Information Center (RIC), located at Crystal Gateway I, First Floor,
1235 Jefferson Davis Highway, Arlington, VA. The Docket Identification
Number is F-2000-CALF-FFFFF. The RIC is open from 9 a.m. to 4 p.m.,
Monday through Friday, excluding federal holidays. To review docket
materials, it is recommended that the public make an appointment by
calling (703) 603-9230. The public may copy a maximum of 100 pages from
any regulatory docket at no charge. Additional copies cost $0.15/page.
The index and some supporting materials are available electronically.
See the beginning of the Supplementary Information section for
information on accessing them.

FOR FURTHER INFORMATION CONTACT: For general information, contact the
RCRA Hotline at (800) 424-9346 or TDD (800) 553-7672 (hearing
impaired). In the Washington, DC, metropolitan area, call (703) 412-
9810 or TDD (703) 412-3323. For information on specific aspects of the
rule, contact Ross Elliott of the Office of Solid Waste (5304W), U.S.
Environmental Protection Agency, 1200 Pennsylvania Avenue, NW,
Washington, DC 20460. [E-mail address and telephone number:
elliott.ross@epamail.epa.gov, (703) 308-8748.]

SUPPLEMENTARY INFORMATION: Wherever ``we'' is used throughout this
document, it refers to the Environmental Protection Agency (EPA).
The index and some supporting materials for this rulemaking are
available on the Internet. Follow these instructions to access these
documents.

WWW: http://www.epa.gov/epaoswer/hazwaste/id
FTP: ftp.epa/gov
Login: anonymous
Password: your Internet address
Files are located in /pub/gopher/OSWRCRA

EPA will keep the official record for this action in paper form.
The official record is the paper record maintained at the address in
ADDRESSES at the beginning of this document.
The contents of the preamble to this final rule are listed in the
following outline:

I. Who Potentially Will Be Affected By Today's Final Rule?
II. What Is The Legal Authority and Background of Today's Final
Rule?
A. What Are the Statutory Authorities for This Rule?
B. Schedule Suit
III. Summary of Today's Action
IV. What Proposed Listing Determinations Led to Today's Final Rule?
A. What was the Proposed Listing Determination for Chlorinated
Aliphatic Wastewaters?
B. What Were the Proposed Listing Determinations for Wastewater
Treatment Sludges?
C. Which Constituents did EPA Propose to Add to Appendix VIII of
40 CFR part 261
D. What Were the Proposed Treatment Standards Under RCRA's Land
Disposal Restrictions Standards?
E. What Risk Assessment Approach was used for Proposed Rule?
V. What Changes Were Made to the Proposed Rule?
A. Listing Determination for Chlorinated Aliphatic Wastewaters
B. Modification of Wastewater Treatment Unit Exemption and
Application of Subpart CC Requirements for Tanks Managing
Chlorinated Aliphatic Wastewaters
C. Landfill Leachate Derived From Previously Disposed VCM-A
Wastewater Treatment Sludges
VI. What Is the Rationale for Today's Final Rule, and What are EPA's
Responses to Comments?
A. Chlorinated Aliphatic Wastewaters (other than wastewaters
from the production of VC-A using mercuric chloride catalyst in an
acetylene-based process)
B. Wastewater Treatment Sludges from the Production of EDC/VCM
C. Wastewater Treatment Sludges and Wastewaters from the
Production of VCM-A
D. Wastewater Treatment Sludges from the Production of Methyl
Chloride
E. Wastewater Treatment Sludges from the Production of Allyl
Chloride
F. What is the Status of Landfill Leachate Derived from Newly-
listed K175?
G. Population Risks
H. Which Constituents are Being Added to Appendix VIII of 40 CFR
part 261?
I. What are the Land Disposal Restrictions Standards for the
Newly-Listed Wastes?
J. Is There Treatment Capacity for the Newly-Listed Wastes?
VII. What is the Economic Analysis of Today's Final Rule?
A. What is the Purpose of the Economic Analysis?
B. How Did the Public Participate in the Economic Analysis?
C. What are the Expected Economic Impacts of this Final Rule?
VIII. When Must Regulated Entities Comply With Today's Final Rule?
A. Effective Date
B. Section 3010 Notification
C. Generators and Transporters
D. Facilities Subject to Permitting
IX. How Will This Rule be Implemented at the State Level?
A. Applicability of Rule in Authorized States
B. Effect on State Authorizations
X. What Are the Reportable Quantity Requirements For Newly-Listed
Wastes (K174 and K175) under the Comprehensive Environmental
Response, Compensation, and Liability Act (CERCLA)?
A. What is the Relationship Between RCRA and CERCLA?
B. Is EPA Adding Chlorinated Aliphatic Wastes to the table of
CERCLA hazardous substances?
C. How Does EPA Determine Reportable Quantities?
D. When Do I Need to Report a Release of K174 or K175 Under
CERCLA?
E. What if I Know the Concentration of the Constituents in My
Waste?
F. How Did EPA Determine the RQs for K174 and K175 and Their
Hazardous Constituents?
G. How Do I Report a Release?
H. Is CERCLA Reporting Required for Spills of EDC/VCM Wastewater
Treatment Sludge That (Prior to the Spill) Does Not Meet the Listing
Description for K174?
I. What is the Statutory Authority for This Program?

[[Page 67069]]

XI. What Are the Administrative Assessments?
A. Executive Order 12866
B. Regulatory Flexibility Act
C. Paperwork Reduction Act
D. Unfunded Mandates Reform Act
E. Executive Order 13132: Federalism
F. Executive Order 13084: Consultation and Coordination with
Indian Tribal Governments
G. Executive Order 13045: Protection of Children from
Environmental Risks and Safety Risks
H. National Technology Transfer and Advancement Act of 1995
I. Executive Order 12898: Environmental Justice
J. Congressional Review Act

I. Who Potentially Will Be Affected by Today's Final Rule?

Today's final rule could directly affect those who generate and
handle the types of chlorinated aliphatic hydrocarbon production wastes
that EPA is adding to the Agency's list of hazardous industrial wastes
under RCRA. Although there are an estimated 39 chlorinated aliphatic
hydrocarbon chemical manufacturing facilities in the United States as
of 1999, the K174 and K175 listing final rule only applies to 18 of
these facilities (17 for the K174 listing and one for the K175
listing), which manufacture two such chemicals; ethylene dichloride
(EDC) and vinyl chloride monomer (VCM). Furthermore, because of the
final rule's ``conditional listing'' approach, in comparison to current
(baseline) waste management practices in this industry, EPA anticipates
that three of the 18 chemical manufacturing facilities subject to the
final rule as generators of K174 and K175 hazardous wastes, will incur
costs to modify their current waste management practices, while the
remaining 15 facilities will incur only minimal regulatory costs,
primarily associated with documentation of current waste management
practices. In addition, EPA anticipates that four industrial waste
management facilities also will be affected by the final rule due to
potential changes in the annual quantities of hazardous wastes handled
and associated changes to business revenues that will be the result of
modifications to current waste management practices to comply with the
provisions of today's final rule.
In addition to waste generators targeted by the rule, because of
RCRA's ``cradle-to-grave'' statutory design, EPA anticipates that four
waste handlers (three for the K174 listing and one for the K175
listing) are likely to experience ``induced effects'' from this final
rule. In addition, EPA's regional offices and states with RCRA-
authorized programs potentially will incur some costs because they must
administer new RCRA listings. Several additional stakeholders also will
have to read the final rule.
As defined in the Economics Background Document prepared for
today's final rule, ``targeted effects'' are the anticipated costs of
the final rule incurred by the unique class of industrial facilities
that generate the newly listed hazardous wastes K174 and K175.
``Induced effects'' are anticipated costs of direct, indirect or
secondary impacts the final rule may have on entities linked
economically to the targeted facilities such as offsite waste
management facilities, and on entities which are likely affected by
other generic provisions of the final rule, such as states with RCRA
authorized programs which will implement and enforce the rule.
``Incidental effects'' are anticipated consequential impacts on other
types of entities, such as on other chemical manufacturers (to read the
rule), other Federal agencies (to read the rule), and other non-
governmental organizations (such as industry trade associations to read
and propagate the rule to its member companies).
EPA's estimate of expected regulatory costs for these 116
potentially affected entities, is described in EPA's ``Economics
Background Document'(USEPA 2000a) \1\ for this final rule, which is
available for public review from the RCRA Docket. A summary of the
potentially affected industry sectors (by respective SIC and NAICS
codes) is displayed in the table below.
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\1\ USEPA. 2000a. Economics Background Document, USEPA Final
Rule Listing Industrial Wastewater Treatment Sludges Generated by
Chlorinated Aliphatic Chemical Manufacturing Facilities, as RCRA
Hazardous Wastecodes K174 & K175: Industry Profile and Estimation of
Regulatory Costs. Office of Solid Waste. 31 July.

Summary of Entities Potentially Affected by the RCRA K174/K175 Final Rule
----------------------------------------------------------------------------------------------------------------
Economic sector classification Number entities potentially affected
Item --------------------------------------------------------------------------------------------
SIC NAICS Description Targeted Induced Incidental Total
----------------------------------------------------------------------------------------------------------------
1.................. 2869 32511 Industrial organic 18 0 21 39
chemical
manufacturers*
(waste generators).
2.................. 4953 562211 Hazardous waste 0 4 0 4
treatment & disposal
(waste handlers).
3.................. 9511 92411 State government 0 49 0 49
environmental
departments (public
administration).
4.................. 9511 92411 Federal government 0 11 1 12
9611 92611 offices
9621 92612 (environmental,
economic &
transportation
public
administration).
5.................. 8742 54161 Management consulting 0 0 12 12
services (non-
governmental
organizations).
---------------------------------------------------
Total................ 18 64 34 116
----------------------------------------------------------------------------------------------------------------
Explanatory Notes:
(a) *Parent company codes may differ from the codes associated with the facility units targeted by the rule.
(b) This list of sector classification codes for ``induced effect'' entities may not be exhaustive for at least
two reasons:
Non-hazardous and hazardous industrial waste collection transporters (SIC 4212, 4953, NAICS 562111,
562112) may be affected, depending upon whether waste collected from K174/K175 generators is transported by
waste treatment/disposal facilities, or by separate, unaffiliated transporter companies.
If waste remediation is required, such entities may be affected (SIC 4959, NAICS 56291).

[[Page 67070]]

The list of potentially affected entities in the above table may
not be exhaustive. Our aim is to provide a guide for readers regarding
those entities that EPA is aware potentially could be affected by this
action. However, this action may affect other entities not listed in
the table. To determine whether your facility is regulated by this
action, you should examine 40 CFR part 260 and 261 carefully in concert
with the rules amending RCRA that are found at the end of this Federal
Register notice. If you have questions regarding the applicability of
this action to a particular entity, consult the person listed in the
preceding section entitled FOR FURTHER INFORMATION CONTACT.

II. What Is the Legal Authority and Background of Today's Final
Rule?

A. What Are the Statutory Authorities for This Rule?

These regulations are being promulgated under the authority of
sections 2002(a), 3001(b), 3001(e)(2) and 3007(a) of the Solid Waste
Disposal Act, 42 U.S.C. 6912(a), 6921(b) and (e)(2), and 6927(a) as
amended several times, most importantly by the Hazardous and Solid
Waste Amendments of 1984 (HSWA). These statutes commonly are referred
to as the Resource Conservation and Recovery Act (RCRA), and are
codified at Volume 42 of the United States Code (U.S.C.), sections 6901
to 6992(k) (42 U.S.C. 6901-6992(k)).
Section 102(a) of the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA), 42 U.S.C. 9602(a) is
the authority under which the CERCLA aspects of this rule are being
promulgated.

B. Schedule Suit

In 1989, the Environmental Defense Fund (EDF) \2\ sued the
Environmental Protection Agency (EPA), in part for failing to meet the
statutory deadlines of Section 3001(e)(2) of RCRA (EDF vs. Browner;
Civ. No. 89-0598 D.D.C.). To resolve most of the issues in the case,
EDF and EPA entered into a consent decree, which has been amended
several times to revise dates. The consent decree sets out deadlines
for promulgating certain RCRA rules and for completing certain studies
and reports. The consent decree obliges EPA to propose a hazardous
waste listing determination for wastewaters and wastewater treatment
sludges generated from the production of specified chlorinated
aliphatic chemicals. The wastewater and wastewater treatment sludges
subject to the consent decree are those from the production of
chlorinated aliphatics for which other process wastes already have been
designated as hazardous waste F024 in 40 CFR 261.31. According to the
consent decree, EPA was required to propose listing determinations by
July 30, 1999 and promulgate final listing determinations on or before
September 30, 2000. Today EPA is promulgating listing determinations
for these wastes in accordance with the consent decree.
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\2\ Now known as Environmental Defense.
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III. Summary of Today's Action

In today's notice, EPA is promulgating regulations that add two
wastes generated by the chlorinated aliphatics industry to the list of
hazardous wastes in 40 CFR 261.32. Below are the wastestreams EPA is
listing as hazardous with their corresponding EPA Hazardous Waste
Numbers.

K174 Wastewater treatment sludges from the production of ethylene
dichloride or vinyl chloride monomer (EDC/VCM)
K175 Wastewater treatment sludges from the production of vinyl
chloride monomer using mercuric chloride catalyst in an acetylene-
based process

EPA is listing these wastes as hazardous based on the criteria set
out in 40 CFR 261.11(a)(3) for listing a waste as hazardous. EPA
assessed and considered these criteria for each of six wastestreams
generated by the chlorinated aliphatics industry through the use of
risk assessments and risk modeling, as well as a consideration of other
pertinent factors. Today's final listing determination follows the
elements of the Agency's listing decision policy that was presented in
the proposed listing determination for wastes generated by the dye and
pigment industries published in the Federal Register on December 22,
1994 (see 59 FR at 66073). This policy uses a ``weight-of-evidence''
approach in which calculated risk information is a key factor
considered in making a listing determination.
Upon the effective date of the hazardous waste listings promulgated
today, wastes meeting the listing descriptions will become hazardous
wastes and need to be managed in accordance with RCRA subtitle C
requirements. Residuals from the treatment, storage, or disposal of the
wastewater treatment sludges proposed to be listed as hazardous also
will be classified as hazardous wastes pursuant to the ``derived-from''
rule (40 CFR 261.3(c)(2)(i)). Also, with certain limited exceptions,
any mixture of a listed hazardous waste and a solid waste is itself a
RCRA hazardous waste (40 CFR 261.3(a)(2)(iv), ``the mixture rule'').
In today's notice, the Agency is promulgating an alternative
approach to listing wastewater treatment sludges from the production of
ethylene dichloride or vinyl chloride monomer (EDC/VCM), rather than
listing this waste in accordance with the Agency's traditional listing
approach. The Agency is promulgating a conditional listing approach
because the Agency evaluated the ways in which the wastes are likely to
be managed and determined that the waste may present significant risks
to human health and the environment, although it concluded that a
particular waste management practice is protective of human health and
the environment. Under the conditional listing approach, EPA is listing
the waste as hazardous only if the waste is managed in a way other than
the manner in which the Agency has determined is protective of human
health and the environment. In developing this conditional-listing
approach, the Agency has determined that wastes that fall outside the
scope of the listing description (e.g., are destined for the
appropriate type of disposal) are non-hazardous when generated.
However, if it turns out that the waste actually is not handled in
accordance with the conditions of the listing at any point in its
management, the generators or other handlers of the waste will be
subject to enforcement actions. The conditional-listing approach being
promulgated today for certain wastes generated from chlorinated
aliphatics processes is further discussed in section VI.B. of today's
rule.
Today's action also promulgates no list decisions for the following
four wastes:
Process wastewaters from the production of chlorinated
aliphatics (other than wastewaters from the production of vinyl
chloride monomer using mercuric chloride catalyst in an acetylene-based
process),
Process wastewaters from the production of vinyl chloride
monomer using mercuric chloride catalyst in an acetylene-based process,
Wastewater treatment sludges from the production of methyl
chloride, and
Wastewater treatment sludges from the production of allyl
chloride.
EPA considers the listing criteria set out in 40 CFR 261.11, in
light of information relevant to the criteria, in making listing
determinations. The criteria provided in 40 CFR 261.11 include eleven
factors for determining whether a waste is capable of posing a
``substantial present or potential hazard to human health and the
environment.'' Nine of these factors, as described

[[Page 67071]]

generally below, are directly incorporated into EPA's completion of a
risk assessment for the wastestreams of concern:
Toxicity (Sec. 261.11(a)(3)(i)) is considered in
developing the health benchmarks used in the risk assessment modeling.
Constituent concentrations and waste quantities
(Secs. 261.11(a)(3)(ii) and 261.11(a)(3)(viii)) are used to define the
initial conditions for the risk evaluation.
Potential to migrate, persistence, degradation, and
bioaccumulation of the hazardous constituents and any degradation
products (Secs. 261.11(a)(3)(iii), 261.11(a)(3)(iv), 261.11(a)(3)(v),
and 261.11(a)(3)(vi)) are all considered in the design of the fate and
transport models used to determine the concentrations of the
contaminants to which individuals are exposed.
We consider two of the remaining factors, plausible mismanagement
and other regulatory actions (Secs. 261.11(a)(3)(vii) and
261.11(a)(3)(x)) in establishing the waste management scenario(s)
modeled in the risk assessment.
EPA conducted analyses of the risks posed by wastewaters and
wastewater treatment sludges from the production of chlorinated
aliphatic chemicals to assist in the determination of whether the
wastes meet the criteria for listing set forth in 40 CFR 261.11(a)(3).
In the preamble to the proposed rule (64 FR 46476), we discussed the
human health risk analyses and ecological risk screening analyses EPA
conducted to support our proposed listing determinations for
chlorinated aliphatics wastewaters, EDC/VCM wastewater treatment
sludges, and methyl chloride wastewater treatment sludges. These
analyses, as well as comments EPA received on the analyses, are further
discussed in this notice in section VI below. We considered the results
of the risk analyses, as well as comments received, and the results of
analyses conducted in response to information provided by public
commenters in finalizing our listing decisions for each wastestream.
The risk analyses conducted in support of our proposed listing
determination are presented in detail in the Risk Assessment Technical
Background Document for the Chlorinated Aliphatics Listing
Determination and in the 1999 Addendum to Risk Assessment Technical
Background Document for the Chlorinated Aliphatics Listing
Determination which are located in the docket for the proposed rule.
Additional information and analyses conducted with regard to our
original risk assessment in response to comments received on our
proposed rule are included in the September 2000 Addendum to Risk
Assessment Background Document for the Chlorinated Aliphatics Listing
Determination. This document is located in the docket for today's final
rule.

IV. What Proposed Listing Determinations Led to Today's Final Rule?

In the August 25, 1999 proposed rule (64 FR 46476), EPA proposed to
list three wastes generated by the chlorinated aliphatics production
industry as hazardous wastes under RCRA. The wastes the Agency proposed
to list as hazardous included chlorinated aliphatics manufacturing
process wastewaters, wastewater treatment sludges generated from the
treatment of wastewaters from the production of ethylene dichloride
and/or vinyl chloride monomer (EDC/VCM), and wastewater treatment
sludges from the treatment of wastewaters from the production of vinyl
chloride monomer using mercuric chloride catalyst in an acetylene-based
process (VCM-A). EPA proposed a conditional listing approach for EDC/
VCM wastewater treatment sludges, based upon available information
regarding the management of these sludges and the results of the
Agency's risk assessment.
In connection with the proposed listings, EPA proposed to amend
Appendix VIII of 40 CFR Part 261 to add two constituents,
octachlorodibenzo-p-dioxin (OCDD) and octachlorodibenzofuran (OCDF).
These constituents are found in chlorinated aliphatic wastewaters and
in EDC/VCM wastewater treatment sludges.
In the proposed rule, the Agency also proposed not to list as
hazardous wastewater treatment sludges generated from the treatment of
wastewaters from the production of methyl chloride and the production
of allyl chloride. In addition, the Agency proposed not to list process
wastewaters from the production of vinyl chloride monomer using
mercuric chloride catalyst in an acetylene-based process.
The Agency proposed to add to the list of CERCLA hazardous
substances those wastes that were proposed to be listed as hazardous.
EPA also proposed adjusted Reportable Quantities (RQs) for each waste.

A. What Was the Proposed Listing Determination for Chlorinated
Aliphatic Wastewaters?

As explained in Section III.A.1. of the proposed rule (64 FR
46479), the Agency segregated wastewaters from the chlorinated
aliphatics industry into two waste groupings. Based upon current waste
management practices, we grouped all chlorinated aliphatic wastewaters,
except for those wastewaters generated from the production of vinyl
chloride monomer using mercuric chloride catalyst in an acetylene-based
process, into a single waste category for the listing determination
investigation. We decided to study these wastewaters collectively
because most chlorinated aliphatic manufacturers commingle wastewaters
generated by individual processes prior to treating the wastewaters in
a common wastewater treatment system. In addition, many process
wastewaters generated from the production of chlorinated aliphatic
hydrocarbons contain similar constituents of concern.
EPA proposed to list as hazardous process wastewaters generated
from the production of chlorinated aliphatic hydrocarbons (other than
those wastewaters generated from the production of vinyl chloride
monomer using mercuric chloride catalyst in an acetylene-based
process). Results of the risk assessment conducted in support of the
proposed rule, indicated that the wastewaters met the criteria set out
at 40 CFR 261.11(a)(3) for listing a waste as hazardous. Risk
assessment results identified risks of concern associated with air
releases of dioxins from wastewater treatment systems using aerated
biological treatment in open tanks.
EPA proposed not to list as hazardous process wastewaters generated
from the production of vinyl chloride monomer using mercuric chloride
catalyst in an acetylene-based process (VCM-A wastewaters). EPA
proposed not to list this waste as hazardous due to the fact that the
wastewater exhibits the toxicity characteristic for both mercury and
vinyl chloride. Therefore, the wastewater already is defined as
hazardous waste. In addition, any risks associated with the management
and disposal not addressed by RCRA (i.e., direct discharge) of the
wastewaters are addressed by other environmental regulations. With
respect to the discharge of this wastewater, the facility treats and
discharges the wastewater in compliance with the conditions of a NPDES
permit. Regarding any air emissions of vinyl chloride from these
wastewaters, vinyl chloride is a hazardous air pollutant, therefore the
facility is subject to the National Emissions Standards for Hazardous
Air Pollutants (NESHAP) requirements specific to vinyl chloride
emissions (40 CFR 61.65), as well as the Hazardous

[[Page 67072]]

Organic NESHAP for the synthetic and organic chemical manufacturing
industry sector (40 CFR Part 63, subpart G)(59 FR 19468, April 22,
1994). For these reasons, the Agency proposed not to list VCM-A
wastewaters as hazardous waste.

B. What Were the Proposed Listing Determinations for Wastewater
Treatment Sludges?

1. EDC/VCM Wastewater Treatment Sludges
EPA proposed to list as hazardous sludges generated from treating
wastewaters from the production of ethylene dichloride (EDC) and/or
vinyl chloride monomer (VCM). The Agency proposed to list this waste
due to the fact that the Agency identified risks of concern associated
with the management of this waste in a land treatment unit. Our risk
assessment identified dioxin and arsenic as contaminants of concern,
and found that high-end cancer risk to the farmer receptor from dioxin
was 2E-04. The dioxin risks are associated with airborne releases and
subsequent deposition and food chain contamination from dioxin. Surface
erosion due to runoff also contributes to risk from dioxin. The risk
assessment results for the land treatment unit scenario indicated a
risk level above EPA's levels of concern for dioxin.
The risk assessment for EDC/VCM wastewater treatment sludges also
included modeling a landfill management scenario. Our risk assessment
showed no significant risk from dioxin, and only marginal risk from
arsenic associated with the groundwater pathway. Based upon the
Agency's findings that EDC/VCM wastewater treatment sludges pose
significant risks when managed in land treatment units but do not pose
significant risks when managed in landfills, the Agency proposed a
``contingent management listing'' for this waste. EPA proposed to list
EDC/VCM wastewater treatment sludges as hazardous, unless the sludges
are managed in landfills.
As explained in the proposal, the Agency believes that allowing the
waste to continue to be managed under a low risk management scenario
(i.e., non-hazardous waste landfilling) outside of the subtitle C
system achieves protection of human health and the environment, and
that little additional benefit will be gained by requiring that all
EDC/VCM wastewater treatment sludges be managed in accordance with RCRA
subtitle C management standards. Given the Agency's finding that no
significant risks are posed from managing EDC/VCM wastewater treatment
sludges in a landfill, the Agency sees no reason to include sludges
managed in this manner in the scope of the hazardous waste listing.
Additionally (and after consideration of the predicted risk
differential between land treatment and landfilling), because only one
facility identified in the RCRA 3007 Survey employs land treatment for
these wastes, this practice is somewhat anomalous compared with land
disposal. The Agency proposed that it does not make sense to apply a
traditional listing approach (i.e., list all wastes regardless of
management practice) based upon a practice occurring at one facility,
especially if a more tailored listing can prevent this risk.
2. VCM-A Wastewater Treatment Sludges
EPA proposed to list as hazardous wastewater treatment sludges from
the production of vinyl chloride monomer using mercuric chloride
catalyst in an acetylene-based process (VCM-A). EPA proposed to list
this waste as hazardous based upon the fact that it exhibited the
toxicity characteristic for mercury when sampled by the Agency and
based upon the Agency's assessment of potential risks from this waste,
given its high mercury content and given the uncertainties associated
with the disposal of untreated wastes of potential high toxicity in
lined landfills.
3. Methyl Chloride Wastewater Treatment Sludges
EPA proposed not to list as hazardous sludges from the treatment of
wastewaters generated from methyl chloride production processes. The
results of our risk assessment indicated that this waste does not pose
a substantial present or potential hazard to human health or the
environment. As explained in the proposal, EPA identified only one
facility that generates sludges from the treatment of wastewaters from
the production of methyl chloride and does not currently manage the
waste as hazardous. This facility generates less than 800 metric tons
of this sludge each year and disposes of the sludge in an on-site
landfill along with other wastes from the facility. The landfill is
lined and has a leachate collection system. The Agency analyzed
potential risks from methyl chloride wastewater treatment sludge by
modeling non-groundwater pathways and conducting a screening analysis
for groundwater pathway risk. The Agency concluded that no significant
risks are posed by the management of methyl chloride sludges in an on-
site landfill.
4. Allyl Chloride Wastewater Treatment Sludges
EPA proposed not to list as hazardous sludges generated from
treating wastewaters associated with the manufacture of allyl chloride.
The Agency identified no risks of concern associated with the current
management of the waste.
Only one facility generates wastewater treatment sludge from the
production of allyl chloride, and this facility does not currently
manage the sludge as hazardous waste. The sludge is generated from the
treatment of commingled wastewaters managed at the facility's
centralized wastewater treatment system. This wastewater treatment
system is a non-dedicated system in that wastewaters from the
facility's multiple production processes are discharged to the single
system for combined treatment. Wastewaters from the production of allyl
chloride contribute less than two percent to the system's total sludge
loading. The sludge generated from the facility's wastewater treatment
system is incinerated on site in a non-hazardous waste incinerator.
TCLP analyses of the sludge conducted by EPA indicated the presence
of no TCLP constituents above regulatory levels. As explained in the
proposal, the Agency does not anticipate any significant risk from the
incineration of allyl chloride wastewater treatment sludge in a non-
hazardous waste incinerator, since both the total arsenic level and the
dioxin level detected in the sludge are well within typical soil
background levels for these constituents.

C. Which Constituents Did EPA Propose To Add to Appendix VIII of 40 CFR
Part 261?

EPA proposed to add two constituents, octachlorodibenzo-p-dioxin
(OCDD) and octachlorodibenzofuran (OCDF) to the list of hazardous
constituents at 40 CFR part 261, Appendix VIII. These two constituents
of concern are present in the EDC/VCM wastewater treatment sludges and
the chlorinated aliphatic wastewaters that the Agency proposed to list
as hazardous. OCDD and OCDF are members of the large family of
polychlorinated dioxins and furans. The Agency proposed to add these
two dioxin congeners to Appendix VIII of 40 CFR part 261 because they
are constituents of concern in the wastes proposed to be listed as
hazardous, studies showed that OCDD and OCDF

[[Page 67073]]

have toxic effects and are therefore hazardous, and EPA also noted that
OCDD and OCDF are the only congeners that make up 2,3,7,8-
tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD or ``TCDD'') toxic
equivalence (TEQ) that are not currently listed in Appendix VIII.

D. What Were the Proposed Treatment Standards Under RCRA's Land
Disposal Restrictions Standards?

In the proposal, EPA proposed to apply existing universal treatment
standards (UTS) to the regulated hazardous constituents of concern in
the wastes that were proposed to be listed as K173 (chlorinated
aliphatic wastewaters) and K174 (EDC/VCM wastewater treatment sludges).
For K175 (VCM-A wastewater treatment sludges), EPA proposed a metals
recovery requirement, roasting and retorting, as the treatment
standard. Since treatment residuals would exist after mercury recovery,
EPA proposed the residuals meet existing UTS prior to land disposal.
Information available to the Agency at the time of the proposal
indicated that each of the wastes proposed to be listed as hazardous,
as well as the treatment residuals, could be managed in existing
treatment and reclamation units that routinely manage similar or as-
difficult-to-treat hazardous wastes that currently are prohibited from
land disposal. The BDAT background document provided detailed
information on EPA's rationale for proposing to apply UTS to the wastes
and for proposing a treatment standard of metals recovery to K175.
In the case of hazardous debris contaminated with proposed K173,
K174 and K175, EPA proposed that the provisions in 40 CFR 268.45 apply
to the treatment and disposal of hazardous debris. Hazardous debris
treated in accordance with the provisions of 40 CFR 268.45 may be
allowed for land disposal in a hazardous waste disposal facility. As a
result, debris contaminated with proposed K173, K174, and K175 would be
required to be treated prior to land disposal, using specific debris
treatment technologies such as extraction, destruction, or
immobilization. Residuals generated from the treatment of contaminated
debris would have to meet the applicable UTS limits proposed for K173,
K174, and K175.
In the case of proposed K175, EPA proposed an alternative treatment
standard. The alternative standard proposed was to subject K175 to a
numerical concentration limit of 0.025 mg/L TCLP mercury. Under the
alternative proposal, K175 could be land disposed if a standard of
0.025 mg/L TCLP mercury is achieved using any technology other than
impermissible dilution.
In the proposal, the Agency explained that the solubility of the
mercury in K175 (in the form of mercuric sulfide) varies as a function
of pH. In fact, above pH 6.0 the presence of sulfide complexes results
in significantly increased solubility. Therefore, controlled treatment
and disposal pH conditions were proposed to avoid mobilization of the
mercury in the waste. To insure operational stability of the treatment
process and proper long-term disposal, EPA proposed two conditions as
part of the LDR treatment standards. First, the waste would have to be
treated to (or otherwise be generated to meet) a pH of 6.0 or below.
Second, EPA proposed that if K175 were to be co-disposed in a landfill
with other wastes, co-disposal would be restricted to wastes with
similar pH (i.e., pH not greater than 6.0). EPA proposed that disposal
facilities be required to certify and maintain operating records
demonstrating compliance with this disposal condition.
EPA also proposed to add the numerical standards derived for the
1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin; 1,2,3,4,6,7,8-
heptachlorodibenzofuran;, 1,2,3,4,7,8,9-heptachlorodibenzofuran;
1,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin (OCDD); and 1,2,3,4,6,7,8,9-
octachlorodibenzofuran (OCDF) to the Table of Universal Treatment
Standards (UTS) at 40 CFR 268.48. As explained in the proposal, these
constituents have been shown to have the potential to cause significant
risks to human health or the environment and their presence in wastes
should be mitigated to avoid such potential risks. EPA proposed that
all characteristic wastes which have these constituents as underlying
hazardous constituents above the UTS be required to be treated to UTS
levels for those constituents before land disposal.
Furthermore, EPA proposed that the constituents 1,2,3,4,6,7,8-
heptachlorodibenzo-p-dioxin; 1,2,3,4,6,7,8-heptachlorodibenzofuran;
1,2,3,4,7,8,9-heptachlorodibenzofuran; OCDD; and OCDF be added to the
list of regulated constituents in hazardous waste F039 multisource
leachate. F039 applies to multiple listed hazardous waste landfill
leachates in lieu of the original waste codes, and F039 wastes are
subject to all numerical treatment standards applicable to all listed
wastes. To maintain the regulatory implementation benefits of having
one waste code for multisource leachate, the treatment standards for
F039 must be updated to include the constituents of newly listed
wastes.

E. What Risk Assessment Approach Was Used for the Proposed Rule?

EPA conducted human health risk analyses for chlorinated aliphatics
wastewaters, EDC/VCM wastewater treatment sludges and methyl chloride
wastewater treatment sludges that provided estimates of the incremental
human health risks resulting from exposure to contaminants detected in
these wastes. The incremental human health risks were expressed as
estimates of excess lifetime cancer risk for carcinogenic (cancer-
causing) contaminants and hazard quotients (HQs) for those contaminants
that produce noncancer health effects.
EPA used two different methods of analysis to estimate risks. These
methods are called ``deterministic risk analysis'' and ``probabilistic
risk analysis.'' A deterministic risk analysis produces a point
estimate of risk or hazard for each receptor based on using a single
value for each parameter in the analysis. A probabilistic analysis
calculates risk or hazard by allowing some of the parameters to have
more than one value, consequently producing a distribution of risk or
hazard for each receptor.
EPA conducted both ``central tendency'' and ``high end''
deterministic risk assessments to attempt to quantify the cancer risk
or non-cancer hazard for the typical receptor in the population (the
central tendency risk) and the risk or hazard for individuals in small,
but definable ``high end'' segments of the population (the high end
risk). In the case of the central tendency deterministic risk analyses,
we set all parameters at their central tendency values. For the
chlorinated aliphatics risk assessments, the central tendency values
generally were either mean (average) or 50th percentile (median)
values.
We used high end deterministic risk analysis to predict the risks
and hazards for those individuals exposed at the upper range of the
distribution of exposures. EPA's Guidance For Risk Characterization
(EPA 1995) \3\ advises that ``conceptually, high end exposure means
exposure above about the 90th percentile of the population
distribution, but not higher than the individual in the population who
has the highest exposure,'' and recommends that ``* * * the assessor
should approach estimating high end by

[[Page 67074]]

identifying the most sensitive variables and using high end values for
a subset of these variables, leaving others at their central values.''
For the chlorinated aliphatics high end deterministic risk analyses,
EPA set two parameters at their high end values (generally 90th
percentile values), and set all other parameters at their central
tendency values. We used a ``sensitivity analysis'' to identify the two
parameters that we set at high end.
---------------------------------------------------------------------------

\3\ EPA. 1995. Guidance for Risk Characterization. U.S.
Environmental Protection Agency Science Policy Council. February.
---------------------------------------------------------------------------

EPA used probabilistic risk assessment to support the results of
the deterministic risk analyses and to allow us to quantify individual
risk at selected percentiles of the risk distribution (for example,
50th percentile, 90th percentile, 95th percentile). EPA conducted
probabilistic risk analyses for those combinations of receptor,
contaminant, and pathway for which risk or hazard estimated using a
high end deterministic analysis exceeded the following criteria: a
cancer risk of 1 x 10-6 or a hazard quotient of 1. The Risk
Assessment Technical Background Document for the Chlorinated Aliphatics
Listing Determination describes the input parameters used in the
probabilistic analysis. In the probabilistic analysis, risk was
approximated through repetitive calculation of the fate and transport
and exposure equations and models using input parameters randomly
selected from the Probability Density Functions (PDFs). The result of
the probabilistic analysis is a distribution of the risks or hazards
for each of the receptors.
The human health risk assessments that EPA conducted to support the
chlorinated aliphatics listing determination included five primary
tasks: (1) Establishing that there are constituents in the wastes that
are of concern to the Agency and that warrant analysis to determine
their risk to human health; (2) establishing a scenario under which
contaminants are released from a waste management unit and subsequently
are transported in the environment to a human receptor; (3) estimating
the concentrations of contaminants to which the receptor might be
exposed; (4) quantifying the receptor's exposure to contaminants and
the contaminants' toxicity to the receptor; and (5) describing the
receptor's predicted risk. The preamble to proposed rule provided a
detailed discussion of how EPA completed each of these tasks for the
risk assessments conducted to support the chlorinated aliphatics
listing determination (see 64 FR 46483).

V. What Changes Were Made to the Proposed Rule?

As a result of comments and additional information provided to the
Agency in response to the proposed rule, we made certain modifications
to the risk modeling assumptions used in the risk assessment for the
proposed rule. Changes made to the risk analysis resulted in changes in
our risk assessment results. These changes subsequently caused us to
re-evaluate, and in some instances change, our proposed listing
determinations. These changes and the consequent scope of today's final
action are described below. Detailed reasoning behind these changes and
a summary of each of our final listing determinations is provided in
Section VI.

A. Listing Determination for Chlorinated Aliphatic Wastewaters

In response to comments and information provided by commenters in
response to the proposed rule, the Agency examined the record and
reconsidered the risk assessment and proposed listing determination for
chlorinated aliphatic wastewaters. Commenters to the proposed rule
provided detailed comments on the risk assessment approach used to
evaluate the potential risks from the management of chlorinated
aliphatic wastewaters in aerated biological treatment tanks. These
comments generally fell into one of six topic areas: concern about the
waste management scenarios EPA evaluated; concern about the exposure
scenarios EPA evaluated; EPA's methods for calculating exposure point
concentrations; the way that EPA estimated exposure; EPA's assessment
of contaminant toxicity; and EPA's characterization of estimated risks.
To fully respond to critical issues raised by commenters, EPA decided
to make modifications to some modeling assumptions and data inputs used
in the risk assessment for the proposed rule. Modifications were made
to fully consider the potential impacts of those issues raised by
commenters that the Agency found to have merit. In addition, we
evaluated the merits of other suggestions provided by commenters, and
found these to be of no importance to the listing determination, or we
disagreed with the suggested changes. Specifically, we agreed with
commenters who pointed out that the intake rates that we used to
calculate exposure to beef should have accounted for the mass of beef
that is lost during cooking and post-cooking activities (for example,
dripping and volatile losses, bones, excess fat, scraps, and juices).
We also adjusted our analysis to reflect the variability of dioxin
concentrations in air over an area that would be more consistent with
the area of a pasture where cattle graze. In addition we were convinced
by commenters that our modeling assumptions should have accounted for
the removal of wastewater solids prior to wastewaters entering aerated
biological treatment tanks.
After we accounted for these modifications, our adjusted risk
assessment results indicated that the management of chlorinated
aliphatic wastewaters in aerated biological treatment tanks do not pose
substantial risks to human health and the environment. The Agency has
concluded that available information provides sufficient basis to
determine that chlorinated aliphatic wastewaters should not be listed
as hazardous waste. A more detailed discussion of the issues raised by
public commenters and the modifications made to our risk assessment
results to account for some of these issues is provided in Section VI
below.
The final listing determination for chlorinated aliphatic
wastewaters is based upon EPA's consideration and review of public
comments submitted in response to the proposed listing determination,
and other relevant information available to the Agency and in the
rulemaking record. The final determination is based on the Agency's
evaluation as to whether the waste meets the criteria in 40 CFR
261.11(a)(3) for listing wastes as hazardous. We have assessed and
considered the factors contained in these criteria primarily by
incorporating them as elements in the revised risk assessment, which is
based on the methodology described in the preamble to the proposed rule
and subsequent modifications described in this preamble and the support
documents in the rulemaking record. EPA bases its final listing
determinations on the entire rulemaking record, including applicable
sections of the preamble to the proposed rule, analyses and background
documents developed for the proposed rule, the Agency's responses to
the comments on significant issues raised in the preamble to the
proposal, and all other relevant information available to the Agency.

B. Modification of Wastewater Treatment Unit Exemption and Application
of Subpart CC Requirements for Tanks Managing Chlorinated Aliphatic
Wastewaters

Because we are not finalizing the listing for chlorinated aliphatic
wastewaters as proposed, the proposed amendments to regulations for
tanks

[[Page 67075]]

managing chlorinated aliphatic wastewaters are not necessary and are
not being finalized in today's rule. This includes the proposed
amendments to the wastewater treatment unit exemption in 40 CFR 264.1
and 265.1, as well as the proposed amendments to the 40 CFR parts 264
and 265 subpart CC requirements for implementing the tank cover
requirements and the waste sampling and analysis requirements.

C. Landfill Leachate Derived From Previously Disposed VCM-A Wastewater
Treatment Sludges

In the proposal, EPA proposed amending the existing exemption from
the definition of hazardous waste (40 CFR 261.4(b)(15)) to include
leachate derived from non-hazardous waste landfills that previously
accepted newly-listed VCM-A wastewater treatment sludges (K175). The
Agency would have temporarily deferred the application of the new waste
code to such leachate to avoid disruption of ongoing leachate
management activities during a time period in which the Agency would
decide how to integrate RCRA and CWA regulations governing the
management of landfill leachate.
The Agency proposed the deferral because information available to
EPA at the time of the proposal indicated that VCM-A wastewater
treatment sludges may have been managed previously in non-hazardous
waste landfills. However, information provided by the one generator of
this waste in response to the proposed rule, indicates that since 1985
these sludges have not been disposed in a non-hazardous waste landfill.
The generator has assured EPA that the VCM-A sludges always have been
disposed in subtitle C landfills. Based upon this information, the
Agency sees no need to finalize the proposed deferral for landfill
leachate at this time.
The Agency is not finalizing (but is deferring a final decision on)
the proposed temporary deferral for applying the new K175 waste code to
leachate from non-hazardous waste landfills that previously accepted
waste that meets the K175 listing description. Should the Agency
receive information at a later date indicating that one or more non-
hazardous waste landfills did accept this waste prior to the effective
date of today's rulemaking, we may re-consider our decision not to
finalize the proposed deferral.

VI. What is the Rationale for Today's Final Rule, and What Are
EPA's Responses to the Comments?

A. Chlorinated Aliphatic Wastewaters (Other Than Wastewaters From the
Production of VCM-A Using Mercuric Chloride Catalyst in an Acetylene-
Based Process)

The sections that follow provide a discussion of the comments
received by the Agency in response to the EPA's proposal to list
chlorinated aliphatic wastewaters as hazardous waste, the Agency's
response to these comments, and the impact of the comments on the
Agency's evaluation of risk and the final listing determination.
1. Summary of the Agency's Listing Decision for Chlorinated Aliphatic
Wastewaters
EPA is issuing a final decision not to list wastewaters from
chlorinated aliphatic production processes. The Agency has determined
that these wastewaters do not pose substantial risks when managed in
aerated biological treatment tanks.
The Agency proposed to list chlorinated aliphatic wastewaters based
upon an estimated high-end deterministic risk from dioxin for an adult
farmer of 2E-05. As explained in more detail below, as a result of our
analysis of information provided by commenters, we determined that it
was appropriate to adjust our risk assessment results to account for
certain factors not addressed in the risk assessment for the proposed
rule. These factors include accounting for cooking and post-cooking
losses for beef, assuming a more realistic size of the pasture (or
field) supporting cattle that are indirectly exposed to dioxin
emissions, and accounting for the potential for solids removal prior to
wastewater treatment in aerated biological treatment tanks. After
calculating these adjustments to our proposed risk assessment results,
EPA found that they would reduce our high end deterministic risk
estimate for the adult farmer. Specifically, accounting for cooking and
post-cooking losses for beef would modify the risk estimate by a factor
of 0.78, and accounting for a more reasonable pasture size would modify
the risk estimate by a factor of approximately 0.50, resulting in an
overall risk estimate of 7E-06. Accounting for solids removal from the
wastewater prior to biological treatment could modify the overall risk
estimate by an additional factor of 0.67 to 0.94, that is, could result
in a risk estimate as low as 4E-06.
Given the Agency's finding, we are not finalizing the proposed
amendment to the existing wastewater treatment unit exemption (40 CFR
264.1(g)(6) and 265.1(c)(10)). In addition, the Agency is not
finalizing the proposed requirement that wastewater treatment units
used to treat chlorinated aliphatic wastewaters comply with specific
RCRA air emissions standards.
Today's decision not to list chlorinated aliphatic wastewaters
applies to all chlorinated aliphatic wastewaters, including wastewaters
managed in underground injection control units. As explained further
below, in the case of chlorinated aliphatic wastewaters managed in
surface impoundments, although the wastewaters are not listed hazardous
wastes, sludges derived from EDC/VCM process wastewaters and generated
in impoundments will meet the scope of the hazardous waste listing for
EDC/VCM wastewater treatment sludges after the effective date of
today's rule.
2. Response to Major Comments Received on Proposed Rule for Chlorinated
Aliphatic Wastewaters
EPA received comments on a number of issues concerning the data and
analyses EPA used to arrive at our listing decision for chlorinated
aliphatic wastewaters. The most significant comments that we received
may be divided generally into six categories: (1) Comments on EPA's
waste management assumptions; (2) comments on the exposure scenarios we
evaluated in our risk assessment; (3) comments on how we calculated
exposure point concentrations in the risk assessment; (4) comments on
EPA's exposure assessment; (5) comments on EPA's toxicity assessment
for dioxin and chloroform; and (6) comments on how we characterized
risks associated with dioxin and chloroform. These comments, and the
Agency's responses to these comments, are summarized below. We have
developed responses to all of the public comments received in response
to the proposed rule. The verbatim comments and our responses to all
comments are provided in Response to Public Comments; Final Listing
Determination for Chlorinated Aliphatics Industry Wastes in the docket
for today's rule.
a. Waste Management Assumptions
The majority of chlorinated aliphatic wastewaters is managed in on-
site, tank-based wastewater treatment systems prior to direct discharge
of the wastewaters in accordance with facility-specific NPDES permits
or discharge to an off-site POTW. As explained in the

[[Page 67076]]

preamble to the proposed rule, two chlorinated aliphatic production
facilities manage their wastewaters in underground injection control
(UIC) wells. In addition, commenters provided information indicating
that one facility pipes its chlorinated aliphatic wastewaters off-site
for treatment in a wastewater treatment system that includes biological
treatment in surface impoundments.

i. Why Did EPA Only Evaluate Air Releases From Tanks?

