National Emission Standards for Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants

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

[Federal Register: December 19, 2003 (Volume 68, Number 244)]
[Rules and Regulations]
[Page 70903-70946]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr19de03-13]
[[Page 70904]]

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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 63
[OAR-2002-0017; FRL-7551-5]
RIN 2060-AE85

National Emission Standards for Hazardous Air Pollutants: Mercury
Emissions From Mercury Cell Chlor-Alkali Plants

AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.

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SUMMARY: This action promulgates national emission standards for
hazardous air pollutants (NESHAP), specifically mercury emissions, from
mercury cell chlor-alkali plants. The final rule will limit mercury air
emissions from these plants. The final rule will implement section
112(d) of the Clean Air Act (CAA) which requires all categories and
subcategories of major sources and area sources listed under section
112(c) to meet hazardous air pollutant emission standards reflecting
the application of the maximum achievable control technology (MACT).
Mercury cell chlor-alkali plants are a subcategory of the chlorine
production source category listed under the authority of section
112(c)(1) of the CAA. The chlorine production source category was also
identified as a source of mercury under section 112(c)(6) that must be
subjected to standards. In addition, mercury cell chlor-alkali plants
were listed as an area source category under section 112(c)(3) and
(k)(3)(B) of the CAA. The final rule, which will satisfy our
requirement to issue 112(d) regulations under each of these listings
(for mercury), will reduce mercury emissions by about 3,068 kilograms
per year from the levels allowed by the existing Mercury NESHAP.
Mercury is a neurotoxicant that accumulates, primarily in the
especially potent form of methylmercury, in aquatic food chains. The
highest levels are reached in predator fish species. Mercury emitted to
the air from various types of sources (usually in the elemental or
inorganic forms) transports through the atmosphere and eventually
deposits onto land or water bodies. When mercury is deposited to
surface waters, natural processes (bacterial) can transform some of the
mercury into methylmercury that accumulates in fish. Ingestion is the
primary exposure route of interest for methylmercury. The health effect
of greatest concern due to methylmercury is neurotoxicity, particularly
with respect to fetuses and young children.
In addition, in this final action, we are utilizing our authority
under section 112(d)(4) of the CAA not to regulation chlorine and
hydrochloric acid (HCl) emissions from the mercury cell chlor-alkali
plant subcategory.

EFFECTIVE DATE: December 19, 2003.

ADDRESSES: Docket. We have established an official public docket for
this action under Docket ID No. OAR-2002-0017, A-2000-32, A-2002-09,
and OAR-2002-0016 available for public viewing at the Office of Air and
Radiation Docket and Information Center (Air Docket) in the EPA Docket
Center, (EPA/DC) EPA West, Room B102, 1301 Constitution Avenue, NW.,
Washington, DC.

FOR FURTHER INFORMATION CONTACT: For information concerning
applicability and rule determinations, contact your State or local
regulatory agency representative or the appropriate EPA Regional Office
representative. For information concerning analyses performed in
developing the final rule, contact Mr. Iliam Rosario, Metals Group,
Emission Standards Division (C439-02), U.S. EPA, Research Triangle
Park, North Carolina 27711; telephone number (919) 541-5308; fax number
(919) 541-5600; electronic mail address: rosario.iliam@epa.gov.

SUPPLEMENTARY INFORMATION: Docket. The official public docket consists
of the documents specifically referenced in this action, any public
comments received, and other information related to this action.
Although a part of the official docket, the public docket does not
include Confidential Business Information or other information whose
disclosure is restricted by statute.
The official public docket is the collection of materials that is
available for public viewing. The EPA Docket Center Public Reading Room
is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding
legal holidays. The telephone number for the Reading Room is (202) 566-
1744, and the telephone number for the Air Docket is (202) 566-1742.
Electronic Docket Access. You may access the final rule
electronically through the EPA Internet under the Federal Register
listings at http://www.epa.gov/fedrgstr/.

An electronic version of the public docket is available through
EPA's electronic public docket and comment system, EPA Dockets. You may
use EPA Dockets at http://www.regulations.gov/ to view public comments,
access the index listing of the contents of the official public docket,
and to access those documents in the public docket that are available
electronically. Although not all docket materials may be available
electronically, you may still access any of the publicly available
docket materials through the docket facility in the above paragraph
entitled ``Docket.'' Once in the system, select ``search,'' then key in
the appropriate docket identification number.
Judicial Review. Under CAA section 307(b), judicial review of the
final NESHAP is available only by filing a petition for review in the
U