One commenter asserted that EPA did not consider releases from
tanks other than air emissions from treatment tanks managing
chlorinated aliphatics wastewaters. As the commenter pointed out, EPA
assumed that the wastewater treatment system tanks are of sufficient
integrity to prevent releases and that the tanks are equipped with
overflow and spill controls that will prevent non-air releases of
wastewaters, even though (as the commenter also points out) no overflow
and spill controls are required for nonhazardous storage waste tanks,
including tanks that manage wastewaters subsequently discharged either
to Publicly Owned Treatment Works (POTWs) or surface waters. The
commenter states that EPA's failure to consider non-air releases from
wastewater treatment system tanks, which in the commenter's opinion are
plausible mismanagement scenarios, violates EPA's criteria for listing
determinations, which requires an assessment of ``plausible types of
improper management.''
When EPA set out to assess risks from managing wastewaters in tank-
based systems, we chose to model only air emissions because we
determined that this was the greatest potential pathway of exposure for
constituents from the tank systems (therefore causing the greatest
potential risk), particularly since we knew from the RCRA Section 3007
Survey responses that the industry uses aerated biological treatment
tanks, many of which are uncovered, or open to the atmosphere. In
addition, survey responses indicated that the tanks are positioned
aboveground and a majority of them are equipped with secondary
containment. Therefore, EPA determined that any leaks or catastrophic
releases from such tanks would be detected relatively quickly and
corrective measures likely would be implemented prior to a release of
significant quantity. In addition, these types of releases, if they
were to occur, are not predictable or routine but rather would be the
result of inordinate events or accidents such as upset conditions or
catastrophic failures, which the Agency presumes would not be routine,
frequent or plausible (mis)management. In sum, we continue to believe
that air emissions from aerated biological treatment tanks is the
predominate exposure pathway and that risks resulting from this pathway
are significantly greater than any risk that may periodically arise
from spills or leaks.

ii. Why Did EPA Not Evaluate Storage of Wastewater?

One commenter stated that EPA did not consider other air emissions
from the storage of chlorinated aliphatic wastewaters prior to placing
these materials in tanks. The commenter said that such analysis is not
needed if EPA finalizes a ``standard'' listing mechanism for K173, but
that EPA must undertake such an analysis if a concentration-based
listing is adopted. EPA assumes that the commenter is describing
wastewaters managed in tanks between the point the wastewater is first
generated until it reaches the headworks of the wastewater treatment
facility. (This is because under the proposed listing options,
wastewater would not be tested to determine whether it exceeds the 1
ng/L dioxin trigger until it enters the first tank in the wastewater
treatment system.) Although EPA is not finalizing the proposed
chlorinated aliphatic wastewater listing in today's rule, we note that
the RCRA Section 3007 questionnaire results indicate that only a few
facilities manage wastewaters in tanks that are not a part of the
wastewater treatment train. In all cases where a facility indicated
having wastewater storage tanks that are not part of the wastewater
treatment system the facility indicated that the tanks are covered. The
fact that such tanks are covered would limit the potential for air
releases. In our risk assessment, we chose to analyze air emissions
from wastewater treatment tanks because, based upon information
provided to the Agency in facility responses to the RCRA Section 3007
questionnaire, such tanks may be used to manage relatively large
quantities of chlorinated aliphatic wastewaters, and often are not
covered and are aerated. In view of our revised risk estimate for
potential releases from these tanks, any potential risks from the
covered, upstream tanks would not be substantial.
b. Exposure Scenarios Evaluated in EPA's Risk Assessment
EPA received comments from a number of parties that challenged
EPA's basic methodology for establishing the exposure scenarios
evaluated in the chlorinated aliphatic wastewater risk analyses. The
commenters believed that EPA should have used a site (or facility)-
specific approach for conducting the risk assessments. The commenters
raised general concerns regarding EPA's approach, and also challenged
specific aspects of EPA's analysis. These two issues are discussed
separately below.

i. Evaluating Site-Specific Exposure Scenarios--General Comments

Commenters on the proposed rule stated that EPA should have used a
site-specific approach to assessing risks from management of
chlorinated aliphatic wastewaters, and presented general arguments why
EPA should adopt a site-specific approach. Specifically, the commenters
believed that EPA should have conducted the chlorinated aliphatics risk
assessments using an approach similar to that used in the final
combustion Maximum Achievable Control Technology (MACT) rulemaking
under the Clean Air Act. For that rulemaking, EPA used facility-
specific data in determining risks (64 FR 52828, September 30, 1999).
The commenters contended that as a result of the public and peer review
comments received on the risk assessment in the proposed combustion
MACT, EPA modified its risk analysis to focus on the entire population
of persons that are exposed to facility emissions rather than persons
living on a few individual farms and residences. Some commenters
recommended that EPA adopt a regulatory approach allowing generators
themselves to determine the site-specific risk (using site-specific
distances to the nearest receptor, wastewater concentrations, etc.) and
subsequently the regulatory status of the wastes addressed under EPA's
proposed rule.
Similarly, some commenters expressed general concern over EPA's use
of ``assumptions,'' rather than site-specific data, in the risk
assessment. The commenters believe that if EPA were challenged with
evaluating hundreds of scenarios across the entire nation, then the use
of assumptions from statistical sampling of databases or best judgment
could be better understood. However, with the limited number of
facilities and waste management units involved in this proposed rule
making (23), the commenters believe that EPA could have spent more time
gathering real, site-specific data to reduce the uncertainty in risk
modeling. The commenters pointed to the limited set of waste sample
data, the lack of site-specific information regarding waste

[[Page 67077]]

management units for the chlorinated aliphatics industry, and the
regional databases used to obtain the parameter values necessary to
model containment fate and transport as data elements that should have
been more site-specific.
EPA acknowledges that we did not conduct site-specific risk
assessments to support the chlorinated aliphatics wastewater listing
determination, but rather evaluated plausible exposure scenarios that
are based on a combination of national data, regional data, and data
collected from the facilities themselves. In some cases we believe that
only one specific management practice is plausible, and existing
locations for that practice are not likely to change. For example,
certain economic or natural resource factors may restrict the nature of
wastes in terms of their constituent concentrations, their quantities,
or the ways in which the wastes are managed. This generally is not the
case for the chlorinated aliphatic chemicals production industry. EPA
described the continued and projected growth of the chlorinated
aliphatic chemicals industry in the Economics Background Document for
the proposed rule, and documented evidence of the industry's
historically dynamic nature (USEPA, 1999b).\4\ Nevertheless, there is
considerable uncertainty in predicting a relationship between industry
growth and waste generation and management. We cannot foresee the
effects that potential (and possibly simultaneous) changes in
technology, facility expansion practices (that is, increasing
production capacity at existing facilities versus building new
facilities), and waste minimization activities may have on waste
generation and management. We also cannot predict whether there will be
an increase in global marketshare of off-shore (non-U.S.) chlorinated
aliphatic chemical production. Consequently, we based our evaluation on
general information describing current chlorinated aliphatic waste
management and exposure scenarios. This is not to say we based the
modeling entirely on assumptions or hypothetical values. Rather, we
used the combination of site-specific information, and other types of
information that we thought would effectively capture what we expected
would remain relatively consistent for one industry while accounting
for likely future variability. For example, we surveyed the potentially
affected facilities to identify existing waste management practices,
and then assumed that those same management practices will continue to
be used by the industry in the future. Additionally, we identified the
location of chlorinated aliphatics facilities, and assumed that in the
future, facilities might locate in the same general geographic regions
(for example, regions with the same meteorological conditions), and in
areas with the same general land use patterns (for example,
agricultural areas). Similarly, we assumed that, although the exact
numbers and locations of facilities may change, the quantities of the
wastes, as well as the types and concentrations of contaminants in the
wastes, will be generally the same over the near to long term. Again,
the specific mix of site-specific and more general information will
vary from one listing rule to another and potentially from one waste to
another within a given rulemaking, depending on how dynamic EPA expects
future waste management practices to be.
---------------------------------------------------------------------------

\4\ USEPA. 1999b. Economics Background Document, Proposal by the
USEPA To List Wastewaters and Wastewater Sludges from Chlorinated
Aliphatic Chemical Manufacturing Plants, as RCRA Hazardous
Wastecodes K173, K174, K175: Industry Profile and Estimation of
Industry Regulatory Compliance Costs. Office of Solid Waste. 30
July.
---------------------------------------------------------------------------

By evaluating the data using the probabilistic and two-high end
deterministic approaches discussed in the preamble to the proposed rule
(64 FR 46483), EPA endeavors to avoid regulating wastes based on
exposure scenarios that are unrealistic (that is, based on too many
protective [high end] assumptions). However, in the case of the
chlorinated aliphatics industry, we did not feel our information
justified an assumption that there would always exist exactly 23
chlorinated aliphatics facilities at 23 specific locations that
continue to generate the same quantities of wastewaters, with the same
types and concentrations of contaminants, that are managed in aerated
biological wastewater treatment tanks under a static set of operating
conditions. Historically, EPA's policy under the listing program has
been to conduct national-scale evaluations that consider the general
characteristics of the wastes under review, and allow facilities to
petition the Agency to have their wastes ``delisted'' if they believe
that the wastes do not meet the criteria for hazardous waste listing.
EPA also notes that, in view of the Congressional mandate to make
final listing determinations on seventeen waste categories in fifteen
months, Congress does not appear to have anticipated that each of these
listings efforts would involve a detailed, facility-by-facility
analysis (RCRA 3001(e)).

ii. Evaluating Site-Specific Exposure Scenarios--Specific Comments

Commenters on the proposed rule raised objections to three specific
aspects of the exposure scenarios on which EPA's risk assessments for
wastewaters are based. The following discussion describes those
comments and EPA's response.
A number of commenters noted that EPA's high end human health risk
analyses are based on dioxin exposures to farmers who live at the same
location within 300 meters (0.18 miles) of a chlorinated aliphatics
facility for 48.3 years or more, who raise fruits, exposed vegetables,
root vegetables, beef cattle, and dairy cattle within this 0.18 mile
range, and whose diet consists of approximately 42 percent home-grown
exposed vegetables, 17 percent home-grown root vegetables, 33 percent
home-grown fruits, 49 percent home-produced beef, and 25 percent home-
produced dairy.\5\ Some commenters questioned why their operations
would be regulated under EPA's proposed rule, contending that it does
not make sense to regulate a waste stream or to require controls and
expenditures to protect a type of individual that will not be present.
Many of the commenters claimed that they were not aware of any farmers
living within 0.18 miles of a chlorinated aliphatics facility that met
all these criteria, and found it difficult to believe that such a
farmer would grow fruit trees and vegetables, and raise beef and dairy
cattle, all on the same plot of land. Moreover, the commenters
maintained that in the south Texas area where several EDC/VCM
manufacturing facilities are located, dairy cattle production is non-
existent due to the climate. One commenter that represents facilities
in Louisiana stated that of the nine companies that they represent,
only at two facilities is there farmland within 300 meters of the
facility boundary (not 300 meters from the wastewater treatment tanks).
The commenters stated that beef cattle are raised on one of the two
farms, and that beef cattle and sugar cane are raised on the other
farm.
---------------------------------------------------------------------------

\5\ The public comments suggest that the commenters believe that
EPA assumed that the farmer consumes 42 percent of the exposed
vegetables, 17 percent of the root vegetables, 33 percent of the
fruits, 49 percent of the beef, and 25 percent of the dairy products
that the farmer grows. EPA assumes that the commenters meant to take
issue with the EPA's assumption that 42 percent of the exposed
vegetables, 17 percent of the root vegetables, 33 percent of the
fruits, 49 percent of the beef, and 25 percent of the dairy products
that the farmer consumes are home-produced (i.e., the rest of the
farmer's diet would be obtained from other sources, such as a
grocery store).

---------------------------------------------------------------------------

[[Page 67078]]

In response, EPA notes that exposure duration was one of the two
high end parameters in our proposed high end dioxin risk estimate for
the farmer, and that the value of 48.3 years is the 90th percentile
exposure duration for households in the ``farm'' housing category as
presented in Table 15-164 of the Exposure Factors Handbook (USEPA, 1997
\6\). Moreover, the information provided in the public comments
confirms that an exposure scenario in which a farmer raises beef cattle
on a farm located within 300 meters of a chlorinated aliphatics
facility (and presumably a wastewater treatment tank located near the
facility boundary) is plausible. Although the commenters clearly
disagree that a farmer also might produce fruits and vegetables on this
farm, these concerns are unwarranted. Table 5-3 of the Risk Assessment
Technical Background Document (USEPA, 1999a) \7\ shows that for the
adult farmer, 99.3 percent of the high end risk from chlorinated
aliphatic wastewaters was due to ingestion of beef and dairy products
and only 0.7 percent was due to ingestion of home grown fruits and
vegetables. As a result, even though EPA believes it is plausible that
a subsistence or hobby farmer would raise fruits and vegetables for
home consumption, the validity of EPA's risk estimate depends almost
entirely on the validity of our assumption that a farmer might consume
both beef and dairy products from cattle raised on a farm located in
the vicinity of a chlorinated aliphatics production facility. To
evaluate the commenters' concerns regarding dairy cattle production in
the vicinity of chlorinated aliphatics facilities, EPA referred to
public data on agricultural production in the regions surrounding
chlorinated aliphatics production facilities that are available from
the Agricultural Census of the United States (see reference for http://
govinfo.library.orst.edu that is included in the docket for the
proposed rule). The census data demonstrate that, in fact, of the 23
chlorinated aliphatic facilities that manage wastewaters, 21
facilities, including all of the facilities in the south Texas area,
are located in counties where dairy cattle were reported to have been
raised in 1997 (all of the facilities are located in counties where
beef cattle were reported to have been raised in 1997). EPA believes
that an individual who raises cattle to support a subsistence lifestyle
might reasonably consume both dairy and beef products from his/her
cattle.
---------------------------------------------------------------------------

\6\ U.S. EPA. 1997. Exposure Factors Handbook, Volumes I, II,
and III. EPA/600/P-95/002Fa, b, c. Office of Research and
Development, Washington, D.C., August.
\7\ U.S. EPA. 1999a. Risk Assessment Technical Background
Document for the Chlorinated Aliphatics Listing Determination.
Office of Solid Waste. July.
---------------------------------------------------------------------------

Some commenters also challenged EPA's assumptions regarding the
percentages of beef and dairy products consumed by the farmer that are
home produced (that is, assumed to be from a contaminated source).
Specifically, EPA assumed that 25.4 percent of the dairy products a
farmer consumes are home produced, and that 48.5 percent of the beef
products a farmer consumes are home-produced. The commenters asserted
that the percentages EPA used apply to a relatively small fraction of
the surveyed population who farm, and as such are overly conservative
by a factor of 21.2 for dairy,\8\ and a factor of 12.7 for beef,\9\ if
applied to the general population (USEPA, 1997). The commenters held
the opinion that the percentages used by EPA overstate the upper end
homegrown beef and dairy consumption markedly. However, one of the same
commenters acknowledged that the commenter was unable to confirm
alternate values that EPA should have used for percentage of beef and
dairy consumed by the farmer that is home grown. One peer reviewer
asked where EPA obtained the values for the percentages of food eaten
by the farmer (EPA provided the source of the values in the preamble to
the proposed rule), but did not indicate whether he believed the
percentages were right or wrong.
---------------------------------------------------------------------------

\8\ The proportion of home-produced dairy consumed by
``households who farm'' (0.254) divided by the proportion of home-
produced dairy consumed by persons in the general population
(0.012).
\9\ The proportion of home-produced beef consumed by
``households who farm'' (0.485) divided by the proportion of home-
produced beef consumed by persons in the general population (0.038).
---------------------------------------------------------------------------

EPA's estimates of the portion (percentage or fraction) of a
farmer's diet that is home-produced are presented in EPA's Exposure
Factors Handbook (USEPA, 1997), and are based on the U.S. Department of
Agriculture's 1987-1988 Nationwide Food Consumption Survey (NFCS).\10\
We did not use the percentages that reflect the consumption of home-
produced foods by the general population in our risk assessment, as
suggested by the commenters, because EPA's objective was to evaluate
risks to farmers, not members of the general population, who consume
home-produced food items. As one would expect, the data in the Exposure
Factors Handbook indicate that farm households consume more home-
produced foods than do households in the general population. The
percentages that correspond to the general population would be applied
more appropriately to an evaluation of residential receptors.
---------------------------------------------------------------------------

\10\ The 1987-1988 NFCS data on intake of home-produced foods
are included for use in the recent (1997) Exposure Factors Handbook
(U.S.EPA, 1997), which has been reviewed by EPA's Science Advisory
Board (SAB) as well as numerous other external reviewers.
---------------------------------------------------------------------------

One commenter claimed that in EPA's Combustion MACT rulemaking, EPA
indicated that according to USDA information, only 40% of farmers who
raise beef eat their own beef (64 FR 52998), and that the percentage of
dairy farmers who consume home grown dairy products is only 40% in the
Northeast, 20% in the Midwest, lower elsewhere in the country, and
averages only 13% nationally (64 FR 52998). The commenter also noted
that in the Combustion MACT rulemaking, EPA acknowledged that
information on the number of farms that produce more than one food
commodity (for example, beef and milk) is not available from the U.S.
Census of Agriculture (64 FR 52828, see 53005-53006), and that in
determining the risk to commercial farmers under the Combustion MACT
rule, EPA stated: ``only the primary food commodity produced on the
farm was assumed to be consumed by farm households (64 FR 52998).
It appears that the commenter somewhat misrepresented the data from
the final MACT rule. Specifically, the Federal Register notice to which
the commenter refers is very clear that while ``[o]nly the primary food
commodity produced on the farm was assumed to be consumed by farm
households,'' ``[a] wide variety of foods was assumed to be produced
and consumed by households engaged in subsistence farming'' (64 FR
52999). In fact, under the subsistence farmer scenario evaluated for
the MACT rulemaking, EPA assumed that 100 percent of the food that the
farmer consumes is home-produced. This assumption clearly results in
greater exposure than the assumptions used in EPA's analysis of the
farmer scenario in the chlorinated aliphatics analysis. Moreover, the
commenter misinterpreted data presented in the MACT rulemaking that
describe the percentages of households that consume beef and dairy
products in various parts of the country. The Federal Register notice
to which the commenters refers states:

In particular, we re-analyzed data collected by USDA to estimate
consumption of home-produced foods, such as meat, milk, poultry,
fish, and eggs. Over half of farm households report consuming home-
produced meats, including nearly 40 percent that report

[[Page 67079]]

consumption of home-produced beef. In the Northeast, nearly 40
percent of farm households report consuming home-produced dairy
products, and in the Midwest, nearly 20 percent do. The percentage
is lower elsewhere, averaging about 13 percent nationally.

The data cited by EPA pertains to the number of all farm households
that consume home-produced beef and dairy products. The commenters
incorrectly assumed that the data applied specifically to households
engaged in raising beef cattle and households engaged in raising dairy
cows, respectively. EPA expects that the consumption of home-produced
beef and dairy products would be much greater for households engaged in
production of these commodities compared to the consumption for all
farm households.
c. Calculation of Contaminant Concentrations at the Point of Human
Exposure (Contaminant Fate and Transport Modeling)
EPA received comments questioning the way that we estimated
emissions from aerated biological wastewater treatment tanks, and the
way that we estimated the concentrations of dioxins in beef and dairy
products. These comments included concerns about how CHEMDAT8 evaluates
dioxins that are sorbed onto solids in wastewaters, and about how EPA
estimated the amount of solids influent to aerated biological
wastewater treatment tanks. Commenters also took issue with the
Agency's assumptions about the diet of dairy and beef cattle and the
productivity of the modeled farm. Each of these assumptions
significantly affects our calculation of contaminant concentrations to
which human receptors are exposed.

i. EPA Did Not Correctly Consider Sorption of Dioxin Onto Solids and
Solids Removal From Wastewater

To evaluate the human health risks posed by dioxins in chlorinated
aliphatic wastewaters, EPA modeled air emissions from aerated
biological wastewater treatment tanks. We conducted the emissions
modeling assuming that the concentrations of dioxins in wastewaters
flowing to aerated biological treatment tanks were equivalent to the
concentrations of dioxins in certain wastewater samples we collected.
For the proposal, we constrained (``capped'') the influent
concentrations of four congeners in the wastewaters at their aqueous
solubility concentrations to account for the fact that dioxins are
strongly hydrophobic and are expected to be sorbed to solids
preferentially in the wastewater influent, thus are unlikely to exist
in the dissolved phase in excess of their solubility limits.
Commenters on the proposed rule expressed a number of concerns
regarding the way that EPA evaluated the solids fraction of chlorinated
aliphatics wastewaters. The commenters' primary concern was that EPA
did not appropriately consider that most dioxins in chlorinated
aliphatics facility wastewaters will be sorbed onto solids in the
wastewaters even when the dioxin congener concentrations in wastewaters
are less than their solubility limits. Certain commenters contended
that in EDC/VCM production facilities that use fluidized bed
oxychlorination processes, attrited catalyst fines (small particles
that are 1 to 20 micrometers in size) that exit the facility process
via the wastewater treatment system have very high surface area
(approximately > 50 m2/g) and thus strongly sorb dioxins that are
present in the wastewaters. The commenters asserted that EPA failed to
account for the fact that almost all of the dioxins in wastewaters are
sorbed to solids and are removed in primary clarifiers prior to
aeration. Moreover, the commenters believed that EPA's model for
estimating emissions from wastewater treatment tanks (CHEMDAT8) does
not correctly model sorption. One commenter stated that CHEMDAT8 takes
into account adsorption onto biomass solids, but claimed that CHEMDAT8
does not adequately address the fact that most dioxin is already sorbed
onto solids (and not available for volatilization) when it enters an
aerated tank. Commenters submitted various analyses and data to
substantiate their claims, and contended that EPA had overestimated the
concentration of dioxins available for volatilization by at least an
order of magnitude.
Although EPA agrees that the primary removal mechanism of dioxins
in wastewater treatment tanks will be through the sorption of dioxins
onto solids (see p. 3-2 of EPA's 1999 Risk Assessment Technical
Background Document, USEPA 1999a), EPA does not agree with the
commenters' concerns that CHEMDAT8 fails to correctly account for
sorption. CHEMDAT8 does in fact model sorption as a reversible, linear,
equilibrium partitioning process, the same process that the commenters
believed should be considered to account for the sorption of dioxins
onto solids in wastewater. CHEMDAT8 is designed to evaluate the
contaminant loss rates for the competing removal mechanisms of
volatilization, biodegradation, sorption and hydrolysis based on the
total contaminant load influent to the system (whether associated with
the dissolved or solid phase). The contaminant loss rate due to
sorption is based on the equilibrium solids partitioning coefficient
and the rate at which solids enter or are generated within the system.
Thus, in estimating the amount of solids available to sorb dioxins,
CHEMDAT8 considers total suspended solids (TSS) in the influent stream
as well as new biomass growth. It does not matter how dioxin is
partitioned onto solids when the wastewater enters the tank, because
the model repartitions the dioxins inside the tank according to the
model's equilibrium partitioning relationship and the relative rates of
the competing removal mechanisms. Consequently, in our analyses we
evaluated the total contaminant load in the tank influent, regardless
of whether the contaminants were associated with the dissolved or solid
phase. In cases where solids are present in the influent, limiting a
CHEMDAT8 analysis to dissolved phase wastewater influent concentrations
might seriously under-represent the total contaminant load to the tank
and result in greatly underestimating emissions, especially for
sorptive chemicals like dioxins. Because CHEMDAT8 considers
partitioning and removal by sorption within the tank, limiting the mass
of dioxin influent to the system (by limiting the influent
concentration to the dissolved phase concentration) may result in
greatly underestimating emissions because only the contaminant mass in
the dissolved phase would be partitioned in the tank, rather than the
total contaminant mass associated with the influent's dissolved plus
solid wastewater phases.
In contrast, EPA agrees with the commenters concerns that we failed
to accurately account for the fact that in aerated biological
wastewater treatment systems, at least some solids removal generally
will occur between the headworks of the wastewater treatment system and
the influent to an aerated biological treatment tank (we addressed
risks from the management of solids separately in this listing
determination). In the preamble to the proposed rule, EPA specifically
stated that we selected wastewater data for evaluation that we believed
represented the concentrations of contaminants in wastewaters at the
influent (headworks) of treatment systems that are used to manage only
wastewaters from the production of chlorinated aliphatic chemicals
(``dedicated'' chlorinated aliphatics wastewater samples; 64 FR 46483).
In

[[Page 67080]]

retrospect, our assumption that the same data that represent
contaminant concentrations at the headworks of wastewater treatment
systems could represent contaminant concentrations at the influent to
aerated biological wastewater treatment tanks was somewhat flawed. The
Agency reviewed information previously provided to us in industry
survey responses and determined that of the eleven facilities that
employ aerated biological processes to treat their wastewaters, nine
employ primary clarification or other processes that have the effect of
removing solids from wastewaters prior to their discharge to aerated
biological treatment tanks. (One of these nine facilities is the
facility from which we collected the ``high end'' wastewater sample
used in the risk analysis that served as the basis for our proposed
listing decision.) The remaining two facilities perform wastewater
equalization in tanks prior to aerated biological treatment. One of
these two facilities also employs wastewater pH adjustment with
resultant precipitation of metal hydroxides prior to aerated biological
treatment. Both of these processes are expected to result in at least
some solids removal from the wastestream. Moreover, EPA does not
anticipate that treatment of the wastewaters in units such as primary
clarifiers and equalization basins would result in dioxin air emissions
greater than those that we originally predicted from aerated biological
treatment tanks, because primary clarifiers are, by design, quiescent
units (Metcalf and Eddy, 1991,\11\ p. 472), and we have no information
that leads us to believe that the equalization tanks in use by the
facilities are agitated.
---------------------------------------------------------------------------

\11\ Metcalf & Eddy, Inc. 1991. Wastewater Engineering:
Treatment, Disposal, and Reuse. Revised by G. Tchobanoglous and F.
Burton. Irwin McGraw-Hill, Boston. 1334 pp.
---------------------------------------------------------------------------

To model the aerated biological treatment tanks correctly, that is,
to determine what the appropriate influent concentration to the
biological treatment tank should be, would have required that EPA model
the wastewater treatment train from the point where wastewater enters
the headworks of the treatment system to the point where the wastewater
enters the aerated biological tank. Metcalf and Eddy (1991, p. 473)
state that ``efficiently designed and operated primary sedimentation
tanks should remove from 50 to 70 percent of the suspended solids * * *
'' from wastewater. Assuming this level of solids removal from
chlorinated aliphatics wastewaters prior to biological treatment we
estimate that the high end deterministic risk estimate for the adult
farmer reported in the proposal would be reduced by a factor ranging
from approximately 0.67 (70 percent removal of solids) to 0.94 (50
percent removal of solids) (USEPA, 2000b).\12\ A complete description
of our analysis is provided in the Addendum to the 1999 Risk Assessment
Technical Background Document (USEPA, 2000).
---------------------------------------------------------------------------

\12\ 12 U.S. EPA. 2000b. Risk Assessment Technical Background
Document for the Chlorinated Aliphatics Listing Determination,
Addendum. Office of Solid Waste. September.
---------------------------------------------------------------------------

ii. EPA Incorrectly Evaluated the Contribution of Feed to Dioxin Levels
in Dairy and Beef

To support the chlorinated aliphatics wastewater listing
determination we estimated risks to a farmer who ingests beef and dairy
products derived from cattle raised on a farmer's pastureland. EPA
assumed that the beef and dairy cattle consume home-grown forage,
grain, and silage, and incidentally ingest pasture soil. We assumed
that beef cattle consume different quantities of the various food items
(and pasture soil) than do dairy cattle. We also assumed that 100% of
the cattle's feed is contaminated by releases from the wastes we
evaluated, that is, that cattle are not provided feed from other
(uncontaminated) sources.
The commenters believed that EPA should have considered that a
cow's consumption of various food sources varies according to the
animal's life stage and intended use. The commenters contended that
these considerations influence both a cow's exposure and the potential
translocation of dioxin to meat or milk. As an example, the commenters
pointed out that beef cattle may be raised for part of their lives on
pasture, but typically are raised on grain prior to slaughter. The
commenters noted that, for instance, the beef cow nurses and pastures
for approximately 180 days, pastures exclusively for 55 days, and
subsists on a grain only diet for the final 130 days of its life
(Stevens and Gerbec, 1988). The commenters asserted that EPA's risk
assessment should have considered contaminant losses from a beef cow's
tissue in the time period between the cow's consumption of contaminated
feed and the cow's slaughter. The commenters also presented alternate
information that they said could be considered in EPA's evaluation of
risk. First, EPA assumed that dairy cattle consume 13.2 kg/day of
forage, 4.1 kg/day of silage, 3 kg/day of grain, and 0.4 kg/day of
soil, based on data cited by Rice (1994)\13\. In contrast, the
commenters presented data from Stevens and Gerbec (1988) \14\ who
reported dairy cattle consumption rates of 6.8 kg/day of forage, 16.3
kg/day of silage, 4.5 kg/day of grain, and 0.14 kg/day of soil. Second,
EPA assumed that beef cattle consume 8.8 kg/day of forage, 2.5 kg/day
of silage, 0.47 kg/day of grain, and 0.5 kg/day of soil (Rice, 1994).
The commenters contended that during the nursing phase the beef cow
receives practically all of its daily dioxin dose through the mother's
milk and this dose has been (and could be) calculated for nursing
cattle (Stevens and Gerbec, 1988). The commenters continued that EPA
should assume that during the pasture phase of its life the beef cow
consumes 13.6 kg/day of feed: 10.2 kg/day of forage, 3.4 kg of silage,
and 0.05 kg/day of soil. The commenters argued that during the cow's
fattening stage of growth prior to its slaughter, during which the beef
cow gains as much as 60 to 70% of its body weight, the cow's diet
consists entirely of grain. The commenters suggested that EPA needs to
take into account the impact of this body weight gain and consider how
dioxin half-life influences the concentration of dioxin residuals in
the meat.
---------------------------------------------------------------------------

\13\ Rice, G. 1994. Quantity of Plants and Soil Consumed by
Animal. Draft Working Papers. Office of Research and Development.
U.S. Environmental Protection Agency, Washington D.C.
\14\ Stevens, J.B. and Gerbec, E.N. 1988. Dioxin in the
agricultural food chain. Risk Analysis. 8(3):329-335.
---------------------------------------------------------------------------

The commenters also asserted that EPA's assumption that all of a
cow's feed is contaminated seemed unrealistic. The commenters believed
that such an assumption implies that a farm not only has both a dairy
and beef cattle operation, but raises grain and silage (in addition to
crops for human consumption) while still maintaining enough pasture to
graze the animals. They noted that the same issue was raised by the
peer reviewers who found some of the assumptions on productivity of the
theoretical farmer unrealistically high and suggested that productivity
necessary to maintain such a farm be researched and used to adjust
EPA's assumptions accordingly. The commenters reasoned that since grain
and silage often are purchased elsewhere, it would be more appropriate
to assume that less than 100% of the cattle's feed is contaminated.
They believed that fixing the percentage of contaminated feed consumed
by the cattle at 100% is not a central tendency assumption, and fails
to reflect the lack of certainty in this parameter. Therefore, they
recommended that EPA assume

[[Page 67081]]

that only 50% of the feed is contaminated in the deterministic
assessment, and that a uniform distribution of values be adopted for
the Monte Carlo assessment, with percentages ranging from 0 to 100
percent.
To understand EPA's response to these comments, it is important to
recall two pieces of information presented in EPA's Risk Assessment
Technical Background Document for the proposed rule. First, as
discussed previously in Section VI.A.2.b.ii, the risks that EPA
estimated for the farmer are due almost exclusively to the farmer's
ingestion of beef and dairy products (Table 5-3; USEPA, 1999a). Second,
the dioxins in the beef and dairy products result almost entirely from
the cattle's consumption of forage that is contaminated by air
emissions from the modeled wastewater treatment tank--negligible levels
of dioxins are contributed to cattle as a result of the cattle's
ingestion of grain, silage, or soil (Appendix H.1, Table H.1-1a; USEPA,
1999a). Consequently, all that is required for the adult farmer to
realize the risk that EPA presented in the proposed rule is that the
farmer consume beef and dairy products derived from cattle that consume
forage from the farmer's pastureland/field. That is, it is not
necessary that the farmer consume home-grown fruits and vegetables, or
that the farmer produce grain or silage for use as cattle feed.
Therefore, in responding to the concerns of the commenters, EPA focused
primarily on the technical validity and plausibility of our assumptions
regarding the (1) consumption rates of forage by beef and dairy cattle
and (2) the percentage of the forage that cattle consume that is
contaminated.
EPA disagrees with the commenters' alternate recommendations
regarding animal feeding practices. Although the feeding practices that
the commenters describe, particularly those for beef cattle, may be
applicable to commercial farming operations, EPA does not believe that
such practices apply to hobby or subsistence farming. As noted by Rice
(1994), a subsistence farmer will tend to feed his/her cattle an
``unsupplemented'' diet, meaning that the cattle will primarily feed on
forage (because the cattle are permitted to graze more in the pasture),
and will not be fattened at a feedlot prior to slaughter. Rice (1994)
explains that in the southern part of the country (where most of the
chlorinated aliphatics facilities are located), cattle will consume
pasture as their major source of roughage the entire year (except in
drought). Consequently, we believe that our assumptions regarding
cattle ingestion of forage under a subsistence/hobby farming scenario
are reasonable. We used the assumptions presented by Rice (1994) in
other rulemakings \15\ and have recommended that these assumptions be
used in estimating risks under other hazardous waste programs (USEPA,
1998 \16\). Furthermore, the feed ingestion rate for dairy cows
presented by the commenters is an average ingestion rate for a dairy
cow in Minnesota (Stevens and Gerbec, 1988). In contrast, EPA's data
for the intake rates of forage, grain, and silage for dairy cows are
based either on data from the South Carolina-Georgia region (see Boone
et al., 1981 \17\) or on more general data (Shor and Fields, 1980; \18\
NAS, 1987; \19\ and Boone et al., 1981). Chlorinated aliphatics
facilities are located primarily in Texas and Louisiana, which we
believe are probably more similar to South Carolina-Georgia than
Minnesota in terms of cattle feeding practices.
---------------------------------------------------------------------------

\15\ We used the assumptions of Rice (1994) in the risk
assessment to support the final combustion MACT Rulemaking (64 FR
52828, September 30, 1999). In addition, we used some of the same
assumptions in the Proposed HWIR Rule (November 19, 1999 Federal
Register; 64 FR 63382) and the Petroleum Refining Residuals Final
Listing (August 6, 1998 Federal Register; 63 FR 42210).
\16\ USEPA. 1998. Human Health Risk Assessment Protocol for
Hazardous Waste Combustion Facilities. Peer Review Draft. Office of
Solid Waste and Emergency Response. EPA530-D-98-001A. July.
\17\ Boone, F.W., Y.C. Ng, and J.M. Palms. 1981. Terrestrial
Pathways of Radionuclide Particulates. Health Physics, vol 41, no.
5, pp. 735-747. November.
\18\ Shor, R.W. and D.E. Fields. 1980. ``Agricultural Factors
Affecting the Radionuclide Foodchain Pathway: Green Forage
Consumption of Dairy Cows.'' Health Physics. vol. 39, pp. 325-332.
\19\ NAS. 1987. Predicting Feed Intake of Food-Producing
Animals. National Research Council, Committee on Animal Nutrition.
National Academy Press, Washington, D.C.
---------------------------------------------------------------------------

With regard to EPA's assumptions for the percent of the cattle's
feed derived from a contaminated source, EPA believes that it is
appropriate to assume that a hobby or subsistence farmer is not
supplying forage to his/her cattle from an outside source, such that
100 percent of the forage that the cattle consumes will be from the
farmer's pasture or field (in our risk assessment, a contaminated
source). This assumption is consistent with the assumptions made for
both the subsistence and commercial farmers in the combustion MACT
final rulemaking, as well as other EPA rulemakings and guidance.\20\
However, in response to the commenters' concerns, we reviewed our
methodology for estimating the concentrations of dioxins in forage to
ensure that we were adequately considering the size of the contaminated
source versus its expected productivity. In the proposed rule we
explained that in evaluating the air pathway we always assume that the
cattle are located along the centerline of the area most greatly
impacted by air releases from the waste management units (64 FR 46486).
We said that the air concentrations within about a 100-meter lateral
distance from this point do not vary appreciably, and stated
specifically in our Risk Assessment Technical Background Document
(Addendum; USEPA, 1999a) that the concentrations vary about 20% within
200 meters of the point of maximum concentration. In the course of our
reevaluation of these data in response to public comments, we concluded
that we should have considered how the concentrations of dioxins in
air, therefore in forage, vary over a wider aerial extent that would be
more consistent with the area of a pasture. We concluded that a more
reasonable approach would be to consider that the size of the pasture
that is used to support the cattle is approximately 275 meters by 275
meters (75,625m 2, approximately 19 acres). We believe a
field of this size would be large enough to support sufficient cattle
to sustain the family of a subsistence farmer (USEPA, 2000b). We used
the results of the air modeling we conducted for the proposed
rulemaking to determine the approximate difference between the air
concentration that we used to calculate the proposed risk estimate (the
air concentration corresponding to a point located 300m from the
modeled wastewater treatment tank) and the average air concentration at
a 75,625m 2 field located 300m from the modeled wastewater
treatment tank. In fact, EPA determined that more reasonably
considering the area that is affected by the emissions from the modeled
wastewater treatment tank would reduce the risk estimate on which our
proposed rule was based, modifying the risk estimate (2 x 10
-5) by a factor of 0.50 (USEPA, 2000b).
---------------------------------------------------------------------------

\20\ For example:
USEPA. 1998. Human Health Risk Assessment Protocol for Hazardous
Waste Combustion Facilities. Peer Review Draft. Office of Solid
Waste and Emergency Response. EPA530-D-98-001A. July.
USEPA. 1998. Methodology for Assessing Health Risks Associated
with Multiple Pathways of Exposure to Combustor Emissions. National
Center for Environmental Assessment. EPA600/R-98/137.
Proposed HWIR Rule (November 19, 1999 Federal Register; 64 FR
63382)
Final Petroleum Listing Rule (August 6, 1998 Federal Register;
63 FR 42210)

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[[Page 67082]]

d. Exposure Assessment--Cooking and Post-cooking Food Losses
Commenters contended that the equations in the risk assessment used
to characterize exposure to chemicals from the consumption of beef do
not appear to account for loss of chemicals due to food preparation,
cooking, and consumption practices. The commenters pointed out that The
Exposure Factors Handbook (``the Handbook;'' USEPA, 1997; referenced in
the preamble to the proposed rule) recommends that these losses be
considered, and provides estimates for percent weight losses from
preparation of various meats from cooking and post cooking actions.
Beef-specific loss estimates range from 11%-42% (mean = 27%) due to
cooking and 10%-46% (mean = 24%) due to post cooking actions.
Therefore, the cancer risk estimates associated with the beef ingestion
pathway should be adjusted by a factor of 0.55 (0.73 x 0.76).\21\
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\21\ The value 0.55 is calculated as follows: If 27 percent of
the mass of meat is lost during cooking, then 73 percent of the meat
remains. Of the remaining 73 percent, 24 percent more is lost after
cooking (76 percent is retained). As a result, the mass of meat
remaining after cooking and post-cooking activities is 76 percent of
73 percent, or 55 percent of the original mass. Therefore, the
amount of meat lost through cooking and post-cooking activities is
45 percent.
---------------------------------------------------------------------------

EPA agrees that the intake rates that we used for the adult farmer
(and certain child of farmer age cohorts) should have incorporated loss
of beef due to cooking and post-cooking activities. The Handbook
explains that the intake rates it provides for home-produced food items
do not reflect actual food consumption (intake), but instead were
derived from the amount of household food consumption in an economic
sense, that is, they are the measure of the weight of food brought into
the household that has been consumed (used up) in some manner. The
Handbook explains that in addition to food being consumed by
individuals, food may be used up by spoiling, by being discarded (for
example, inedible parts), through cooking processes, etc. The Handbook
provides estimated preparation losses for beef that include cooking
losses (which include dripping and volatile losses) and post-cooking
losses (which include cutting, bones, excess fat, scraps, and juices.)
The authors of the Handbook averaged these losses across all cuts and
cooking methods to obtain a mean net cooking loss and a mean net post-
cooking loss for beef. The Handbook explains that the preparation loss
factors presented ``are intended to convert intake rates based on
`household consumption' to rates reflective of what individuals
actually consume. However, these factors do not include losses to
spoilage, feeding to pets, food thrown away, etc.'' EPA acknowledges
that considering the mean cooking and post-cooking losses for beef
(45%) as presented by the commenters would result in reducing the risk
estimate, modifying the total (beef plus dairy, see section VI.A.3)
high end deterministic dioxin risk estimate for the adult farmer (2E-
05) by a factor of 0.78.
e. Toxicity Assessment
The proposed rule presented an assessment of the toxicity of
dioxins and chloroform, the constituents of concern in chlorinated
aliphatics wastewaters. Commenters on the proposed rule challenged data
and analyses EPA relied upon to characterize the toxicity of the
dioxins and chloroform. First, the commenters believed that EPA's use
of draft documents under review was inappropriate for obtaining
toxicity information for dioxins. Second, the commenters contended that
EPA should have used a different cancer slope factor to calculate risks
for two of the hexachlorodibenzo-p-dioxin (HXCDD) congeners.
Third, the commenters believed that EPA overestimated certain toxicity
equivalency factors (TEFs, described below) that we used in our risk
analysis. Lastly, commenters on the proposed rule challenged two of the
assumptions inherent in the development of the toxicity benchmarks that
we used to evaluate dioxins and chloroform. These two assumptions are
as follows:

To develop cancer benchmarks using animal studies,
scientists often extrapolate dose-response data derived from the
animal studies to lower levels that are within the range of human
exposure. EPA historically has extrapolated response data in the
low-dose range using a linear approach called the linearized
multistage (LMS) model. However, in 1996, EPA published the Proposed
Guidelines for Carcinogen Risk Assessment (hereafter referred to as
the ``1996 Guidelines;'' USEPA, 1996 \22\) that provided new
recommendations for evaluating responses in the low-dose range when
biologically-based or case-specific models are not available. While
still recommending a linear extrapolation (a straight line
extrapolation) as a default procedure for evaluating low-dose
response, the 1996 Guidelines also suggest that extrapolation in the
low-dose range can be performed using a nonlinear approach, when the
data on the mode of action for the contaminant are sufficient to
support such an approach. Commenters on the proposed rule contended
that, for 2,3,7,8-TCDD (``TCDD'') and chloroform, a nonlinear
approach is more appropriate for extrapolating response data in the
low-dose range than the LMS approach used by EPA.
---------------------------------------------------------------------------

\22\ USEPA. 1996. Proposed Guidelines for Carcinogen Risk
Assessment. 61 FR 17960.
---------------------------------------------------------------------------

To calculate human equivalent doses from animal doses
used in toxicity studies, scientists typically scale animal doses
based on the ratio of animal and human body weights. The 1996
Guidelines recommend that the default approach is to scale daily
applied doses experienced for a lifetime in proportion to body
weight raised to the \3/4\ power. This recommendation is a change
from EPA's previous recommendation to scale doses in proportion to
body weight raised to the \2/3\ power.

Commenters on the proposed rule believed that EPA should account for
this revised guidance in our risk assessments for dioxin and
chloroform.

i. Assessment of the Toxicity of Dioxins and Furans

EPA used a cancer slope factor of 156,000 (mg/kg-
day)-\1\ for TCDD to calculate cancer risk from exposure to
dioxins and furans in chlorinated aliphatics wastes. The cancer slope
factor is a measure of the relative potency of carcinogens. That is,
the higher the cancer slope factor, the more potent the carcinogen. The
toxicity of each of the 17 dioxin and furan congeners with TCDD-like
toxicity is expressed in terms of TEFs. TEFs are estimates of the
toxicity of specific dioxin and furan congeners relative to the
toxicity of TCDD, which is assigned a TEF of 1. The sections that
follow present public comments on the slope factor and TEFs that EPA
used to evaluate dioxins and furans, and provide the Agency's response
to those comments.

TCDD Cancer Slope Factor and Health Effects

The existing cancer slope factor for TCDD is based on human
equivalent doses calculated from laboratory animal data by scaling
doses to body weight raised to the \2/3\ power. Commenters maintained
that this practice is obsolete, and does not reflect a change in EPA
policy recommending that doses be scaled to body weight raised to the
\3/4\ power. The commenters calculated that compared to a cancer slope
factor that is based on scaling doses to body weight raised to the \3/
4\ power, the existing cancer slope factor overestimates cancer risk
from dioxin-like compounds by at least 35% (assuming a linear dose-
response), and as a result, all of EPA's cancer risk estimates for
dioxin-like compounds should be adjusted by at least a factor of 0.65.
Commenters also claimed that the existing slope factor for TCDD does
not take into account mechanistic information suggesting there is a
threshold for TCDD

[[Page 67083]]

carcinogenesis. The commenters noted that this point is emphasized in a
recent letter to the editor of Risk Analysis, written and signed by
nearly twenty of the world's leading pharmacologists (Byrd et al., 1998
\23\) which states: ``A dose-response assessment for dioxin based on
receptor binding would predict a nonlinear dose-response relationship
with a threshold for tumor induction. A nonlinear relationship is more
consistent with the available chronic animal bioassays and human
epidemiology studies.'' The commenters contended that, given this
information, the cancer risk posed by all of the dioxin-like dioxin and
furans may well be zero for all pathways considered in EPA's risk
assessment.
---------------------------------------------------------------------------

\23\ Byrd III, D.M., Allen, D.O., Beamer, R.L., et al. 1998.
Letter to the Editor: The dose-response model for dioxin. Risk
Analysis. 18(1):1-2.
---------------------------------------------------------------------------

Commenters also took issue with EPA's use of the Health Assessment
Document for 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) and Related
Compounds issued by EPA in 1994. These documents have been reviewed by
the EPA Science Advisory Board (SAB), but have not been finalized. Some
commenters noted that the SAB made substantial comments on the 1994
draft documents that are directly relevant to the risk assessment for
the Chlorinated Aliphatics Listing Determination, and, because the SAB
comments have not yet been incorporated in a final document, it is
premature and incorrect to use the draft in this current rulemaking.
The commenters noted that the front cover of the draft chapters state:
``Review Draft (Do not Cite or Quote)'' and

Notice: This document is a preliminary draft. It has not been
formally released by EPA and should not at this stage be construed
to represent Agency Policy. It is being circulated for comment on
its technical accuracy and policy implications.

In addition, the commenters pointed out that page 5-33 of EPA's
Risk Assessment Technical Background Document for the Chlorinated
Aliphatics Listing Determination, July 30, 1999, states: ``Most of the
information in this summary is from this draft document and is subject
to change, pending release of the final document.'' Thus, the
commenters believe that conclusions made concerning dioxin in the risk
assessment for chlorinated aliphatics wastes are based on a document
that is preliminary and possibly incorrect.
In contrast to the comments above, one commenter strongly supported
the proposal to list chlorinated aliphatics wastewaters because of
significant risks posed by dioxins, and cited the 1994 draft Health
Assessment Document for 2,3,7,8-TCDD and Related Compounds that was
challenged by other commenters. The commenter asserted that dioxins are
a probable human carcinogen and that, in animal testing, TCDD is one of
the most potent carcinogens ever evaluated. The commenter noted that
noncarcinogenic effects resulting from TCDD exposure also have been
reported. Specifically, some studies suggest evidence of
immunotoxicity, such as alteration in lymphocyte populations, cell
surface markers or lymphocyte proliferative response. There also is
evidence of reproductive and developmental effects from exposure to
dioxins. The commenter pointed out that studies discussed in EPA's
draft Dioxin Reassessment provide evidence of further health impacts.
EPA acknowledges the commenters' concerns regarding the use of a
draft document to support our toxicity assessment for dioxin-like
compounds. In the preamble to the proposed rule, and in the Risk
Assessment Technical Background Document for the Chlorinated Aliphatics
Listing Determination (USEPA, 1999a), we presented a summary of the
health effects believed to be associated with exposure to dioxins.
Although the source of our information concerning dioxin health effects
was the 1994 draft health assessment document challenged by commenters,
the health effects we presented at the time of proposal continue to
reflect our understanding of the health affects associated with
exposure to dioxins. A December 1998 toxicological profile for
chlorinated dibenzo-p-dioxins published by the Agency for Toxic
Substances and Disease Registry (ATSDR, 1998 \24\) supports our
appraisal of the adverse health effects associated with dioxin
exposure. Our reassessment of dioxin risks is still ongoing and we are
not relying on draft findings for this final listing determination.
---------------------------------------------------------------------------

\24\ ATSDR. 1998. Toxicological Profile for Chlorinated Dibenzo-
p-Dioxins (Update). U.S. Department of Health and Human Services.
December.
---------------------------------------------------------------------------

As discussed above, the Agency also received comments on the value
of the TCDD cancer slope factor that we used to evaluate cancer risk
due to dioxins. The cancer slope factor that we used in our proposed
chlorinated aliphatics risk analyses, 156,000 (mg/kg-
day)-\1\, is cited in a final Agency report published in
1985, \25\ and is comparable to the TCDD slope factor published in the
Health Effects Assessment Summary Tables (HEAST; USEPA, 1997), 150,000
(mg/kg-day)-\26\. We understand that the 1996 Proposed
Guidelines for Carcinogen Risk Assessment recommends the body weight
scaling factor approach noted by the commenters, and provides guidance
for considering nonlinear contaminant dose-response relationships in
developing cancer slope factors. EPA anticipates that we will consider
these recommendations of the 1996 Guidelines, as well as other relevant
recommendations of the 1996 Guidelines, in the course of future
development or reevaluation of contaminant cancer slope factors.
However, given that the Agency has not completed its comprehensive
reassessment of TCDD carcinogenicity and toxicity, the Agency has
decided to use the 1985 cancer slope factor for TCDD (USEPA, 1985) for
this rulemaking. Moreover, decreasing the slope factor for TCDD as
recommended by commenters would not have any impact on our ultimate
listing decisions for chlorinated aliphatics wastewaters, EDC/VCM
wastewater treatment sludges, or methyl chloride wastewater treatment
sludges. Our decision not to list chlorinated aliphatic wastewaters is
supported by other factors that decrease our proposed risk estimate
(section VI.A.3), and reducing the slope factor as recommended by the
commenters would not reduce our risk estimates enough to alter our
listing decisions for the EDC/VCM wastewater treatment sludges (section
VI.B.2.b.iv). Nevertheless, EPA may choose to reevaluate today's
listing decisions in the future, pending the final outcome of the
Agency's ongoing reevaluation of TCDD toxicity.
---------------------------------------------------------------------------

\25\ USEPA. 1985. Health Assessment Document for Polychlorinated
Dibenzo-p-Dioxins. Office of Health and Environmental Assessment.
EPA/600/8-84/014F. September.
\26\ The cancer slope factor for TCDD that we used to calculate
the cancer risk resulting from exposure to dioxins in chlorinated
aliphatics wastewaters, as well as EDC/VCM wastewater treatment
sludges (see section VI.B) was 156,000 (mg/kg-
day)-\1\(USEPA, 1985). We incorrectly cited HEAST as the
source of our slope factor in Appendix C of the Risk Assessment
Technical Background Document (USEPA, 1999a). A risk estimate
calculated using the slope factor presented in HEAST would be only a
factor of 0.96 (150,000/156,000) times a risk estimate calculated
based on the slope factor presented in the 1985 document. This
difference would have no discernable impact on our risk estimates
(use of either would have resulted in the high end risk estimate for
the adult farmer, 2E-05, that we presented in the proposed rule).
USEPA. 1997. Health Effects Assessment Summary Tables: Annual
Update (HEAST). Office of Emergency and Remedial Response.
Washington, D.C. July.

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[[Page 67084]]

Use of the Cancer Slope Factor for HxCDD

EPA's Integrated Risk Information System (IRIS) database includes a
cancer slope factor of 6,200 (mg/kg-day)-\1\ for HxCDD
mixtures. Commenters believed it was curious that EPA did not choose to
use this slope factor for any of the HxCDDs or hexachlorinated
dibenzofurans (HxCDFs) evaluated in the chlorinated aliphatics risk
assessment. Instead, EPA used the TCDD cancer slope factor of 156,000
(mg/kg-day)-\1\ and a TEF value of 0.1, yielding an
effective cancer slope factor of 15,600 (mg/kg-day)-\1\, to
evaluate all dioxin-like HxCDDs and HxCDFs. Commenters argued that the
risk assessment for HxCDDs and HxCDFs would be greatly improved if it
were based on the value of 6,200 (mg/kg-day)-\1\ because (1)
The cancer slope factor for HxCDD mixtures is verified on USEPA's IRIS
database, whereas the value for TCDD is not, and (2) the slope factor
for HxCDD mixtures is based on exposure to a mixture of congeners,
whereas the value for TCDD is based on exposure to a single congener.
The commenters believe that the slope factor for HxCDD mixtures
replaces the TEF approach, which was created as an interim approach in
the absence of chemical-specific data, with one that is based on
chemical-specific dose-response data for this family of congeners. The
commenters assert that in using the cancer slope factor for HxCDD
mixtures, the inherent uncertainties associated with the application of
the TEF approach would be eliminated. For these reasons, the commenters
recommended that all cancer risk estimates for HxCDDs and HxCDFs be
adjusted by a factor of 0.40 (6,200/15,600). Additionally, since the
slope factor of 6,200 (mg/kg-day)-\1\ is based on scaling
doses using body weight raised to the \2/3\ power, the commenters
believed that the slope factor should be reduced further to account for
the Agency's more recent recommendation that doses be scaled to body
weight raised to the \3/4\ power, resulting in a net adjustment factor
of 0.26 for HxCDD and HxCDF risk estimates.
EPA disagrees with the commenters' suggestion that the slope factor
for HxCDD mixtures that is presented in IRIS is applicable to all
dioxin-like HxCDDs and HxCDFs. The slope factor presented in IRIS
clearly is based on studies of only the 1,2,3,6,7,8- and 1,2,3,7,8,9-
congeners of HxCDD, thus these are the congeners to which the slope
factor would apply if EPA chose to use it in the chlorinated aliphatics
risk analyses. Although the commenters suggested that use of the IRIS
slope factor would have an impact on the results of the risk analysis,
particularly if the slope factor is adjusted using a revised scaling
factor, EPA strongly disagrees. Upon review of the congener-specific
risk estimates provided in the Risk Assessment Technical Background
Document for the proposed rule (USEPA, 1999a) it is clear that
eliminating the 1,2,3,6,7,8- and 1,2,3,7,8,9- congeners of HxCDD from
the risk analysis completely would have the impact of modifying the
high end risk estimate for the adult farmer only by a factor of 0.96.

Use of the WHO TEFs

Commenters contended that a hidden area of conservatism in EPA's
risk assessment lay in the fact that the TEF values for many congeners,
including 2,3,4,7,8-PeCDF and 1,2,3,4,7,8-HxCDF (the congeners that are
the primary contributors to EPA's risk estimates), do not reflect
central tendency values, but are instead upper bound values. Using the
World Health Organization's (WHO's) database of Relative Potency (REP)
estimates for these two congeners, the commenters determined that the
TEF value of 0.5 for 2,3,4,7,8-PeCDF is equivalent to the 81st
percentile of REP estimates obtained from 59 in vivo studies, and that
the geometric mean from these 59 studies corresponds to a value of
0.19. Similarly, the commenters determined that the TEF value of 0.1
for 1,2,3,4,7,8-HxCDF is equivalent to the 93rd percentile of REP
estimates obtained from 10 in vivo studies for this congener, and that
the geometric mean from these 10 studies corresponds to a value of
0.041. The commenters asserted that EPA's risk estimates for dioxin
should be adjusted downward to correct for EPA's use of upper-bound TEF
values. Curiously, one of the same commenters who opposed the manner in
which the WHO-TEFs were developed, also applauded the use of the WHO-
TEFs: ``Thus, [the commenter] fully supports EPA's shift from I-TEF to
WHO-TEF. This replacement by WHO-TEF needs to be adopted promptly by
all EPA programs to avoid unnecessary confusion among the general
public'' and ``[the commenter] commends EPA for several good policy
decisions in this proposal. Specifically [the commenter] supports EPA's
adoption of the WHO-TEF * * *.''
In response, EPA points out that the TEF values are based on all
available studies. These studies were conducted under a variety of
exposure scenarios, including chronic, subchronic, short-term and
acute, and examining a broad spectrum of endpoints including
biochemical, developmental, immunotoxicological, neurological,
carcinogenic and teratogenic. Whereas the resulting range of in vitro/
in vivo REP values for a particular congener may span 3-4 orders of
magnitude, final selection of a TEF value gave greater weight to REPs
from repeat dose in vivo experiments (chronic > subchronic > subacute >
acute). Furthermore, studies examining toxic effects were given greater
weight than studies examining biochemical effects. This weighting
scheme and the use of professional judgment are designed to give more
weight to studies that provide exposure scenarios similar to humans and
for studies examining effects of concern.
As pointed out by the commenter, the range of the REPs for a
particular chemical can vary across studies. However, the commenters'
proposed use of the geometric mean or Monte Carlo simulations is cause
for concern. The variability in the REPs for a particular chemical can
be due to several factors. As with any other determination, there is
variability in the measurement which can be due to either inter-
laboratory variability and variability in the actual measurement (that
is, experimental variability in determining ethoxyresorufin O-
deethylase [EROD] activity). Another source of variability could be due
to species or endpoint differences in the REP of a chemical. Finally,
the REP of a chemical can be due to differences in study design, for
example, in vitro studies vs. in vivo studies, or short-term vs. long
term in vivo studies. The use of expert judgment and the weighting
scheme described above allows for consideration of the important
biological factors regulating the relative potency of a chemical. Use
of the geometric mean ignores this biological information.
More importantly, the information presented by the commenters is
not representative of the actual data available on TEFs and how this
information is used. Of all the chemicals included in the TEF
methodology, only 5 of these chemicals account for over 80% of the TCDD
equivalents in human tissues, 2,3,7,8-TCDD, 1,2,3,7,8-PeCDD,
1,2,3,6,7,8-HxCDD, 2,3,4,7,8-PeCDF and PCB 126. The TEF values for, PCB
126, 1,2,3,7,8-pentachlorodibenzo-p-dioxin, and 2,3,4,7,8-
pentachlorodibenzofuran, are similar to the mean of the relative
potencies of these chemicals from in vivo studies and in some cases
they are lower than the mean of the relative potencies. Chemicals for
which there is limited data tend to have TEFs assigned that are
conservative estimates of the

[[Page 67085]]

relative potencies specifically because of the limited data.
Another short-coming of the proposed statistical method for
determining the TEF is the lack of a weighting scheme. In assigning a
TEF value for a particular congener, all available data comparing the
relative potency of a chemical to TCDD or PCB 126 are considered. The
expert panel examines these data sets and places more emphasis on
studies which examine toxic responses following chronic or subchronic
exposures. The proposed alternative approach, in which the TEF is
assigned based in the mean of the relative potency values, ignores the
weighting scheme and places a relative potency for biochemical
alterations in vitro equal to that for relative potencies based on
toxic responses following subchronic exposures in vivo. While the
statistical approach recommended by the commenters provides an estimate
of the variability, it ignores biological phenomena that influence the
relative potencies of these chemicals. In contrast, the use of expert
opinion provides a TEF that is based on endpoints of concern and
considers biological factors that influence the relative potency of
these chemicals. In the development of the TEF methodology, the use of
expert opinion to provide an estimate of the variability of the TEF has
not been applied. However, the data base that the expert panel uses to
derive the TEF is available from the WHO and does present the range of
relative potencies.
Finally, the commenter describes the present TEFs as overly
conservative based on comparison to the geometric mean of the REPs. It
is unclear what the commenter means by ``overly conservative.'' The
true relative potency of these chemicals in humans is uncertain.
Because the true value is uncertain, it is difficult to determine if
the TEF values are over estimates of the potency or if they
underestimate the true potency of these chemicals. For the chemicals
described, 2,3,4,7,8-PeCDF and 1,2,3,4,7,8-HxCDF, the TEF is based on
giving greater consideration to studies using the most relevant dosing
regimen and examining toxic endpoints. Use of the geometric mean down
plays the importance of the more relevant studies and provides greater
weight to acute and in vitro studies.

ii. Chloroform

One commenter claimed that, as was the case for TCDD, EPA's unit
risk of 2.3 x 10-5 (ug/m3)-1 for
chloroform was calculated using the outdated practice of scaling dose
in proportion to body weight raised to the \2/3\ power, rather than to
the \3/4\ power, as recommended in the 1996 Guidelines (USEPA, 1996).
The commenter believed that, as a result, the cancer risks attributable
to chloroform should be adjusted by a factor of 0.52 (calculated in the
same manner as discussed for TCDD in section VI.A.2.e.i). Another
commenter asserted that, in evaluating cancer risks due to chloroform
exposure, EPA failed to consider the EPA Office of Water's (OW)
reanalysis of chloroform carcinogenicity. The commenter noted that
EPA's December 16, 1998 rulemaking on disinfection byproducts firmly
rejected the LMS approach for assessing cancer risks from chloroform
exposure. The commenter contended that in the preamble for OW's
rulemaking, EPA concluded specifically that ``the nonlinear cancer
extrapolation approach is the most appropriate means'' to assess cancer
risks from chloroform (63 FR 69400). The commenter contended that using
the nonlinear approach, exposures to chloroform of 0.3 mg/L are
considered to pose no cancer risk. The commenter believed that,
therefore, the 0.2 mg/L central tendency concentration for chloroform
in chlorinated aliphatics wastewater poses no cancer risk.
In contrast, a third commenter strongly supported the proposal to
list chlorinated aliphatics wastewaters because of the significant
risks posed by the hazardous constituents in the waste, including
chloroform. The commenter pointed out that health risks from chloroform
are well documented, and noted that chloroform is a recognized human
carcinogen, as well as ``a suspected toxicant of the following human
health systems: cardiovascular or blood toxicant; developmental
toxicant; endocrine toxicant; gastrointestinal or liver toxicant;
kidney toxicant; neurotoxicant; reproductive toxicant; and respiratory
toxicant.'' The commenter noted that chloroform is ``more hazardous
than most chemicals in 11 out of 14 ranking systems and is ranked as
one of the most hazardous compounds (worst 10%) to ecosystems and human
health.'' (The commenter referenced ``EDF's Scorecard, www.
scorecard.org, on chloroform. Scorecard incorporates governmental and
other authoritative information on chemicals, including their known and
suspected health effects.'') The commenter believed that EPA is clearly
justified in listing chlorinated aliphatics wastewaters.
While EPA acknowledges the concerns of the commenter who
highlighted chloroform's adverse health effects, EPA agrees with the
commenter who, based on evaluations conducted by OW, challenged our
assessment of chloroform carcinogenicity at low doses. Based on mode of
action considerations, EPA's Science Advisory Board (SAB), WHO, the
Society of Toxicology, and EPA all strongly endorse the nonlinear
approach for assessing risks from chloroform. Although OW conducted its
evaluation of chloroform carcinogenicity for oral exposure, the
nonlinear approach for low-dose extrapolation cited by the commenter
would apply to inhalation exposure to chloroform as well, since
chloroform's mode of action is understood to be the same for both
ingestion and inhalation exposures. Specifically, tumorgenesis for both
ingestion and inhalation exposures is induced through cytotoxicity
(cell death) produced by the oxidative generation of highly reactive
metabolites (phosgene and hydrochloric acid), followed by regenerative
cell proliferation (63 FR 15685). As explained in EPA OW's March 31,
1998, and December 16, 1998, Federal Register notices pertaining to
chloroform (63 FR 15673 and 63 FR 69389, respectively), EPA now
believes that ``based on the current evidence for the mode of action by
which chloroform may cause tumorgenesis, * * * a nonlinear approach is
more appropriate for extrapolating low dose cancer risk rather than the
low dose linear approach * * *'' (63 FR 15685). In fact, OW determined
that given chloroform's mode of carcinogenic action, liver toxicity (a
noncancer health effect) actually ``is a more sensitive effect of
chloroform than the induction of tumors'' and that protecting against
liver toxicity ``should be protective against carcinogenicity given
that the putative mode of action understanding for chloroform involves
cytotoxicity as a key event preceding tumor development'' (63 FR
15686).
Given the recent evaluations conducted by OW that conclude that
protecting against chloroform's noncancer health effects protects
against excess cancer risk, EPA now believes that the noncancer health
effects resulting from inhalation of chloroform would precede the
development of cancer and would occur at lower doses than tumor
(cancer) development. Although EPA has not finalized a noncancer health
benchmark for inhalation exposure (a reference concentration, RfC), the
Agency for Toxic Substances and Disease Registry (ATSDR) has developed
a Minimal Risk Level (MRL) for inhalation exposure to chloroform. An
MRL is ``an estimate of the daily human exposure to a hazardous
substance that is likely to be

[[Page 67086]]

without appreciable risk of adverse noncancer health effects over a
specified duration of exposure [acute, intermediate, or chronic]''
(http://www.atsdr.cdc.gov/mrls.html). To evaluate the noncancer hazard
associated with exposure to chloroform in air, we compared the
concentration of chloroform that we predicted to occur at a high end
receptor's point of exposure to the ATSDR MRLs for inhalation exposure
to chloroform. The high end chloroform exposure point concentration in
air for chlorinated aliphatics wastewaters, approximately 0.0001 ppm
(0.74 ug/m\3\), is more than two orders of magnitude below the chronic
inhalation MRL for chloroform, 0.02 ppm (the chronic MRL is more
protective than either the acute or intermediate MRLs), indicating that
there is no concern for adverse noncancer health effects, or,
therefore, significant increased risk of cancer, resulting from
inhalation exposure to chloroform derived from chlorinated aliphatics
wastewaters.
In response to the commenter who disagreed with EPA's use of a
slope factor based on animal data that had been adjusted to human
equivalent doses using body weight raised to the \2/3\ power, EPA notes
that in OW's comprehensive reevaluation of chloroform carcinogenicity,
EPA adjusted the animal data to equivalent human doses using body
weight raised to the \3/4\ power (63 FR 15686), as recommended in EPA's
1996 Guidelines (USEPA, 1996).
f. Noncancer Dioxin Risks for Adults and Nursing Infants
One commenter asserted that EPA should have considered dioxin
noncancer endpoints for adults and for nursing infants in developing a
dioxin concentration limit that triggers air emission control
requirements for wastewater tanks. The commenter explained that a
trigger level based on noncancer endpoints may be higher than the
cancer-based trigger level, but that EPA should not assume that is the
case. The commenter said that EPA should approximate and consider a
trigger level for noncancer endpoints.
First, we note that the lead option proposed by EPA was a
`standard' listing for chlorinated aliphatic wastewaters, (i.e., listed
regardless of dioxin concentration) with the dioxin trigger level
proposed as an attempt to provide a means to implement tank cover
requirements more appropriate to the potential risk, particularly
because our data indicated that dioxin levels varied among generators
(64 FR at 46503). However, as discussed in section VI.A.3 of today's
preamble we have made a decision not to list chlorinated aliphatics
wastewaters based on revised estimates of cancer risk. EPA also does
not believe there is reason for listing chlorinated aliphatics
wastewaters based on dioxin noncancer effects, as discussed further
below. Although the proposed wastewater trigger level to implement tank
cover requirements is moot because we are not finalizing the listing as
proposed, we do not believe any increased risk of adverse noncancer
effects due to dioxin in chlorinated aliphatic wastewaters is of
concern in any event.
Typically, EPA calculates a hazard quotient (HQ) to assess the
noncancer health effects resulting from contaminant exposure. For oral
exposures, the HQ is the ratio of an individual's average daily
contaminant dose to the reference dose (RfD \27\) for the contaminant.
EPA has not established RfDs for any of the dioxin or furan congeners
(USEPA, 1994 \28\). EPA is awaiting the finalization of the Draft
Reassessment before formalizing an approach to evaluating noncancer
risks from dioxin. In recent years EPA's Office of Solid Waste and
Emergency Response (OSWER) has calculated a modified margin of
incremental exposure (MOIE) to dioxin on a case-by-case basis (for
example, see 64 FR 52828, September 30, 1999). The MOIE is a tool for
evaluating the potential for the occurrence of noncancer health effects
due to dioxin. The margin of incremental exposure is an expression of
the additional (increment of) exposure to dioxin that an individual
receives in excess of background exposure to dioxin. Using this
approach, we compare the estimated average daily dose attributable to
chlorinated aliphatic wastewaters to background exposures in the
general population. As a measure of risk, the MOIE presupposes that if
exposures are small relative to background, then risks from these
exposures are likely to have limited significance for human health.
While the MOIE analysis is not specific to any particular health
endpoint, it does allow direct comparison of exposures related to
chlorinated aliphatics wastewaters to background dioxin exposure
experienced by the general population. Using the high end exposure
estimates developed for the proposed rule, the high end margin of
incremental exposure due to chlorinated aliphatic wastewaters would be
0.17 for an adult farmer and 0.19 for the breast-feeding infant of an
adult farmer. However, we estimate that exposures attributable to
chlorinated aliphatics wastewaters are actually lower than we
originally presented in the proposed rule, due to our reevaluation of
our air dispersion modeling results, beef intake rates, and air
emissions modeling assumptions (see section VI.A.3). Therefore, we
project that the actual high end margin of incremental exposure for
both the adult farmer and breast-feeding infant of the adult farmer is
less than 0.1, that is, an order of magnitude or more lower than any
risk that may be attributable to background exposures (USEPA, 2000b).
---------------------------------------------------------------------------

\27\ In the preamble to the proposed rule, in an effort to
present the concept of RfDs and RfCs in plain language, we
incorrectly characterized RfDs and RfCs as levels that EPA considers
``acceptable.'' RfDs and RfCs are not by themselves action levels;
they do not establish acceptable exposures, nor do they establish
danger levels. RfCs and RfDs are used as tools in establishing
concern for non-cancer effects resulting from exposure to
contaminants, and they serve as a common reference point from which
risk managers can make decisions regarding estimates of exposure.
\28\ United States Environmental Protection Agency (USEPA).
1994. Health Assessment for 2,3,7,8-TCDD and Related Compounds.
Public Review Draft. Office of Research and Development. EPA/600/EP-
92/001a-c. September.
---------------------------------------------------------------------------

3. Rationale for the Final Listing Determination: Summary of the Impact
of Public Comments on the Proposed Listing Determination for
Chlorinated Aliphatic Wastewaters
As discussed above, public commenters presented arguments that
EPA's high end deterministic risk estimate for the adult farmer was in
error and overestimated potential risks to human health and the
environment. After reviewing and carefully considering all information
provided by commenters, we re-evaluated our risk assessment results for
air releases of dioxins and chloroform from chlorinated aliphatics
wastewaters managed in aerated biological treatment tanks. Based on
information provided by commenters, we decided it was appropriate to
adjust our risk assessment results to account for cooking and post-
cooking losses for beef, a more realistic size of the pasture
supporting cattle indirectly exposed to dioxin emissions, and the
potential for solids removal prior to wastewater treatment in aerated
biological treatment tanks. After calculating these adjustments to our
proposed risk assessment results, EPA found that accounting for cooking
and post-cooking losses for beef would modify the high end risk
estimate for the adult farmer by a factor of 0.78, and accounting for a
more reasonable pasture size would modify the risk estimate by a factor
of 0.50, resulting in an overall risk estimate of 7E-06. This risk
estimate does not consider the impact of

[[Page 67087]]

assuming solids removal from the wastewater, which could reduce risk to
an even greater extent, reasonably by an additional factor of 0.67 to
0.94, such that our final risk estimate could be as low as 4E-06.
Moreover, our proposed estimate of risk due to emissions of chloroform,
which we previously believed would be additive to our dioxin risk
estimate, is no longer valid given recent Agency information regarding
chloroform's mode of action. Specifically, there is no concern for
adverse noncancer health effects resulting from inhalation exposure to
chloroform derived from chlorinated aliphatics wastewaters, therefore,
there is no concern for increased risk of cancer. Furthermore, the
noncancer health effects due to dioxin that we characterized in
response to comments presented above also would be affected by the
adjustments to our analysis, and would be even less than projected.
Thus, EPA believes that the risk from this waste is well below 1
x 10-\5\. We acknowledge that there is some uncertainty
associated with the analyses we have conducted in response to the three
comments we found persuasive--for example, we do not have data to
support specific conclusions with respect to the percentage of solids
removed from wastewater by prior to biological treatment. Nonetheless,
we have been conservative in accounting for the factors raised by the
comments and believe the risk is unlikely to be higher than our revised
estimates. In addition, we note that the risk level presented for these
wastewaters in the proposal (2 x 10-\5\ as marginal. As we
have explained, we make listing determinations based on a weight-of-
the-evidence approach, and the result of a decision is not dictated by
whether the risk calculated for a waste is slightly more or less than 1
x 10-\5\. So, even aside from the specific revised risk
numbers we have calculated, we would decide not to list this waste
based on the determination that the already marginal risk level
presented in the proposal clearly overstates the actual risk associated
with the waste, and that the actual risk is almost certainly
considerably below the 1 x 10-\5\ level.
Therefore, the Agency concludes that potential air releases from
wastewaters managed in biological treatment tanks do not present
significant risk to human health and the environment and do not support
listing chlorinated aliphatic wastewaters as hazardous wastes. After
carefully reviewing our analyses and making necessary adjustments to
our risk estimates based upon arguments and information presented in
public comments, we estimate that air releases from the management of
chlorinated aliphatic wastewaters would result in high end cancer risk
risks less than 1 x 10-\5\. The Agency therefore is
finalizing a decision to not list chlorinated aliphatic wastewaters as
hazardous waste.
4. Waste Management Practices / Scope of Listing Determination for
Chlorinated Aliphatic Wastewaters
EPA believes that the rulemaking record for this rule supports a
decision not to list chlorinated aliphatic wastewaters based on the
typical management scenario of biological treatment in tanks. As
mentioned above, and explained in more detail in Listing Background
Document for the Chlorinated Aliphatics Listing Determination (USEPA,
1999c),\29\ the majority of chlorinated aliphatic manufacturing
facilities manage their wastewaters in tank-based wastewater treatment
systems and either directly discharge treated wastewaters under NPDES
permits, or discharge the wastewaters to POTWs. However, the Agency is
aware that two facilities treat their chlorinated aliphatic wastewaters
on-site and dispose of the wastewaters in on-site UIC wells. In
addition, the Agency learned from public comments, that one facility
pipes its wastewaters off-site to a nearby chemical manufacturing
facility that commingles the chlorinated aliphatic wastewaters with
other wastewaters, and treats the combined wastewaters in a wastewater
treatment system that includes surface impoundments.
---------------------------------------------------------------------------

\29\ U.S. EPA. 1999c. Listing Background Document for the
Chlorinated Aliphatic Listing Determination (Proposed Rule). Office
of Solid Waste. July.
---------------------------------------------------------------------------

a. Wastewaters Managed in Underground Injection Control (UIC) Wells
With respect to the two facilities that manage their chlorinated
aliphatic wastewaters in on-site UIC wells, one of the facilities
already manages its wastewaters as hazardous due to the fact that the
wastewaters exhibit the toxicity characteristic. This facility manages
its hazardous wastewaters in covered tanks, pipes the wastewater
directly to a Class I hazardous UIC well and complies with RCRA and CAA
(HON) air emissions requirements. Due the fact that this wastewater is
being managed as a hazardous waste and in full compliance with RCRA
subtitle C and applicable CAA requirements, we conclude that this
wastestream does not present significant risk and we believe that our
decision not to list these wastewaters as hazardous waste will have no
potential adverse impact in terms of protecting human health and the
environment.
In the case of the other chlorinated aliphatic production facility
that manages its wastewaters by disposing of them in UIC wells, some of
the facility's wastewaters were, until recently, defined as hazardous
waste (i.e., derived from previously listed hazardous waste) and
disposed in a Class I hazardous UIC well and in compliance with a no-
migration petition. Recently, the facility was granted a delisting for
these wastewaters by the Region VI EPA Regional Administrator. Given
that the Regional Administrator has evaluated these wastewaters and
determined that the wastewaters, as generated, do not pose significant
risks to human health and the environment and warrant the award of a
delisting, we believe that our decision not to list chlorinated
aliphatic wastewaters as hazardous waste is appropriate for this
wastestream and this decision will result in no adverse impact to human
health and the environment.
This facility also manages some of its chlorinated aliphatic
wastewaters as non-hazardous waste and injects the wastewaters into a
Class I non-hazardous UIC well. Although we did not model this
management practice in our evaluation of potential risks from the
management of chlorinated aliphatic wastewaters, we did examine the
specific waste management requirements governing these wastewaters. Our
evaluation of the specific management requirements applicable to these
wastewaters included a comparison of the state requirements governing
Class I non-hazardous UIC wells and those governing Class I hazardous
UIC wells. We found that the requirements in Louisiana, where this
facility is located, for Class I non-hazardous UIC wells are virtually
identical to those governing Class I hazardous waste UIC wells. EPA
staff confirmed this conclusion after consulting numerous sources,
including a direct examination of the state regulations and discussions
with state authorities and EPA Regional personnel. We also note that in
our evaluation of these wastewaters, we determined that the levels of
constituents in the wastewaters are equivalent to the levels for which
the facility's other wastewaters were recently delisted. This indicates
that these wastewaters will not pose risk when managed in Class I UIC
wells at this specific facility. Given these conclusions, we think this
practice is protective and believe that our decision not to list
chlorinated

[[Page 67088]]

aliphatic wastewaters will have no adverse impact on human health and
the environment due to the management of this facility's wastewaters in
non-hazardous UIC wells.
b. Wastewaters Managed in Surface Impoundments
At the time EPA published the proposed listing determination for
chlorinated aliphatic production wastes, the Agency was not aware that
any chlorinated aliphatic wastewaters were managed in surface
impoundments. EPA noted in the preamble to the proposed rule that
although information available to the Agency, at the time of the
proposed rule, indicated that surface impoundments had been used in the
past, available information indicated that chlorinated aliphatic
wastewaters are not managed in surface impoundments today. However, as
a result of public comments to the proposed rule, the Agency obtained
information indicating that a single facility, which is not a
chlorinated aliphatics manufacturing facility, accepts wastewaters from
a chlorinated aliphatic manufacturer and treats the chlorinated
aliphatic wastewater stream after commingling it with other wastewaters
generated at the chemical manufacturing facility. The commingled
wastewaters are treated in a wastewater treatment system that includes
biological treatment in surface impoundments.
After receiving information indicating that one facility was
managing chlorinated aliphatic wastewaters in surface impoundments, the
Agency conducted additional research to determine if other chlorinated
aliphatic wastewaters were being managed in impoundments. The results
of this research are that the Agency could identify no other facilities
managing chlorinated aliphatic wastewaters in surface impoundments.
As a result of comments received in response to the proposed rule
indicating that one facility treats chlorinated aliphatic wastewaters
in surface impoundments, EPA did a screening analysis of potential
risks from these wastewaters when managed in an impoundment. That risk
screening analysis was based on very conservative assumptions that
result in an overestimate of risk, given that the Agency assumed there
would be no dilution of the wastewater in the environment and that an
individual would drink the wastewater directly from the impoundment.
The screening analysis suggested that wastewaters might pose risks in
impoundments under the very conservative (and unrealistic) assumptions
used in the screening analysis (that is, it may not be safe to drink
the wastewaters as generated in the impoundment). However, given the
overly protective nature of that screening assessment, the ``screening
analysis'' does not provide meaningful information about any risks
actually associated with this waste management practice and, therefore,
it does not provide a basis for listing the wastewaters as hazardous.
EPA has to make the best decision it can with the information and
analysis it has at the time of its evaluation. EPA has decided at this
time not to list as hazardous chlorinated aliphatic wastewaters,
regardless of how the wastewaters are managed. We are finalizing this
no list determination, given that the data and analysis before us,
while indicating some potential for risks from the management of
wastewaters in surface impoundments, does not warrant a decision to
list these wastewaters as hazardous. Simply put, EPA was unable, in the
time afforded under the consent decree, to perform a full risk
assessment for this waste management practice and to subject that
decision to public comment, and the screening assessment that EPA was
able to do was indeterminate. Although EPA cannot rule out the
possibility that this practice may present some risk to human health
and the environment, EPA has fully assessed the risk presented by the
predominant mode of waste management and made the determination that it
does not present a substantial hazard. In fact, of the 23 chlorinated
aliphatic manufacturing facilities that generate wastes effected by
this rulemaking, only 3 facilities manage wastewaters in non-tank based
systems. Under these circumstances, EPA has concluded that it is
appropriate to make a final decision based on the information and
analyses with respect to all the units and practices other than this
impoundment.
This conclusion is based in part on our interpretation of our
obligation under RCRA section 3001(e)(2). Under that provision,
Congress required that EPA make final listing determinations for 17
different waste categories in 15 months. In view of the scope of the
task and the tightness of the timeframe established, Congress could not
have intended that EPA conduct an in-depth review of every unit
managing any amount of waste within the categories. Rather, Congress
must have intended that EPA make the best reasoned judgment it can
based on analyses and information that are reasonably representative of
the waste categories. In practice, EPA has gone well beyond this in its
listing decisions and generally has tried to account for all the waste
management practices and units of which it is aware. However, in this
rulemaking, EPA was faced with the choice of continuing this practice--
which would have meant diverting time from completing the rulemaking to
attempt to negotiate a further extension of the consent decree--or
completing the rulemaking on schedule. Although EPA could always
perform more complete and rigorous analysis given more time on any
rule, at some point it is appropriate to move toward finalizing a
decision and cut off further analysis. In view of the length of time
already devoted to this rulemaking and the number of extensions
previously negotiated to the consent decree, and the fact that only one
waste management unit was unaccounted for in our analysis, EPA decided
to issue a final determination not to list aliphatics wastewaters
without accounting for this unit.
EPA is not deferring a decision for chlorinated aliphatics
wastewaters; it is making a final decision not to list the wastewaters.
Of course, EPA can always consider additional information and analyses
in the future and make further regulatory decisions based on that. In
addition, should EPA learn that the management of waste at this
impoundment presents a threat to human health and the environment, EPA
could consider taking site-specific action to abate the threat without
listing the waste, e.g., an action under RCRA Section 7003.

B. Wastewater Treatment Sludges From the Production of EDC/VCM

EPA is listing as hazardous sludges generated from treating
wastewaters associated with the manufacture of ethylene dichloride and
vinyl chloride monomer. This wastestream meets the criteria set out at
40 CFR 261.11 (a)(3) for listing a waste as hazardous and is capable of
posing a substantial present or potential hazard to human health or the
environment when managed in land treatment units. EPA is finalizing a
conditional listing for this waste, based upon the Agency's
determination that the waste does not pose a substantial risk when
disposed of in a landfill.

K174 * * * Wastewater treatment sludges from the production of
ethylene dichloride or vinyl chloride monomer (including sludges
that result from commingled ethylene dichloride or vinyl chloride
monomer wastewater and other wastewater), unless the sludges meet
the following conditions: (i) they are disposed of in a subtitle C
or non-hazardous landfill licensed or permitted by the state or
federal

[[Page 67089]]

government; (ii) they are not otherwise placed on the land prior to
final disposal; and (iii) the generator maintains documentation
demonstrating that the waste was either disposed of in an on-site
landfill or consigned to a transporter or disposal facility that
provided a written commitment to dispose of the waste in an off-site
landfill. Respondents in any action brought to enforce the
requirements of subtitle C must, upon a showing by the government
that the respondent managed wastewater treatment sludges from the
production of vinyl chloride monomer or ethylene dichloride,
demonstrate that they meet the terms of the exclusion set forth
above. In doing so, they must provide appropriate documentation
(e.g., contracts between the generator and the landfill owner/
operator, invoices documenting delivery of waste to landfill, etc.)
that the terms of the exclusion were met.

1. Summary of the Agency's Listing Decision for EDC/VCM Wastewater
Treatment Sludges
EPA evaluated potential risks from the management of wastewater
treatment sludges generated by producers of ethylene dichloride (EDC)
and vinyl chloride monomer (VCM). This waste grouping consists of all
sludges generated from the treatment of EDC/VCM wastewaters, excluding
sludge generated from the treatment of VCM-A wastewaters (discussed
elsewhere in today's rule). EPA estimates, based upon 1996 data, that
approximately 104,600 metric tons of wastewater treatment sludges are
generated annually by facilities that produce EDC and/or VCM.
EDC/VCM wastewater treatment sludges are generated by 12
facilities. Most facilities manage these sludges by disposing of them
either in a hazardous waste landfill or a non-hazardous waste landfill.
However, one facility manages its EDC/VCM sludges in an on-site land
treatment unit. To assess the potential human health risks associated
with EDC/VCM sludges, EPA evaluated potential risks from managing this
waste in an off-site non-hazardous waste (unlined) landfill and an on-
site land treatment unit. The highest risk estimates were calculated
for an adult farmer who ingests beef and dairy products containing
dioxin derived from airborne releases and erosion/runoff from the land
treatment unit. The proposed high end and central tendency risk results
for the farmer exposed to dioxin from the land treatment unit were 2E-4
and 4E-6, respectively. The Agency also concluded in the proposal that
the management of EDC/VCM wastewater treatment sludges in landfills
does not present risks of sufficient concern to support a decision to
list the sludges as hazardous waste when managed in this manner. 64 FR
46476; 64 FR 49052 (September 9, 1999 Federal Register).
Issues raised by commenters, and data provided in comments received
in response to the proposed rule, caused the Agency to reevaluate the
risk analyses that were the basis of our proposed risk estimates. After
careful consideration of information provided by commenters, we lowered
the estimated risk associated with the management of EDC/VCM sludges in
a land treatment unit. While the Agency's proposed high-end
deterministic risk estimate for the land treatment unit (2E-4) was at a
level at which the Agency presumes a waste poses sufficient risk to be
listed (i.e., 1E-4 or greater), the revised risk estimate (7E-5) falls
within the range of risks where the Agency may decide to list the waste
as hazardous (i.e., between 1E-4 and 1E-6), upon consideration of
additional factors. 59 FR at 66077. More specifically, EPA has
previously stated that where risk estimates are within the 1E-4 to 1E-6
range, there is a ``presumption of candidacy for either listing (risk
>1E-5) or no listing (risk 1E-5).'' 59 FR at 66077. Applying that
approach in this instance, the risk estimate for the land treatment
unit of 7E-5 is not only greater than 1E-5, it is in the upper end of
the range between 1E-5 and 1E-4. Comments received on the Agency's
proposed risk analysis for the landfill waste management scenario did
not result in the Agency modifying the risk estimate for the landfill.
High-end deterministic risk estimates for the landfill scenario were
all well within the presumptive no-list range (i.e., less than 1E-6)
with the exception of arsenic, the groundwater risk for which was
estimated at 3E-5. (The Agency's discussion of additional factors that
led EPA to decide that the arsenic risk estimate alone did not support
listing EDC/VCM wastewater treatment sludges managed in landfills is
presented below in Section VI.B.2.b.v. of this preamble.)
The Agency is therefore listing as hazardous EDC/VCM wastewater
treatment sludges (using a conditional listing approach as proposed)
based upon EPA's consideration of the risk estimates and additional
factors. The Agency's decision was influenced by the fact that dioxin
has been heavily studied, and the dioxin concentrations and volumes of
EDC/VCM sludge have been well characterized in EPA's study of this
industry (and, along with the toxicity \30\ of dioxin, were
incorporated into the risk assessment). Additionally, there was
evidence that the land application unit where these wastes are
currently managed had releases of other constituents to the
environment, which indicates that there may not be adequate coverage by
other regulatory programs.\31\ Because industrial solid waste land
treatment is a plausible management scenario for these wastes, EPA is
concerned about EDC/VCM sludges managed in this manner where dioxin (a
chemical that is persistent over the long term) is the constituent of
concern.
---------------------------------------------------------------------------

\30\ Dioxin has the highest slope factor (an indicator of
carcinogenic potency) of any chemical in the EPA IRIS database.
\31\ See Appendix A.--Environmental Release Descriptions, in
Hazardous Waste Characteristics Scoping Study U.S. EPA, November 15,
1996, pp. A-28 and A-29.
---------------------------------------------------------------------------

Finally, the EPA's concern is that not only is the application of
dioxin-containing wastes in a land treatment unit plausible, it is in
fact occurring. No commenter provided evidence that absent a decision
to list the waste, there is other regulatory authority that would
assure that the risks the Agency estimates for this practice would not
continue, either at the facility currently utilizing this practice, or
at a different facility.
The Agency concludes, based upon the estimated risk for dioxin of
7E-5, and after considering other relevant factors described above,
that EDC/VCM wastewater treatment sludges pose a substantial hazard
when managed in land treatment units. In addition, the Agency concludes
that this waste does not pose a substantial hazard when managed in
landfills. Based on these conclusions the Agency is promulgating a
conditional listing for this waste. EPA is listing EDC/VCM wastewater
treatment sludges as hazardous waste, unless the sludges are managed in
landfills. The conditional listing promulgated today also requires that
EDC/VCM wastewater treatment sludges not be placed on the land prior to
disposal. In addition, generators must be able to demonstrate that the
sludges are managed in accordance with the conditions for being
excluded from the hazardous waste listing.
2. Response to Major Comments Received on Proposed Rule for EDC/VCM
Wastewater Treatment Sludges
EPA received comments on a number of issues concerning the data and
analyses EPA used to arrive at our listing decisions for EDC/VCM
wastewater treatment sludges. In addition, one commenter asserted that
many of the comments on EPA's analysis of dioxin risks from the
management of chlorinated aliphatics

[[Page 67090]]

wastewaters (for example, comments relating to the dioxin cancer slope
factor) also apply to EPA's analysis of dioxin risks from the
management of EDC/VCM wastewater treatment sludges in a land treatment
unit. The comments we received may be generally divided into nine
categories: (1) Comments on EPA's waste management assumptions; (2)
comments on the exposure scenarios we evaluated in our risk assessment;
(3) comments on how we calculated exposure point concentrations in the
risk assessment; (4) comments on EPA's exposure assessment; (5)
comments on EPA's toxicity assessment for dioxin; (6) comments on how
we characterized risks associated with arsenic; (7) comments on
demonstrating compliance with the listing description; (8) comments on
the status of EDC/VCM sludges that are managed in ways other than land
treatment or landfilling; and (9) comments on whether or not a
contingent management approach to the listing is appropriate. The
comments, and the Agency's responses to these comments, are described
below.
a. Waste Management Assumptions
Eleven facilities manage EDC/VCM wastewater treatment sludges by
disposing of them either in a hazardous waste landfill or a non-
hazardous waste landfill. One facility manages this waste in an on-site
land treatment unit. As a result of public comment, the Agency has
learned that one facility generates and manages EDC/VCM wastewater
treatment sludges in surface impoundments.
In 1996, approximately 104,561 metric tons of wastewater treatment
sludges were generated in wastewater treatment systems used to treat
process wastewaters from the manufacture of EDC/VCM. Of this volume,
approximately 6,574 metric tons is attributable to the production of
EDC/VCM. The remaining sludge volumes are associated with the treatment
of other process wastewaters that are commingled with EDC/VCM process
wastewaters and treated in the same wastewater treatment system.

i. Waste Volumes

One commenter questioned whether EPA used the correct assumption
with regard to waste volume in the risk assessment, given that the
production of EDC/VCM may be increasing in the United States. The
commenter cited information provided in the Agency's Economics
Background Document for the proposed rule. The commenter asserted that
had EPA assumed a larger waste volume, based upon increased future
production capacity, the result would be an increase in the predicted
level of risk associated with the management of EDC/VCM sludges in
landfills. The same commenter questioned whether or not the Agency had
accounted for the likelihood that EDC/VCM wastewater treatment sludges
generated by different facilities may be co-disposed in the same
landfill.
In response to the commenter's concerns regarding co-disposal of
sludges, the Agency wishes to clarify that we did, in fact, account for
co-disposal of EDC/VCM sludges where information provided in the RCRA
3007 questionnaire responses showed that multiple generators dispose of
the sludges in the same off-site landfill. As documented in the Listing
Background Document (USEPA, 1999c, USEPA, 2000e), the Agency accounted
for two instances where sludges generated by two generators are
disposed in the same landfill.\32\ In both cases, the Agency used the
combined sludge volume in assessing the quantities of sludges managed
in off-site landfills.
---------------------------------------------------------------------------

\32\ See page 56 of ``Listing Background Document for the
Chlorinated Aliphatics Listing Determination'' (USEPA, 1999c).
---------------------------------------------------------------------------

In response to other concerns raised by the commenter, the Agency
reviewed the sensitivity analyses for the landfill analyses that were
presented in the July 1999 Risk Assessment Technical Background
Document. Our conclusion is that predicted risk levels are not very
sensitive to changes in waste volume. As shown in Table H.3.3 in
Appendix H of the Risk Assessment Technical Background Document (USEPA
1999a), we found that increasing waste volume from the central tendency
value of approximately 15,000 m\3\ to the high end value of
approximately 51,000 m\3\ increases the maximum 9-year average receptor
well concentration, thus risk, by only a factor of 1.6 in the 10,000
year time period that we modeled. This means that if waste volumes more
than tripled, the risk estimate would be expected to increase by only a
factor of 1.6 (that is, to 5E-05). Such an increase in production and
waste generation, which results in a relatively small change in
potential risk, would not cause the Agency to change its listing
decision. The Agency also points out that there may be significant
uncertainties in projecting changes in the volume of waste generated,
based upon increased production capacity, due to uncertainties in the
relationship between production rates and waste generation rates and
the effects that technology changes, types of facility expansions
(i.e., increased production capacity at existing facilities versus
building new facilities) and the impact of potential (and simultaneous)
adoption of waste minimization activities.

ii. Interpretation of Analytical Results

A commenter questioned the Agency's use of analytical results from
``dedicated'' sludge samples in its risk analysis and the commenter
indicated that some of the ``non-dedicated'' sludge samples appear to
have higher dioxin concentrations than the dedicated samples. As
explained in the preamble to the proposed rule (see 64 FR 46483),
``dedicated'' wastes are those wastes attributable only to the
production of EDC/VCM and do not include wastes derived from the
production of other chlorinated aliphatic wastes and commingled with
EDC/VCM sludges. In our risk analysis, EPA used analytical information
from samples of dedicated sludges only to isolate the risks from
constituents attributed to those wastes generated from the production
of the chlorinated aliphatic chemicals of concern to this listing
determination. Given the commenter's concerns, the Agency did review
the dioxin concentrations in the sludge samples not included in the
risk analysis. The Agency found that on the basis of dioxin TEQs, the
highest dioxin concentration in the ``non-dedicated'' samples (those
not included in our analysis) was less than one fourth of the highest
concentration of dioxins (on a TEQ basis) found in the samples used in
the analysis. Therefore, had the Agency used the analytical results
from the non-dedicated samples in its analysis, the use of the dioxin
concentrations would not have caused an increase in the risk estimate.
A commenter also questioned EPA's use of TCLP analytical results to
predict leachate concentrations of contaminants from landfill disposal
of EDC/VCM wastewater treatment sludges. The commenter questioned why
EPA's data showed that lead and chromium are not detected using the
TCLP, given that these constituents were found in the total constituent
analysis of the sludges. The commenter suggested that high iron content
in the sludges may affect the concentration of lead predicted by the
TCLP analysis, citing data in a previous EPA rulemaking (Phase IV Land
Disposal Restrictions, or LDR, proposed rule) that suggests high iron
content effects lead. EPA believes that the commenter is referring to
an issue first raised in the Phase III LDR proposed rule and
subsequently finalized in the Phase IV LDR final rule on May 26, 1998
(63 FR 28556). In the Phase IV LDR final rule, EPA determined that the
addition

[[Page 67091]]

of iron filings to lead-containing hazardous wastes was not a
legitimate form of treatment, and was in fact impermissible dilution,
because the iron filings can interfere with the TCLP test used to
determine whether the waste has been effectively treated (40 CFR
268.3(d)). The commenter stated that EPA should determine whether the
non-detects for lead in the sludge samples are an artifact of the TCLP,
and if so, that EPA should instead use partitioning equations rather
than TCLP data in the landfill modeling.
In response, the Agency notes it has consistently relied on the
results of TCLP leach tests in estimating the leaching potential of
wastes for making listing determinations, although more recently this
use in listing determinations has narrowed to evaluation of leaching
potential of wastes actually or plausibly being managed in Municipal
Solid Waste (MSW) landfills (see for example, 65 FR 55684, September
14, 2000 Federal Register). As presented elsewhere in today's preamble,
the Agency modeled an unlined, MSW landfill for EDC/VCM sludges, which
is not only plausible but is actually occurring as well (see section
below on landfill controls).
In addition, after reviewing the information related to the LDR
rulemakings referenced by the commenter, and the analytical data for
the EDC/VCM sludge samples EPA used in the landfill analysis, EPA does
not believe there would be potential risks from groundwater even if all
of the lead leached out of the samples EPA used in the landfill
modeling, therefore the screening analysis performed was quite adequate
to conclude that no significant risks would be posed by the lead in the
EDC/VCM sludges. For further information the reader is referred to the
Response to Comments Document for today's rule.

iii. Landfill Controls

Two commenters questioned why EPA assumed, in its risk assessment
for EDC/VCM sludges managed in landfills, that non-hazardous waste
landfills are covered daily and have runoff and runon controls. The
commenters stated that some states do not require industrial, non-
hazardous waste, landfills to apply daily cover and/or install runon
and runoff control systems. The Agency contacted state agency officials
in states where generators of EDC/VCM wastewater treatment sludges are
located and where landfills identified in the RCRA 3007 questionnaires
as accepting EDC/VCM wastewater treatment sludges are located.
Officials in each state indicated that either industrial landfills are
required to have daily cover and runon/runoff controls, or in the case
of one state, although state regulations do not require these controls,
the controls are generally required and enforced through permits. In
addition, EPA called the owner/operators of each of the landfills
identified in the RCRA 3007 questionnaires as accepting EDC/VCM
wastewater treatment sludges for disposal. In every case, the owner/
operators indicated that daily cover is applied and that the facility
is equipped with runon/runoff controls. In addition, all but one of the
landfills contacted accepts municipal solid waste. Therefore, Federal
and state regulations require these landfills to apply daily cover and
be equipped with runon and runoff controls. In addition, we expect that
state agencies will continue to require these technical standards in
future. Given that all landfills currently accepting EDC/VCM wastewater
treatment sludges currently are applying daily cover and are equipped
with runon/runoff controls and given that state agencies in states
where EDC/VCM sludges currently are generated and managed require these
controls, the Agency concludes that the commenters' concerns are
unfounded.
b. Risk Assessment Exposure Scenarios, Contaminant Fate and Transport
Modeling, Exposure Assessment, and Toxicity Assessment
EPA received comments on several aspects of the landfill and land
treatment unit risk assessments that we conducted to support the EDC/
VCM wastewater treatment sludge listing determination. EPA received two
specific comments concerning the exposure scenarios that we evaluated
in the landfill risk assessment: 1) that we did not evaluate
particulate emissions from landfills, and 2) that we failed to consider
``non-routine'' exposures. EPA also received a comment on the
contaminant fate and transport modeling that was conducted for the
groundwater pathway analysis under the landfill scenario. EPA uses
contaminant fate and transport modeling to estimate the contaminant
concentrations at the receptor's point of exposure. Commenters
contended that we had not correctly evaluated groundwater pathway risk
for the landfill because we assumed that leaching of the landfill did
not begin until after landfill closure. Lastly, we received a general
comment that we believe applies to several aspects of our land
treatment unit risk assessment: the exposure scenarios evaluated, the
contaminant fate and transport modeling, and the exposure and toxicity
assessments. This comment asserted that ``much of the same type of over
conservatism'' present in the risk assessment for the chlorinated
aliphatic wastewaters also was present in the risk assessment for EDC/
VCM sludges managed in a land treatment unit.

i. Particulate Emissions From Landfills

Based upon information provided in responses to the RCRA Sec. 3007
questionnaires, EPA evaluated the risks associated with the management
of EDC/VCM wastewater treatment sludges in unlined municipal landfills
and in a land treatment unit. We determined that releases from
landfills could occur through the release of vapor emissions to the air
and through leaching of the waste into the subsurface. One commenter
was concerned that EPA had not considered the risks due to exposure to
particulate emissions from landfills in which EDC/VCM wastewater
treatment sludges are disposed. The commenter acknowledged that the
Agency did not evaluate particulate emissions because the Agency
assumed that the moisture content of the waste would prevent the
release of particulates. The commenter indicated that the assumption
that sludges would have sufficient moisture content to prevent
particulate emissions was ``not well founded, given possible climate
and wind conditions (for example, location of a landfill in an arid
climate with high wind).''
The Agency disagrees with the commenter. As explained in the
proposed rule (64 FR 46484), data collected by the Agency in support of
the listing determination indicate that the EDC/VCM sludges have a high
moisture content. Samples analyzed by the Agency had moisture contents
of between 41 and 74 percent, which should prevent generation and
release of particulates to the air during the time between placement of
the waste in the landfill and the application of daily cover (or the
application of new waste). Moreover, based on the results of our risk
analyses for the land treatment unit, we do not think that particulate
emissions from landfills, even if they did occur, would present
significant risk. Under the land treatment unit scenario, dioxins were
the only contaminants for which we identified significant risks due to
air releases, and only 8 percent of the dioxin risk was due to particle
phase air releases, while 92 percent of the risk was due to vapor phase
air releases (Table 5-8; USEPA, 1999a). Under the landfill scenario,
the vapor pathway dioxin risk was estimated to be 4E-10 (Appendix
H.3.1,

[[Page 67092]]

Table H.3-1c; USEPA, 1999a). Even though we did not calculate risks
from particle emissions, we expect they would be even less than 4E-10,
based on the relative risks from land treatment units.

ii. ``Non-Routine'' Exposures

One commenter claimed that virtually the entire risk modeling
effort was confined to long-term chronic risk exposures, that is,
primarily indirect exposures offsite of a management facility. The
commenter believed that EPA ignored activities at the waste management
unit itself, and therefore ignored risks to workers and others at the
waste management facilities. The commenter believes EPA also should
consider acute exposure risks through accidents and other ``non-
routine'' waste management conditions. Examples of such conditions
provided by the commenter include high winds (40--60 mph) on dry days,
drought or arid conditions, heavy rainfall, and hurricanes. The
commenter stated that heavy rainfall and hurricane conditions could
cause substantial amounts of dioxin-laden solids to be moved over land
and into streams if the wastes were disposed in an unbermed area. The
commenter expressed concern that during windy and arid conditions,
dioxin-laden particulates may be dispersed from the landfill and beyond
the unit boundaries. The commenter argued that the analysis of non-
routine exposures is appropriate because of the toxicity and
persistence of dioxin relative to other contaminants.
The commenter was concerned that EPA did not evaluate acute
exposure to dioxins under scenarios involving workers, extreme
climatological events, or accidents. EPA agrees that it can be
appropriate to assess acute exposure scenarios or accidents in certain
cases. However, in the case of chlorinated aliphatic sludges, we did
not believe that such scenarios merited explicit analysis because the
sludges, which result from the treatment of wastewaters, do not contain
the very high concentrations of dioxins that we believe would be
necessary to result in estimates of significant acute risk or hazard.
For example, the highest TCDD TEQ concentration reported for dedicated
EDC/VCM wastewater treatment sludges, 0.907 ug TCDD TEQ/kg, is below
EPA's Superfund soil action level of 1 ug TCDD TEQ/kg which was
developed to be protective of direct long term exposure to dioxins in
residential soils and therefore clearly would be protective of shorter
term exposure (OSWER Directive 9200.4-26, April 13, 1998).

iii. Delay of Landfill Leaching Until After Closure

In evaluating releases to groundwater from the landfill used to
manage EDC/VCM sludge, EPA made a simplifying assumption that
contaminant leaching from the landfill does not occur until after the
landfill closes (that is, after 30 years). As we explained in the
proposed rule, we made this assumption because of the complexities
associated with linking the output of our landfill partitioning
equations and our groundwater model, EPACMTP (EPA's Composite Model for
Leachate Migration with Transformation Products). Two of the public
commenters and all three of the peer reviewers questioned the
appropriateness of our assumption, suggesting that it would lead to an
underestimate of risk. One commenter noted that during the period when
the landfill is open and the waste is exposed directly to storm water,
``leachate migration of contaminants is at its highest level.''
In retrospect, we realize that we were not completely clear
concerning how our landfill modeling approach considers the production
of leachate over the life of the landfill. Because of the way our
landfill model is constructed, the application of daily cover and a
final cap only limits the release of air emissions from the landfill,
daily cover and final cap do not limit the production of landfill
leachate. This is because the infiltration rate that we use for the
landfill during its active life is the same as the infiltration rate
that we use for the landfill once it is closed--we assume that the
infiltration through the daily cover and final cap is the same as the
infiltration through the exposed waste. Our basis for assuming that the
cap will not reduce infiltration is that we predict that over the long
term a cap will fail, and will cease to function effectively.
Consequently, the effect of delaying leaching of the landfill until
after closure is only to ``offset'' the arrival of the peak contaminant
concentration at the groundwater receptor well by 30 years. For the
sole contaminant of concern for the landfill, arsenic, the peak arrival
time was estimated to be 8800 years. Reducing this time estimate by 30
years is clearly insignificant.

iv. Overly Conservative Land Treatment Unit Risk Analysis

One commenter maintained that ``much of the same type of over
conservatism'' that was present in the risk assessment for the
chlorinated aliphatic wastewaters also was present in the risk
assessment for EDC/VCM sludges managed in a land treatment unit. The
commenter contended that ``[f]or the same reasons articulated'' for
wastewaters, ``EPA should reevaluate and adjust risk assessment
parameters as necessary before proposing to list such wastes, even
under a land treatment scenario.''
Although the commenter was not specific regarding which aspects of
their comments on the wastewater risk analysis they felt applied to the
Agency's evaluation of EDC/VCM sludges managed under a land treatment
unit scenario, we reviewed the risk assessment comments for wastewaters
to determine which could be relevant to the land treatment unit
analysis. The comments that we focused on are discussed below. Section
VI.B.3 summarizes how the comments influence the proposed risk estimate
for EDC/VCM sludges managed in a land treatment unit.

Cooking and Post-Cooking Losses for Beef

The commenter claimed that the intake rates that EPA used for beef
should have been adjusted downward to account for cooking and post-
cooking weight loss, as recommended in the Exposure Factors Handbook
(USEPA, 1997). As was the case for wastewaters (see section VI.A.2.d.),
EPA agrees that we should have accounted for cooking and post-cooking
losses of beef in our exposure analysis for the land treatment unit.

Assessment of the Toxicity of Dioxins and Furans

In our evaluation of the comments on wastewaters, we disagreed with
the commenter's claim that we should modify the cancer slope factor
that we used for TCDD and that our TEFs represent upper-bound values.
Our responses to these comments are provided in section VI.A.2.e.i.
Although we also disagree with the commenter's assertions that we
should use the IRIS slope factor for HxCDD mixtures in our risk
assessment (see section VI.A.2.e.i.), eliminating the 1,2,3,6,7,8- and
1,2,3,7,8,9-congeners of HxCDD from the land treatment unit risk
analysis completely would have the impact of modifying the high end
risk estimate for the adult farmer only by a factor of 0.97, which
would not significantly change the results of the risk analysis.

EPA Should Have Evaluated Site-Specific Exposure Scenarios

The commenter maintained that EPA should have used a site-specific
approach to assessing risks from

[[Page 67093]]

management of chlorinated aliphatics wastewaters (see section
VI.A.2.b). The commenter suggested that such an approach would
recognize that EPA's assumption that a farmer lives at the same
location within 300 meters of a chlorinated aliphatics facility for
48.3 years, and raises fruits, exposed vegetables, root vegetables,
beef cattle, and dairy cattle within this distance, is unrealistic. In
addition, the commenter challenged the amounts of home-produced beef,
dairy products, vegetables, and fruits that EPA assumed were consumed
by the farmer.
Although the Agency's response to these comments is presented in
our discussion of chlorinated aliphatics wastewaters in section
VI.A.2.b, there are a few additional points that we can make with
regard to the exposure scenario we considered in our evaluation of the
risk associated with management of EDC/VCM wastewater treatment sludges
in a land treatment unit. Although our land treatment unit analysis was
inherently more site-specific than our analysis of wastewaters (since
only one facility uses a land treatment unit to manage EDC/VCM
sludges), we do not believe, for the reasons presented in section
VI.A.2.b.i, that it would have been appropriate to conduct facility-
specific risk analyses for chlorinated aliphatics wastes.
In response to concerns regarding the likelihood that a farmer
would raise fruits and vegetables for home consumption, in addition to
producing beef and dairy products, EPA refers to Table 5-8 of the Risk
Assessment Technical Background Document (USEPA, 1999a) that shows that
only 4 percent of the high end risk for the adult farmer was due to
ingestion of home grown fruits and vegetables. As was the case for
wastewaters, even though EPA believes it is plausible that a
subsistence or hobby farmer would raise fruits and vegetables for home
consumption, the validity of EPA's risk estimate depends almost
entirely on the validity of our assumption that a farmer might consume
both beef and dairy products from cattle raised on a farm located near
a chlorinated aliphatics production facility. While we responded to
this comment in our previous discussion of wastewaters, EPA notes that
even in the specific case of the facility where the existing land
treatment unit is located, there is evidence of the potential close
proximity of grazing cattle. First, the most recently available
agricultural census data (1997) indicate that both beef and dairy
cattle were reported as being raised in the parish in which the land
treatment unit is located. Second, although the potential proximity of
cattle farming operations to chlorinated aliphatics facilities was
confirmed by commenters on the wastewater risk analysis, EPA notes
that, in addition, a land use map depicts the location of the facility
that operates the land treatment unit as adjacent to land described as
cropland and pasture (USEPA, 2000b). In addition, in a 1994 aerial
photograph of the facility (located in the docket for the final rule),
areas adjacent to the facility are depicted as being used for
agriculture. Third, a 1986 RCRA Facility Assessment (RFA) conducted at
the facility at which the land treatment unit is located noted the
following for a landfarm/land treatment area at the facility: ``* * *
the State issued a violation to the facility for allowing cows to graze
in this area.''

EPA Incorrectly Evaluated the Contribution of Feed to Dioxin Levels in
Dairy and Beef

The commenter raised several issues related to how EPA evaluated
the contribution of feed to dioxin levels in dairy and beef. The
Agency's responses to most of these concerns are addressed in section
VI.A.2.c.ii. As was the case for wastewaters, we reviewed our
methodology for estimating the concentrations of dioxins in beef and
dairy products. The dioxins in the beef and dairy products result
primarily from the cattle's intake of forage and soil that are
contaminated by air emissions and runoff/erosion from the modeled land
treatment unit--minor levels of dioxins are contributed to cattle as a
result of the cattle's ingestion of grain or silage (USEPA, 2000b).
Consequently, all that is required for the adult farmer to realize the
risk that EPA presented in the proposed rule is that the farmer consume
beef and dairy products derived from cattle that consume forage and
incidentally ingest soil from the farmer's pastureland/field. That is,
it is not necessary that the farmer consume home-grown fruits and
vegetables, or that the farmer produce grain or silage for use as
cattle feed. As was the case for wastewaters, we felt that we likely
should have considered how the concentrations of dioxins in air vary
over a wider areal extent that would be more consistent with the area
of a pasture where cattle graze. Similar to wastewaters, we calculated
what the impact would be to the risk estimate if we accounted for a
more reasonable pasture/field size (USEPA, 2000b). In addition, in
response to comments from peer reviewers, we also reviewed the method
by which we evaluated risk attributable to the runoff/erosion pathway
to ensure that we appropriately characterized the dioxin concentrations
in feed, thus the concentrations in dairy and beef. In subsequently
evaluating the land treatment unit dioxin mass balance, we determined
that, due to limitations of the available model, we overestimated the
amount of dioxin-contaminated soil lost from the land treatment unit
due to erosion over long durations (USEPA, 2000b). The revised risk
estimate that considers these modifications is presented in section
VI.B.3.

v. Characterization of Arsenic Risk Results

Several commenters were concerned that although EPA found risks
from arsenic that are within its discretionary range for listing EDC/
VCM wastewater treatment sludges, EPA did not include arsenic as a
basis for the listing determination and the contingent management
listing for EDC/VCM wastewater treatment sludges allows this waste to
be managed in landfills despite our risk assessment results for
arsenic.
EPA evaluated potential risks from arsenic resulting from both
landfill management of EDC/VCM wastewater treatment sludges and
management of the waste in a land treatment unit. In the case of the
landfill scenario, risk assessment results showed a high-end risk from
arsenic from a groundwater ingestion exposure pathway, to be 3E-05.
However, this potential risk level is predicted to occur only after a
very significant period of time. Our modeling results indicate that,
after a period of 8,800 years, the disposal of EDC/VCM sludge in an
unlined landfill would result in an increase in the concentration of
arsenic in groundwater in a down gradient well (102 meters from the
landfill) by only 1.4 ug/L and would add approximately 2 ug/day of
arsenic to the average daily exposure level (about 20 ug/day) for the
highly exposed individual.
Given these predicted circumstances, we conclude that the risks
from arsenic for the landfill scenario are not significant for several
reasons. The predicted risks levels are associated with a peak arsenic
concentration in a receptor well that is estimated to occur only after
a very long period of time. In addition, the predicted high-end arsenic
concentration at a receptor well (1.4 ppb) is very close to the median
arsenic background concentration of 1.0 ppb found in groundwater in
Texas and Louisiana.\33\ The predicted high-end

[[Page 67094]]

arsenic concentration also is well below the current maximum
contaminant level (MCL) allowed for arsenic in drinking water and below
the revised MCL for arsenic recently-proposed by EPA's Office of Ground
Water and Drinking Water. The current MCL for arsenic is 50 ppb, the
revised MCL proposed by EPA is 5 ppb (65 FR 38888).
---------------------------------------------------------------------------

\33\ Focazio, M.J., Welch, A.H., Watkins, S.A., Helsel, D.R.,
and Horn, M.A., 1999, A Retrospective Analysis on the Occurrence of
Arsenic in Ground-water Resources of the United States and
Limitations in Drinking-Water-Supply Characterizations: U.S.
Geological Survey Water-Resources Investigation Report 99-4279, 21
p.
---------------------------------------------------------------------------

Given that the estimate of potential risk for arsenic is within the
range of risk levels in which the Agency exercises discretion with
regard to a listing decision (i.e., predicted risk levels are less that
1E-04), the Agency's established policy provides that it may take into
account other factors affecting the potential risk associated with the
waste in making its listing determination. The risk estimate for
arsenic in EDC/VCM wastewater treatment sludges managed in landfills is
the result of predicted concentrations of arsenic that are close to
background levels, do not exceed the MCL in the modeled receptor well,
and the result of a peak arsenic concentration in a receptor well that
is predicted to occur only after a period of 8,800 years. Given that
there are uncertainties associated with our risk estimates we do not
think it makes sense to impose requirements now to address a marginal
risk that may be realized so far in the future. In addition, even if
the arsenic concentrations predicted to occur very far in the future
were to occur now, these concentrations are not at levels of concern,
given that the peak concentration of arsenic in groundwater is
predicted to be below the current (and all recently proposed) MCL(s).
Therefore, EPA concludes that EDC/VCM wastewater treatment sludges do
not pose a significant risk due to the presence of arsenic when managed
in landfills.
In the case of the potential risks associated with arsenic in EDC/
VCM wastewater treatment sludges managed in a land treatment unit, we
found that arsenic may present some risk from potential releases to
groundwater from the land treatment unit. However, we conclude that the
estimated level of potential risk is not significant for the very same
reasons we concluded that the risk from arsenic in a landfill scenario
is not significant (i.e., predicted concentrations of arsenic in
groundwater wells is close to background levels, and is the result of a
peak arsenic concentration in a receptor well that is predicted to
occur only after a long period of time). The Agency concludes that the
risk posed from potential releases of arsenic in this wastestream does
not warrant listing the waste as hazardous. However, in the case of the
land treatment unit scenario, the Agency determined that the waste
should be listed as a hazardous waste based upon the potential risks
associated with dioxin concentrations found in the waste. The Agency
therefore is listing EDC/VCM wastewater treatment sludges based solely
on the presence of dioxin and the potential risk associated with dioxin
when this waste is managed in a land treatment unit.

vi. Regulatory Compliance Demonstration

Two commenters were concerned that the proposed conditional listing
approach for EDC/VCM wastewater treatment sludges would be burdensome
to generators due to commenters' view that the proposal required
generators to document their ``intent'' to properly manage and dispose
of the waste. In response, the Agency notes that we are not imposing
any new paperwork requirements as part of the conditional listing. In
the final listing determination, the Agency is requiring that
generators and other handlers of EDC/VCM wastewater treatment sludges
merely be able to demonstrate that past and on-going waste management
practices are in compliance with the conditions of the contingent
management listing approach. Our intent in describing potential types
of records or contracts that could fulfill the demonstration
requirement was merely to provide examples of appropriate
demonstrations, and not to impose stringent or specific paperwork
requirements. As explained above, the Agency is finalizing, as part of
the listing description, a flexible performance standard similar to the
documentation requirement provided in 40 CFR 261.2(f) for documenting
claims that materials are not solid wastes, when managed in certain
ways. Generators and other handlers of EDC/VCM wastewater treatment
sludge that claim the waste is not a hazardous waste must merely
demonstrate that the generator or handler has handled the waste or
intends to handle the waste in compliance with the conditions of the
conditional listing. One manner in which this demonstration may be made
is by presenting a copy of a signed contract between the generator and
a state-licensed landfill under which the landfill agrees to accept the
EDC/VCM waste. Again, in cases where such a contract does not exist,
other documentation of past and on-going disposal practices such as
signed non-hazardous waste manifests, shipping papers, and/or invoices
may provide an appropriate demonstration of proper management. The
Agency points out that a generator's or handler's ability to
demonstrate recent and/or on-going shipments of EDC/VCM wastewater
treatment sludges to appropriate disposal facilities will serve as
sufficient demonstration of their intent to continue such management
practices for wastes being appropriately stored on-site (i.e., stored
in a manner that does not involve direct placement of the waste on the
land) prior to off-site disposal and not yet offered for off-site
shipment.

vii. Status of EDC/VCM Sludges Managed by Methods Other Than Land
Treatment and Landfilling

Incineration

Several commenters requested that EPA include incineration of EDC/
VCM wastewater treatment sludges as a contingent management option for
this waste. Commenters argued that incineration should be allowed to
occur without the sludge falling within the scope of the listing
description (i.e., commenters requested that EPA allow the incineration
of EDC/VCM wastewater treatment sludges as non-hazardous wastes).
The Agency disagrees with the commenters. First, the Agency notes
that commenters provided no information indicating that incineration of
presently non-hazardous EDC/VCM sludges is occurring and indicated only
that they were considering the practice. Some commenters stated
specifically that they currently do not incinerate presently non-
hazardous EDC/VCM wastewater treatment sludges. Information available
to the Agency during development of the proposed rule indicated that
there were no facilities presently incinerating non-hazardous forms of
the waste, and EPA did not evaluate potential risks from on-site or
off-site incineration of EDC/VCM wastewater treatment sludges in non-
hazardous waste incinerators. EPA bases listing determinations on an
assessment of plausible (and worst-case) management scenarios. It is
not practicable for EPA to evaluate every possible management scenario,
and particularly not those management practices that are found not to
be plausible (or are hypothetical). This is consistent with the
Agency's mandate to evaluate determine whether or not to list wastes,
and not management practices. EPA does carve out particular

[[Page 67095]]

waste management practices in certain circumstances (e.g., here, where
there is a widespread practice we have modeled fully), but we cannot
possibly evaluate every practice, particularly hypothetical practices,
that any commenter says they might employ.
Our policy with regard to hazardous waste listings is that in cases
where we have identified one plausible management practice that
presents a significant risk to human health and the environment (in
this case, land treatment), the waste warrants being listed as a
hazardous waste. However, since the Agency identified another plausible
management approach (landfill), evaluated the risk from this management
approach, and determined that the second management approach does not
present a significant risk to human health and the environment, the
Agency determined that it is appropriate to exclude the waste from the
hazardous waste listing, when managed in this particular manner.
Without evaluating potential risks from additional management
approaches, the Agency cannot determine whether or not the waste, when
managed in a different manner, warrants being excluded from the
hazardous waste listing. Given that EDC/VCM wastewater treatment
sludges currently are not managed in non-hazardous waste incinerators,
we have not used the limited time and resources we have for the
rulemaking to conduct an analysis of potential risks associated with
this potential management practice. Therefore, we do not have a basis
to exclude sludges managed in this manner from the listing description.
Should the Agency receive information in the future indicating that
non-hazardous waste incineration is occurring, the Agency may re-visit
the decision to preclude the management of these sludges in non-
hazardous waste incinerators. However, given that these sludges contain
dioxin, EPA would want to carefully consider the potential risks of
managing these wastes in non-hazardous waste incinerators, before
concluding that this practice does not pose a risk.
The final rule, as promulgated in today's notice, provides that
EDC/VCM wastewater treatment sludges are listed hazardous wastes,
unless the sludges are disposed in a subtitle C landfill or a non-
hazardous waste, state-licensed landfill and are not placed on the land
prior to final disposal in a landfill. Under the conditional listing,
the incineration of EDC/VCM wastewater treatment sludges in a non-
hazardous waste incinerator and the disposal of the ash in a landfill
does not meet the conditions of the listing. EDC/VCM wastewater
treatment sludges destined for incineration are hazardous wastes (i.e.,
are K174).

EDC/VCM Wastewater Treatment Sludges Derived From the Management of
Chlorinated Aliphatic Wastewaters in Surface Impoundments

As mentioned above, at the time of the proposed rule EPA was not
aware that any chlorinated aliphatic production facility was managing
chlorinated aliphatic wastewaters in surface impoundments, or
potentially generating EDC/VCM wastewater treatment sludges in surface
impoundments. However, the Agency received information from public
comments indicating that one chlorinated aliphatic manufacturing
facility produces VCM and sends its process wastewaters to an adjacent
facility, where the VCM wastewater is combined with other non-
chlorinated aliphatic wastewaters for treatment in surface
impoundments. The commenter described the type of treatment occurring
in these impoundments to include biological treatment followed by
clarification; therefore, we presume wastewater treatment sludges are
generated in these impoundments. Because these wastewater treatment
sludges are the result of treating wastewaters from the production of
VCM, they will meet the definition of today's K174 hazardous waste
listing on the effective date of today's rule.
The listing description for EDC/VCM wastewater treatment sludges
finalized in today's rulemaking includes sludges that are placed on the
land prior to final disposal in a landfill. EPA's long-standing policy
under RCRA subtitle C is that wastes generated in surface impoundments
are subject to regulation while actively managed in the impoundment
(not just when the sludges are removed from the unit) (see 45 FR at
72024; 55 FR 39409; 55 FR 46380). Therefore, sludges resulting from
treating wastewaters from the production of EDC/VCM after the effective
date of today's rule, when actively managed in surface impoundments in
which they are generated, fall within the scope of today's listing
determination for EDC/VCM wastewater treatment sludges (K174).
With regard to the regulatory status of surface impoundments used
to treat EDC/VCM wastewaters prior to the effective date of the today's
rule, EPA has articulated in prior rulemakings certain circumstances
where a surface impoundment, in which newly-regulated wastes were
generated prior to the effective date of the listing, would not become
subject to subtitle C management standards (see 55 FR 39410 and 55 FR
46380). In the November 2, 1990 rulemaking finalizing the hazardous
waste listings for F037 and F038, EPA provided that in cases where
wastes become defined as hazardous as a result of new listing
determinations, if the wastes are removed from the impoundment prior to
the effective date of the rule defining them as hazardous, then the
impoundment does not become subject to Subtitle C.
In the Federal Register notice published on September 27, 1990, EPA
clarified the regulatory status of surface impoundments containing
sludges newly defined as hazardous that were deposited in an
impoundment prior to the effective date of the rule defining the waste
as hazardous, and where the impoundment ceased to receive hazardous
wastes on or before the effective date of the rule. In that notice, EPA
stated: If (1) the newly identified hazardous waste remains in the
surface impoundment after the effective date of the rule, and (2) the
impoundment does not receive or generate any other hazardous wastes
after the effective date, and (3) the impoundment is the final disposal
site for the waste, then the impoundment is not subject to RCRA
subtitle C. Additionally, the Agency clarified that if newly-listed
wastes are removed from an impoundment as part of a one-time removal,
including a one-time removal after the date on which the waste becomes
defined as hazardous, the impoundment will not be subject to RCRA
subtitle C. The Agency also clarified in the September 27, 1990
rulemaking that EPA will not view the one-time removal of waste as part
of a closure as changing the status of the surface impoundment (i.e.,
subjecting the impoundment to RCRA subtitle C), as long as there is no
ongoing management of the waste in the impoundment after the effective
date of the hazardous waste listing.
Therefore, if a facility ceases to manage EDC/VCM process
wastewater sludge in surface impoundments prior to the effective date
of today's listing determination, and the facility undertakes a one-
time removal of the newly-listed waste, the surface impoundment will
not be subject to RCRA subtitle C. The sludges removed from an
impoundment as part of a one-time removal after the effective date of
today's listing (that were derived from the previously managed
chlorinated aliphatic wastewaters), will be defined as K174, unless the
waste meets the conditions for exclusion from the hazardous waste
listing. If the sludge does meet these conditions (i.e., it is

[[Page 67096]]

disposed in a subtitle C landfill or a non-hazardous waste landfill
permitted or licensed by a state, and it is not placed on the land
other than in such a landfill after it is removed from the
impoundment), it will be exempt from the listing. After the one-time
removal of sludge generated from the chlorinated aliphatic wastewaters,
and as long as no additional chlorinated aliphatic wastewaters are
managed in the impoundment, sludges generated in the impoundment will
not meet the listing description for K174. In other words, the
impoundment would not become regulated. In addition, sludges removed in
subsequent removals (e.g., as part of routine maintenance activities)
will not be considered EDC/VCM wastewater treatment sludge (K174), as
long as chlorinated aliphatic wastewaters were not managed in the
impoundment after the effective date of the rule.
The above discussion pertains to facilities that choose to continue
operating their surface impoundments as non-hazardous waste units after
the effective date of today's rule. However, a facility could choose to
continue to manage chlorinated aliphatic wastewaters in surface
impoundments after the effective date of today's rule. In this case,
the sludge generated in the impoundments will meet the K174 listing
description and the surface impoundments will become subject to RCRA
subtitle C. Any newly listed EDC/VCM wastewater treatment sludges that
are managed in a newly regulated surface impoundment (i.e., an
impoundment that becomes subject to RCRA regulation as a result of the
new waste listing) may continue to be managed in the impoundment for up
to four years, provided that the impoundment is in compliance with the
groundwater monitoring requirements of 40 CFR part 265, Subpart F
within 12 months after promulgation of the new waste listing (40 CFR
part 268.14).\34\ Surface impoundments also may continue to treat
wastes that do not meet LDR treatment standards if the surface
impoundments are in compliance with 40 CFR 268.4 (the surface
impoundment exemption), or if facilities obtain no-migration variances
for the units (40 CFR 268.6, 264.221(b), 265.221(c)). Under the surface
impoundment exemption, owners or operators must follow specific
sampling and testing, removal, subsequent management, and recordkeeping
requirements. Some impoundments may be granted a delay of closure (see
40 CFR 265.113 and 40 CFR 264.113) and thus will be allowed to remain
in operation, providing that hazardous waste is removed and the
impoundment is used for non-hazardous wastes (see section VIII.B for a
discussion of permitting requirements and compliance dates applicable
to the management of newly-listed wastes). Facilities that currently
manage EDC/VCM wastewater treatment sludges in surface impoundments
must meet the terms of these regulations or discontinue their use for
the management of these sludges prior to the effective date of the
listing and land disposal restrictions.
---------------------------------------------------------------------------

\34\ RCRA Sec. 3005(j)(6) provides that facilities managing
wastes in surface impoundments that are newly brought into the
subtitle C system by a new listing or characteristic have four years
to retrofit or close impoundments receiving newly identified or
listed wastes (and no other hazardous wastes).
---------------------------------------------------------------------------

viii. Contingent Management Approach

A few commenters asserted that a contingent management approach to
listing EDC/VCM wastewater treatment sludges is not appropriate.
Commenters pointed out that such an approach would allow the waste to
be land disposed without treatment in compliance with the land disposal
restrictions requirements. One commenter stated that RCRA does not
provide EPA with the statutory authority to list a waste as hazardous
on the basis of how the waste is or is not managed. Another commenter
stated that the management process should not decide whether a waste is
hazardous or not. The commenter further stated that waste management
practices only should ensure that the waste is properly treated.
Given the Agency's finding (discussed in Section VI.B.1. of this
preamble) that the predominant approach for managing EDC/VCM wastewater
treatment sludges does not pose a substantial hazard to human health
and the environment, we see no reason to include sludges managed in
this manner in the scope of the hazardous waste listing. In fact, the
Agency knows of only two facilities that manage these sludges in a
manner other than landfilling. It does not make sense to list the bulk
of EDC/VCM wastewater treatment sludges managed safely in landfills
based upon the management approaches used by two facilities. On the
other hand, we do not believe that it is appropriate to promulgate a
no-list determination, given the Agency's finding (discussed in Section
VI.B.1. of this preamble) that EDC/VCM sludges pose a substantial
hazard to human health and the environment when managed in a land
treatment unit. Therefore, the Agency is promulgating a contingent
management listing to ensure that EDC/VCM wastewater treatment sludges
are managed only in a manner that EPA has shown does not pose a
substantial hazard to human health and the environment.
Because the Agency has made a finding that the waste does not pose
a substantial hazard to human health and the environment if disposed in
a landfill, without being treated prior to disposal, we do not agree
with commenters' regarding the necessity of imposing treatment
requirements under RCRA subtitle C. Our finding that treatment is not
necessary to insure protection of human health and the environment is a
major factor supporting the contingent management approach. In
addition, the land disposal restrictions apply to hazardous wastes
only. Since the Agency has determined that EDC/VCM wastewater treatment
sludges, when managed in a landfill, are not hazardous wastes, the
treatment standards are not necessary to ensure protection of human
health and the environment.
A contingent management listing approach is within EPA's statutory
authority. Section 3001(a) requires the Administrator to promulgate
criteria for identifying and listing wastes that ``should'' be subject
to the requirements of RCRA. The word ``should'' in section 3001(a)
calls for an exercise of judgment and, therefore, confers discretion
upon EPA to determine whether listing is warranted. RCRA sections 3002,
3003 and 3004 direct the Agency to issue regulations ``necessary to
protect human health and the environment.'' Accordingly, the decision
whether a waste should be regulated under RCRA turns upon EPA's
assessment of whether such regulation is necessary to protect human
health and the environment. Because a hazardous waste is by definition
a solid waste that poses ``a substantial threat to human health and the
environment when improperly treated, stored, transported, or disposed
of, or otherwise managed,'' (RCRA section 1004(5)) EPA concludes that
where a waste might pose a hazard only under limited management
scenarios, and other regulatory programs already address such
scenarios, the Agency is not required to list a waste as hazardous.
The Agency's decision with regard to whether a waste should be
regulated under subtitle C turns upon EPA's assessment of whether RCRA
regulation is necessary to protect human health and the environment. In
particular, in Military Toxics Project v. EPA, 146 F.3d 948 (D.C. Cir.
1998) the court found that, if EPA concludes that a waste might pose a
hazard only under limited management scenarios, EPA can reasonably and
permissibly determine that the waste should be regulated as

[[Page 67097]]

hazardous only under those scenarios. In the Military Toxics Project
case, EPA reasonably determined that waste munitions would not pose a
hazard if managed in accordance with existing military munitions
handling regulations. Similarly, with regard to EDC/VCM wastewater
treatment sludges in today's rulemaking we have reasonably determined
that the waste will not pose a hazard if managed in hazardous waste
landfills or non-hazardous waste landfills licensed or permitted by a
state. We base this conclusion on the results of the Agency's risk
assessment and in view of existing state and federal controls for non-
hazardous waste landfills. We note that the finding by the court in
Military Toxics Project did not hinge upon EPA deferring to a
comprehensive regulatory program, but only to programs that address the
appropriate waste management scenarios in a manner that EPA determined
is necessary to protect health and the environment. Given the results
of the Agency's risk assessment, we find that the management of these
wastes in non-hazardous waste landfills licensed or permitted by a
state is protective of human health and the environment. On the basis
of this conclusion and in light of the Military Toxics Project
decision, we conclude that EPA has the authority to promulgate a
conditional listing for this waste.
3. Rationale for Final Listing Determination: Summary of the Impact of
Public Comments on the Proposed Listing Determination for EDC/VCM
Wastewater Treatment Sludges
The Agency decided to finalize a contingent management listing for
EDC/VCM wastewater treatment sludges based on the EPA's finding that
these wastes posed a substantial hazard to human health and the
environment when managed in a land treatment unit, but did not pose
this hazard when managed in a landfill. As discussed above, commenters
argued that EPA's risk estimates for the landfill and land treatment
unit were in error. After reviewing and carefully considering all
information provided by commenters, we re-evaluated our risk assessment
results. Based on information provided by commenters, we decided it was
appropriate to adjust our proposed risk estimate, 2E-04, for the land
treatment unit. As mentioned above in response to a commenter's
concerns regarding the expected productivity of EPA's modeled
agricultural field, EPA's risk estimate for the land treatment unit
almost entirely was due to a farmer's ingestion of beef and dairy
products from cattle that consume dioxin-contaminated forage and
pasture soil. That is, the risk estimate is 2E-04 even when the portion
of risk associated with cattle consumption of grain and silage are
eliminated. Correcting the risk estimate to account for both cooking
and post-cooking loss of beef and an overestimate of risk attributable
to the erosion pathway analysis would reduce the risk estimate to 1E-
04. Accounting for a more reasonable pasture size would reduce this
risk estimate (1E-04) to approximately 7E-05. Moreover, adjusting the
TCDD slope factor downward as recommended by the commenter, and
removing 1,2,3,6,7,9- and 1,2,3,7,8,9-HxCDD from the risk assessment
completely, would reduce this risk estimate only to 5E-05. Although EPA
does not support making these adjustments to the toxicity values, doing
so demonstrates that accepting the commenter's recommendation would not
reduce the risk estimate to a value that, after consideration of other
factors as described in Section VI.B.1. of this preamble, would change
the Agency's finding that these wastes pose a substantial hazard to
human health and the environment. Our analysis of the comments did not
reveal any justification for modifying our proposed risk estimate for
the landfill scenario.
Therefore, the Agency is listing EDC/VCM wastewater treatment
sludges as EPA Hazardous Waste Number K174, unless the sludges are
managed in a subtitle C landfill, or a non-hazardous waste landfill
permitted or licensed by a state. The Agency believes that allowing the
waste to continue to be managed under a low risk management scenario
(i.e., non-hazardous waste landfilling) outside of the subtitle C
system achieves protection of human health and the environment, and
that little additional benefit would be gained by requiring that all
EDC/VCM wastewater treatment sludges be managed in accordance with RCRA
subtitle C management standards. Given the Agency's finding that the
level of risk posed from managing EDC/VCM wastewater treatment sludges
in a landfill is not at a sufficient level to support a hazardous waste
listing determination, the Agency sees no reason to include sludges
managed in this manner in the scope of the hazardous waste listing.
Additionally (and after consideration of the predicted risk
differential between land treatment and landfilling), because only one
facility employs land treatment for these wastes, this practice is
somewhat anomalous compared with land disposal. It does not make sense
to apply a traditional listing approach (i.e., list all wastes
regardless of management practice) based upon a practice occurring at
one facility, especially if a more tailored listing can prevent
potential risks from the practice.
Under the contingent management listing approach finalized today
for EDC/VCM wastewater treatment sludges, EDC/VCM sludges will be
hazardous wastes unless they are disposed in a landfill. EDC/VCM
wastewater treatment sludges that are handled in compliance with the
contingent management approach will be considered nonhazardous from the
point of generation. Such sludges will not be subject to RCRA subtitle
C management requirements for generation, transport, or disposal
(including the land disposal restrictions), if the waste is destined
for disposal in a landfill and is not placed directly on the land prior
to disposal in a landfill. If the waste is not disposed of in a
subtitle C landfill or a state-licensed non-hazardous waste landfill,
then the waste meets the listing description and must be managed in
compliance with subtitle C management standards from the point of
generation.
In addition to requiring that EDC/VCM wastewater treatment sludges
be disposed in a subtitle C landfill or a state-licensed landfill to
meet the contingent management listing, the Agency also is restricting
the placement of EDC/VCM wastewater treatment sludges directly on the
land prior to disposal in a landfill (e.g., storage in surface
impoundments, storage in waste piles, spills). EPA wants to ensure that
these wastes are managed in the manner found to be protective of human
health and the environment. Under the terms of the listing, storage of
EDC/VCM wastewater treatment sludge in tanks or containers, or in any
manner other than direct placement on the land, prior to disposal will
not constitute a violation of the conditions for exclusion from the
hazardous waste listing.
Generators, and other parties involved in the management of EDC/VCM
wastewater treatment sludges, claiming that their wastes fall outside
the scope of the hazardous waste listing must be able to document or
demonstrate that sludges excluded from the listing description are
being managed in accordance with the conditions for being excluded from
the listing. This means that parties claiming the waste falls outside
the scope of subtitle C must be able to demonstrate that (1) previously
generated and managed waste (which is being claimed as not meeting the
K174 listing) was disposed of in a landfill; and (2) waste currently

[[Page 67098]]

being managed is not being stored, or otherwise managed, on the land
(e.g., waste piles, surface impoundments) as well as demonstrate that
the waste is disposed of in a landfill. We note that the Agency is not
imposing any specific recordkeeping requirements as part of today's
final rule. Instead the Agency is finalizing, as part of the listing
description, a more flexible performance standard similar to the
documentation requirement provided in 40 CFR 261.2(f) for documenting
claims that materials are not solid wastes. Generators and other
handlers of EDC/VCM that claim the waste is not a hazardous waste must
merely demonstrate that the generator or handler has, and continues to
handle the waste in compliance with the contingent management
conditions. One of the simplest ways to make such a demonstration may
be to provide a compliance or enforcement official, upon request, with
a copy of a signed contract with a state-licensed landfill. In cases
where such a contract does not exist, other documentation of past and
on-going disposal practices such as signed non-hazardous waste
manifests, shipping papers, and/or invoices should provide an
appropriate demonstration of proper management. The Agency points out
that a generator's or handler's ability to demonstrate recent and/or
on-going shipments of EDC/VCM wastewater treatment sludges to
appropriate disposal facilities will serve as sufficient demonstration
of intent to continue such management practices for wastes being stored
on-site in tanks or containers (or in any other manner other than
direct placement on the land) and not yet offered for off-site
shipment.
The Agency points out that should EDC/VCM wastewater treatment
sludges meet a listing description for another listed hazardous waste,
or if the wastewater treatment sludges exhibit one or more of the
characteristics of hazardous waste, the sludges must be managed as
hazardous wastes and are not exempt from regulation, due to the fact
that they may be characterized as EDC/VCM wastewater treatment sludge.

C. Wastewater Treatment Sludges and Wastewaters From the Production of
VCM-A

1. Wastewater Treatment Sludges From VCM-A Production
The EPA is listing as hazardous wastewater treatment sludge from
the production of vinyl chloride monomer using mercuric chloride
catalyst in an acetylene-based process (VCM-A). This wastestream meets
the criteria set out at 40 CFR 261.11(a)(3) for listing a waste as
hazardous because it may pose a substantial or potential hazard to
human health or the environment. The Agency identified significant
potential risks to consumers of groundwater due to the release of
mercury from this waste when managed in a landfill. We are not
promulgating the proposed alternative option of conditionally listing
this waste (i.e., listing the waste only if it is not managed in a
subtitle C landfill) because after reviewing comments we remain
convinced that the current management practice of disposing of
untreated forms of this waste in a subtitle C landfill, even after
taking into account landfill controls, can pose significant risk as
explained in more detail below.

K175--Wastewater treatment sludges from the production of vinyl
chloride monomer using mercuric chloride catalyst in an acetylene-
based process.

In the August 25, 1999 Federal Register we proposed to list VCM-A
wastewater treatment sludge due to the potential risk from consuming
groundwater containing concentrations of mercury, arising from the
landfill disposal of the VCM-A sludge, that exceed the Maximum
Contaminant Limit (MCL).\35\ At proposal, we considered risks arising
from both an unlined landfill disposal and a subtitle C landfill
disposal management scenario, because at that time we believed both
scenarios were plausible forms of managing this waste. Under the
unlined landfill scenario, we used the mercury TCLP analytical results
for the VCM-A sludge (0.26 mg/L; facility split sample was 0.654 mg/L)
and calculated a predicted groundwater concentration at a receptor well
using a dilution and attenuation factor (DAF) of 40.\36\ The predicted
receptor well groundwater concentration exceeded the mercury MCL by a
factor of three based on a mercury leachate concentration of 0.26 mg/L
(obtained from a sample of the waste analyzed by EPA), and by a factor
of eight using the mercury leachate concentration from the facility's
split sample of 0.654 mg/L (64 FR at 46510).
---------------------------------------------------------------------------

\35\ The Maximum Contaminant Level Goal (MCLG) for mercury is
0.002 mg/L because EPA has determined that drinking water below this
level of protection would not cause any adverse health effects. The
MCL for mercury is also 0.002 mg/L, and is an enforceable standard
set as close to the MCLG as possible, considering the ability of
public water systems to detect and remove contaminants using
suitable treatment technologies.
\36\ As noted at proposal, the DAF of 40 for mercury was
developed for the 1995 proposed Hazardous Waste Identification Rule
(60 FR 66344, December 21, 1995) for landfill leachate.
---------------------------------------------------------------------------

Under the subtitle C landfill scenario, we took into account
additional information regarding the increased mobility of mercuric
sulfide (the form of mercury in the VCM-A sludge) under higher pH
environments, and the degree to which subtitle C landfill controls
(e.g., liner systems) would have to perform to prevent releases that
exceed the MCL in groundwater at a modeled receptor well (64 FR at
46511). We documented that the pH measured in leachate from the
subtitle C disposal cell where this waste is currently managed is
greater than 9, which is in all likelihood due to the presence in the
landfill of alkaline materials commonly used to stabilize many types of
hazardous wastes. We also cited analytical results from a draft
treatability study on the VCM-A waste, indicating that mercuric sulfide
is less stable in a higher pH environment, and that the leachate
resulting from a constant pH leach test at pH=10 contained 1.63 mg/L of
mercury. We concluded that mercury in the VCM-A waste would be
significantly mobilized under the conditions found in the subtitle C
landfill scenario, and at proposal we said that ``* * * even assuming a
low probability of [liner] failure * * * there may still be a release
of mercury that results in an accedence of the MCL. While there are
uncertainties in this assessment, it still illustrates that the mercury
concentrations in the receptor well may be close to, and could even be
higher than the MCL'' (64 FR 46511). In other words, with a leachate
concentration of 1.63 mg/L at pH=10 and a DAF of 40, the modeled
receptor well mercury concentration is 0.041 mg/L when no credit is
given to the liner system (i.e., assuming an unlined landfill).
Assuming that no mercury is released to groundwater if a liner system
is 100% effective, one only has to reduce the ``effectiveness'' of the
subtitle C liner system by a small margin, to 95%, to predict a mercury
concentration in a modeled receptor well equal to the MCL for
mercury.\37\ The issue of the uncertainty with engineered liner systems
is discussed in more detail further below.
---------------------------------------------------------------------------

\37\ (0.05)(0.041 mg/L) = 0.002 mg/L
---------------------------------------------------------------------------

Therefore, we presented at proposal two plausible management
scenarios upon which we based our proposed listing, an unlined landfill
and a subtitle C landfill. As discussed below in section VI.C.1.a,
because we received information after proposal indicating that the
unlined landfill scenario was not plausible, our final decision today
to list the VCM-A sludge as hazardous is based only upon the subtitle C
landfill scenario described above.

[[Page 67099]]

a. Response to Major Comments Received on Proposed Rule for VCM-A
Wastewater Treatment Sludges
VCM-A sludge is generated by only one facility in the United
States, Borden Chemical and Plastics (BCP) in Geismar, Louisiana;
therefore, the industry comments relating directly to this waste stream
were from BCP. Environmental groups and waste treatment industry
representatives also commented on the EPA's proposal to list this
wastestream as hazardous.

i. Risk Assessment Submitted by BCP

In response to the Agency's proposed decision to list wastewater
treatment sludges from the production of VCM-A, BCP provided the Agency
with a groundwater pathway exposure and risk analysis for mercury in
VCM-A wastewater treatment sludges managed in landfills, conducted by a
contractor on their behalf. BCP concludes, based upon their risk
assessment, that there would be no human health risks to consumers of
groundwater resulting from releases of mercury from VCM-A waste managed
in a landfill.
BCP's analysis was designed to parallel the manner in which EPA
conducts contaminant fate and transport modeling when evaluating
landfills. Specifically, BCP stated that its ``methods and assumptions
followed to the extent possible those presented in [EPA's] Chlorinated
Aliphatics Risk Assessment document when feasible.'' However, rather
than using EPA's groundwater fate and transport model, EPACMTP, BCP's
analysis used a simpler analytical groundwater transport model, AT123D.
This model is not specifically designed to simulate leachate migration
from land disposal units; although, when used appropriately, AT123D
should be able to produce results that are protective and comparable to
those obtained with EPACMTP. However, after carefully reviewing the
risk assessment submitted by BCP, EPA found that there are significant
deficiencies associated with certain aspects of the modeling and risk
assessment and therefore is not persuaded by the conclusions drawn from
BCP's analysis. These deficiencies are described below:

EPA's most significant concern regarding the way in
which BCP conducted its groundwater modeling is that BCP limited the
period of time that the contaminant plume is allowed to migrate to
70 years from the time mercury was introduced into the groundwater.
BCP's assumption has the effect of considering only exposure and
hazard to current receptors and ignores potential hazard to future
generations. In fact, in the case of release of leachate from a
landfill, the greatest risk is often to future generations. This is
because wastes initially are accumulated in landfills for many years
prior to landfill closure, then, subsequent to landfill closure,
leachate generation and migration in groundwater can occur for
additional tens, hundreds, or thousands of years.
EPA disagrees with the way that BCP considered the area
of the landfill in its modeling efforts. Although the area of the
waste management unit is not input directly into the AT123D model
employed by BCP, the model does require an equivalent source length
and width. In its analysis, BCP modeled an areal source with an area
of one meter by one meter, and a depth (thickness) of 6 meters. The
analysis submitted by BCP does not provide the area of the actual
landfill in which the VCM-A sludge is disposed, but a source area
equal to 1 m2 does not represent a realistic landfill
size, since industrial landfills are typically on the order of
50,000 to 100,000 m2. Moreover, a landfill of the size
modeled by BCP (6m3) would not be large enough to contain
the quantity of sludge that we estimate BCP generates in 1 year,
109m3), let alone the quantity we estimate BCP might
generate over a 30 year period (3,273m3).
In its AT123D modeling efforts, BCP assumed an aquifer
hydraulic conductivity of 1E-04 centimeters per second (cm/s). The
median hydraulic conductivity value that we would have selected to
correspond to the location of the landfill where BCP disposes of
their waste is 8E-03 cm/s.\38\ In the context of BCP's analysis, it
does not appear that the hydraulic conductivity value used was
protective. On the contrary, BCP's conclusion that: ``* * * in the
70-year time span evaluated, mercury would move no further than
between approximately 37-46 meters * * *.'' was supported in part
through use of a hydraulic conductivity value that was 80 times less
than the median hydraulic conductivity value that EPA would have
selected, potentially resulting in an underestimate of the predicted
groundwater flow rate. This could result in a significant
underestimation of predicted contaminant migration.
---------------------------------------------------------------------------

\38\ The source of our hydraulic conductivity data is a database
prepared by the American Petroleum Institute (Newell, Charles J.,
Loren P. Hopkins, and Philip B. Bedient, 1989. Hydrogeologic
Database for Ground Water Modeling. API Publication No. 4476,
American Petroleum Institute, Washington, D.C.). The range of values
from which the median is derived is 1E-05 to 4E-01 cm/s.
---------------------------------------------------------------------------

The value BCP used for the parameter that defines the
dispersion of the contaminant plume (the dispersivity) was
unrealistically large for the transport distances that BCP
evaluated. Dispersion causes a contaminant plume to spread both
ahead of the bulk flow of groundwater (longitudinally) and
perpendicular to the bulk flow of groundwater (transversely and
vertically). The effect of dispersion is to cause the leading edge
of the plume to travel more rapidly and spread more widely than the
bulk (average) groundwater flow. Dispersion also will cause the
plume to become more diluted due to mixing with ambient
(uncontaminated) groundwater. This dilution effect will be most
pronounced at the periphery of the plume. BCP's methodology for
estimating dispersivity was based on designating where the
concentration value for the plume will be measured (that is, the
location of the receptor well) and calculating an appropriate
dispersivity value for that location, since dispersivity increases
with distance from the source. Accordingly, BCP calculated
dispersivity values corresponding to the location of a receptor well
152 meters from the landfill source. EPA acknowledges that this
approach is consistent with generally accepted practices, and does
not disagree with the approach in principle; that is, the
dispersivity values used in BCP's modeling would have been
appropriate to characterize the effect of hydrodynamic dispersion on
plume concentrations at the location of the designated receptor well
(152m from the source). BCP's error occurred when they elected to
use the modeled concentration at a distance of 37m (the predicted
leading edge of the contaminant plume) as the basis for their
calculation of mercury hazard. BCP did not modify their estimate of
plume dispersion to correspond to a closer distance to the source.
By not correctly accounting for distance from the source, BCP's
groundwater modeling analysis significantly overestimated the effect
of dispersion at the edge of the plume, and the resulting dilution
of the plume due to dispersive mixing. Consequently, the mercury
concentration (and associated hazard) that BCP predicted to
correspond to the edge of the plume was much lower than it would
have been had they accurately estimated dispersion. More
appropriately, BCP should have extended their modeling timeframe, as
discussed above, such that they could have more accurately predicted
contaminant concentrations at their designated receptor well
distance.

BCP concluded from their analysis that essentially no migration of
mercury would occur in groundwater, and that mercury concentrations in
groundwater are below levels of concern. Because BCP limited their
analysis to the evaluation of current receptors, potentially
underestimated the hydraulic conductivity of the aquifer, overestimated
aquifer dispersivity, and grossly underestimated the area of the
landfill, EPA does not believe BCP's risk analysis can be used to
support a listing decision for VCM-A sludge.

ii. Plausibility of Unlined Landfill Management Scenario

In the proposed rule, EPA stated that disposal of Borden's VCM-A
sludge in a non-hazardous, unlined landfill was plausible, based upon
gaps in the record, particularly prior to 1990. BCP commented that in
all of the time it had responsibility for the operation of the VCM-A
plant (which records indicate is since the early 1980's) Borden always
managed its VCM-A sludge at a facility that was ``constructed and
operated in

[[Page 67100]]

accordance with the hazardous waste regulations that existed at the
time of disposal.'' Upon consideration of BCP's claim that the specific
inventory of VCM-A waste, cited by EPA as having been stored on site in
1985, was in fact disposed of as hazardous waste between March and May
of 1985, there is no evidence the waste has ever been disposed of in an
unlined, non-hazardous landfill. Moreover, given BCP's record of
disposal of this waste in a hazardous waste landfill during the 1990's,
and its comments that this is where BCP will continue to send the waste
in the future, we see no compelling information to suggest the company
would do otherwise. Accordingly, we agree that disposal in an unlined
landfill is not plausible.

iii. Constant pH Leach Results Versus TCLP

BCP took issue with our overall approach to determining that the
VCM-A waste poses significant risk when mismanaged. Specifically, BCP
disagreed with EPA's assertion that the VCM-A waste, which is in the
form of mercuric sulfide, leaches mercury more readily at higher pH
conditions. In particular, BCP criticized our reliance on the results
of a preliminary EPA-sponsored study \39\ indicating (using only one
sample) a leachate concentration for mercury at 1.63 mg/L at pH=10, and
that the pH conditions of the landfill cell where this waste is
presently disposed indicate an elevated pH as well (pH=9.48 to 9.7 as
reportedly measured in the leachate collected from this landfill cell).
Furthermore, BCP questioned our application of these analytical results
to the circumstances surrounding the disposal of the VCM-A waste. BCP
also argued that it appears that because we stated in the proposed rule
that the TCLP may not be a reliable indicator of mercury mobility under
these conditions, that EPA has ``invalidated its own regulatory
procedures for this particular [waste] stream'' by relying on the
waste-specific pH results discussed above, instead of relying on the
existing TCLP method for defining whether or not the VCM-A sludge is
hazardous. BCP was concerned that EPA's reliance on a waste-specific
approach to determining the hazard of the VCM-A waste, rather than
relying instead on the existing toxicity characteristic to determine
hazardousness, was an ``unconventional method to single out this
particular waste stream'' and was therefore arbitrary and capricious.
BCP is arguing that it is inappropriate for EPA to assess the hazard of
mercury in a waste when there is already an existing toxicity
characteristic for mercury, and that by doing so for one specific waste
EPA is selectively ``changing the rules'' for that waste.
---------------------------------------------------------------------------

\39\ Paul Bishop, Renee A. Rauche, Linda A. Rieser, Markram T.
Suidan, and Jain Zhang; ``Stabilization and Testing of Mercury
Containing Wastes,'' Draft, Department of Civil and Environmental
Engineering, University of Cincinnati, March 31, 1999.
---------------------------------------------------------------------------

EPA disagrees with BCP's comment that EPA should rely on the
existing TCLP, and that doing otherwise unfairly or inappropriately
singles out its waste. First, because EPA has undertaken a listing
determination for a certain category of wastes (chlorinated aliphatic
wastewater treatment sludges), and has further identified VCM-A sludge
as a reasonable subcategory due to the markedly different manufacturing
process from which the waste is generated, it is entirely reasonable
for us to assess the hazards of this specific waste in the context of
this listing determination. The fact that only one facility in the
United States currently is generating the waste in this subcategory is
irrelevant to the sound technical conclusion that it merits separate
consideration. Second, in making a specific listing determination EPA
is not limited to looking only at whether the waste is hazardous under
the existing characteristics approach to defining hazardous waste.
While the listing criteria in 40 CFR 261.11(a)(3)(i) do require EPA to
consider whether a waste is characteristically hazardous, there are
other criteria in Sec. 261.11(a)(3) that the EPA also addresses in
making listing determinations, which include a determination as to
whether the waste poses significant risk based on a waste-specific
evaluation.
Additionally, the toxicity characteristic regulation is a
regulation of general applicability; that is, it potentially applies to
all non-exempt solid waste generated. The TCLP leaching test was
designed to represent likely leaching potential of waste in an MSW
landfill, which was considered plausible worst-case management
conditions for industrial solid waste generally. BCP's comments
expressed concern that the Agency is singling this waste out for
assessment under an approach different (and more stringent) than that
applied to other wastes or to evaluation of solid waste under the TC
regulation. The Agency is considering the pH dependency of mercury
sulfide solubility, and considering other data on this key waste
constituent, including both the changes in likely leachability under
conditions different from the TCLP test but matching those of the
landfill where the waste is actually disposed. In doing so, the Agency
is not singling this waste out for more stringent assessment. Rather,
the Agency is attempting to more fully consider all the scientific data
on the waste, its constituents, and its actual management conditions,
and applying these data in an assessment of the likely risks from the
waste as it is actually managed. The whole point of a listing
determination is to decide, on a wastestream-specific basis, whether
the existing characteristics adequately address risks from the waste.
Regarding BCP's comment questioning the results from the EPA/ORD
study on mercury mobility, while BCP claims to not necessarily dispute
the results, it pointed out that the results were from a preliminary
study that had not yet been peer reviewed, and that any decision EPA
makes should be based upon peer-reviewed, final analytical reports with
all QA/QC data available. BCP also commented that it attempted to
duplicate the extraction of the VCM-A waste at varying pH (6, 8, and
10) but found very little difference in the resultant mercury leachate
concentration, and all results were below the TCLP limit of 0.2 mg/L.
BCP points out that contradicting results cast doubt on EPA's
conclusions that mercury is more mobile at elevated pH when in the
mercuric sulfide state.
EPA continues to believe that available evidence supports the
conclusion that the solubility of mercuric sulfide increases with
increasing pH, and that this conclusion is supported by scientific
literature cited in the proposed rule \40\ as well as additional
scientific literature and EPA calculations presented below. A recently
published study on mercury speciation in the presence of polysulfides
agrees with our finding that there is an increase in the solubility of
cinnabar (mercury sulfide) in the presence of elemental sulfur,
particularly at high pH.\41\ This same study also indicated that at a
pH of 10, mercury can solubilize from mercuric sulfide at
concentrations very similar to what was reported in the draft EPA/ORD
study. EPA performed additional calculations using the geochemical
assessment model MINTEQA2. We calculated the solubility of mercuric

[[Page 67101]]

sulfide using conditions reported for the VCM-A waste (e.g., pH
reported for subtitle C landfill leachate where waste is disposed,
sulfide concentration of VCM-A waste) and found the calculated mercury
solubility agreed well with the mercury concentration data for the
landfill leachate (originally included in the docket to the proposed
rule). This further supports our assertion that sulfide and pH are
controlling factors in the solubility of mercuric sulfide, and that
this conclusion reasonably can be applied to the VCM-A waste as
well.\42\ Therefore, while we did indicate at proposal that the EPA/ORD
study was preliminary, we believed it was important to present these
results as evidence because they represented direct studies on the
instant waste being evaluated for listing. EPA has received no specific
information in comment that effectively contradicts this evidence, and
has identified specific information in the scientific literature that
supports it.
---------------------------------------------------------------------------

\40\ H. Lawrence Clever, Susan A. Johnson, and M. Elizabeth
Derrick, The Solubility of Mercury and Some Sparingly Soluble
Mercury Salts in Water and Aqueous Electrolyte Solutions, J. Phys.
Chem. Ref. Data, Vol. 14, No. 3, 1985, page 652.
\41\ Jenny Ayla Jay, Francois M. M. Morel, and Harold F. Hemond,
Mercury Speciation in the Presence of Polysulfides, Environmental
Science and Technology, 2000, Vol. 34, No. 11, pages 2196-2200.
\42\ Memorandum from John Austin to Ross Elliott, May 12, 2000.
---------------------------------------------------------------------------

Regarding the results from BCP's own leach testing experiment,
which BCP claims did not show a strong correlation between pH and
mercury solubility, BCP stated that it had attempted to replicate EPA's
study ``in the absence of any information regarding how the EPA
contractor samples were extracted.'' \43\ While EPA does not have any
information on BCP's experiment (other than a summary of the findings)
to explain why there might be differences between Borden's results and
those from the EPA study, EPA's results are consistent with literature
sources regarding the relationship between pH and mercury solubility
from the mercuric sulfide form; therefore EPA does not agree that BCP's
results indicate that EPA's conclusions are invalid.\44\ Again, even
absent the draft EPA/ORD study, the effect of pH on the solubility of
mercury in mercuric sulfide is established independently in the
scientific literature, as discussed above.
---------------------------------------------------------------------------

\43\ EPA notes that there was a summary description of the
constant pH leaching procedure in Section 4.4 of the draft EPA
report, which was part of the proposed regulatory docket.
\44\ EPA also points to data in the proposed rule record from
BCP's analysis of their mercuric sulfide sludge at three different
pH values, which were all above the current TCLP limit and did vary
with pH. See Appendix 1, Reclassification Petition Submitted to
LDEQ, September 1987.
---------------------------------------------------------------------------

iv. Liner Effectiveness

EPA requested comment on the basis for listing as hazardous the
VCM-A waste that is presently being disposed in a lined subtitle C
landfill. BCP stated that EPA's reliance on some degree of liner
failure as part of predicting the release of mercury to groundwater
from a subtitle C landfill amounts to a ``repudiation of existing
standards for * * * landfill management of hazardous waste.'' BCP
argues that EPA's statement that there is ``inherent uncertainty''
associated with liner integrity in a subtitle C landfill is no greater
with respect to its VCM-A waste than it is for any other waste
currently disposed in C landfills. BCP continues by making numerous
arguments that subtitle C liner systems are designed to be compatible
with the wastes being disposed, and that the regulatory requirements
applicable to these systems (e.g., groundwater monitoring, leak
detection, leachate collection, post-closure care and maintenance,
etc.) are all designed to ensure system integrity in both the short-
and long-term.
EPA has acknowledged the uncertainty associated with liner systems
in the past. Taking this uncertainty into account when evaluating the
potential risk from this specific waste stream is in no way a
repudiation of EPA's reliance on liner systems overall. Indeed, the
premise of the statutory land disposal restrictions requirements--one
of the core features of RCRA--is precisely that liners and other
containment systems, no matter how well designed, are inherently
uncertain and cannot be relied upon alone to fully mitigate threats
posed by hazardous wastes. In general, we believe releases from
landfills are significantly reduced by well-constructed, monitored, and
maintained liner and cap systems. However, we recognize that there is
still uncertainty associated with liner performance, both in the near
term as well as in the long term. While some studies indicate that
engineering properties of liners may last for many (perhaps several
hundred) years, there are a variety of factors that may influence
longevity and performance, such as poor construction, installation, or
geologic movement below the liner that can cause holes, tears, or
larger failures. Some defects are likely to have little to moderate
effect on the leakage rate. Other defects may have a significant effect
and may necessitate corrective action (64 FR at 31582).
We are only considering this uncertainty to the extent that, as
discussed previously in section VI.C.1, even if a liner system is
capable of preventing 95% of releases over the long-term, the waste
likely will present substantial risk to consumers of groundwater due to
a release of mercury from the landfill unit (i.e., exceedance of the
MCL). We are not saying we believe that liners will necessarily fail.
What we are saying is that given the specific evaluation we have made
of the VCM-A waste, a liner system can be 95% effective and we still
would predict a release to groundwater that potentially poses risk
(exceedance of the mercury MCL at a modeled receptor well). We think
that over the long term such a change in effectiveness is sufficiently
plausible to merit consideration in this listing decision. We emphasize
that this assessment is specific to a waste containing a highly toxic,
very persistent constituent coupled with the possibility of a small
degree of liner degradation, and does not mean that EPA would choose to
list any wastes voluntarily put into a subtitle C landfill.
Despite the uncertainty noted above on predicting how well liners
will perform over periods of say, 100, 1000, or 10,000 years, and the
fact that the oldest subtitle C units are less than 30 years old, EPA
is nevertheless obligated in this listing determination to make a
judgment whether waste disposed of in these units ``is capable of
posing a substantial present or potential hazard to human health and
the environment.'' Given that landfill controls would have to be 95%
effective forever to prevent substantial risks from this highly
concentrated, toxic, and persistent waste, EPA concludes that the waste
is capable of posing a substantial hazard. While EPA cannot say how
effective these units will be over the long term, we believe it is
plausible that at least some will not be 95% effective forever. The
alternative course would be for EPA to conclude the waste is not
capable of posing a substantial hazard, by concluding that a Subtitle C
landfill will most likely be 95% effective forever. But, we conclude
that that is an unreasonable and unsupportable conclusion and are
acting upon what seems like the more reasonable conclusion under the
circumstances.
EPA also points out that under RCRA, the subtitle C management
standards provide that hazardous wastes that are land disposed must be
treated to reduce the risk of hazardous constituents being released to
the environment as well as be disposed in landfills equipped with
liners and leak detection. The existing standards for the safe
management of hazardous wastes rest on more than the landfill
management requirements, or liner integrity. The legislative history to
RCRA 3004(m) states that this section of the statute ``makes
Congressional intent clear that land disposal without prior treatment
of these wastes with significant concentrations of highly persistent,
bioaccumulative constituents

[[Page 67102]]

is not protective of human health and the environment.'' (130 Cong.
Rec. S 9178; daily ed. July 25, 1984). Mercury is exactly the type of
``highly persistent, bioaccumulative constituent'' to which Congress
was directing this statutory mandate.

v. pH Conditions of Disposal Environment

BCP questioned EPA's conclusions that the disposal conditions at
the subtitle C landfill cell where the VCM-A waste is presently
disposed are at elevated pH levels, based upon the recorded pH
measurements EPA obtained for the leachate collected from this same
cell. BCP also cited several factors that it stated led to the
conclusion that the VCM-A waste will not be subjected to elevated pH
conditions when disposed in the subtitle C cell where it currently is
sent. BCP described several factors that would limit the influence of
other co-disposed wastes on the VCM-A waste (and thus, BCP appears to
be saying, reduce the likelihood of the VCM-A waste being subject to
elevated pH conditions). BCP points out that the volume of the VCM-A
waste disposed in the cell since 1985, which is relatively minor,
compared with the large volume of other hazardous wastes in the
disposal cell, the supposed absence of free liquids in a subtitle C
landfill, the lower pH and resultant buffering capacity of the VCM-A
waste, and the fairly solid nature of the VCM-A waste, all reduce the
influence that other co-disposed wastes may have on the potential for
mercury to leach from the disposed VCM-A sludge.
EPA disagrees that these factors would change the conclusion that
is drawn from the measured elevated pH of the leachate removed from
this landfill cell. In addition to the leachate pH measurements cited
in the proposed rule for the same cell where BCP's VCM-A sludge is
disposed, additional information from the landfill facility confirms
these leachate pH measurements are consistent with the nature of the
landfill leachate for this facility.\45\ In fact, to the extent that
these factors affect the pH of the landfill environment, we believe it
is reasonable to conclude that the measured leachate pH provided by the
landfill operator reflects the sum total of these various factors.
Borden's comments give us no reason to believe that the leachate
collected from this cell is not indicative of elevated pH conditions
within the unit. We thus conclude that BCP's waste, while in the same
disposal cell and coming into contact with leachate, would be exposed
to the type of alkaline conditions that result in higher mercury
mobility when in the sulfide form.
---------------------------------------------------------------------------

\45\ See Memorandum from Ross Elliott, U.S. EPA Office of Solid
Waste, to RCRA Docket, ``Summary of Phone Call Between EPA and Carl
Carlsson, Chemical Waste Management Inc.,'' July 12, 2000.
---------------------------------------------------------------------------

vi. Other Comments

BCP commented that should EPA decide to list the VCM-A waste as
hazardous, we should select the alternative option proposed which would
result in the VCM-A waste only being listed if sent anywhere other than
to a subtitle C landfill (and provided the waste does not exhibit the
toxicity characteristic for mercury). EPA proposed this alternative
option in the event that we received comment persuading us that our
assumptions were incorrect regarding mercury being more mobile in the
presence of sulfides in a higher pH environment, or that our assessment
of liner uncertainty is insufficient to predict a risk to consumers of
groundwater. As discussed above, EPA remains convinced that mercuric
sulfide is less stable under the elevated pH conditions of disposal in
a subtitle C landfill, and that a liner system can be 95% effective and
we still would predict a release to groundwater that potentially poses
risk.
BCP also requested that should EPA proceed with a decision to list
the VCM-A waste as hazardous, that we re-phrase the K175 listing
description so it only applies to mercuric sulfide forms of sludge. The
commenter said that this was so future technologies could be developed
that are ``better'' and the sludge would no longer meet the listing if
these changes are employed. Aside from suggesting that the reference to
mercuric sulfide be removed, the commenter did not provide any specific
potential changes that might occur, or how these changes would make the
wastewater treatment sludge significantly different or less risky. The
listing description proposed refers to the manufacturing process that
uses mercuric chloride catalyst, and the commenter did not suggest
changing that part of the listing; therefore EPA concludes that the
commenter would still be faced with a wastewater treatment sludge
containing very high levels of total mercury (to comply with regulatory
limits on the amount of mercury in the discharged wastewater). Absent
any specific examples, EPA can think of one possible change that could
result in a sludge that could pose a greater potential risk. It is
possible that the facility could continue to use the mercuric chloride
catalysts (as is currently the case for the acetylene-based process),
but alter the wastewater treatment process to produce a mercuric oxide
sludge, in order to make the sludge more amenable to retorting for
mercury recovery. Sludge from such a process might pose a greater risk,
because the mercury would be more soluble than the current sulfide. We
believe that the current listing description is appropriate, because it
appropriately describes the waste subject to our evaluation.
b. Summary
In conclusion, EPA is listing as hazardous the VCM-A wastewater
treatment sludge described above because this wastestream meets the
criteria set out at 40 CFR 261.11(a)(3) for listing a waste as
hazardous. Our analysis that showed potential risk to consumers of
groundwater due to a predicted exceedance of the MCL takes into account
the toxicity and concentration of mercury in the waste (criteria at 40
CFR 261.11(a)(3)(i) and (ii)). This is because the mercury MCL is based
upon toxic human health effects from ingestion of mercury, and because
the high mercury concentration in the waste results in the predicted
MCL at the modeled receptor well. We also determined that the potential
of mercury to migrate from the waste into the environment under a
plausible disposal scenario (criteria at 40 CFR 261.11(a)(3)(iii) and
(vii)) and mercury's persistence and lack of degradation into non-
harmful constituents (criteria at 40 CFR 261.11(a)(3)(iv) and (v)) also
supported a decision to list this waste. This is because there is
increased solubility of mercury in this waste at the elevated pH
conditions in the landfill cell where the waste is disposed, and only a
relatively small degradation of liner performance results in
unacceptable risk to potential groundwater consumers. In addition,
mercury is a persistent contaminant and therefore will not degrade
before any predicted impact to groundwater occurs.
Listing criteria that the EPA considered but which did not form the
basis for listing this waste include the ability of mercury to
bioaccumulate in ecosystems, the nature and severity of human health or
environmental damage from improper management of these wastes, and
actions taken by other governmental agencies or regulatory programs.
(40 CFR 261.11(a)(3)(vi), (ix), and (x)). Bioaccumulation of mercury is
not relevant to the exposure pathway EPA assessed (ingestion of
groundwater). Although no documented damage incidents were found for
this particular waste, EPA believes that on balance this fact alone
does not

[[Page 67103]]

persuade us to make a finding that this waste should not be listed,
when weighed against the other criteria described in this section that
support a decision to list this wastestream. No governmental or
regulatory actions \46\ were identified that would lead EPA to decide
to list this waste or conclude that waste was already sufficiently
controlled to render further regulation moot.
---------------------------------------------------------------------------

\46\ Although we noted at proposal that the facility had
obtained a ``reclassification'' of the waste as non-hazardous from
the State of Louisiana, this determination did not appear to be a
blanket exemption from hazardous waste requirements, for example,
should a process change result in a waste that fails the toxicity
characteristic for mercury, the waste would have to be handled as
hazardous waste).
---------------------------------------------------------------------------

Finally, EPA did consider certain ``other factors as may be
appropriate'' together with the quantities of this waste generated
(criteria at 40 CFR 261.11(a)(3)(xi) and (viii)) in a ``weight-of-
evidence'' approach to reach a decision to list this waste as
hazardous. As discussed in the Land Disposal Restrictions section of
today's preamble (section VI.I.3), EPA believes that this waste can be
disposed in a manner that helps ensure the mercury is more stable and
less likely to leach. Because this waste is already being sent to a
hazardous waste landfill, one important effect of today's listing is
the assurance that the waste is properly treated (or otherwise meets
specific standards as generated) and is disposed in a manner to reduce
the likelihood of mercury releases to groundwater, releases that may
result in unacceptable risk to consumers of groundwater. Given the
reported amount of this waste generated per year (120 metric tons), and
the high total concentration of mercury in the waste (approximately one
percent mercury by weight), the total loading to the landfill is
approximately one metric ton of mercury per year. Ensuring that this
amount of mercury is disposed of in a form that minimizes releases of
mercury was considered by EPA when making its final listing decision.
2. Wastewaters From VCM-A Production
a. Summary of Agency's Listing Determination for VCM-A Wastewaters
The EPA is not listing as hazardous wastewaters generated from the
production of vinyl chloride monomer using mercuric chloride catalyst
in an acetylene-based process (VCM-A). This wastestream does not meet
the criteria set out at 40 CFR 261.11(a)(3) for listing a waste as
hazardous, for the reasons described below.
b. Discussion of Agency's Listing Determination
As discussed above, only one facility in the United States operates
an acetylene-based VCM production process, which uses mercuric chloride
catalysts in the production of VCM. The management of spent mercuric
chloride catalyst used in the VCM-A production process results in the
generation of a wastewater containing mercuric chloride, as well as
vinyl chloride. EPA proposed not to list this wastewater due to the
fact that the wastewater already is identified as hazardous waste. As
explained in the preamble to the proposed rule, the wastewater exhibits
the toxicity characteristic for mercury and vinyl chloride. EPA
received only one comment addressing the Agency's proposed decision not
to list VCM-A wastewaters. This comment favored EPA's proposed
decision.
The Agency bases its decision not to list VCM-A wastewaters as
hazardous on the fact that the wastewaters already are identified as
hazardous wastes under the toxicity characteristic. In fact, the
concentration of mercury in a sample of this wastestream analyzed by
EPA was over 40 times above the TC regulatory limit for mercury.
Therefore, it is highly probable that the wastewater routinely contains
levels of mercury which cause this wastestream to be defined
consistently as characteristically hazardous waste. Therefore, EPA
concludes that the TC adequately defines this wastestream as hazardous.
Additionally, the facility's dedicated wastewater treatment system
is designed and optimized expressly for the removal of mercury, the
source of which is the mercuric chloride catalysts, to comply with
regulations promulgated under the Clean Water Act. The criteria in 40
CFR 261.11(a)(3) for evaluating whether or not a solid waste is a
hazardous waste provide that EPA should consider how the waste (and
potential risk) is affected by other regulatory programs (i.e.,
261.11(a)(3)(x)). In the case of the VCM-A wastewaters, EPA notes that
the Agency's decision not to list this wastewater as hazardous is based
on the fact that the waste already is defined as a hazardous waste
because it exhibits the toxicity characteristic and the potential risks
posed by the wastestream are regulated both under RCRA and other
programs. With respect to the discharge of the wastewater, the facility
treats and discharges the wastewater in compliance with the conditions
of a NPDES permit issued under the authority of the Clean Water Act.
Regarding any air emissions of vinyl chloride from these wastewaters,
vinyl chloride is a hazardous air pollutant; therefore the facility is
subject to the National Emissions Standards for Hazardous Air
Pollutants (NESHAP) requirements specific to vinyl chloride emissions
(40 CFR 61.65), as well as the Hazardous Organic NESHAP for the
synthetic and organic chemical manufacturing industry sector (40 CFR
Part 63, subpart G)(59 FR 19468, April 22, 1994).
Given that this waste currently is regulated as hazardous because
it exhibits the TC and given the fact that management of the
wastestream is adequately regulated under a number of environmental
regulatory programs, the Agency is promulgating a decision not to list
VCM-A wastewaters as hazardous waste.

D. Wastewater Treatment Sludges from the Production of Methyl Chloride

1. Summary of Agency's Listing Determination for Methyl Chloride
Wastewater Treatment Sludges
EPA is not listing as hazardous sludges from the treatment of
wastewaters generated from methyl chloride production processes. The
Agency has determined that this wastestream does not meet the criteria
set out at 40 CFR 261.11(a)(3) for listing a waste as hazardous.
2. Discussion of Agency's Listing Determination
Only one facility generates a non-hazardous wastewater treatment
sludge from the production of methyl chloride. The facility generates
less than 800 metric tons of the sludge annually and disposes of the
sludge in an on-site landfill. As discussed in the preamble to proposed
rule (64 FR 46516), EPA conducted a risk assessment of this waste,
modeling one management scenario (the on-site landfill). The Agency's
analysis of potential risks due to volatile emissions from the landfill
found negligible risks (i.e., estimated risks less than 1E-6) to
individuals in the surrounding area. The Agency also conducted a
bounding (i.e., worst case) risk analysis to estimate potential risks
to groundwater consumers. This analysis used the leachate concentration
measured from a sample of the facility's methyl chloride wastewater
treatment sludge, and assumed the direct ingestion of this leachate by
an adult for a period of 58 years. This bounding analysis resulted in a
risk of 5E-5 for one constituent, arsenic. This estimate of individual
risk, together with additional factors described below in

[[Page 67104]]

EPA's response to specific comments, led the Agency to conclude that
this waste did not pose a substantial risk to human health and the
environment.
3. Response to Major Comments Received on the Proposed Listing
Determination for Methyl Chloride Wastewater Treatment Sludges
Two commenters questioned why the Agency proposed not to list the
wastewater treatment sludges from methyl chloride production as
hazardous, given that the individual cancer risk level from arsenic,
via the groundwater pathway, is within the range of risk values that
EPA generally associates with potential candidacy for listing the waste
as hazardous. The commenters argued that EPA should not ignore the
potential risks from the arsenic in the wastewater treatment sludges
and should list the waste as hazardous.
EPA did not ignore the potential risk from arsenic. The estimated
risk described by the commenter was the result of the Agency conducting
a bounding analysis using worst case assumptions. Given that the
Agency's assumptions were very conservative (i.e., an adult receptor
would drink leachate generated from the disposal of the methyl chloride
wastewater treatment sludges for 58 years), and taking into account
additional factors described below, the Agency determined that there is
no substantial hazard to human health and the environment on which to
base a decision to list the waste as hazardous.
As described in more detail in Section VI.B.1. of this preamble,
EPA's policy for listing wastes as hazardous (originally outlined in
the in 1994 Dyes and Pigments proposal, 59 FR 66077) is that
wastestreams with risks in the range of 1E-6 to 1E-4 may be either
listed or not listed after taking into account additional factors.
Generally, our benchmark level for listing is the middle of the range
(1E-05), but, as described in the preamble to the Dyes and Pigments
proposal, we use a ``weight of evidence'' approach that considers other
factors. In the case of our listing determination for methyl chloride
wastewater treatment sludges, these additional factors include the
conservative assumptions that resulted in the groundwater risk estimate
for arsenic, along with additional information available to the Agency
regarding the manner in which the waste is currently managed (i.e., in
a landfill). We also evaluated our risk assessment results in
conjunction with additional information available to the Agency with
regard to the constituent of concern (i.e., arsenic).
If the Agency assumes a less direct pathway of ingestion (i.e.,
taking into account some dilution and attenuation expected with a
landfill scenario, so that a person drinks groundwater contaminated
with leachate, rather than the leachate directly), and applying a DAF
of 5 (which would be a reasonable assumption for an unlined landfill),
the predicted risk becomes 1E-5. However, the Agency also notes that
assuming a DAF of 5 (as was described in the proposed rule) is likely
too conservative, given that the landfill in which the methyl chloride
sludge is disposed has a 24-inch clay liner and a leachate collection
system. Therefore, the actual risk from arsenic in this waste will be
much lower than the risk level predicted by the bounding analysis,
given that the landfill currently used by the single facility
generating this waste is lined and has a leachate collection system.
To further illustrate why assuming a DAF of 5 would be a very
conservative assumption, in our assessment of risk from the EDC/VCM
wastewater treatment sludge presented elsewhere in today's rule,
arsenic was an initial constituent of potential concern. To support our
analysis of potential groundwater risks from the landfilling of EDC/VCM
wastewater treatment sludges, we modeled arsenic releases and obtained
estimates of DAFs for arsenic (assuming an unlined landfill) of 13 for
the high-end risk estimate, and a DAF of 93 for the central tendency
estimate. Thus, even if the Agency does not take into account the liner
and leachate collection system in the one landfill where currently non-
hazardous methyl chloride sludge is managed, applying reasonable
estimates of DAFs lowers the estimated risk to the lower end of the
range of risks where the Agency may or may not list a waste; and upon
consideration of the very conservative approach used in generating the
arsenic risk estimate, the Agency concludes that the potential risk
associated with arsenic in the waste is well below the range in which
the Agency would deem the waste to pose a substantial hazard to human
health and the environment. Therefore, EPA is finalizing a no list
determination for wastewater treatment sludges from the production of
methyl chloride.

E. Wastewater Treatment Sludges From the Production of Allyl Chloride

1. Summary of Agency's Listing Determination for Allyl Chloride
Wastewater Treatment Sludges
EPA is not listing as hazardous waste sludges from the treatment of
wastewaters generated from allyl chloride production processes. The
Agency has determined that this wastestream does not meet the criteria
set out at 40 CFR 261.11(a)(3) for listing a waste as hazardous. The
Agency identified no risks of concern associated with the current
management of this waste.
2. Discussion of Agency's Listing Determination
As discussed in the proposal, currently non-hazardous wastewater
treatment sludges from allyl chloride production are generated at a
single facility. The sludges are generated from the facility's
centralized wastewater treatment system in which the facility manages
wastewaters from multiple production processes and facilities.
Wastewaters from the production of allyl chloride contribute less than
two percent to the system's total sludge loading. According to the RCRA
Section 3007 survey response from the one facility generating a non-
hazardous allyl chloride sludge, the sludge generated from the
facility's wastewater treatment system is incinerated on site in a non-
hazardous waste incinerator.
As described in the proposed rule, during the investigations
undertaken in support of the listing determinations EPA collected one
sample of sludge from the facility's combined wastewater treatment
system. Two duplicate TCLP analyses were performed using the sample
collected. The TCLP analyses indicated the presence of no TCLP
constituents above regulatory levels. The sample also was analyzed for
total constituent concentrations including arsenic and dioxins and
furans. The total arsenic concentration in the waste was 11.7 mg/kg,
and the total dioxin (TEQ/TCDD) concentration was 11.79 ng/kg.
The Agency did not assess risks by modeling management practices
and exposure pathways, since both the total arsenic level and the total
dioxin level detected in the sludge are below levels of concern and
well within the range of background levels of those constituents

[[Page 67105]]

in soils.\47\ \48\ In addition, the waste is generated by a single
facility and currently is not managed in a manner other than non-
hazardous waste incineration.
---------------------------------------------------------------------------

\47\ Alkhatib, Eid, and O'Connor, Timothy, ``Background Levels
of Priority Pollutant Metals in Soil, American Environmental
Laboratory, Vol. 10, No. 3, April, 1998.
Hunter, Philip M., ``Air-Force Wide Background Concentrations of
Inorganics Occurring in Ground Water and Soil,'' Proceedings from
the Fourteenth Annual Waste Testing and Quality Assurance Symposium,
Pp. 73-77, 1998.
Welch, Alan H., Lico, Michael S., and Hughes, Jennifer L.,
``Arsenic in Ground Water of the Western United States,'' Ground
Water, Vol. 26, No. 3, May/June, 1988.
\48\ See Table 4-4 of ``Risk Assessment Technical Background
Document for the Chlorinated Aliphatics Listing Determination,''
EPA, June 25, 1999a.
---------------------------------------------------------------------------

Given that wastewater treatment sludges from allyl chloride
production are generated by a single facility, that the sludge
generated is the product of a facility-wide non-dedicated (i.e., not
process-specific) wastewater treatment system, and that the waste
contains no constituents of concern at concentrations of concern, the
Agency concludes that no significant risks are posed by the waste. The
Agency is finalizing a determination not to list this waste as
hazardous.
3. Response to Major Comments Received on the Proposed Listing
Determination for Allyl Chloride Wastewater Treatment Sludges
One commenter questioned whether EPA had considered the fact that
the one facility generating wastewater treatment sludges from the
production of allyl chloride may manage this waste in a manner other
than on-site combustion in the future. The commenter suggested that EPA
should have conducted a risk analysis of managing the waste both in a
non-hazardous waste incinerator and in an unlined landfill.
Given that the one facility generating this waste is managing the
waste in an on-site incinerator and that the Agency has no information
indicating that the facility has or intends to manage the waste in a
manner other than on-site incineration, we believe that landfill
management is not plausible for this wastestream. In the case of a
waste that is generated by a single facility, we would not project a
change in management practices without information or cause. EPA
evaluated information provided by the facility regarding current
management practices to project plausible scenarios. The Agency
concluded that the facility has sufficient on-site capacity to continue
to treat the waste in its non-hazardous waste incinerator. The total
arsenic and total dioxin concentrations in the waste are below levels
of concern.
A commenter suggested that the analytical work performed on the
wastewater treatment sludge generated from allyl chloride production
was inadequate, given that only one sample of the sludge was collected
and analyzed by EPA.
The commenter did not provide any specific information as to why
the allyl chloride sample collected by EPA was inadequate, other than
it was one sample. As noted in Table 2-10 of the Listing Background
Document (USEPA, 1999c), the Agency sampled 100% of the facilities
producing allyl chloride, that is, EPA visited and sampled the one
facility that produces this chlorinated aliphatic chemical. As
discussed above and in the proposed rule, EPA is not listing this
facility's allyl chloride wastewater treatment sludge because the
chlorinated aliphatic production process at this facility contributes
less than two percent of the total wastewater volume to the wastewater
treatment process from which the sludges are generated. Given that
there is only one generator of this waste and that the wastewaters from
the allyl chloride production process contribute a relatively small
portion to the facility's wastewater treatment system, EPA believes
that our data, though perceived as limited by the commenter, is
adequate to support the listing determination.

F. What is the Status of Landfill Leachate Derived-From Newly-Listed
K175?

At the time of the proposed rule, information available to EPA
indicated that wastewater treatment sludges from the production of VCM-
A may have been managed previously in non-hazardous waste landfills. If
these sludges had been managed in non-hazardous waste landfills, and if
the leachate and gas condensate generated at such landfills is actively
managed after the effective date of today's rule, the landfill leachate
and gas condensate derived from the newly-listed VCM-A waste in such
landfills could be classified as K175. As explained in the preamble to
the proposed rule and in the final rule for leachate derived from
newly-listed petroleum wastes (64 FR 6806), in such circumstances, we
would be concerned about the potential disruption in current leachate
management that could occur, and the possibility of redundant
regulation (under RCRA and CWA) due to the application of the
``derived-from'' rule to the leachate. In the case of non-hazardous
waste landfills receiving newly-listing hazardous wastes prior to the
effective date of the listing decision, the leachate that is collected
and managed from the landfills would be classified as hazardous, due to
the application of the waste code for the newly-listed K175 to the
leachate. As noted by a commenter in response to proposed petroleum
listing determination, this could lead to vastly increased treatment
and disposal costs without necessarily any environmental benefit.
In the chlorinated aliphatics proposed listing determination, EPA
requested comment on whether or not VCM-A wastewater treatment sludges
were previously disposed in non-hazardous waste landfills. Information
provided to the Agency by the one generator of this waste indicates
that this waste was not previously managed in non-hazardous waste
landfills. The generator stated that they have always disposed of the
VCM-A sludge in a subtitle C landfill. Since EPA has no evidence that
this waste has been disposed of in non-hazardous waste landfills, the
Agency sees no reason at this time to finalize the proposed temporary
deferral for landfill leachate and gas condensate derived from newly-
listed VCM-A wastes. Therefore, today EPA is not finalizing the
proposed temporary deferral for landfill leachate as was proposed.
Although the Agency is not finalizing the proposed temporary
deferral for applying the new K175 waste code to leachate from non-
hazardous waste landfills that previously accepted K175, should the
Agency, in the future, receive information indicating that one or more
non-hazardous waste landfills did accept this waste prior to the
effective date of today's rulemaking, we may re-consider our decision
not to finalize the proposed deferral. The Agency notes that the
proposed regulatory language for the temporary deferral, as published
in the August 25, 1999 Federal Register, inadvertently included both
the K174 and K175 waste codes. The regulatory language in the proposal
only should have included the K175 waste code. Given that the Agency is
finalizing the conditional listing approach for K174 (and thus EDC/VCM
sludge disposed in a licensed landfill will not be listed hazardous
waste) there is no reason to include (nor did EPA intend to include at
proposal) the K174 waste code in the temporary deferral for the
application of waste codes to leachate from non-hazardous waste
landfills that previously accepted newly-listed wastes (40 CFR
261.4(b)(15)).

[[Page 67106]]

G. Population Risks

As discussed previously, our proposed and final listing
determinations were based upon estimates of individual risk. For the
EDC/VCM wastewater treatment sludges, the projected population risks
are low. We relied on individual risk estimates (excess lifetime cancer
risk), and not population risk estimates, because we are concerned
about risks to individuals who are exposed to releases of hazardous
constituents. EPA concludes that, under certain waste management
practices, these wastes are capable of posing a substantial present or
potential hazard to human health or the environment. We have determined
that using individual risk as a basis for this listing determination,
which is consistent with past practices, also is appropriate because
the Agency must protect against potential, as well as present hazards
that may arise due to the generation and management of particular
wastestreams. EPA acknowledges that in cases where small populations
are exposed to particular wastes and waste management practices,
population risk estimates may be very small. EPA finds it is important
to address the current or potential substantial hazards to individuals
living in small communities. Where individuals may be subject to
substantial risks, EPA finds that such individuals deserve protection.
In promulgating the final listing determinations for EDC/VCM and VCM-A
wastewater treatment sludges, it is the increased risk for currently or
potentially exposed individuals, regardless of how few individuals are
exposed, against which EPA is reasonably protecting.
In the proposed rule, in addition to presenting the results of our
risk assessments estimating individual risks, we also discussed the
potential risk posed to populations from the management of chlorinated
aliphatic wastewaters managed in tanks, and EDC/VCM sludges managed in
land treatment units and landfills. We requested comment on whether or
not it is appropriate to give weight to population risk in making our
final listing determinations. We also invited comment on the effect of
such an approach with respect to the Agency's environmental justice
goals, including our goal of protecting human health in rural areas.
In response to the proposal, we received comments both supporting
the use of population risk estimates in making listing determinations,
and comments against this approach. Several commenters stated that the
population risks estimated by EPA do not justify a decision to list as
hazardous the wastes proposed for listing (chlorinated aliphatic
wastewaters, EDC/VCM wastewater treatment sludges, VCM-A wastewater
treatment sludges). Commenters argued that consideration of the risks
posed by the management of these wastes to the entire population
potentially exposed would lead to the conclusion that these residuals
do not pose substantial hazards to human health. Therefore, the wastes
should not be listed as hazardous. Commenters argued that EPA's failure
to give serious consideration to the low levels of population risk is
at odds with the RCRA statute, the listing criteria, and regulatory
precedent within the federal government. Some commenters claimed that,
due to the low population risk estimates, EPA cannot conclude that any
of the residuals ``is capable of posing a substantial present or
potential hazard to human health or the environment,'' as required in
40 CFR 261.11, and therefore EPA should not list any of the residuals.
In response, EPA notes that the use of ``population risk'' is not
explicitly required nor prohibited in either the RCRA statute or the
hazardous waste listing criteria in 40 CFR 261.11. EPA does not believe
it is appropriate to allow contamination from waste management units to
potentially cause substantial hazards to nearby residents simply
because there are few individuals or wells in the immediate area. As
stated above, our decision to list EDC/VCM and VCM-A wastewater
treatment sludges is based on our concern about the present and
potential hazards to those individuals who may be significantly
exposed, even if there are few of them. In addition, the regulations
clearly state that wastes are to be listed as hazardous, if they are
``capable of posing a substantial present or potential hazard''
(emphasis added). Therefore, it is the Agency's past and current view
that as a policy matter, the Agency considers the threats to
individuals, whether they exist today or in the future. EPA's
discretion to base its hazardous waste listing decisions upon
substantial risks to individuals, even if risk to the overall
population is low or near zero, recently was upheld by the U.S. Court
of Appeals for the District of Columbia Circuit in American Petroleum
Institute, et al. v. EPA (No. 94-1683).
Specific comments received in response to the proposed rule
included several commenters who argued that the legal standard in the
RCRA statute for whether a waste is hazardous--that is, that the waste
poses a ``substantial present or potential hazard to human health or
the environment''--cannot be met unless EPA establishes that a large
number of people are likely to have increased cancer risk due to
exposure to the hazardous constituents in the waste, i.e., the so-
called ``population risk'' is high. We disagree with these commenters.
EPA concludes in this listing (and has concluded in previous listings)
that even if relatively few people may be subject to substantial
hazards, those individuals still deserve protection. Accordingly,
consistent with our past practice, we have based the EDC/VCM hazardous
waste listing determination on the substantial hazard to currently or
potentially exposed individuals, rather than on the increased number of
cancer cases in the population at-large. The D.C. Circuit Court in
American Petroleum Institute, et al., v. EPA upheld EPA's practice in a
previous listing decision to base the decision on its concern for
substantial risks to individuals.
EPA points out that the use of the word ``substantial'' in the RCRA
statute (i.e., ``* * * substantial present or potential hazard * * *'')
need not be restricted to a quantitative meaning or applied exclusively
to population risk. In the case of the wastes being listed as hazardous
wastes today, we have determined that risks to individuals are
``substantial.'' The estimated increased risk of cancer for the exposed
individual is greater than 1 in 100,000. Consistent with EPA policy
(see 59 FR 66072, at 66077), wastestreams for which the calculated
high-end individual cancer risk level is 1 in 100,000 or higher
generally are considered initial candidates for a listing decision.
Wastestreams for which these risks are calculated to be 1 in 10,000 or
higher will generally be listed as hazardous waste, although even for
some of these wastestreams, there can be in some cases factors which
could mitigate the high hazard presumption. Listing determinations for
wastestreams with calculated high-end individual lifetime cancer risks
falling into the range of 1 in 10,000 and 1 in 1,000,000 are also
potentially listable but always involve an assessment of additional
factors.\49\ For specific discussion of how EPA

[[Page 67107]]

addressed these factors for EDC/VCM sludge see Section VI.B.1. of
today's preamble.
---------------------------------------------------------------------------

\49\ ``The Superfund program has always designed its remedies to
be protective of all individuals * * * that may be exposed at a
site.'' 55 F.R. 8666, 8710 (Mar. 8, 1990). EPA's Superfund
regulations at 40 C.F.R. Sec. 300.430(e)(2)(i)(A)(2) establish
remediation goals at levels that represent an excess upper bound
lifetime cancer risk to an individual cancer risk to an individual
at between 10-4 and 10-6.
---------------------------------------------------------------------------

In addition to comments arguing the legality of basing hazardous
waste listing decisions on estimated risks to individuals, rather than
population risks, we received comments claiming that the individual
risk approach used by EPA was ``overly conservative and unrealistic.''
These commenters stated that EPA needs to use population risk estimates
as a ``reality check'' on individual risk estimates. Two commenters
also said that we should use individual central tendency risk estimates
as a more meaningful or realistic estimate of potential risk.
EPA disagrees with commenters' assertions that the highly-exposed
individual risk approach used in the risk assessment supporting today's
listing determinations was overly conservative and unrealistic. In
today's notice, as well as in the Response to Comment Document
accompanying today's rule, we address specific comments regarding the
risk assessment. Even though our listing decisions in today's rule are
based upon predicted risks to highly-exposed individuals, we believe
that these risks are within the distribution of risks that could
reasonably be expected to exist in the population. In support of this
conclusion, we note that as part of the analyses to support the notice
of proposed rulemaking, we also conducted probabilistic modeling to
more directly evaluate the anticipated distribution of risk levels. The
high end deterministic risk estimate for the adult farmer under the
EDC/VCM land treatment unit scenario fell at the 95th percentile of the
probabilistic distribution. EPA's Guidance For Risk Characterization
(USEPA, 1995) states: ``Conceptually, high end exposure means exposure
above about the 90th percentile of the population distribution, but not
higher than the individual in the population who has the highest
exposure.''
One commenter cited a 1987 study of 13 regulatory determinations
where low population risk was cited as a reason not to regulate, and
noted that the study suggests that EPA should not establish regulatory
controls on the management of wastes, if the population burden is less
than one cancer in 100 years.\50\ The commenter described where the
individual risk levels in the proposed chlorinated aliphatics listings
fell in comparison to the individual risk levels in these other
regulatory decisions.
---------------------------------------------------------------------------

\50\ Travis, Curtis C., 1987. Environment Science and
Technology, Vol. 21, No. 5.
---------------------------------------------------------------------------

EPA does not find this study leads it to change today's listing
decisions. As already noted, the Agency has the discretion to base its
listing decisions on the substantial hazard to highly exposed
individuals, even if there is only a small number of them, as upheld by
the U.S. Court of Appeals for the D.C. Circuit in American Petroleum
Institute v. EPA. The study itself, however, has a number of flaws
which lead EPA to reject its use. It deals with no RCRA decisions, but
instead deals with a number of other statutes that have different
mandates. This study also is outdated in that it was conducted a number
of years ago when Agency risk assessment was less sophisticated than it
is now. In particular, the study notes that at the time federal
agencies overestimated risk assuming maximum exposures. Since issuance
of EPA's 1992 ``Guidance on Risk Characterization for Risk Managers and
Risk Assessors,\51\ EPA has modified its risk assessment approach to
determine a plausible high-end exposure analysis, which is intended not
to overestimate risks to highly exposed individuals. Moreover, EPA's
current guidance acknowledges that in situations where small
populations are exposed ``individual risk estimates will usually be a
more meaningful parameter for decision-makers.'' \52\
---------------------------------------------------------------------------

\51\ 1992 Memorandum from the then Deputy Administrator F. Henry
Habicht, ``Guidance on Risk Characterization for Risk Managers and
Risk Assessors.''
\52\ 1995 Guidance for Risk Characterization (section III.C.2),
page 17.
---------------------------------------------------------------------------

The study merely presents a listing of decisions made by various
federal agencies under different statutory requirements. It does not
suggest any rationale for the regulatory decisions other than the fact
that they occurred. It seems to suggest that, because we decided
against specific regulations in the past that coincided with a
particular individual risk level (e.g., 1 x 10-4) and low
numbers of cancer cases avoided, we are somehow obligated to make that
same decision now. The commenter does not offer any other rationale for
determining at what point the number of cancer cases avoided would
support an Agency decision to list a waste as hazardous.
For several additional reasons, EPA disagrees with the suggestion
that the Agency base today's listing decisions on total population risk
or total number of cancer cases. In the first place and as previously
noted, we believe we should not ignore substantial risks to
individuals, if that might consign individuals to substantial risks,
simply because only a few individuals potentially will be exposed. In
addition, risk estimates alone do not dictate any particular listing
decision. Even if EPA finds an individual risk of 1 x 10-5
or greater, for example, the Agency considers other factors and may
decide to list or not list a waste as hazardous, based upon the
consideration of all relevant factors. In finalizing today's listing
determinations, the Agency is basing its decisions on the listing
policy described in the December, 1994 proposed listing determination
for dyes and pigment industry wastes (59 FR 66072). Furthermore, the
Agency does not think that it is adequate to base a hazardous waste
listing determination upon a comparison of potential risks posed by
wastes covered by one rulemaking relative to risks posed by other
wastes and potentially unrelated rulemakings. The Agency considers
relevant factors particular to a waste and the plausible management
practices affected when making each regulatory decision. As we have
discussed thoroughly in this preamble and in the accompanied background
documents, in this case we think the individual risk estimates and our
consideration of other factors provide an adequate justification for
listing both EDC/VCM and VCM-A wastewater treatment sludges as
hazardous wastes.
Other comments received by the Agency include comments that stated
that society does not have unlimited resources to address risks unless
they are ``clearly substantial,'' as indicated by population risk. We
point out however that the regulations state that EPA may list a waste
if it is ``capable'' of posing a hazard and the underlying RCRA
statutory language states that hazardous wastes are those that ``may *
* * pose'' a hazard. Thus, the Agency disagrees that risks must be
``clearly'' substantial to be subject to RCRA regulation. Further, EPA
disagrees that ``clearly substantial'' risk (or even a risk that
``may'' occur) must be indicated by a high population risk estimate.
The statutory standard for listing a waste is ``substantial hazard.''
Where EPA finds that a waste poses a substantial hazard to highly
exposed individuals, EPA will list the waste to protect those
individuals potentially exposed.
Other commenters supported the Agency's use of individual risk
estimates as the appropriate criteria for making hazardous waste
listing determinations. For example, one commenter said that EPA should
weigh individual risk more than population risk because the commenter
believes there is greater uncertainty in population risk estimates than
in

[[Page 67108]]

individual risk estimates. No information was provided by the commenter
as to why this would necessarily be the case. EPA agrees with the
commenter that individual risk is an appropriate decision parameter,
for the reasons already stated above.
Another commenter who supports the use of individual risk over
population risk, argued that EPA is not compelled by governing
regulation or statue to define ``substantial hazard'' in terms of
population risk. The commenter also stated that EPA should take into
account risks to populations from more than just the industry under
study, since populations are potentially impacted by risks from many
different facilities. For example, in parts of the country concerns
have been raised previously about certain minority and poor populations
bearing a disproportionate amount of risk for a variety of industries
and wastes.
We agree that we are not compelled by governing regulation or
statue to define ``hazard'' in terms of population risk. We may define
``hazard'' on the basis of substantial risk to individuals even when
population risk estimates are low. Although population risk is one of
many factors that has been considered in some Agency decisions, there
are numerous precedents where the Agency has taken action, for example
at Superfund sites and in previous listing determinations, when there
are relatively few people potentially affected. Superfund is a
particularly apt example since it, like RCRA, deals with protecting
human health and the environment from harm arising from the
mismanagement of waste. The D.C. Circuit Court particularly noted the
consistency with Superfund in American Petroleum Institute et al., v.
EPA described above. While a different statute, the Agency has stated
that the key objective of the CERCLA National Contingency Plan (NCP) is
to protect individuals at contaminated sites (see 55 FR at 8710), and
rejected using population risk as the point of departure for setting
clean-up levels (see 55 FR at 8718). In addition, the CERCLA
regulations (see 300.430(e)(2)(I)(A)(2), and 55 FR at 8848) direct EPA
to establish preliminary remediation goals for carcinogens based on
``cancer risks to an individual.''
The Agency disagrees with the commenter's claim that potential
risks from other industries should be estimated or accounted for in
estimating potential risks from a particular wastestream generated by
one specific industry. The benefits of this listing are the risks
avoided from management of the newly-listed wastes. The Agency has no
reason to factor in risks from other industrial wastes, unless a
synergetic effect can be identified, which the commenter does not
claim.
The Agency is committed to addressing environmental justice
concerns and does consider risks to minority and disadvantaged
populations in its decision making. Our goal is to ensure that no
segment of the population bears a disproportionally high risk as a
result of our decision making. The hazardous waste listing
determinations promulgated today are based upon analyses conducted with
a goal of protecting all potentially exposed individuals. No segment of
the overall population will be placed at a disadvantage as a result of
today's rulemaking.
Finally, the Agency is also concerned that land use patterns can
change over time. For example, when evaluating a waste that adversely
impacts groundwater, the Agency also is concerned about the potential
contamination of future drinking water supplies, and of groundwater
which may have other uses (e.g., livestock watering, irrigation,
aquaculture). If regulatory decisions were based solely on population
risks at a particular point in time, beneficial uses could be precluded
or, if the future users were unaware of the contamination, unacceptable
risks could occur. This same objective, the protection of reasonably
anticipated land use is an integral part of the Agency's Superfund
remedy selection process.\53\ Under Superfund, it is not sufficient
only to consider potential risks to populations surrounding a
particular site at the time of contamination or remediation; reasonably
anticipated future land use patterns and future populations (i.e.,
future receptors) are considered in risk assessments supporting remedy
decision making and in selecting the final remedy.\54\ In fact, the
extensive experience with the Superfund program bears out these
concerns. There are Superfund sites, for example, where residential
developments were placed over former landfills that have turned out to
be dangerous to the new populations, leading not only to risks to the
population but expensive and time-consuming cleanups.
---------------------------------------------------------------------------

\53\ Memorandum EPA Regional Waste Management Division Directors
from Elliott P. Laws, ``Land Use in the CERCLA Remedy Selection
Process,'' OSWER Directive No. 9355.7-04.
\54\ See ``Risk Assessment Guidance for Superfund (RAGs), Volume
I--Human Health Evaluation Manual, Part A,'' (Chapter 6), 1989.
---------------------------------------------------------------------------

H. Which Constituents Are Being Added to Appendix VIII to 40 CFR Part
261?

1. Summary of Agency's Decision To Add Two Constitutents to Appendix
VIII
Two of the constituents of concern that are present in the EDC/VCM
wastewater treatment sludges (K174) that will be designated as listed
hazardous wastes as a result of today's rule do not currently appear on
the list of hazardous constituents at 40 CFR part 261, Appendix VIII.
Therefore, EPA is adding these two constituents, octachlorodibenzo-p-
dioxin (OCDD) and octachlorodibenzofuran (OCDF), to Appendix VIII.
2. Discussion of Agency's Decision To Add Constituents to Appendix VIII
OCDD and OCDF are members of the large family of polychlorinated
dioxins and furans. Certain of these compounds, most notably, 2,3,7,8 -
TCDD, have been shown to be toxic. The Agency found substantial hazard
associated with the presence of dioxins in EDC/VCM wastewater treatment
sludges, when these sludges are managed in land treatment units. In our
risk assessment, dioxin/furan risk was reported on a TCDD TEQ basis. As
previously discussed in today's final rule, as well as in the proposal,
TCDD TEQ concentrations are calculated by multiplying each 2,3,7,8
substituted congener by the appropriate TEF, and then summing the
resultant concentrations to come up with a TCDD TEQ value. OCDD and
OCDF are included in this calculation.
Several studies, as noted in the response to comments below, show
that OCDD and OCDF have toxic effects on life forms. Therefore, we have
concluded, based upon the results presented in these scientific
studies, that OCDD and OCDF should be added to Appendix VIII of 40 CFR
part 261.
3. Response to Major Comments Addressing Agency's Decision To Add
Constituents to Appendix VIII
One commenter opposed the addition of OCDD and OCDF to Appendix
VIII of 40 CFR part 261 on the basis that OCDD and OCDF contribute very
little to the actual risk attributable to dioxin compounds. The
commenter also contended that the assignment of non-zero TEFs to OCDD
and OCDF cannot form the basis for a regulatory decision to list the
compounds as hazardous constituents, since TEFs are intended only to be
used as a tool to aid risk managers in thinking about potential health
risks associated with the compounds. The commenter argued that

[[Page 67109]]

TEFs are not intended to provide a scientific basis for drawing the
conclusion that OCDD or OCDF are toxic, carcinogenic, mutagenic, or
tetratogenic. The commenter also argued that OCDD and OCDF do not meet
the criteria in 40 CFR 261.11(a) for listing a substance on the
Appendix VIII hazardous constituent list.
The commenter contends that the 1988 study by Couture, Elwell, and
Birnbaum, although it led to a raising of the TEF for OCDD/OCDF to
0.001 by NATO/CCMS, does not support a non-zero TEF for OCDD/OCDF. A
reevaluation of the study resulted in a downgrading of the TEF to
0.0001 by the World Health Organization. The commenter further contends
that few statistically significant physiological effects have been
observed in the study and that they are transitory in nature and are of
uncertain toxicological significance. The commenter also points out
that a longer-term subchronic study has been reported which
dramatically demonstrates that dioxin-like effects are not produced by
OCDD in animals even at high dose levels.
The commenter concludes that an extensive body of data exists that
does not support the conclusion that OCDD is a toxicant, carcinogen,
mutagen, or teratogen. In addition, the commenter states that
essentially no toxicological data has been published for OCDF
supporting the listing of the compound in Appendix VIII.
EPA disagrees with the commenter's arguments for several reasons.
First, the Agency notes, in response to issues raised by the commenter,
that as a preliminary matter, dioxin TEFs are irrelevant to EPA's
decision to list OCDD and OCDF in Appendix VIII. The criteria in 40 CFR
261.11(a) for listing a substance on the list of hazardous constituents
in Appendix VIII are that the constituents be ``shown in scientific
studies to have toxic, carcinogenic, mutagenic or teratogenic effects
on humans or other life forms.'' The Agency has determined that OCDD
and OCDF meet these criteria, independent of any TEF calculation.
There are data from subchronic studies for both OCDD and OCDF which
demonstrate dioxin-like effects (Couture et al., 1988; DeVito et al.,
1997). Couture et al. (1988) is one of the best studies of OCDD and
describes not only the effects but the importance of study design in
examining the effects of OCDD. Couture et al. (1988) demonstrate toxic
response of OCDD following subchronic exposures. In addition, this
study also provides tissue concentrations at which these effects are
observed. Couture et al. (1988) demonstrate that the absorption of OCDD
is dependent upon both dosing volume and concentration of the solution.
The higher the concentration the lower the absorption and the larger
the volume (up to 5 ml/kg) the greater the absorption. Hence, high dose
single exposures are unlikely to induce significant effects due to the
limited absorption of OCDD. In contrast, low dose repeated exposures
will allow for the bioaccumulation of OCDD, which eventually leads to
biological effects. This is clearly demonstrated in the Couture et al.
study (1988). The repeated exposure to 1 ug/kg of OCDD in a dose volume
of 5 ml/kg produces time dependent effects that also are associated
with increasing tissue accumulation of OCDD. OCDD induces hepatic
CYP1A1 activity and increases CYP1A1 and CYP1A2 protein. Induction of
CYP1A1 occurred as early as two weeks after treatment, and this
response increased with time and with hepatic OCDD accumulation.
Induction of CYP1A1 is a dioxin-like effect and is indicative of
activation of the Ah receptor. Hepatic cytoplasmic vacuolization in the
livers was also induced in a time dependent manner, first occurring
after 40 doses and increasing in incidence and severity after 65 does
of OCDD.
The Agency disagrees with the commenter's argument that these
effects are transitory or of uncertain toxicological significance.
First, the cytoplasmic vacuolization (lesions) in the liver increased
in incidence and severity in a time dependent manner. The increased
incidence and severity of these lesions were associated with increasing
hepatic concentrations of OCDD. Animals at the last time point examined
in the study of Couture et al. (1988) demonstrated the highest
incidence and severity of these lesions; it is difficult to describe
them as ``transitory'' as the commenters suggest, given that the
effects worsened over the last five weeks of the study. Indeed,
hepatotoxicity can be considered as part of a continuum of events
leading to necrosis or carcinogenicity. Demonstration of events early
in this continuum, such as cytoplasmic vacuolization, are cause for
concern. The commenter also attributes the liver effects to
``nutritional, metabolic or hormonal imbalances.'' Indeed, dioxins are
endocrine disruptors and hormonal imbalances are expected to be induced
by OCDD and other dioxins. These hormonal imbalances should be
considered adverse responses based on our understanding of the
endocrine disrupting actions of these chemicals.
The commenter neglects to mention that not only was enzyme activity
induced by OCDD in the rats, but CYP1A1 and CYP1A2 protein were also
increased as demonstrated by western blot analysis (Couture et al.,
1988). These proteins have been implicated in playing important roles
in oxidative damage and porphyria (Sinclair et al., 2000). According to
Nebert and colleagues ``metabolism of endogenous and exogenous
substrates by perhaps every P450 enzyme, but certainly CYP1A1 and
CYP1A2 (which are located, in part, in the mitochondrion), have been
shown to cause reactive oxygenated metabolite (ROM)-mediated oxidative
stress'' (Nebert et al., 2000). Ames and colleagues have clearly
demonstrated the role of CYP1A1 in oxidative stress (Park et al.,
1996).
The commenter cites a number of studies which suggest that OCDD is
not toxic, in contrast to the studies of Couture et al. The studies
cited are generally inadequately designed to address the toxicity of
OCDD. Several studies have demonstrated that, while OCDD is poorly
absorbed in biological systems (Norback et al. Birnbaum and Couture,
1988; Couture et al., 1988) it can bioaccumulate through repeated
exposures to low concentrations. In addition, in the Couture et al.,
study, it took at least 40 doses over approximately nine weeks before
enough of the chemical could accumulate to produce alterations in liver
histology. Acute, single exposures to high concentrations of OCDD are
unlikely to result in significant accumulation to induce a toxic
response since very little of the dose shall be absorbed. In fact, this
is one of the conclusions in the McConnell et al. study (1978). Hence,
the acute studies on the effects of OCDD demonstrated none of the
typical signs of dioxin-like toxicity due to the limited absorption of
the chemical. Other studies have to a lesser or greater degree
attempted subchronic exposures. However, these studies either are too
short (Holsapple et al. (1986)) or use too concentrated a dosing
solution (Norback et al., 1975). In either case, too little OCDD was
absorbed to induce effects.
The commenter cites a study by Wermelinger et al. (1990) as
evidence that OCDD does not induce dioxin-like effects. The USEPA
strongly disagrees with this conclusion. This manuscript was published
as an extended abstract from the dioxin meetings (Organohalogen
Compounds, 1:221-224). These data clearly demonstrate that both OCDD
and OCDF administered in the diet result in clear dioxin-like activity.
Both OCDD and OCDF resulted

[[Page 67110]]

in dose dependent increases in CYP1A1 activity and decreases in thymic
atrophy. These responses are clearly the hallmark of dioxin-like
effects in experimental animals. The Wermelinger et al. study clearly
supports the finding of Couture et al., that repeated low dose
administration of OCDD results in dioxin-like effects. In addition,
both Wermelinger et al. and Couture et al. provide similar estimates of
the relative potency of OCDD, further supporting the inclusion of these
chemicals in the TEF methodology.
The commenter cites a study by the National Toxicology Program in
which a two year feeding study of OCDD produced no effects. We could
not locate any reports of this study in the NTP databases. After
contacting the NTP, it was determined that the study of OCDD was halted
due to uncertain technical difficulties and no reports were ever
prepared on any study of OCDD by the NTP. It is unclear where the
commenter obtained its information, since a citation for the report was
not provided.
The effects of OCDF are not as well studied as those of OCDD.
Recent studies do document that subchronic exposure to OCDF
demonstrates dioxin-like activities in mice (DeVito et al., 1997). The
subchronic exposure resulted in EROD induction in liver, lung and skin
(DeVito et al., 1997) and hepatic porphyrin accumulation (van Birgelen
et al., 1996) in these mice. These studies demonstrate that OCDF also
possesses dioxin-like properties.

I. What Are the Land Disposal Restrictions Standards for the Newly-
Listed Wastes?

1. What Are EPA's Land Disposal Restrictions (LDRs)?
The RCRA statute requires EPA to establish treatment standards for
all wastes destined for land disposal. These are the so called ``land
disposal restrictions'' or LDRs. For any hazardous waste identified or
listed after November 8, 1984, EPA must promulgate LDR treatment
standards within six months of the date of identification or final
listing (RCRA Section 3004(g)(4), 42 U.S.C. 6924(g)(4)). RCRA also
requires EPA to set as these treatment standards ``* * * levels or
methods of treatment, if any, which substantially diminish the toxicity
of the waste or substantially reduce the likelihood of migration of
hazardous constituents from the waste so that short-term and long-term
threats to human health and the environment are minimized.'' RCRA
Section 3004(m)(1), 42 U.S.C. 6924(m)(1). Once a hazardous waste is
prohibited, the statute provides only two options for legal land
disposal: meet the treatment standard for the waste prior to land
disposal, or dispose of the waste in a land disposal unit that
satisfies the statutory no migration test. A no migration unit is one
from which there will be no migration of hazardous constituents for as
long as the waste remains hazardous. RCRA Sections 3004 (d), (e), (f),
and (g)(5).
5. What Are the LDR Standards for K174?
In today's rule, we are adopting treatment standards for several
forms of dioxins and furans as well as a treatment standard for
arsenic. With respect to the dioxins and furans being regulated, our
standard requires either treatment by means of combustion (denoted as
CMBST in the 40 CFR 268.40 Table) or that the specified types of
dioxins and furans meet numerical standards prior to land disposal.
For most of the specified types of dioxins and furans (e.g., the
hexa, penta, and tetra classes of congeners) as well as arsenic, we are
adopting the existing universal treatment standards and no significant
issues have been encountered. However, the setting of congener-specific
numerical standards for 3 hepta and 2 octa forms of dioxin/furan
warrants some additional discussion. In previous rulemakings, we have
not adopted treatment standards for these isomers. Several reasons
convince us that we should do so in today's rule.
First, with the K174 waste, our risk analysis indicates that,
should this waste be mismanaged in a land treatment unit, the hepta-
and octa-chlorinated dioxin and furan isomers present high-end
deterministic risks that, as described in Section VI.B.1. of today's
rule, form the basis for EPA's decision to list this waste as
hazardous. Second, studies have attributed dioxin-like toxicity to both
the hepta and octa isomers. Based on the TCDD cancer slope factor and
TEFs used in the risk analysis for this rule, the slope factors for
OCDD and OCDF are effectively 15.6 (mg/kg-day)-1 and the
slope factors for the 2,3,7,8-substituted hepta dioxin and furan
isomers are effectively 156 (mg/kg-day)-1. These are by
comparison 10 and 100 times, respectively, the slope factor for
arsenic, an Appendix VIII constituent and known carcinogen.
The carcinogenicity and risk levels of the 5 hepta and octa isomers
and their potential conversion to even more toxic isomers by
dechlorination or photolytic mechanisms lead us to conclude that
adopting specific treatment standards (i.e., numerical or CMBST) for
these isomers is warranted for the K174 wastes. Because we typically
include the same standards for new listings into those for F039
(multisource leachate) to maintain equivalence within the LDR
regulatory structure, we are also adding the same treatment standards
in the F039 section of the 268.40 table (see section below on
conforming changes).
In summary, today, we are promulgating as final the numerical
standards that were proposed for the constituents of concern in the
K174 wastewater treatment sludges from the production of ethylene
dichloride and vinyl chloride monomer. We are finalizing the numerical
standards based on the data received and analyzed at proposal. No
comments or additional data were received regarding the achievability
of the proposed standards so, therefore, we are adopting the same
numerical standards as final. In addition we also are promulgating the
option of complying with the technology standard of combustion (CMBST)
for the organic constituents present in K174. The final treatment
standards are presented in the following table.

Table I-1.--Treatment Standards for K174
--------------------------------------------------------------------------------------------------------------------------------------------------------
Regulated harzardous constituent Wastewaters Nonwastewaters
--------------------------------------------------------------------------------------------------------------------------------------------------------
Concentration in mg/L\1\, or technology code Concentration in mg/kg \3\ unless noted as
Common name CAS \2\ No. \2\ ``mg/L TCLP'', or technology code
--------------------------------------------------------------------------------------------------------------------------------------------------------
1,2,3,4,6,7,8-Heptachlorodibenzo-p-dioxin 35822-39-4 0.000035 or CMBST \4\......................... 0.0025 or CMBST \4\
1,2,3,4,6,7,8-Heptachlorodibenzofuran.... 67562-39-4 0.000035 or CMBST \4\......................... 0.0025 or CMBST \4\
1,2,3,4,7,8,9-Heptachlorodibenzofuran.... 55673-89-7 0.000035 or CMBST \4\......................... 0.0025 or CMBST \4\
HxCDDs (All Hexachlorodibenzo-p-dioxins). 34465-46-8 0.000063 or CMBST \4\......................... 0.001 or CMBST \4\
HxCDFs (All Hexachlorodibenzofurans)..... 55684-94-1 0.000063 or CMBST \4\......................... 0.001 or CMBST \4\

[[Page 67111]]

1,2,3,4,6,7,8,9-Octachlorodibenzo-p- 3268-87-9 0.000063 or CMBST \4\......................... 0.005 or CMBST \4\
dioxin (OCDD).
1,2,3,4,6,7,8,9-Octachlorodibenzofuran 39001-02-0 0.000063 or CMBST \4\......................... 0.005 or CMBST \4\
(OCDF).
PeCDDs (All Pentachlorodibenzo-p-dioxins) 36088-22-9 0.000063 or CMBST \4\......................... 0.001 or CMBST \4\
PeCDFs (All Pentachlorodibenzofurans).... 30402-15-4 0.000035 or CMBST \4\......................... 0.001 or CMBST \4\
TCDDs (All tetrachlorodi-benzo-p-doxins). 41903-57-5 0.000063 or CMBST \4\......................... 0.001 or CMBST \4\
TCDFs (All tetrachlorodibenzofurans)..... 55722-27-5 0.000063 or CMBST \4\......................... 0.001 or CMBST \4\
Arsenic.................................. 7440-36-0 1.4........................................... 5.0 mg/L TCLP
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ CAS means Chemical Abstract Services. When the waste code and/or regulated constituents are described as a combination of a chemical with its salts
and/or esters, the CAS number is given for the parent compound only.
\2\ Concentration standards for wastewaters are expressed in mg/L and are based on analysis of composite samples.
\3\ All treatment standards expressed as a Technology Code or combination of Technology Codes are explained in detail in 40 CFR 268.42 Table 1--
Technology Codes and Descriptions of Technology-Based Standards.
\4\ For these wastes, the definition of CMBST is limited to: (1) Combustion units operating under 40 CFR 266, (2) combustion units permitted under 40
CFR Part 264, Subpart O, or (3) combustion units operating under 40 CFR 265, Subpart O, which have obtained a determination of equivalent treatment
under 268.42(b).

Regarding the use of combustion (CMBST) for the regulated organic
constituents, commenters requested that we allow combustion as an
alternative to the proposed (and now final) numerical treatment
standards. This is consistent with the approach taken for F024, a set
of previously listed chlorinated aliphatic wastes (62 FR 26000-3, May
12, 1997). We agree and are promulgating the requested change. As a
consequence, facilities treating K174 wastes will have the option of
complying with either the numerical standards promulgated or the
technology standard of CMBST for the regulated organic constituents.
Adopting combustion as an alternative to the numerical standards
serves a general LDR programmatic interest as well. We typically
promulgate numerical performance standards to allow facilities maximum
flexibility in determining for themselves how best to achieve
compliance with the LDR treatment standards. If we promulgate a
technology-specific treatment standard (such as combustion) instead,
this flexibility is lost. In today's rule, by promulgating combustion
as an alternative compliance option, we are not disturbing the degree
of flexibility afforded to facilities; rather, we are maintaining or
enhancing it.
However, when we specify a treatment technology like CMBST as the
LDR standard, the analytical elements of compliance change. Typically,
when we specify a method of treatment (like CMBST), no testing and
analysis of treatment residuals is required because we are confident
that use of the specified technology will reduce the level of target
constituents (organics in the case of CMBST) to levels that minimize
threats to human health and the environment. For K174, the regulated
organic constituents of concern are dioxin/furan congeners, which, if
combustion is used for treatment, will not be individually analyzed in
the treatment residue (e.g., the ash).
Several factors suggest that such individual constituent analysis
is not necessary and that specifying CMBST is appropriate. First, if
combustion in well designed and operated units is used to treat K174,
the structural features of dioxin/furan congeners (e.g., the presence
of the oxygen in the ring formation) suggest that all dioxins and
furans in K174 should be substantially destroyed by the high
temperature combustion process that would have to be used.
Second, we ensure that combustion will occur in well designed,
operated, and highly regulated units. Part of the CMBST standard itself
(as modified in today's rule for K174 waste) is that combustion of K174
must occur either in units subject to the standards in 40 CFR part 264
subpart O or 40 CFR part 266, subpart H, or in interim status
incinerators where the owner/operator has made a specific demonstration
that the unit can operate in a manner equivalent to a part 264 or part
266 combustion unit. The type of facilities that can combust K174 is
thereby restricted to highly-regulated RCRA units (or, after the
current transition period, Clean Air Act permitted units subject to
MACT standards). This will ensure that combustion is done only in a
closely-regulated facility and in a manner that provides protection for
human health and the environment. More specifically, combustion will
occur only in units subject to the recently upgraded dioxin/furan
emission standards of the MACT Hazardous Waste Combustion Rule as well
as standards for other hazardous air pollutants, such as metals (64 FR
52828, September 30, 1999). Given this level of regulation and
permitting oversight, we do not find the need to impose additional and,
with respect to other dioxin/furan congeners, unique analytical burdens
on the regulated community regarding these 5 hepta and octa congeners.
Of course, K174 does have metal constituents of concern, which
would not be treated by the combustion process and that would remain in
the combustion treatment residuals (e.g., ash and scrubber water). We
therefore are retaining metal treatment standards for all
circumstances, i.e., whether or not the treatment used by a facility
involves combustion. When combustion is used to treat the organics to
achieve LDR compliance, facilities still will need to conduct
compliance testing and analysis for all regulated metal constituents in
the combustion treatment residuals prior to disposal. This approach is
patterned after EPA's promulgation of a similar alternative treatment
standard for F024 (wastes from production of chlorinated aliphatics)
and also for F032 (wastes from wood preserving processes). See 55 FR
22580-22581, June 1, 1990. See also 62 FR 26000-26003, May 12, 1997.
Another issue warranting brief discussion concerns a related, but
in reality quite different, issue. Commenters, in general, oppose the
regulation of the additional congeners individually, and state that the
existing dioxin and furan congeners covered under UTS standards are
sufficient to serve as surrogates for the effective treatment of the 5
hepta and octa

[[Page 67112]]

congeners. These commenters would omit the 5 hepta and octa congeners
entirely from list of regulated hazardous constituents for which LDR
treatment standards are set.
We do not agree with this approach. Absent a specific requirement
that hepta and octa congeners be treated (i.e., by including them as
regulated hazardous constituents for K174 in the table in 268.40),
generators would not be obliged to determine the presence of these
congeners. Without such a determination, it is certainly possible that
generators would not engage in any organic-oriented treatment at all.
For example, if the other dioxin/furans are below treatment levels,
generators would not have to combust the K174 waste. Given our concern
about the potential threats posed to human health and the environment
by dioxins and furans, we are choosing to require treatment wherever
harmful congeners are present above the treatment standard. Also, the
formation pathways for dioxins and furans are highly waste specific,
such that we have no way of knowing the concentration of one isomer
based on the presence or absence of another.
We conclude that a surrogate approach without compliance testing
for the 5 hepta and octa isomers, such as that which would be the
consequence of the commenters' views, would not be adequate. Therefore,
with today's rule, we are promulgating treatment standards for each of
the 5 hepta and octa dioxin and furan isomers identified in the
proposal.
3. What Are the LDR Treatment Standards for K175?
We proposed two options for establishing treatment standards under
the LDRs for the mercury-bearing waste to be listed as K175 (64 FR
46521). The first option would have included three treatment standards
that would essentially be the same as those for other mercury-bearing
wastes. These standards are:

(1) for K175 wastes containing greater than 260 mg/kg total mercury,
the treatment would be recovery of the waste's mercury content via
roasting and retorting (RMERC);
(2) for K175 RMERC residues containing less than 260 mg/kg total
mercury, the residues would have to meet a numerical standard of 0.2
mg/L TCLP mercury prior to land disposal; and
(3) for K175 wastes and non-RMERC treatment residues containing less
than 260 mg/kg total mercury, these wastes and treatment residues
would have to meet a numerical standard of 0.025 mg/L TCLP mercury
prior to land disposal

We also proposed that wastes and residues in this last category be
treated so that a pH of 6.0 or less is achieved prior to land disposal,
and that disposal of these wastes and residuals be restricted to
landfill cells where only wastes with similar pH properties are co-
disposed.
Because of the potential difficulty in roasting and retorting K175
waste, the Agency requested performance data, and solicited comment on
a second treatment standard option. This option would require that K175
waste exhibit no more than 0.025 mg/L TCLP mercury for disposal without
any requirement that the waste be roasted or retorted.
The K175 wastes are typically much greater than 260 mg/kg mercury,
ranging from approximately 3,000 to 17,700 mg/kg mercury, and are
greater than one percent in total organic constituents.\55\ As noted in
the proposal (64 FR at 46521), when these wastes (high mercury and 1%
or more organics) exhibit the toxicity characteristic, they would
already be subject to requirements of either RMERC (roasting and
retorting) or IMERC (incineration in units operated in accordance with
RCRA incinerator standards).
---------------------------------------------------------------------------

\55\ See 64 FR at 46510; see also Table 4-14 from Listing
Background Document for Chlorinated Aliphatics Listing Determination
(Proposed Rule) (USEPA, 1999c).
---------------------------------------------------------------------------

Commenters questioned the ability and willingness of commercial
retorting and roasting treatment facilities to accept K175 wastes,
citing two factors. First, with a K175 mercury content of approximately
one percent, commercial retorters may not recover enough mercury to be
cost-effective, and second, most commercial retort facilities may not
be able to accept wastes in excess of 500 ppm Appendix VIII organics
and still comply with their RCRA permitting limits (USEPA, 1999c).\56\
This information suggests that adopting an RMERC standard for K175 may
present significant practical difficulties that could not be overcome
in the near term.
---------------------------------------------------------------------------

\56\ In accordance with 40 CFR 266.100, a ``metals recovery''
unit such as a commercial mercury retorter is conditionally excluded
from most RCRA permit requirements provided that the facility
complies with certain operating restrictions, one being a
prohibition against accepting wastes in excess of 500 ppm Appendix
VIII organics.
---------------------------------------------------------------------------

In addition to the practical points made by commenters, no roasting
and retorting performance information for the subject waste or even a
similar waste was submitted in comment. Since the Agency itself lacks
data on the properties of the subject waste following roasting and
retorting, we are not able to persuasively conclude that this type of
treatment technology can achieve the level of mercury removal desired.
In addition, we have no firm basis for determining whether the RMERC
residues from treating K175 could meet the existing 0.2 mg/L TCLP total
mercury standard so that the RMERC residues could be land disposed. We
are therefore disinclined to adopt a K175 treatment standard that
involves mandatory roasting and retorting.
Conversely, with respect to the second option proposed for K175
treatment standards, several factors suggest that this is a better
approach to adopt. First, as discussed above, the commercial roasting
and retorting alternatives may not exist. Second, the physical
properties of the waste indicate that the waste can readily achieve
0.025 mg/L TCLP mercury. Testing conducted for EPA shows the waste
sample tested readily achieved 0.025 mg/L TCLP mercury, as the sample
tested leached only 0.0027 and 0.0058 mg/L total mercury at pH 4 and 6
respectively.\57\
---------------------------------------------------------------------------

\57\ Paul Bishop, Renee A. Rauche, Linda A. Rieser, Markram T.
Suidan, and Jain Zhang; ``Stabilization and Testing of Mercury
Containing Wastes,'' Department of Civil and Environmental
Engineering, University of Cincinnati, March 31, 1999.
---------------------------------------------------------------------------

Third, at this point in time, the Agency is reviewing the
appropriateness of thermal treatment and recovery of mercury in all
forms of hazardous waste, not solely K175. See 64 FR 28949, May 28,
1999. Therefore, requiring RMERC for K175 at this juncture may prove to
be somewhat premature even if adequate data and assurance of commercial
treatment capacity were to exist. Because we have an acceptable and
effective treatment alternative, we are able to postpone having to make
a policy judgment about promoting or requiring mercury recovery and
recycling in today's rule (which would just apply to K175) until we are
better prepared to resolve the longer term issues of mercury recovery
in a comprehensive and more environmentally effective manner.
Based on all these factors, the Agency has selected stabilization
as the appropriate technology upon which to base our K175 treatment
standard, and is setting 0.025 mg/L TCLP mercury together with control
of the pH of co-disposed wastes (as discussed below) as the land
disposal restrictions for K175. This standard may be achieved by any
technology (other than impermissible dilution), and does not prohibit
roasting/retorting should it be shown to achieve the performance
standard. While no data were provided in response comment on this
proposal, subsequently a vendor has indicated a willingness to
demonstrate that the

[[Page 67113]]

waste could be retorted successfully.\58\ Should subsequent testing
demonstrate that retorting produces a waste form better suited for
stabilization and having less potential for long-term mercury release,
the standards promulgated today could potentially be adjusted as part
of the ongoing re-evaluation of mercury waste treatment technologies.
See 64 FR 28949, May 28, 1998. Any modification of today's promulgation
would be the subject of a future proposal.
---------------------------------------------------------------------------

\58\ Personal communication with SepraDyne Corporation
representatives.
---------------------------------------------------------------------------

Other comments focused upon the proposed requirement that disposal
of K175 wastes and treatment residues which are less than 260 mg/kg
total mercury be restricted to landfill cells into which disposal of
wastes in excess of pH 6.0 is prohibited. Commenters noted that the
waste could readily be treated to a pH 6.0 but stated that, given the
relative small quantity of waste generated, monofill disposal of K175
or co-disposal only with similar wastes would not be feasible. One
commenter suggested macroencapsulation of the K175 waste as is
currently performed for debris would provide a viable alternative to
achieve isolation of the waste from surrounding, potentially adverse
landfill conditions. Subsequent discussions with Chemical Waste
Management Inc. confirm that acidic wastes make up only a small portion
of hazardous wastes and that it would not be feasible to manage a small
cell for only K175 or for K175 and only similar wastes of pH 6.0.\59\
---------------------------------------------------------------------------

\59\ Memorandum from Ross Elliott, U.S. EPA Office of Solid
Waste, to RCRA Docket, ``Summary of Phone Call Between EPA and Carl
Carlsson, Chemical Waste Management Inc.,'' July 12, 2000.
---------------------------------------------------------------------------

Control of the disposal site conditions is essential to ensure that
the mercury present in this waste remains immobile so that long-term
threats to human health and the environment are minimized. The
solubility measurements conducted on the waste for EPA are consistent
both with results found in the mercury literature \60\ as well as with
calculations from a geochemical stability model for mercury sulfide
complexes.\61\ The testing and subsequent solubility calculations
confirm that above pH 6.0, increased mobility of mercury as mercuric
sulfide/hydrogen sulfide complexes occurs with increasing pH and
sulfide concentration.
---------------------------------------------------------------------------

\60\ See 64 FR at 46522. See also Jenny Ayla Jay, Francois M. M.
Morel, and Harold F. Hemond, Mercury Speciation in the Presence of
Polysulfides, Environmental Science and Technology, 2000, Vol. 34,
No. 11, pages 2196-2200.
\61\ Memorandum from John Austin to Ross Elliott, May 12, 2000.
---------------------------------------------------------------------------

Therefore, we find that to minimize the potential future threats
from mercury mobilization, our treatment standard must ensure that pH
is maintained at 6.0 or less for K175 waste. Because we agree with the
commenter's suggestion about the practical advantages of
macroencapsulation in some situations, we are finalizing treatment
standards that require, prior to land placement: (1) Wastes to be at pH
6.0 or less, and placement is restricted to landfill cells in which
disposal of other wastes in excess of pH 6.0 is prohibited; or (2)
wastes to be at pH 6.0 or less, and macroencapsulation per the
requirements of 40 CFR 268.45. The pH restriction in the latter
standard is to ensure that mercury is not in a mobile form should the
macroencapsulation vessel fail over time. This additional level of
protection is part of the best demonstrated and available treatment
(BDAT) needed to minimize the threats posed by potential mobilization
of the mercury within a landfill over the long-term. Furthermore,
macroencapsulation itself is not viewed as BDAT (except in unusual
cases such as debris) because it merely isolates the waste from the
environment for a period of time and does not actually effect any
treatment. We have amended the regulations promulgated today
accordingly.
Affected parties and other stakeholders should note that we may
revisit the requirement for macroencapsulation should we determine, at
some future date, that the generation rate of materials requiring
disposal at low pH has increased to the point where maintaining a
separate cell for these wastes is an operationally feasible option for
a landfill.
We did not pursue to regulatory conclusion other potential avenues
by which mercury mobilization could be affected for a number of
reasons. Two avenues would be to regulate the sulfide content of the
waste itself or the sulfide concentration in the disposal environment,
or both. These approaches are fraught with technical and implementation
difficulties. For example, chemical and biological processes within the
disposal unit may reduce sulfate to sulfide at varying rates depending
on in situ conditions. Also, current test methods do not readily
distinguish free sulfide from that bound as mercuric sulfide in the
waste. Hence, adopting sulfide limits on incoming K175 wastes or
mandating in situ sulfide levels would likely not be reliable or
implementable means of ensuring mercury immobility. On the other hand,
pH can readily be determined using the existing procedure SW-846 Method
9045C. Thus, practical considerations also favor limitation of waste pH
at the time of disposal as a more viable option to control potential
mobilization of mercury once the wastes are disposed.
In summary, for K175 waste, we are finalizing a treatment standard
requiring that, prior to land disposal: (1) The waste must meet a TCLP
leachate concentration of 0.025 mg/L mercury or less, (2) the waste
must be at or below a pH 6.0 when disposed, and (3) the wastes must be
macroencapsulated or, if not, placement is restricted to landfill cells
in which disposal of other wastes in excess of pH 6.0 is prohibited. We
are promulgating these land disposal restriction requirements for K175
to ensure the long term protection of human health and the environment.
4. What Are the Conforming Changes to F039 and Universal Treatment
Standards?
We proposed that the constituents 1,2,3,4,6,7,8-heptachlorodibenzo-
p-dioxin; 1,2,3,4,6,7,8-heptachlorodibenzofuran; 1,2,3,4,7,8,9-
heptachlorodibenzofuran; 1,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin
(OCDD); and 1,2,3,4,6,7,8,9-octachlorodibenzofuran (OCDF) be added to
the list of regulated constituents in hazardous waste F039 multisource
leachate. The F039 waste code applies to hazardous waste landfill
leachates in lieu of the original waste codes when multiple waste codes
would otherwise apply. F039 wastes are subject to numerical treatment
standards equivalent to UTS. We proposed these additions to the
constituents regulated by F039 to maintain the implementation benefits
of having one waste code for multisource leachate.
Commenters correctly noted that the Agency did not add the
constituents of the carbamate waste listing to F039 (61 FR 15566), an
issue not directly within the purview of this rulemaking. As a result,
multisource F039 leachates that also contain one of the listed
carbamate wastes must be treated to comply with carbamate hazardous
waste codes to meet the 40 CFR 268.48(c) requirement for treatment to
achieve the lowest treatment standard for constituents of concern.
Therefore, such wastes would be subject to multiple codes; the very
situation F039 sought to eliminate. The Agency's intent upon
promulgating F039 was that the single F039 waste code would replace the
multiple codes to which such wastes were then subject (52 FR 22619,
June 1, 1990). To limit

[[Page 67114]]

any further proliferation of circumstances where treatment standards in
addition to F039 may apply, we are promulgating the additional K174
dioxin and furan constituents of concern as proposed. Resources
permitting, conforming changes may be proposed for the carbamate waste
constituents at some future date.
We also proposed that the numerical standards derived for
1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin; 1,2,3,4,6,7,8-
heptachlorodibenzofuran; 1,2,3,4,7,8,9-heptachlorodibenzofuran; OCDD;
and OCDF be added to the Table of Universal Treatment Standards (UTS)
at 40 CFR 268.48. These constituents contribute to the overall risks
that formed the basis for EPA's decision the EDC/VCM sludges pose a
substantial risk to human health and the environment, as shown in the
risk assessment accompanying this rule. Their presence in other
hazardous wastes should be mitigated by effective treatment to avoid
similar risks after land disposal. By adding these numerical standards
for five dioxin and furan congeners, we are ensuring that treatment of
hazardous waste addresses these risks.
Following the adoption of today's rule, all characteristic wastes
that have these constituents as underlying hazardous constituents above
the UTS levels will require treatment of these additional constituents
before land disposal. This is in direct accord with our mandate under
the LDR treatment program to ``substantially diminish the toxicity of
the waste or substantially reduce the likelihood of migration of
hazardous constituents from the waste so that short-term and long-term
threats to human health and the environment are minimized.'' \62\
---------------------------------------------------------------------------

\62\ RCRA Section 3004(m).
---------------------------------------------------------------------------

Commenters in general objected to changes to UTS because of their
perceived cost of the analysis and concerns over available treatment
capacity, which will be discussed in the following section. We were not
persuaded by the commenters' arguments. Waste generators must already
comply with treatment requirements for tetra-, penta-, and hexa-
chlorinated dibenzo-p-dioxin and dibenzofuran congeners. Much of the
labor and cost of analysis of the currently regulated congeners can not
be separated from the costs associated solely with the hepta and octa
congeners because the analysis of these 5 additional isomers is
accomplished intrinsically as part of the overall method and is not
separable. Hence, sample preparation, labor, and instrument time are
not increased by including these 5 additional congeners.
Commenters also suggest that treatment and control of the existing
regulated dioxin/furan congeners provides adequate protection against
potential risks associated with the hepta and octa congeners.
Commenters appear to recognize that the hepta- and octa-dioxin/furan
congeners contribute significantly to the overall carcinogenicity of
K174 wastes and waste treatment residues, and that they also must be
controlled if human health and the environment are to be protected. In
essence, these commenters would have us make broad assumptions for all
situations about the ancillary impacts of treating and controlling
certain dioxin and furan congeners, but not others that nevertheless
present significant risks to human health and the environment.
We are not in a position to make such broad assumptions regarding
our degree of control over dioxin and furan congeners that present
significant risks. We have chosen to take a more conservative tack,
providing treatment standards that, when met, ensure that long-term
threats to human health and the environment are minimized (RCRA Section
3004(m)). For reasons noted earlier (e.g., carcinogenicity of these
congeners, dechlorination or photolytic changes to more toxic
congeners, and assuring treatment if these congeners are present), we
conclude that direct control of these 5 hepta and octa congeners is
warranted.
For these reasons, the Agency is promulgating the proposed
additions to the Table of Universal Treatment Standards (UTS) at 40 CFR
268.48 and to the list of regulated constituents for F039, multisource
leachate from hazardous waste, in 40 CFR 268.40.

J. Is There Treatment Capacity for the Newly-Listed Wastes?

1. Introduction
Under the land disposal restrictions (LDR) determinations, the
Agency must demonstrate that adequate commercial capacity exists to
manage listed hazardous wastes in compliance with BDAT standards before
the Agency can restrict the listed waste from further land disposal.
The Agency performs capacity analyses to determine the effective date
of the LDR treatment standards for the proposed listed wastes. This
section summarizes the results of EPA's capacity analysis for the
wastes covered by today's rule. For a detailed discussion of capacity
analysis-related data sources, methodology, and detailed responses to
comments for each waste covered in this rule, see USEPA, 2000f \63\
(i.e., the Capacity Background Document).
---------------------------------------------------------------------------

\63\ U.S. EPA. 2000f. Background Document for Capacity Analysis
for Land Disposal Restrictions: Newly Identified Chlorinated
Aliphatics Production Wastes (Final Rule), September.
---------------------------------------------------------------------------

EPA's decisions on whether to grant a national capacity variance
are based on the availability of alternative treatment or recovery
technologies capable of achieving the prescribed treatment standards.
Consequently, the methodology focuses on deriving estimates of the
quantities of newly-listed hazardous waste that will require either
commercial treatment or the construction of new on-site treatment or
recovery as a result of the LDRs. The resulting estimates of required
commercial capacity are then compared to estimates of available
commercial capacity. If adequate commercial capacity exists, the waste
is restricted from further land disposal unless it meets the LDR
treatment standards prior to disposal. If adequate capacity does not
exist, RCRA Section 3004(h)(2) authorizes EPA to grant a national
capacity variance for the waste for up to two years or until adequate
alternative treatment capacity becomes available, whichever is sooner.
2. Capacity Analysis Results for Newly Identified Wastes
In conducting the capacity analysis for the wastes newly-listed by
today's rule, EPA examined data on waste characteristics and management
practices gathered for the purpose of the chlorinated aliphatics
hazardous waste listing determinations and on available treatment or
recovery capacity for these wastes. The data sources for the analyses
are primarily the 1992 RCRA Section 3007 survey, the follow-up survey
specific to these wastes conducted in 1997 (see the docket for this
rule for more information on these survey instruments), the available
treatment capacity data submission that was collected in the mid-
1990's, and the 1997 Biennial Report (BR). EPA analyzed the capacity-
related information from these data sources, reviewed the public
comments received in response to the proposed rule, and corresponded or
met with several commenters to obtain more specific information.
We identified the following annual quantities of the newly-listed
wastes that are generated and therefore the quantities of waste that
potentially could require commercial treatment. Information available
to the Agency indicates that up to 6,100 tons of K174 per year could
potentially require

[[Page 67115]]

commercial treatment capacity. The Agency notes, however, that because
EPA is finalizing a conditional listing approach for the K174
wastewater treatment sludges under which these wastes are not hazardous
if disposed of in a subtitle C or a non-hazardous waste landfill, it is
possible that little or no hazardous waste treatment capacity will be
required for this waste. In addition, approximately 130 tons of K175
are generated annually and potentially could require commercial
treatment capacity. EPA has determined that there is adequate
commercial treatment or recovery capacity available to treat both of
these wastes.
For wastewaters from chlorinated aliphatic production processes
(proposed as K173), some commenters requested a national capacity
variance for this waste in response to the proposed rule. Since EPA is
finalizing a decision not to list wastewaters from chlorinated
aliphatic production processes as hazardous (as discussed in section
VI.A), there is no need for a capacity variance determination for this
waste stream.
EPA proposed not to grant a capacity variance for K174 waste (EDC/
VCM wastewater treatment sludge). No comments were received regarding
the variance determination, available treatment or disposal capacity,
or the quantity of the waste potentially requiring treatment, either in
nonwastewater or wastewater forms. As described in section VI.I above,
we are finalizing the proposed numerical treatment standards as well as
an alternative treatment standard of hazardous waste combustion. We
estimate that the commercially available sludge and hazardous waste
combustion capacity is at least 300,000 tons per year (see details in
the Capacity Background Document) and therefore sufficient to treat any
K174 hazardous wastes that could require treatment.
As discussed earlier in this preamble, EPA has identified (as a
result of public comments) that one facility may generate K174 in a
surface impoundment as a result of today's rule. The facility may
remove K174 waste before the effective date of the new listing and
therefore may not be subject to LDR requirements.\64\ The impoundment
can also be retrofitted, closed, or replaced with tank systems. If the
impoundment continues to be used to actively manage K174 waste, the
unit will be subject to subtitle C requirements. In addition, any
hazardous wastes that are actively managed in an impoundment (other
than wastes removed from an impoundment as part of a one-time removal)
after the effective date of today's rule are subject to the land
disposal prohibitions.\65\ EPA expects that the one facility currently
managing chlorinated aliphatic wastewaters in surface impoundments (and
which therefore may potential manage EDC/VCM sludges in impoundments
after the effective date of today's rule) will cease to do so before
the effective date of this rule.
---------------------------------------------------------------------------

\64\ If the waste is actively managed in unretrofitted
impoundments (i.e., impoundments not satisfying the minimum
technology requirements specified in RCRA sections 3004(o) and
3005(j)(11)) after the effective date of today's rule, it would be
land disposed in a prohibited manner.
\65\ See RCRA Sec. 3004(m)(1) ``Simultaneously with the
promulgation of regulations under subsection (d), (e), (f), or (g)
prohibiting one or more methods of land disposal of a particular
hazardous waste * * * promulgate regulations specifying those levels
or methods of treatment * * * ''
---------------------------------------------------------------------------

However, as described earlier in this preamble (see section
VI.B.2.b.vii) regarding the listing determination for EDC/VCM
wastewater treatment sludges, this facility (or others) could manage
newly-listed K174 in surface impoundments, provided they are in
compliance with the appropriate standards for impoundments (40 CFR
parts 264 and 265 subpart K) and the special rules regarding surface
impoundments (40 CFR 268.14). EPA notes that those provisions require
(by reference) basic groundwater monitoring (40 CFR parts 264 and 265
subpart F), management, and recordkeeping, but are afforded up to 48
months to retrofit to meet minimum technological requirements (see RCRA
Section 3005(j)(6)(A)).
Based on the foregoing, EPA concludes that sufficient treatment or
disposal capacity is available to manage K174 waste generated after the
effective date of the LDR treatment standards either on site or
offsite, even if generators seek offsite management for all K174 wastes
in a permitted subtitle C disposal or treatment unit. Therefore, EPA is
finalizing its decision not to grant a capacity variance for wastewater
and nonwastewater forms of K174.
With respect to K175 waste, several commenters raised issues with
regard to permitting requirements and constraints of commercial
treatment facilities, including the ability of commercial facilities to
accept nonwastewater forms of K175 waste and comply with the proposed
land disposal restrictions of RMERC. As discussed earlier, EPA is
finalizing a numerical treatment standard for this waste (in
conjunction with other pH-related restrictions and macroencapsulation),
which has been demonstrated to be achievable using stabilization.
Sufficient commercial stabilization, pH, and macrocapsulation treatment
capacity exists to treat and dispose of mercury-containing wastes and
to meet the final treatment standards adopted today. In addition, the
one facility generating K175 uses a sulfide precipitation technology
and therefore may be able to meet the numerical mercury concentration
standard upon generation of the waste. Depending on their ability to
control pH and to perform on-site macrocapsulation, no other commercial
treatment might be necessary prior to off-site hazardous waste
landfilling. EPA notes that generators can use any treatment technology
(except impermissible dilution) to meet the numerical mercury
concentration and pH standards promulgated today.
EPA proposed that the K175 waste (about 130 tons per year) be co-
disposed in a landfill with other wastes with similar pH (6.0 or less).
Commenters did not indicate the existence of any technical difficulties
in meeting the additional pH requirement. Furthermore, they did not
provide any data or information on the issue of available monofill
disposal capacity for this waste or landfill co-disposal with similarly
acidic (pH 6.0 or less) wastes. Based on previous activities in the
commercial sector as well as the lack of adverse comment, we find no
reason to doubt that owners of commercial landfills can and at some
point will create a special cell based on customer's needs, compliance
conditions, and contract negotiation.
However, as noted earlier, we understand from one stakeholder that
facilities with hazardous commercial landfill capacity may not have
sufficient volumes of similarly acidic wastes to make it cost-effective
to designate an entire unit or cell for disposal of only low pH wastes.
We have therefore adopted an alternative that allows land disposal in
other types of landfill cells following macroencapsulation of the waste
(assuming the waste meets other applicable standards, such as Hg
concentration and pH 6.0 or less). Based on a discussion with a
hazardous waste management facility,\66\ we find that
macroencapsulation of K175 waste can be made readily available for K175
waste. Based on available data and analyses, EPA has therefore
determined that sufficient commercial treatment and disposal capacity
exists to manage K175 waste to meet the LDR standards, and we are today
finalizing our decision not to grant a capacity variance for

[[Page 67116]]

wastewater or nonwastewater forms of K175.
---------------------------------------------------------------------------

\66\ Personal communication with Carl Carlson, Chemical Waste
Management Inc.
---------------------------------------------------------------------------

In summary, we conclude that sufficient capacity exists for the
management of both wastewater and nonwastewater forms of K174 and K175.
For K174 and K175 wastes, the customary time period of six months is
sufficient to allow facilities to determine whether their wastes are
affected by this rule, to identify onsite or commercial treatment and
disposal options, and to arrange for treatment or disposal capacity if
necessary. LDR treatment standards thus will become effective when the
listing determinations become effective for the wastes covered under
this rule--the earliest possible date. This conforms to RCRA section
3004(h)(1), which indicates that land disposal prohibitions must take
effect immediately when there is sufficient treatment or disposal
capacity available for the waste.
Further, for soil and debris contaminated with the newly-listed
wastes, EPA proposed not to grant a national capacity variance. EPA
received no comments regarding this issue. We expect that the majority
of contaminated soil and debris will be managed on-site and therefore
would not require substantial off-site commercial treatment capacity.
Therefore, EPA is not granting a national capacity variance for
hazardous soil and debris contaminated with the newly listed wastes
covered under this rule. LDR treatment standards for K174 and K175
hazardous soil and debris will therefore become effective when these
listing determinations become effective.
Based on the 1992 RCRA section 3007 questionnaire and the 1997
updated responses, there were no data showing underground injection of
the newly-listed wastes or indicating that the newly-listed wastes are
mixed with radioactive wastes or with both radioactive wastes and soil
or debris. EPA did not receive comments indicating that these wastes
are underground injected or that they are mixed with radioactive wastes
or with both radioactive wastes and soil or debris. Therefore, EPA is
not granting a national capacity variance for K174 and K175 wastes that
might be underground injected, mixed with radioactive wastes, or mixed
with both radioactive wastes and soil or debris. LDR treatment
standards for K174 and K175 underground injected and mixed wastes (if
any exists) will therefore become effective when these listing
determinations become effective.
Finally, EPA may consider a case-by-case extension to the effective
date based on the requirements outlined in 40 CFR 268.5, which includes
a demonstration that adequate alternative treatment, recovery, or
disposal capacity for the petitioner's waste cannot reasonably be made
available by the effective date due to circumstances beyond the
applicants' control, and that the petitioner has entered into a binding
contractual commitment to construct or otherwise provide such capacity.
3. Available Treatment Capacity for Other Wastes Subject to Revised UTS
and F039 Standards
Several commenters expressed concern that EPA did not adequately
consider the need for alternative treatment capacity for other
hazardous wastes subject to the proposed revisions to the UTS and F039
(multiple source leachate) standards. Such additional treatment would
be necessary to meet the treatment standards for the five additional
dioxin and furan congeners being added to the UTS table (Sec. 268.48)
and the list of regulated constituents in F039 (Sec. 268.40).
Commenters noted that EPA must consider the potential need for national
capacity variances by determining what fraction of the hazardous wastes
are required to meet these new requirements, the appropriate means of
treatment (if any), and the sufficiency of national treatment capacity
for these wastes.
When changing the treatment requirements for wastes already subject
to LDR (including F039 and characteristic wastes), EPA no longer has
authority to use RCRA section 3004(h)(2) to grant a capacity variance
to these wastes. However, EPA is guided by the overall objective of
section 3004(h), namely that treatment standards which best accomplish
the goal of RCRA section 3004(m) (to minimize threats posed by land
disposal) should take effect as soon as possible, consistent with
availability of treatment capacity. Our task is therefore to balance
the points raised by commenters against the clear statutory direction
that treatment standards, such as those at issue here, should be
imposed in the shortest feasible time provided capacity is available.
With respect to the issue of capacity availability, we find first
that only a limited quantity of hazardous waste leachate is expected to
be generated from the disposal of newly-listed K174 and K175 wastes and
added to the generation of leachates from other multiple restricted
hazardous wastes already subject to LDR. Absent any data from
commenters suggesting to the contrary, we have no reason to delay
imposition of the LDRs on this ground.
Second, with respect to the other, and potentially much larger
volumes of, wastes that would be affected, we evaluated the universe of
wastes that could be impacted by today's revisions to the lists of
regulated constituents for F039 and UTS. Commenters themselves did not
supply any information on these volumes in support of their generalized
claims of insufficient capacity or their views that delaying the
effective date of these treatment standards is warranted. However,
based on 1997 Biennial Report data and some assumptions of waste
compositions and their potential for land disposal, we were able to
estimate the potential need for additional treatment. For example, EPA
estimated an upper bound of 68,000 tons per year of the nonwastewaters
mixed with other waste codes, the F039 leachate from which would be
potentially impacted by the revisions to the F039 treatment standards.
In a similar fashion, we estimated that no more than 130,000 tons per
year of characteristic nonwastewaters potentially could be affected by
the promulgated changes to the UTS.
Of course, these upper bound estimates are most likely very
overstated since only a portion of each estimated waste volume may
contain one or more of the five congeners at concentrations above the
numerical concentrations specified in the UTS table and the F039 list.
Available hazardous waste landfill leachate characterization data from
EPA's Office of Water indicate that only one of 15 samples analyzed
shows leachate concentration of OCDD exceeding the numerical UTS level
adopted today. Any concentrations below these numerical standards would
not trigger any treatment obligation or the concomitant need for
treatment capacity. (See the Capacity Background Document for detailed
analysis.) Furthermore, EPA does not anticipate that waste volumes
subject to treatment for F039 or characteristic wastes would
significantly increase because waste generators already are required to
comply with the treatment requirements for tetra-, penta-, and hexa-
chlorinated dioxin/furan congeners. The volumes of wastes for which
additional treatment is needed solely due to the addition of the five
new congeners to the F039 and UTS lists is therefore expected to be
very small. Both of these factors indicate the highly conservative
nature of our volume estimates.
However, even though our volume estimates are highly conservative
and overstated, we find that there still would be no shortage of
treatment capacity. Based on data submittals in the mid-1990's and the
1997 Biennial

[[Page 67117]]

Report, EPA has estimated that approximately 37 million tons per year
of commercial wastewater treatment capacity are available, and well
over one million tons per year of liquid, sludge, and solid commercial
combustion capacity are available. These are well above the quantities
of wastewater and nonwastewater forms of F039 or characteristic wastes
potentially requiring treatment for the 5 hepta and octa isomers even
under the conservative screening assumptions described above. We find
therefore that there is sufficient treatment capacity for these wastes
to ensure that the wastes meet today's revisions to the UTS and F039
treatment standards. For this reason, EPA is finalizing its decision
not to delay the effective date for adding the five hepta-and octa-
dioxin and furan congeners to the lists of constituents for F039 and
UTS. As with the other treatment standards being promulgated today,
these revised F039 and UTS standards will become effective six months
after the date of promulgation, the same date on which the K174 and
K175 listing will become effective. This will provide sufficient time
to allow facilities to determine whether their wastes are affected by
this rule, to identify onsite or commercial treatment and disposal
options, and to arrange for treatment or disposal capacity if
necessary.

VII. What Is the Economic Analysis of Today's Final Rule?

A. What Is the Purpose of the Economic Analysis?

In 1999, the EPA presented an initial economic analysis (in the
form of both a preamble discussion, and a supplementary ``Economics
Background Document'(USEPA, 1999b), for public review in support of the
RCRA K173/K174/K175 listing proposed rule (64 Federal Register, 46517-
46519, August 25, 1999). The primary purpose of the 1999 economic
analysis was to estimate regulatory compliance costs associated with
the proposed rule. Secondary purposes were to provide (1) descriptive
information about the economic sectors (i.e. the chemical industry) and
other types of facilities potentially affected by the proposed rule,
and (2) descriptive information about the economic activities involving
chlorinated aliphatic hydrocarbon chemicals (CAHCs).
As a result of both public comments and changes to the rule, EPA
revised the 1999 ``Economics Background Document'' (USEPA 1999b). In
comparison to the 1999 economic analysis, the primary objectives of
this final economic analysis are: (1) to present and respond to the
public comments received about the economic analysis for the 1999
proposed rule, and (2) to estimate the impacts of the final rule. The
findings for each objective are summarized below.
The Economics, Methods, and Risk Assessment Division (EMRAD) of
EPA's Office of Solid Waste (OSW) conducted the economic analyses for
both the 1999 proposed rule, and for this final rule. The ``Economics
Background Document'' (USEPA, 2000a) \67\ in support of this final
rule, is available to the public from the EPA's RCRA Docket (refer to
the introduction to this preamble for instructions on how to obtain a
copy). References to statements below pertaining to facts, data,
assumptions and other types of information, are identified in the final
rule background document.
---------------------------------------------------------------------------

\67\ U.S. EPA. 2000a. Economics Background Document. Office of
Solid Waste. September.
---------------------------------------------------------------------------

B. How Did the Public Participate in the Economic Analysis?

In conjunction with the 1999 proposed rule (64 FR 46517), EPA
requested public comment on the following eleven specific information
elements pertaining to the data, assumptions, design, accuracy,
representativeness and completeness of the initial ``Economic
Background Document'' (dated 30 July 1999, 127pp., which is available
over the Internet at http://www.epa.gov/epaoswer/hazwaste/id/chlorali/
economic.pdf): (1) Economic study design, (2) industry facility
universe, (3) affected waste volumes/sources, (4) industry sector
profile, (5) baseline (current) waste management practices, (6)
regulatory compliance waste management, (7) compliance facility process
modifications, (8) waste management costs, (9) regulatory impact
financial benchmarks, (10) economic analysis data sources, and (11)
other impact considerations. As described elsewhere in this preamble,
EPA received a total of 20 sets of public comments on the 1999 proposed
rule, of which 14 commenters offered a total of 61 remarks on the 1999
economic analysis. EPA presents and addresses each comment in the
``Response to Public Comments'' background document (USEPA, 2000g)
\68\, also available from the EPA RCRA Docket.
---------------------------------------------------------------------------

\68\ U.S. EPA. 2000g. Response to Public Comments on Proposed
Listing Determination for Chlorinated Aliphatic Wastes. Office of
Solid Waste. September.
---------------------------------------------------------------------------

For purpose of summary here, the 61 remarks made by the 14
commenters who targeted the 1999 economic analysis may be grouped
according to six topics: (1) K173 compliance cost estimates, (2) K174
compliance cost estimates, (3) K175 compliance cost estimates, (4)
economic analysis framework, (5) overall magnitude of rule cost, and
(6) industry characterization. Many of the commenters made remarks
about multiple economic analysis topics (as well as about other aspects
of the proposed rule, such as preamble language and risk analysis).
Forty-two of the 61 remarks were directed at the EPA's K173 compliance
cost estimate, stating that EPA's 1999 estimate was too low for a
variety of reasons, including lack of complete descriptive information
about all possible wastewater tanks affected, as well as incomplete
assessment of all potential costs involved in retrofitting wastewater
tanks with covers and tank air emission control devices. However,
because the K173 listing is dropped from the final rule, EPA has
dropped the K173 cost estimate from the economic analysis, rather than
revise it. Otherwise, EPA has incorporated into the final rule economic
analysis, information contained in other public comments addressing the
K174 listing, K175 listing, economic analysis framework, and industry
characterization. Four of the comments also contained remarks about the
K174 listing, questioning the magnitude of its associated recordkeeping
burden, and claiming that EPA did not consider other impacts arising
from RCRA's ``mixture and derived-from'' clause. One commenter
challenged EPA's assertion of the current market availability of K175
waste retorting treatment. The 14 commenters made nineteen remarks
questioning the industrial scope of the listing, whether the rule would
impact other types of facilities/wastes, and the appropriateness of
EPA's cost annualization and future industry waste generation
parameters. The 14 commenters also offered thirty-three remarks about
the cost-effectiveness of the rule, the total industry cost of the
rule, and challenged EPA's assertion that the proposed rule was not
economically ``significant'' according to the $100 million annual
effect threshold established in Executive Order 12866 (30 September
1993). Finally, commenters offered seven remarks raising questions
about EPA's count of the affected number of facilities, EPA's
characterization of the size of wastewater tanks in the affected
industry, and EPA's characterization of the affected industry's annual
sales and growth rate.

[[Page 67118]]

C. What Are the Expected Economic Impacts of This Final Rule?

As of the late 1990s, 39 facilities in the US manufacture
chlorinated aliphatic hydrocarbon chemicals. Eighteen of these are
potentially subject to the rule, 17 as generators of K174 waste, and
one as a generator of K175 waste. None of these 18 facilities are owned
by small-sized companies. The 21 remainder facilities do not currently
manufacture the types of chemicals and associated industrial wastes
which are listed as RCRA ``hazardous'' industrial wastes by the rule.
The anticipated economic impacts associated with the final rule
primarily consist of industry compliance costs, likely to be incurred
by three of the 18 relevant waste generators (two K174 and one K175),
and by four commercial waste handlers.
Because of the facts that: (1) Many of the CAHC manufacturing
facilities and commercial industrial waste handlers are currently
regulated under RCRA (via the existing RCRA F024 and F025 wastecodes,
among others), (2) some CAHC manufacturing facilities currently manage
some wastewater sludges as hazardous waste, (3) the K174 listing is
targeted upon a subset of chlorinated aliphatic production processes,
and/or (4) the K174 final rule is ``conditional'' upon only certain
waste management practices, the incremental impact of this listing is
expected to be substantially less than it otherwise would be if all
waste generators fitting the listing descriptions, or if all 39
chemical class manufacturers, were affected. Consequently, the
incremental impact of the final rule is expected to be less than it
otherwise could be (e.g., impacts could be higher under a listing
affecting all facilities across the industry sector, rather than the
final targeted and ``conditional'' listing approach which affects only
a few facilities).
EPA estimates that the average annualized national cost of this
rule will be between $0.42 and $4.05 million per year (consisting of
$0.53 to $7.21 million in initial costs and $0.35 to $3.25 million in
recurring annual costs), if one generator of EDC/VCM wastewater
treatment sludge (K174) is able to make arrangements for the apparent
lower-cost option for managing its affected industrial wastewaters. But
if that generator is not able to make the appropriate waste management
arrangements prior to the effective date for the final rule, such that
the one facility might find it cannot make arrangements for a lower
cost means of managing its affected wastewater (from which the EDC/VCM
wastewater treatment sludges are derived), then it could face
relatively high monthly costs for temporarily transporting its
wastewater offsite to a commercial hazardous waste management facility,
until it can complete an alternative (and lower-cost) waste management
arrangement for its wastewaters. For the purpose of reflecting EPA's
uncertainty about this facility's actual cost impacts, as well as other
cost estimation parameters, EPA included other higher cost waste
management options and industry compliance cost contingencies (such as
possible surface impoundment corrective action costs) in the economic
analysis for the final rule (Economics Background Document USEPA
2000a). Inclusion of all of these high-cost assumptions results in an
upper-end EPA cost estimate of $23.37 million in average annualized
cost (which includes up to 22 months of temporary offsite transport for
the generator of EDC/VCM wastewater treatment sludge currently managing
its wastewaters in a surface impoundment). EPA notes that total costs
also include minor impacts on EPA regional offices and states with
authorized RCRA programs to implement the new rule, as well as other
``incidental effects.'' The reader is referred to the ``Economics
Background Document'' for additional details about all cost items
included in EPA's estimate of national cost.

VIII. When Must Regulated Entities Comply With Today's Final Rule?

A. Effective Date

The effective date of today's rule is May 7, 2001.

B. Section 3010 Notification

Pursuant to RCRA section 3010, the Administrator may require all
persons who handle hazardous wastes to notify EPA of their hazardous
waste management activities within 90 days after the wastes are
identified or listed as hazardous. This requirement may be applied even
to those generators, transporters, and treatment, storage, and disposal
facilities (TSDFs) that have previously notified EPA with respect to
the management of other hazardous wastes. The Agency has decided to
waive this notification requirement for persons who handle wastes that
are covered by today's hazardous waste listings and already have (1)
notified EPA that they manage other hazardous wastes, and (2) received
an EPA identification number. The Agency has waived the notification
requirement in this case because it believes that most, if not all,
persons who manage the wastes listed as hazardous in today's rule
already have notified the Agency and received an EPA identification
number. However, any person who generates, transports, treats, stores,
or disposes of these newly listed wastes and has not previously
received an EPA identification number must obtain an identification
number pursuant to 40 CFR 262.12 to generate, transport, treat, store,
or dispose of these hazardous wastes by February 6, 2001.

C. Generators and Transporters

Persons who generate newly identified hazardous wastes may be
required to obtain an EPA identification number if they do not already
have one (as discussed in section VIII.B, above). If generating or
transporting these wastes after the effective date of this rule,
generators of the wastes listed today will be subject to the generator
requirements set forth in 40 CFR Part 262. These requirements include
standards for hazardous waste determination (40 CFR 262.11), compliance
with the manifest (40 CFR 262.20 through 262.23), pretransport
procedures (40 CFR 262.30 through 262.34), generator accumulation (40
CFR 262.34), record keeping and reporting (40 CFR 262.40 through
262.44), and import/export procedures (40 CFR 262.50 through 262.60).
We note that the generator accumulation provisions of 40 CFR 262.34
allow generators to accumulate hazardous wastes without obtaining
interim status or a permit only in certain specified units; the
regulations also place a limit on the maximum amount of time that
wastes can be accumulated in these units. If these wastes are actively
managed in surface impoundments or other units that are not tank
systems, containers, drip pads, or containment buildings as outlined in
40 CFR 262.34, accumulation of these wastes is subject to the
permitting requirements of 40 CFR Parts 264 and 265, and the generator
is required to obtain interim status and seek a permit (or modify
interim status or a permit, as appropriate). Also, persons who
transport newly identified hazardous wastes will be required to obtain
an EPA identification number (if they do already have one) as described
above and will be subject to the transporter requirements set forth in
40 CFR Part 263. [NOTE: Generators of EDC/VCM wastewater treatment
sludge who manage the waste in compliance with the requirements of the
conditional listing (i.e., dispose of the waste in a landfill and do
not store the waste directly on the land prior to landfilling, are not
subject to the hazardous waste

[[Page 67119]]

generator requirements at 40 CFR Part 262.]

D. Facilities Subject to Permitting

Today's rule is issued pursuant to HSWA authority. Therefore, EPA
will regulate the management of the newly identified hazardous wastes
until states are authorized to regulate these wastes. EPA will apply
Federal regulations to these wastes and to their management in both
authorized and unauthorized states.
1. Facilities Newly Subject to RCRA Permit Requirements
Facilities that treat, store, or dispose of wastes that are subject
to RCRA regulation for the first time by this rule (that is, facilities
that have not previously received a permit pursuant to Section 3005 of
RCRA and are not currently operating pursuant to interim status), might
be eligible for interim status (see Section 3005(e)(1)(A)(ii) of RCRA).
To obtain interim status based on treatment, storage, or disposal of
such newly identified wastes, eligible facilities are required to
comply with 40 CFR 270.70(a) and 270.10(e) by providing notice under
Section 3010 and submitting a Part A permit application no later than
May 7, 2001. Such facilities are subject to regulation under 40 CFR
Part 265 until a permit is issued.
In addition, under Section 3005(e)(3) and 40 CFR 270.73(d), not
later than November 8, 2001, land disposal facilities newly qualifying
for interim status under section 3005(e)(1)(A)(ii) also must submit a
Part B permit application and certify that the facility is in
compliance with all applicable groundwater monitoring and financial
responsibility requirements. If the facility fails to submit these
certifications and a permit application, interim status will terminate
on that date.
2. Existing Interim Status Facilities
Pursuant to 40 CFR 270.72(a)(1), all existing hazardous waste
management facilities (as defined in 40 CFR 270.2) that treat, store,
or dispose of the newly identified hazardous wastes and are currently
operating pursuant to interim status under section 3005(e) of RCRA,
must file an amended Part A permit application with EPA no later than
the effective date of today's rule (i.e., May 7, 2001). By doing this,
the facility may continue managing the newly listed wastes. If the
facility fails to file an amended Part A application by that date, the
facility will not receive interim status for management of the newly
listed hazardous wastes and may not manage those wastes until the
facility receives either a permit or a change in interim status
allowing such activity (40 CFR 270.10(g)).
3. Permitted Facilities
Facilities that already have RCRA permits must request permit
modifications if they want to continue managing newly listed wastes
(see 40 CFR 270.42(g)). This provision states that a permittee may
continue managing the newly listed wastes by following certain
requirements, including submitting a Class 1 permit modification
request by the date on which the waste or unit becomes subject to the
new regulatory requirements (i.e., the effective date of today's rule),
complying with the applicable standards of 40 CFR Parts 265 and 266 and
submitting a Class 2 or 3 permit modification request within 180 days
of the effective date.
Generally, a Class 2 modification is appropriate if the newly
listed wastes will be managed in existing permitted units or in newly
regulated tank or container units and will not require additional or
different management practices than those authorized in the permit. A
Class 2 modification requires the facility owner to provide public
notice of the modification request, a 60-day public comment period, and
an informal meeting between the owner and the public within the 60-day
period. The Class 2 process includes a ``default provision,'' which
provides that if the Agency does not reach a decision within 120 days,
the modification is automatically authorized for 180 days. If the
Agency does not reach a decision by the end of that period, the
modification is permanently authorized (see 40 CFR 270.42(b)).
A Class 3 modification is generally appropriate if management of
the newly listed wastes requires additional or different management
practices than those authorized in the permit or if newly regulated
land-based units are involved. The initial public notification and
public meeting requirements are the same as for Class 2 modifications.
However, after the end of the 60-day public comment period, the Agency
will grant or deny the permit modification request according to the
more extensive procedures of 40 CFR part 124. There is no default
provision for Class 3 modifications (see 40 CFR 270.42(c)).
Under 40 CFR 270.42(g)(1)(v), for newly regulated land disposal
units, permitted facilities must certify that the facility is in
compliance with all applicable 40 CFR part 265 groundwater monitoring
and financial responsibility requirements no later than May 7, 2001. If
the facility fails to submit these certifications, authority to manage
the newly listed wastes under 40 CFR 270.42(g) will terminate on that
date.
4. Units
Units in which newly identified hazardous wastes are generated or
managed will be subject to all applicable requirements of 40 CFR part
264 for permitted facilities or 40 CFR part 265 for interim status
facilities, unless the unit is excluded from such permitting by other
provisions, such as the wastewater treatment tank exclusions (40 CFR
264.1(g)(6) and 265.1(c)(10)) and the product storage tank exclusion
(40 CFR 261.4(c)). Examples of units to which these exclusions could
never apply include landfills, land treatment units, waste piles,
incinerators, and any other miscellaneous units in which these wastes
may be generated or managed.
5. Closure
All units in which newly identified hazardous wastes are treated,
stored, or disposed after the effective date of this regulation that
are not excluded from the requirements of 40 CFR parts 264 and 265 are
subject to both the general closure and post-closure requirements of
Subpart G of 40 CFR parts 264 and 265 and the unit-specific closure
requirements set forth in the applicable unit technical standards
Subpart of 40 CFR part 264 or part 265 (e.g., Subpart N for landfill
units). In addition, EPA promulgated a final rule that allows, under
limited circumstances, regulated landfills, surface impoundments, or
LTUs to cease managing hazardous waste but to delay subtitle C closure
to allow the unit to continue to manage non-hazardous waste for a
period of time prior to closure of the unit (see 54 FR 33376, August
14, 1989). Units for which closure is delayed continue to be subject to
all applicable 40 CFR 264 and 265 requirements. Dates and procedures
for submittal of necessary demonstrations, permit applications, and
revised applications are detailed in 40 CFR 264.113(c) through (e) and
265.113(c) through (e).

IX. How Will This Rule Be Implemented at the State Level?

A. Applicability of Rule in Authorized States

Under section 3006 of RCRA, EPA may authorize qualified States to
administer the RCRA hazardous waste program within the State. See 40
CFR part 271 for the overall standards and requirements for
authorization. Following authorization, the State

[[Page 67120]]

requirements authorized by EPA apply in lieu of equivalent Federal
requirements and become Federally enforceable as requirements of RCRA.
EPA maintains independent authority to bring enforcement actions under
RCRA sections 3007, 3008, 3013, and 7003. Authorized States also have
independent authority to bring enforcement actions under State law. A
State may receive authorization by following the approval process
described under 40 CFR part 271.
After a State receives initial authorization, new Federal
requirements promulgated under RCRA authority existing prior to the
1984 Hazardous and Solid Waste Amendments (HSWA) do not apply in that
State until the State adopts and receives authorization for equivalent
State requirements. The State must adopt such requirements to maintain
authorization.
In contrast, under RCRA section 3006(g) (42 U.S.C. 6926(g)), new
Federal requirements and prohibitions imposed pursuant to HSWA
provisions take effect in authorized States at the same time that they
take effect in unauthorized States. Although authorized States are
still required to update their hazardous waste programs to remain
equivalent to the Federal program, EPA carries out HSWA requirements
and prohibitions in authorized States, including the issuance of new
permits implementing those requirements, until EPA authorizes the State
to do so.
Authorized States are required to modify their programs only when
EPA promulgates Federal requirements that are more stringent or broader
in scope than existing Federal requirements. RCRA section 3009 allows
the States to impose standards more stringent than those in the Federal
program. See also 40 CFR 271.1(i). Therefore, authorized States are not
required to adopt Federal regulations, both HSWA and non-HSWA, that are
considered less stringent.

B. Effect on State Authorizations

EPA is promulgating this rule (with the exception of the changes to
Part 302) pursuant to sections 2002(a), 3001(b), 3001(e)(2), and
3007(a) of the Solid Waste Disposal Act, which are HSWA provisions. We
will add the new requirements to Table 1 at 40 CFR 271.1, which
identifies Federal program requirements promulgated pursuant to HSWA.
Because this rule is promulgated pursuant to the HSWA, after its
effective date EPA will implement it rule in all States, including
authorized States. Once authorized States modify their programs to
adopt equivalent rules and receive authorization for such rules from
EPA, those rules will become RCRA subtitle C requirements that apply in
that States in lieu of the equivalent federal requirements.
Because this rule is promulgated pursuant to HSWA, a State
submitting a program modification may apply to receive either interim
or final RCRA authorization under RCRA 3006(g) or (b) on the basis that
State regulations are, respectively, substantially equivalent or fully
equivalent to EPA's regulations. The procedures and schedule for State
programs modifications for either interim or final authorization are
described in 40 CFR 271.21 and 271.24. Note that all HSWA interim
authorizations will expire on January 1, 2003 (see 40 CFR 271.24(c)).

X. What Are the Reportable Quantity Requirements for Newly-Listed
Wastes (K174 and K175) Under the Comprehensive Environmental
Response, Compensation, and Liability Act (CERCLA)?

A. What Is the Relationship Between RCRA and CERCLA?

CERCLA defines the term ``hazardous substance'' to include RCRA
hazardous wastes. When EPA lists a hazardous waste under RCRA, the
waste is also a hazardous substance pursuant to CERCLA 101(14), and the
Agency adds the waste to the table of CERCLA hazardous substances in
the CFR. EPA establishes a reportable quantity or RQ for each CERCLA
hazardous substance. EPA provides a list of the CERCLA hazardous
substances along with their RQs in Table 302.4 at 40 CFR 302.4. If you
are the person in charge of a vessel or facility that releases a CERCLA
hazardous substance in an amount that equals or exceeds its RQ, then
you must report that release to the National Response Center (NRC). You
also may have to notify State and local authorities.

B. Is EPA Adding Chlorinated Aliphatic Wastes to the Table of CERCLA
Hazardous Substances?

Yes. Today, EPA is adding the newly listed chlorinated aliphatic
wastes (K174 and K175) to the list of CERCLA hazardous substances. As
discussed below, EPA also is finalizing adjusted RQs for these wastes.

C. How Does EPA Determine Reportable Quantities?

Under CERCLA, all new hazardous substances generally have a
statutory one-pound RQ. EPA adjusts the RQ of a newly added hazardous
substance based on an evaluation of its intrinsic physical, chemical,
and toxic properties. These intrinsic properties--called ``primary
criteria''--are aquatic toxicity, mammalian toxicity (oral, dermal, and
inhalation), ignitability, reactivity, chronic toxicity, and potential
carcinogenicity. EPA evaluates the data for a hazardous substance for
each primary criterion. To adjust the RQs, EPA ranks each criterion on
a scale that corresponds to an RQ value of 1, 10, 100, 1,000, or 5,000
pounds. For each criterion, EPA establishes a tentative RQ. A hazardous
substance may receive several tentative RQ values based on its
particular intrinsic properties. The lowest of the tentative RQs
becomes the ``primary criteria RQ'' for that substance.
After the primary criteria RQs are assigned, EPA further evaluates
substances for their susceptibility to certain degradative processes.
These are secondary adjustment criteria. The natural degradative
processes are biodegradation, hydrolysis, and photolysis (BHP). If a
hazardous substance, when released into the environment, degrades
rapidly to a less hazardous form by one or more of the BHP processes,
EPA generally raises its RQ (as determined by the primary RQ adjustment
criteria) by one level. Conversely, if a hazardous substance degrades
to a more hazardous product after its release, EPA assigns an RQ to the
original substance equal to the RQ for the more hazardous substance.
The standard methodology used to adjust the RQs for RCRA hazardous
waste streams differs from the methodology applied to individual
hazardous substances. The procedure for assigning RQs to RCRA waste
streams is based on the results of an analysis of the hazardous
constituents of the waste streams. The constituents of each RCRA
hazardous waste stream are identified in 40 CFR part 261, Appendix VII.
EPA first determines an RQ for each hazardous constituent within the
waste stream using the methodology described above. The lowest RQ value
of these constituents becomes the adjusted RQ for the waste stream.
When there are hazardous constituents of a RCRA waste stream that are
not CERCLA hazardous substances, the Agency develops an RQ, called a
``reference RQ,'' for these constituents in order to assign an
appropriate RQ to the waste stream (see 48 FR 23565, May 25, 1983). In
other words, the Agency derives the RQ for waste streams based on the
lowest RQ of all of the hazardous constituents, regardless of whether
they are CERCLA hazardous substances.

[[Page 67121]]

D. When Do I Need To Report a Release of K174 or K175 Under CERCLA?

Today, EPA is promulgating adjusted statutory RQs for newly-listed
hazardous wastes K174 and K175 waste streams of one pound based on
their hazardous constituents. EPA also is adjusting the RQ at one pound
for K174 based on its hazardous constituents, chlorinated dibenzo-p-
dioxins (CDDs) and chlorinated dibenzofurans (CDFs). EPA is
promulgating an adjusted RQ of one pound for newly-listed waste K175
based on its hazardous constituent, mercury. However, in determining
when to report a release of K174 or K175, EPA will allow you to apply
the mixture rule, codified in 40 CFR 302.6, using the maximum observed
concentrations of the hazardous constituents within the respective
waste streams.
The mixture rule provides that when you know the quantities of all
hazardous constituents of a mixture or solution, you must notify of
releases of an RQ or more of such constituents (40 CFR 302.6).
Therefore, if you know the concentration of the hazardous constituents
of a hazardous waste, you can calculate the amount of waste released
needed to reach the RQ for the constituents. By using the maximum
observed concentration that EPA is promulgating today, you may apply
the mixture rule, even if you do not know the concentration of
constituents released. That is, if you are the person in charge, you
must immediately report the release as soon as you know that you have
released K174 or K175 in an amount that will reach the RQ for any of
the hazardous constituents. This approach is reasonable and
conservative because the sampling data presented in the Listing
Background Document (USEPA, 1999c) accurately identify the maximum
observed concentrations of the hazardous constituents in the
chlorinated aliphatics waste streams. Table X-1 below identifies the
hazardous constituents for each waste stream, their maximum observed
concentrations in parts per million (ppm), and their constituents' RQs
or reference RQs.

Table X-1.--Maximum Observed Concentration and Corresponding RQ for
Hazardous Constituents That Are Basis for Newly-Listed K174 and K175
------------------------------------------------------------------------
Max.
Waste Constituent concentration RQ (lb)
(ppm (mg/kg))
------------------------------------------------------------------------
K174............. 2,3,7,8-TCDD............. 0.000039 1
1,2,3,7,8-PeCDD.......... 0.0000108 1
1,2,3,4,7,8-HxCDD........ 0.0000241 1
1,2,3,6,7,8-HxCDD........ 0.000083 1
1,2,3,7,8,9-HxCDD........ 0.000062 1
1,2,3,4,6,7,8-HpCDD...... 0.00123 1
OCDD..................... 0.0129 1
2,3,7,8-TCDF............. 0.000145 1
1,2,3,7,8-PeCDF.......... 0.0000777 1
2,3,4,7,8-PeCDF.......... 0.000127 1
1,2,3,4,7,8-HxCDF........ 0.001425 1
1,2,3,6,7,8-HxCDF........ 0.000281 1
1,2,3,7,8,9-HxCDF........ 0.00014 1
2,3,4,6,7,8-HxCDF........ 0.000648 1
1,2,3,4,6,7,8-HpCDF...... 0.0207 1
1,2,3,4,7,8,9-HpCDF...... 0.0135 1
OCDF..................... 0.212 1
K175............. Mercury.................. 9200 1
------------------------------------------------------------------------

For example, if K174 is released from your facility and you do not
know the actual concentrations of its constituents, you may assume that
the concentrations are those identified in Table X-1. Thus, if K174 is
released from your facility and you do not know the actual
concentrations of its constituents, you may apply the mixture rule to
the assumed maximum concentrations indicated in the table. You would
have to release 4,716,981 pounds of K174 to reach the RQ for this waste
(based on the maximum observed concentration of OCDF). If K175 is
released from your facility and you do not know the actual
concentration of mercury, you may assume that the concentration is 9200
ppm. Applying the mixture rule, you would have to release 108.7 pounds
of K0175 to reach the RQ.

E. What if I Know the Concentration of the Constituents in My Waste?

If you know the concentration levels of all the hazardous
constituents in a particular chlorinated aliphatic waste, you may apply
the mixture rule (see 40 CFR 302.6(b)) to the actual concentrations.
You would need to report a release of either waste when an RQ or more
of any of their respective hazardous constituents is released.

F. How Did EPA Determine the RQs for K174 and K175 and Their Hazardous
Constituents?

The hazardous constituents identified as the basis for listing K174
as hazardous waste include chlorinated dibenzo-p-dioxins (CDDs) and
chlorinated dibenzofurans (CDFs). Previously, EPA had established an
adjusted RQ of one pound for 2,3,7,8-TCDD (see 54 FR 33426). EPA has
not established adjusted RQs for the other CDD and CDF congeners.
However, EPA recognizes that a number of these congeners exhibit
dioxin-like toxicity and has established ``reference RQs'' of one pound
for these congeners to support the development of the adjusted RQs for
K174.
The adjusted RQ for 2,3,7,8-TCDD was established as one pound based
on potential carcinogenicity, considering the weight of evidence that
this substance is carcinogenic, and considering its estimated
carcinogenic potency. To establish reference RQs for the other CDD and
CDF congeners in the waste stream, EPA applied the toxicity equivalency
factors (TEFs) established for dioxin-like compounds to the potency
factor used as the basis for the adjusted RQ for 2,3,7,8-TCDD. Of the
210 CDD and CDF congeners, only those with chlorine substitutions in,
at least,

[[Page 67122]]

the 2, 3, 7, and 8 positions (a total of 17 CDD and CDF congeners) are
considered to have dioxin-like toxicity. Applying the TEFs established
for these 17 congeners to the potency factor established for 2,3,7,8-
TCDD indicates that all of the congeners fit into RQ Potency Group 1
with a corresponding reference RQ of one pound.\69\ Therefore, because
each of the hazardous constituents has an RQ or reference RQ of one
pound, EPA is promulgating an adjusted RQ of one pound for K174.
---------------------------------------------------------------------------

\69\ For an explanation of how potency factors are calculated
and potency groups and RQs are established, see the Technical
Background Document to Support Rulemaking Pursuant to CERCLA Section
102, Volume 3, July 27, 1989. This document can be viewed by calling
the EPA Superfund Docket Center, 703-603-8917, and requesting
document number 102 RQ 273C.
---------------------------------------------------------------------------

The hazardous constituent identified as the basis for listing as
hazardous VCM-A wastewater treatment sludges (K175) is mercury.
Previously, EPA had established an adjusted RQ of one pound for mercury
(see 50 FR 13456, April 4, 1985). Because the hazardous constituent
used as the basis for listing K175 has an RQ of one pound, EPA is
promulgating an adjusted RQ of one pound for this waste.

G. How Do I Report a Release?

To report a release of K174 or K175 (or any other CERCLA hazardous
substance) that equals or exceeds its RQ, you must immediately notify
the National Response Center (NRC) as soon as you have knowledge of
that release. The toll-free telephone number of the NRC is 1-800-424-
8802; in the Washington, DC, metropolitan area, the number is (202)
267-2675.
You also may have to notify State and local authorities. The
Emergency Planning and Community Right-to-Know Act (EPCRA) requires
that owners and operators of certain facilities report releases of
CERCLA hazardous substances and EPCRA extremely hazardous substances
(see list in 40 CFR part 355, Appendix A) to State and local
authorities. After the release of an RQ or more of any of those
substances, you must report immediately to the community emergency
coordinator of the local emergency planning committee for any area
likely to be affected by the release, and to the State emergency
response commission of any State likely to be affected by the release.

H. Is CERCLA Reporting Required for Spills of EDC/VCM Wastewater
Treatment Sludge That (Prior to the Spill) Does Not Meet the Listing
Description for K174?

Commenters to the proposed rule asked whether spills of EDC/VCM
wastewater treatment sludge, where prior to being spilled the sludge
does not meet the K174 listing because of the manner in which it is
being managed, would have to be reported in compliance with the CERCLA
RQ reporting requirements. The Agency notes that we are finalizing a
contingent management listing for EDC/VCM wastewater treatment sludges
under which these sludges would be regulated as K174 wastes unless they
are destined for management in a subtitle C landfill or a non-hazardous
waste landfill licensed or permitted by a state. As part of the listing
description, once the EDC/VCM wastewater treatment sludge is placed on
the land it meets the listing description. Therefore, contrary to the
commenter's suggestion, spills of EDC/VCM sludges would not be excluded
from the K174 listing. A spill of EDC/VCM wastewater treatment sludges
would constitute the release of a CERCLA hazardous substance, and
provided that an amount equal to or exceeding the RQ had been released,
would be subject to CERCLA notification requirements.

I. What Is the Statutory Authority for This Program?

Section 101(14) of CERCLA defines the term hazardous substance by
referring to substances listed under several other environmental
statutes, as well as those substances that EPA designates as hazardous
under CERCLA section 102(a). In particular, CERCLA section 101(14)(C)
defines the term hazardous substance to include ``any hazardous waste
having the characteristics identified under or listed pursuant to
section 3001 of the Solid Waste Disposal Act.'' CERCLA section 102(a)
gives EPA authority to establish RQs for CERCLA hazardous substances.
CERCLA section 103(a) requires any person in charge of a vessel or
facility that releases a CERCLA hazardous substance in an amount equal
to or greater than its RQ to report the release immediately to the
federal government. EPCRA section 304 requires owners or operators of
certain facilities to report releases of CERCLA hazardous substances
and EPCRA extremely hazardous substances to State and local
authorities.

XI. What Are the Administrative Assessments?

A. Executive Order 12866

Under Executive Order 12866 (September 30, 1993), EPA must
determine whether a regulatory action is ``significant'' and,
therefore, subject to OMB review and the other provisions of the
Executive Order. A significant regulatory action is defined by
Executive Order 12866 as one that may:

(1) Have an annual effect on the economy of $100 million or more
or adversely affect in a material way the economy, a sector of the
economy, productivity, competition, jobs, the environment, public
health or safety, or State, local, or tribal governments or
communities;
(2) Create a serious inconsistency or otherwise interfere with
an action taken or planned by another agency;
(3) Materially alter the budgetary impact of entitlements,
grants, user fees, or loan programs or rights and obligations or
recipients thereof; or
(4) Raise novel legal or policy issues arising out of legal
mandates, the President's priorities, or the principles set forth in
Executive Order 12866.

Pursuant to the terms of Executive Order 12866, EPA has determined
that this rule is a ``significant regulatory action'' because of point
four (4) above: The rule includes a novel legal or policy issue arising
out of legal mandates, the President's priorities, or the principles
set forth in this Executive Order. Today's final rule, which includes
an alternative listing approach for one of the newly-listed
wastestreams, deviates from the Agency's standard or historic listing
approach in that the Agency is listing as hazardous only those
quantities of the waste that are managed in a manner that reflects
unacceptable risks. This differs from the Agency's traditional approach
to listing a waste as hazardous, in which the listing determination
captures the entire quantity of a targeted wastestream that poses
unacceptable risks to human health and the environment when managed in
one or more particular manners.
Due to the Agency's decision to promulgate a listing approach that
deviates from our historical hazardous waste listing approach, the
Agency is deeming today's action to be ``significant.'' Prior to
finalizing today's rule, EPA submitted this proposed policy change to
OMB for review. Changes made to the Agency's proposal in response to
OMB suggestions or recommendations are documented in the public record.
Although today's final rule is not ``economically significant,''
the Agency prepared an Economics Background

[[Page 67123]]

Document (USEPA 1999b) in support of today's rule. The Agency's
economic assessment addresses, among other factors, industry compliance
costs, industry financial impacts, and potential for small entity
impacts. A summary of findings from our economic assessment is
presented in Section VII. The complete Economics Background Document
(USEPA 1999b) is available for public review from the RCRA docket,
according to instructions provided in the introduction to this
preamble.
EPA anticipates that the final rule will primarily affect three of
the 18 known US generators of K174 and K175 hazardous wastes, causing
these three facilities to modify current waste management practices,
according to the terms and conditions of the final rule. None of these
18 facilities are owned by small-sized companies. The 15 remainder
chemical plants will incur relatively minor annual costs for
documentation of current waste management practices. In addition, EPA
anticipates that four industrial waste management operators will be
affected by either increased or decreased annual volumes and business
revenues associated with the management of wastes from the three
affected chemical plants. EPA also anticipates that states with
authorized RCRA programs will be affected as they will be required to
implement and enforce the final rule. Finally, EPA anticipates that
other Federal agencies and non-governmental organizations may be incur
relatively minor costs associated with reading and propagating the
final rule.
EPA estimates that the national average annual cost of the final
rule will be between $0.42 to $4.05 million. Under broader cost
estimation uncertainty assumptions which allow for temporary offsite
trucking of affected wastes by one facility if it requires additional
time beyond the final rule six-month compliance deadline to modify its
current waste management practices, the upper-bound of this cost
estimate increases to $23.37 million in average annual cost.

B. Regulatory Flexibility Act

Pursuant to the 1980 Regulatory Flexibility Act (RFA)(5 U.S.C. 601
et seq., as amended by the Small Business Regulatory Enforcement
Fairness Act (SBREFA) of 1996), whenever an agency is required to
publish a notice of rulemaking for any proposed or final rule, it must
prepare and make available for public comment, a regulatory flexibility
analysis that describes the effect of the rule on small entities (i.e.,
small businesses, small organizations, and small governmental
jurisdictions). However, a regulatory flexibility analysis is not
required if the head of an agency certifies that the rule will not have
a ``significant'' economic impact on a substantial number of small
entities.
SBREFA amended the Regulatory Flexibility Act to require Federal
agencies to provide a statement of the factual basis for certifying
that a rule will not have a ``significant'' economic impact on a
substantial number of small entities. The following discussion explains
EPA's determination.
EPA has examined this rule's potential effects on small entities as
required by the RFA/SBREFA, and has determined that this action will
not have a significant economic impact on a substantial number of small
entities. This is evidenced by the fact that only one of the
potentially affected, parent companies determined to be producers of
chlorinated aliphatic products in the U.S., may be classified as a
``small business,'' according to the U.S. Small Business
Administration's employee size standards (i.e., less than or equal to
1,000 employees) and according to that company's primary Standard
Industrial Classification (SIC) code (SIC 2869).
I hereby certify that this rule will not have a significant
economic impact on a substantial number of small entities. This rule,
therefore, does not require a regulatory flexibility analysis.

C. Paperwork Reduction Act

The information collection requirements in this final rule have
been submitted for approval to the Office of Management and Budget
(OMB) under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. An
Information Collection Request (ICR) document was prepared by EPA (ICR
No. 1924.01) and a copy may be obtained from Sandy Farmer by mail at OP
Regulatory Information Division; U.S. Environmental Protection Agency
(2137); 1200 Pennsylvania Avenue NW.; Washington, DC 20460, by E-mail
at farmer.sandy@epamail.epa.gov, or by calling (202) 260-2740. A copy
also may be downloaded off the Internet at
http://www.epa.gov/icr.
This final rule includes new information collection requirements
subject to OMB review under the Paperwork Reduction Act of 1995, 44
U.S.C. 3501 et seq. In addition to complying with the existing subtitle
C recordkeeping and reporting requirements for the newly listed waste
streams, EPA is requiring that facilities generating EDC/VCM wastewater
treatment sludges be able to document their compliance with the
conditions provided for exclusion from the scope of the conditional
hazardous waste listing promulgated today. This requirement is
necessary to ensure that EDC/VCM wastewater treatment sludges are
managed in a manner that is safe for human health and the environment.
In addition, EPA is requiring disposal facilities that manage VCM-A
wastewater treatment sludges to maintain records documenting that these
sludges are co-disposed only with other wastes that have a pH level of
6.0 or lower. This requirement is necessary to ensure that the mercury
contained in the waste does not leach from the waste after disposal.
The Agency estimated the burden associated with complying with the
requirements in this proposed rule. Included in the ICR are the burden
estimates for the following requirements for industry respondents:
reading the regulations; keeping records documenting compliance with
conditions for exclusion from hazardous waste listings; and keeping
records documenting compliance with landfill waste disposal
requirements for the disposal of VCM-A wastewater treatment sludges.
Included also are the burden estimates for State respondents for
applying for State authorization. The Agency determined that all of
this information is necessary to ensure compliance with today's final
rule.
To the extent that this rule imposes any information collection
requirements under existing RCRA regulations promulgated in previous
rulemakings, those requirements have been approved by the Office of
Management and Budget (OMB) under the Paperwork Reduction Act, 44
U.S.C. 3501 et seq., and have been assigned OMB control numbers 2050-
0009 (ICR No. 1573, Part B Permit Application, Permit Modifications,
and Special Permits); 2050-0120 (ICR No. 1571, General Facility
Hazardous Waste Standards); 2050-0028 (ICR No. 261, Notification of
Hazardous Waste Activity); 2050-0034 (ICR No. 262, RCRA Hazardous Waste
Permit Application and Modification, Part A); 2050-0039 (ICR No. 801,
Requirements for Generators, Transporters, and Waste Management
Facilities under the Hazardous Waste Manifest System); 2050-0035 (ICR
No. 820, Hazardous Waste Generator Standards); and 2050-0024 (ICR No.
976, 1997 Hazardous Waste Report).
EPA estimates that the projected annual hour burden for industry
respondents will be 93 hours, and the annual cost associated with the
additional paperwork burden will be $5,254. Total estimates over three
years are 279 hours and $15,762.

[[Page 67124]]

Burden means the total time, effort, or financial resources
expended by persons to generate, maintain, retain, or disclose or
provide information to or for a Federal agency. This includes the time
needed to review instructions; develop, acquire, install, and use
technology and systems for the purposes of collecting, validating, and
verifying information, processing and maintaining information, and
disclosing and providing information; adjust the existing ways to
comply with any previously applicable instructions and requirements;
train personnel to be able to respond to a collection of information;
search data sources; complete and review the collection of information;
and transmit or otherwise disclose the information.
An agency may not conduct or sponsor, and a person is not required
to respond to a collection of information unless it displays a
currently valid OMB control number. The OMB control numbers for EPA's
regulations are listed in 40 CFR part 9 and 48 CFR chapter 15.

D. Unfunded Mandates Reform Act

Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Pub.
L. 104-4, establishes requirements for Federal agencies to assess the
effects of their regulatory actions on State, local, and tribal
governments and the private sector. Under Section 202 of the UMRA, EPA
generally must prepare a written statement, including a cost-benefit
analysis, for proposed and final rules with ``Federal mandates'' that
may result in expenditures by State, local, and tribal governments, in
the aggregate, or by the private sector, of $100 million or more in any
one year. Before promulgating an EPA rule for which a written statement
is needed, section 205 of the UMRA generally requires EPA to identify
and consider a reasonable number of regulatory alternatives and adopt
the least costly, most cost-effective or least burdensome alternative
that achieves the objectives of the rule. The provisions of Section 205
do not apply when they are inconsistent with applicable law. Moreover,
Section 205 allows EPA to adopt an alternative other than the least
costly, most cost-effective or least burdensome alternative if the
Administrator publishes with the final rule an explanation why that
alternative was not adopted. Before EPA establishes any regulatory
requirements that may significantly or uniquely affect small
governments, including tribal governments, it must have developed under
section 203 of the UMRA a small government agency plan. The plan must
provide for notifying potentially affected small governments, enabling
officials of affected small governments to have meaningful and timely
input in the development of EPA regulatory proposals with significant
Federal intergovernmental mandates, and informing, educating, and
advising small governments on compliance with the regulatory
requirements.
Today's rule contains no Federal mandates (under the regulatory
provisions of Title II of the UMRA) for State, local, or tribal
governments or the private sector. The rule would not impose any
federal intergovernmental mandate because it imposes no enforceable
duty upon state, tribal or local governments. States, tribes and local
governments would have no compliance costs under this rule. It is
expected that states will adopt similar rules, and submit those rules
for inclusion in their authorized RCRA programs, but they have no
legally enforceable duty to do so. For the same reasons, we determined
that this rule contains no regulatory requirements that might
significantly or uniquely affect small governments, and thus, is not
subject to the requirements of sections 202 and 205 of UMRA. In
addition, EPA has determined that this rule does not contain a Federal
mandate that may result in expenditures of $100 million or more for
State, local, and tribal governments, in the aggregate, or the private
sector in any one year.

E. Executive Order 13132: Federalism

Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August
10, 1999), requires EPA to develop an accountable process to ensure
``meaningful and timely input by State and local officials in the
development of regulatory policies that have federalism implications.''
The Executive Order defines ``policies that have federalism
implications'' to include regulations that have ``substantial direct
effects on the States, on the relationship between the national
government and the States, or on the distribution of power and
responsibilities among the various levels of government.''
This final rule does not have federalism implications. It will not
have substantial direct effects on the States, on the relationship
between the national government and the States, or on the distribution
of power and responsibilities among the various levels of government,
as specified in Executive Order 13132. This proposed rule directly
affects the chlorinated aliphatics industry. States and local
governments will not incur direct compliance costs under this rule. It
is expected that states will adopt similar rules, and submit those
rules for inclusion in their authorized RCRA programs, but they have no
legally enforceable duty to do so. Thus, Executive Order 13132 does not
apply to this rule.

F. Executive Order 13084: Consultation and Coordination With Indian
Tribal Governments

Under Executive Order 13084, EPA may not issue a regulation that is
not required by statute, that significantly or uniquely affects the
communities of Indian tribal governments, and that imposes substantial
direct compliance costs on those communities, unless the Federal
government provides the funds necessary to pay the direct compliance
costs incurred by the tribal governments, or EPA consults with those
governments. If EPA complies by consulting, Executive Order 13084
requires EPA to provide to the Office of Management and Budget, in a
separately identified section of the preamble to the rule, a
description of the extent of EPA's prior consultation with
representatives of affected tribal governments, a summary of the nature
of their concerns, and a statement supporting the need to issue the
regulation. In addition, Executive Order 13084 requires EPA to develop
an effective process permitting elected officials and other
representatives of Indian tribal governments ``to provide meaningful
and timely input in the development of regulatory policies on matters
that significantly or uniquely affect their communities.''
Today's rule does not significantly or uniquely affect the
communities of Indian tribal governments. There is no impact to tribal
governments as the result of the proposed action. In addition, this
rule is required by statute (HSWA). Accordingly, the requirements of
section 3(b) of Executive Order 13084 do not apply to this rule.

G. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks

Executive Order 13045, ``Protection of Children from Environmental
Health Risks and Safety Risks'' (62 FR 19885, April 23, 1997), applies
to any rule that: (1) is determined to be ``economically significant''
as defined under E.O. 12866, and (2) concerns an environmental health
or safety risk that EPA has reason to believe may have a
disproportionate effect on children. If the regulatory action meets
both criteria, the Agency must evaluate the environmental health or
safety effects of the planned rule on children, and explain why the
planned regulation is preferable to other potentially effective

[[Page 67125]]

and reasonably feasible alternatives considered by the Agency. This
rule is not subject to the Executive Order because it is not
economically significant as defined in E.O. 12866, and because the
Agency does not have reason to believe the environmental health or
safety risks addressed by this action present a disproportionate risk
to children.
The topic of environmental threats to children's health is growing
in regulatory importance as scientists, policy makers, and village
leaders continue to recognize the extent to which children are
particularly vulnerable to environmental hazards. Recent EPA actions
have been in the forefront of addressing environmental threats to the
health and safety of children. Today's final rule further reflects our
commitment to mitigating environmental threats to children.
A few significant physiological characteristics are largely
responsible for children's increased susceptibility to environmental
hazards. First, children eat proportionately more food, drink
proportionately more fluids, and breathe more air per pound of body
weight than do adults. As a result, children potentially experience
greater levels of exposure to environmental threats than do adults.
Second, because children's bodies are still in the process of
development, their immune systems, neurological systems, and other
immature organs can be more easily and considerably affected by
environmental hazards.
Today's rule will reduce risks posed by the hazardous constituents
found in the listed waste streams by requiring more appropriate and
safer management practices. EPA considered risks to children in its
risk assessment. The more appropriate and safer management practices
promulgated in this rule are projected to reduce risks to children
potentially exposed to the constituents of concern.

H. National Technology Transfer and Advancement Act of 1995

Section 12(d) of the National Technology Transfer and Advancement
Act of 1995 (``NTTAA''), Pub L. No. 104-113, section 12(d) (15 U.S.C.
272 note) directs EPA to use voluntary consensus standards in its
regulatory activities, unless to do so would be inconsistent with
applicable law or otherwise impractical. Voluntary consensus standards
are technical standards (e.g., materials specifications, test methods,
sampling procedures, and business practices) that are developed or
adopted by voluntary consensus standards bodies. The NTTAA directs EPA
to provide Congress, through OMB, explanations when the Agency decides
not to use available and applicable voluntary consensus standards.
This rulemaking does not involve technical standards. Therefore,
EPA is not considering the use of any voluntary consensus standards.

I. Executive Order 12898: Environmental Justice

Under Executive Order 12898, ``Federal Actions to Address
Environmental Justice in Minority Populations and Low-Income
Populations,'' as well as through EPA's April 1995, ``Environmental
Justice Strategy, OSWER Environmental Justice Task Force Action Agenda
Report,'' and National Environmental Justice Advisory Council, EPA has
undertaken to incorporate environmental justice into its policies and
programs. EPA is committed to addressing environmental justice
concerns, and is assuming a leadership role in environmental justice
initiatives to enhance environmental quality for all residents of the
United States. The Agency's goals are to ensure that no segment of the
population, regardless of race, color, national origin, or income,
bears disproportionately high and adverse human health and
environmental effects as a result of EPA's policies, programs, and
activities.
Today's rule is intended to reduce risks from the generation and
management of hazardous wastes and to benefit all populations. As such,
this rule is not expected to cause any disproportionately high and
adverse impacts to minority or low-income communities versus non-
minority or affluent communities.
In making hazardous waste listing determinations, we base our
evaluations of potential risk from the generation and management of
solid wastes on an analysis of potential individual risk. In conducting
risk evaluations, our goal is to estimate potential risk to any
population of potentially exposed individuals (e.g., home gardeners,
adult farmers, children of farmers, anglers) located in the vicinity of
any generator or facility handling a waste. Therefore, we are not
putting poor, rural, or minority populations at any disadvantage with
regard to our evaluation of risk or with regard to how the Agency makes
its proposed hazardous waste listing determinations.
In promulgating decisions to list two wastes as hazardous (i.e.,
EDC/VCM wastewater treatment sludges managed in land treatment units,
and VCM-A wastewater treatment sludges), all populations potentially
exposed to these wastes or potentially exposed to releases of the
hazardous constituents in the wastes will benefit from the listing
determinations. In addition, listing determinations are effected at the
national level. The wastes proposed to be listed as hazardous will be
hazardous regardless of where they are generated and regardless of
where they may be managed. Although the Agency understands that the
listing determinations may affect where these wastes are managed in the
future (in that hazardous wastes must be managed at subtitle C
facilities), the Agency's decision to list these wastes as hazardous is
independent of any decisions regarding the location of waste generators
and the siting of waste management facilities.
Similarly, in cases where the Agency is not listing a solid waste
as hazardous because the waste does not meet the criteria for being
identified as a hazardous waste, these decisions are based upon an
evaluation of potential individual risks located in proximity to any
facility handling the waste. In the case of wastewater treatment
sludges from the production of allyl chloride and methyl chloride and
in the case of EDC/VCM wastewater treatment sludges managed in
landfills, we believe the potential risk levels associated with the
wastes are safe for all populations potentially exposed to the wastes
and their constituents.

J. Congressional Review Act

The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the
Small Business Regulatory Enforcement Fairness Act of 1996, generally
provides that before a rule may take effect, the agency promulgating
the rule must submit a rule report, which includes a copy of the rule,
to each House of the Congress and to the Comptroller General of the
United States. EPA will submit a report containing this rule and other
required information to the U.S. Senate, the U.S. House of
Representatives, and the Comptroller General of the United States prior
to publication of the rule in the Federal Register. A Major rule cannot
take effect until 60 days after it is published in the Federal
Register. This action is not a ``major rule'' as defined by 5 U.S.C.
804(2). This rule will be effective May 7, 2001.

List of Subjects

40 CFR 148

Administrative practice and procedure, Hazardous waste, Reporting
and recordkeeping requirements, Water supply.

[[Page 67126]]

40 CFR 261

Environmental protection, Hazardous materials, Waste treatment and
disposal, Recycling.

40 CFR Part 268

Environmental protection, Hazardous materials, Waste management,
Reporting and recordkeeping requirements, Land disposal restrictions,
Treatment standards.

40 CFR Part 271

Environmental protection, Administrative practice and procedure,
Confidential business information, Hazardous material transportation,
Hazardous waste, Indians--lands, Intergovernmental relations,
Penalties, Reporting and recordkeeping requirements, Water pollution
control, Water supply.

40 CFR Part 302

Environmental protection, Air pollution control, Chemicals,
Emergency Planning and Community Right-to-Know Act, Extremely hazardous
substances, Hazardous chemicals, Hazardous materials, Hazardous
materials transportation, Hazardous substances, Hazardous waste,
Intergovernmental relations, Natural resources, Reporting and
recordkeeping requirements, Superfund, Waste treatment and disposal,
Water pollution control, Water supply.

Dated: September 29, 2000.
Carol M. Browner,
Administrator.

For the reasons setforth in the preamble, title 40, chapter I of
the Code of Federal Regulations is amended as follows:

PART 148--HAZARDOUS WASTE INJECTION RESTRICTIONS

1. The authority citation for part 148 continues to read as
follows:

Authority: Sec. 3004, Resource Conservation and Recovery Act, 42
U.S.C. 6901 et seq.

2. Section 148.18 is amended by adding paragraphs (j) and (k) to
read as follows:

Sec. 148.18 Waste-specific prohibitions--newly listed and identified
wastes.

* * * * *
(j) Effective May 8, 2001, the wastes specified in 40 CFR 261.32 as
EPA Hazardous Waste Numbers K174 and K175 are prohibited from
underground injection.
(k) The requirements of paragraphs (a) through (j) of this section
do not apply:
(1) If the wastes meet or are treated to meet the applicable
standards specified in subpart D of 40 CFR part 268; or
(2) If an exemption from a prohibition has been granted in response
to a petition under subpart C of this part; or
(3) During the period of extension of the applicable effective
date, if an extension has been granted under Sec. 148.4 of this part.

PART 261--IDENTIFICATION AND LISTING OF HAZARDOUS WASTE

3. The authority citation for part 261 continues to read as
follows:

Authority: 42 U.S.C. 6905, 6912(a), 6921, 6922, 6924(y), and
6938.

4. In Sec. 261.32, the table is amended by adding in alphanumeric
order (by the first column) the following waste streams to the subgroup
``Organic Chemicals'' to read as follows:

Sec. 261.32 Hazardous waste from specific sources.

------------------------------------------------------------------------
Industry and EPA hazardous
waste No. Hazardous waste Hazardous code
------------------------------------------------------------------------

* * * *
* * *
Organic chemicals:

* * * *
* * *
K174..................... Wastewater T
treatment sludges
from the
production of
ethylene
dichloride or
vinyl chloride
monomer
(including
sludges that
result from
commingled
ethylene
dichloride or
vinyl chloride
monomer
wastewater and
other
wastewater),
unless the
sludges meet the
following
conditions: (i)
they are disposed
of in a subtitle
C or non-
hazardous
landfill licensed
or permitted by
the state or
federal
government; (ii)
they are not
otherwise placed
on the land prior
to final
disposal; and
(iii) the
generator
maintains
documentation
demonstrating
that the waste
was either
disposed of in an
on-site landfill
or consigned to a
transporter or
disposal facility
that provided a
written
commitment to
dispose of the
waste in an off-
site landfill.
Respondents in
any action
brought to
enforce the
requirements of
subtitle C must,
upon a showing by
the government
that the
respondent
managed
wastewater
treatment sludges
from the
production of
vinyl chloride
monomer or
ethylene
dichloride,
demonstrate that
they meet the
terms of the
exclusion set
forth above. In
doing so, they
must provide
appropriate
documentation
(e.g., contracts
between the
generator and the
landfill owner/
operator,
invoices
documenting
delivery of waste
to landfill,
etc.) that the
terms of the
exclusion were
met.
K175..................... Wastewater T
treatment sludges
from the
production of
vinyl chloride
monomer using
mercuric chloride
catalyst in an
acetylene-based
process.

* * * *
* * *
------------------------------------------------------------------------

[[Page 67127]]

5. Appendix VII to Part 261 is amended by adding the following
wastestreams in alphanumeric order (by the first column) to read as
follows:

Appendix VII To Part 261--Basis for Listing Hazardous Waste

------------------------------------------------------------------------
Hazardous constituents for which
EPA hazardous waste no. listed
------------------------------------------------------------------------

* * * *
* * *
K174.................................. 1,2,3,4,6,7,8-Heptachlorodibenzo-
p-dioxin (1,2,3,4,6,7,8-HpCDD),
1,2,3,4,6,7,8-
Heptachlorodibenzofuran
(1,2,3,4,6,7,8-HpCDF),
1,2,3,4,7,8,9-
Heptachlorodibenzofuran
(1,2,3,6,7,8,9-HpCDF), HxCDDs
(All Hexachlorodibenzo-p-
dioxins), HxCDFs (All
Hexachlorodibenzofurans),
PeCDDs (All Pentachlorodibenzo-
p-dioxins), OCDD
(1,2,3,4,6,7,8,9-
Octachlorodibenzo-p-dioxin,
OCDF (1,2,3,4,6,7,8,9-
Octachlorodibenzofuran), PeCDFs
(All Pentachlorodibenzofurans),
TCDDs (All tetrachlorodi-benzo-
p-dioxins), TCDFs (All
tetrachlorodibenzofurans).
K175.................................. Mercury
------------------------------------------------------------------------

Appendix VIII to Part 261--Hazardous Constituents

6. Appendix VIII to Part 261 is amended by adding in alphabetical
order of common name the following entries:

----------------------------------------------------------------------------------------------------------------
Chemical
Common name Chemical abstracts name abstracts Hazardous
No. waste No.
----------------------------------------------------------------------------------------------------------------

* * * * * *
*
Octachlorodibenzo-p-dioxin (OCDD)............. 1,2,3,4,6,7,8,9-Octachlorodibenzo-p- 3268-87-9 ...........
dioxin.
Octachlorodibenzofuran (OCDF)................. 1,2,3,4,6,7,8,9-Octachlorodibenofuran. 39001-02-0 ...........

* * * * * *
*
----------------------------------------------------------------------------------------------------------------

PART 268--LAND DISPOSAL RESTRICTIONS

7. The authority citation for part 268 continues to read as
follows:

Authority: 42 U.S.C. 6905, 6912(a), 6921, and 6924.

Subpart C--Prohibitions on Land Disposal

8. Section 268.33 is revised to read as follows:

Sec. 268.33 Waste specific prohibitions--chlorinated aliphatic wastes.

(a) Effective May 8, 2001, the wastes specified in 40 CFR part 261
as EPA Hazardous Wastes Numbers K174, and K175, soil and debris
contaminated with these wastes, radioactive wastes mixed with these
wastes, and soil and debris contaminated with radioactive wastes mixed
with these wastes are prohibited from land disposal.
(b) The requirements of paragraph (a) of this section do not apply
if:
(1) The wastes meet the applicable treatment standards specified in
subpart D of this part;
(2) Persons have been granted an exemption from a prohibition
pursuant to a petition under Sec. 268.6, with respect to those wastes
and units covered by the petition;
(3) The wastes meet the applicable treatment standards established
pursuant to a petition granted under Sec. 268.44;
(4) Hazardous debris has met the treatment standards in Sec. 268.40
or the alternative treatment standards in Sec. 268.45; or
(5) Persons have been granted an extension to the effective date of
a prohibition pursuant to Sec. 268.5, with respect to these wastes
covered by the extension.
(c) To determine whether a hazardous waste identified in this
section exceeds the applicable treatment standards specified in
Sec. 268.40, the initial generator must test a sample of the waste
extract or the entire waste, depending on whether the treatment
standards are expressed as concentrations in the waste extract or the
waste, or the generator may use knowledge of the waste. If the waste
contains regulated constituents in excess of the applicable levels of
subpart D of this part, the waste is prohibited from land disposal, and
all requirements of part 268 are applicable, except as otherwise
specified.
(d) Disposal of K175 wastes that have complied with all applicable
40 CFR 268.40 treatment standards must also be macroencapsulated in
accordance with 40 CFR 268.45 Table 1 unless the waste is placed in:
(1) A Subtitle C monofill containing only K175 wastes that meet all
applicable 40 CFR 268.40 treatment standards; or
(2) A dedicated Subtitle C landfill cell in which all other wastes
being co-disposed are at pH6.0.

9. In Sec. 268.40, the Table is amended by adding entries to F039
in alphabetical order, by adding in alphanumeric order new entries for
K174 and K175, and by adding footnote 12 to read as follows:

Sec. 268.40 Applicability of treatment standards.

* * * * *

BILLING CODE 6560-50-P

[[Page 67128]]

[GRAPHIC] [TIFF OMITTED] TR08NO00.000

[[Page 67129]]

[GRAPHIC] [TIFF OMITTED] TR08NO00.001

[[Page 67130]]

[GRAPHIC] [TIFF OMITTED] TR08NO00.002

BILLING CODE 6560-50-C

[[Page 67131]]

* * * *
* * *
Footnotes to Treatment Standard Table 268.40
\1\ The waste descriptions provided in this table do not replace
waste descriptions in 40 CFR Part 261. Descriptions of Treatment/
Regulatory Subcategories are provided, as needed, to distinguish
between applicability of different standards.
\2\ CAS means Chemical Abstract Services. When the waste code
and/or regulated constituents are described as a combination of a
chemical with its salts and/or esters, the CAS number is given for
the parent compound only.
\3\ Concentration standards for wastewaters are expressed in mg/
L and are based on analysis of composite samples.
\4\ All treatment standards expressed as a Technology Code or
combination of Technology Codes are explained in detail in 40 CFR
268.42 Table 1-Technology Codes and Descriptions of Technology-Based
Standards.
\5\ Except for Metals (EP or TCLP) and Cyanides (Total and
Amenable) the nonwastewater treatment standards expressed as a
concentration were established, in part, based upon incineration in
units operated in accordance with the technical requirements of 40
CFR part 264, subpart O or 40 CFR part 265, subpart O, or based upon
combustion in fuel substitution units operating in accordance with
applicable technical requirements. A facility may comply with these
treatment standards according to provisions in 40 CFR 268.40(d). All
concentration standards for nonwastewaters are based on analysis of
grab samples.
* * * *
* * *
\11\ For these wastes, the definition of CMBST is limited to:
(1) combustion units operating under 40 CFR 266, (2) combustion
units permitted under 40 CFR part 264, subpart O, or (3) combustion
units operating under 40 CFR 265, subpart O, which have obtained a
determination of equivalent treatment under 268.42(b).
\12\ Disposal of K175 wastes that have complied with all
applicable 40 CFR 268.40 treatment standards must also be
macroencapsulated in accordance with 40 CFR 268.45 Table 1 unless
the waste is placed in:
(1) A Subtitle C monofill containing only K175 wastes that meet
all applicable 40 CFR 268.40 treatment standards; or
(2) A dedicated Subtitle C landfill cell in which all other
wastes being co-disposed are at pH6.0.
* * * * *

10. In Sec. 268.48 the Table is amended by adding in alphabetical
sequence the following entries under the heading organic constituents:
(The footnotes are republished without change.)

Sec. 268.48 Universal treatment standards.

(a) * * *

Universal Treatment Standards
[Note: NA means not applicable]
----------------------------------------------------------------------------------------------------------------
Wastewater Nonwastewater
standard standard
-------------------------------------
Regulated constituent common name CAS1 Concentration in
number Concentration in mg/Kg3 unless
mg/L2 noted as ``mg/L
TCLP''
----------------------------------------------------------------------------------------------------------------

* * * * * * *
1,2,3,4,6,7,8-Heptachlorodibenzo-p-dioxin (1,2,3,4,6,7,8- 35822-46-9 0.000035 0.0025
HpCDD)......................................................
1,2,3,4,6,7,8-Heptachlorodibenzofuran (1,2,3,4,6,7,8-HpCDF).. 67562-39-4 0.000035 0.0025
1,2,3,4,7,8,9-Heptachlorodibenzofuran (1,2,3,4,7,8,9-HpCDF).. 55673-89-7 0.000035 0.0025

* * * * * * *
1,2,3,4,6,7,8,9-Octachlorodibenzo-p-dioxin (OCDD)............ 3268-87-9 0.000063 0.005
1,2,3,4,6,7,8,9-Octachlorodibenzofuran (OCDF)................ 39001-02-0 0.000063 0.005

* * * * * * *
----------------------------------------------------------------------------------------------------------------
* * * * * * *
1 CAS means Chemical Abstract Services. When the waste code and/or regulated constituents are described as a
combination of a chemical with its salts and/or esters, the CAS number is given for the parent compound only.
2 Concentration standards for wastewaters are expressed in mg/L and are based on analysis of composite samples.
3 Except for Metals (EP or TCLP) and Cyanides (Total and Amenable) the nonwastewater treatment standards
expressed as a concentration were established, in part, based upon incineration in units operated in
accordance with the technical requirements of 40 CFR Part 264, Subpart O, or 40 CFR Part 265, Subpart O, or
based upon combustion in fuel substitution units operating in accordance with applicable technical
requirements. A facility may comply with these treatment standards according to provisions in 40 CFR
268.40(d). All concentration standards for nonwastewaters are based on analysis of grab samples.

* * * * *

PART 271--REQUIREMENTS FOR AUTHORIZATION OF STATE HAZARDOUS WASTE
PROGRAMS

11. The authority citation for Part 271 continues to read as
follows:

Authority: 42 U.S.C. 6905, 6912(a), and 6926.

12. In Sec. 271.1(j) tables 1 and 2 are amended by adding the
following entries in chronological order by date of publication to read
as follows.

Sec. 271.1 Purpose and scope.

* * * * *
(j) * * *

[[Page 67132]]

Table 1.--Regulations Implementing the Hazardous and Solid Waste Amendments of 1984
----------------------------------------------------------------------------------------------------------------
Federal Register
Promulgation date Title of regulation reference Effective date
----------------------------------------------------------------------------------------------------------------

* * * * * * *
September 29, 2000................... Listing of Hazardous 65 FR 67132 May 7, 2001.
Wastes K174 and K175.

* * * * * * *
----------------------------------------------------------------------------------------------------------------

Table 2.--Self Implementing Provisions of the Solid Waste Amendments of 1984
----------------------------------------------------------------------------------------------------------------
Self-implementing Federal Register
Effective date provision RCRA citation reference
----------------------------------------------------------------------------------------------------------------

* * * * * * *
May 7, 2001.......................... Prohibition on land 3004(g)(4)(C) and November 8, 2000.
disposal of K174 and 3004(m). 65 FR 67132.
K175 wastes, and
prohibition on land
disposal of
radioactive waste
mixed with K174 and
K175 wastes, including
soil and debris..

* * * * * * *
----------------------------------------------------------------------------------------------------------------

* * * * *

PART 302--DESIGNATION, REPORTABLE QUANTITIES, AND NOTIFICATION

13. The authority citation for part 302 continues to read as
follows:

Authority: 42 U.S.C. 9602, 9603, and 9604; 33 U.S.C. 1321 and
1361.

14. In Sec. 302.4, Table 302.4 is amended by adding the following
new entries in alphanumeric order at the end of the table to read as
follows:

Sec. 302.4 Designation of hazardous substances.

* * * * *

Table 302.4--List of Hazardous Substances and Reportable Quantities
[Note: All Comments/Notes Are Located at the End of This Table]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Statutory Final RQ
---------------------------------------------------------------------------
Hazardous substance CASRN Regulatory synonyms Pounds
RQ Code RCRA waste No. Category (KG)
------------------------------------------------------------------------------------------------------------------------------------------------

* * * * * * *
K174f............................. ................ .................. 1* 4 K174 X 1(0.454)

* * * * * * *
K175f............................. ................ .................. 1* 4 K175 X 1(0.454)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Indicates the statutory sources as defined by 1, 2, 3, and 4 below.
1 *--Indicates that the 1-pound RQ is a CERCLA statutory RQ.
4--Indicates that the statutory source for designation of this hazardous substance under CERCLA is RCRA Section 3001.
f See 40 CFR 302.6(b)(1) for application of the mixture rule to this hazardous waste.

15. Section 302.6 is amended by revising paragraph (b)(1)(iii) to
read as follows:

Sec. 302.6 Notification requirements.

* * * * *
(b) * * *
(1) * * *
(iii) For waste streams K169, K170, K171, K172, K174, and K175,
knowledge of the quantity of all of the hazardous constituent(s) may be
assumed, based on the following maximum observed constituent
concentrations identified by EPA:

[[Page 67133]]

------------------------------------------------------------------------
Waste Constituent max ppm
------------------------------------------------------------------------
K174.......... 2,3,7,8-TCDD............................. 0.000039
1,2,3,7,8-PeCDD.......................... 0.0000108
1,2,3,4,7,8,-HxCDD....................... 0.0000241
1,2,3,6,7,8,-HxCDD....................... 0.000083
1,2,3,7,8,9,-HxCDD....................... 0.000062
1,2,3,4,6,7,8-HpCDD...................... 0.00123
OCDD..................................... 0.0129
2,3,7,8-TCDF............................. 0.000145
1,2,3,7,8-PeCDF.......................... 0.0000777
2,3,4,7,8-PeCDF.......................... 0.000127
1,2,3,4,7,8-HxCDF........................ 0.001425
1,2,3,6,7,8-HxCDF........................ 0.000281
1,2,3,7,8,9-HxCDF........................ 0.00014
2,3,4,6,7,8-HxCDF........................ 0.000648
1,2,3,4,6,7,8-HpCDF...................... 0.0207
1,2,3,4,7,8,9-HpCDF...................... 0.0135
OCDF..................................... 0.212
K175.......... Mercury.................................. 9200
------------------------------------------------------------------------

* * * * *
[FR Doc. 00-25928 Filed 11-7-00; 8:45 am]
BILLING CODE 6560-50-P

Notices For
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994

Hazardous Waste Management System; Identification and Listing of Hazardous Waste; Chlorinated Aliphatics Production Wastes; Land Disposal Restrictions for Newly Identified Wastes; and CERCLA Hazardous Substance Designation and Reportable Quantities

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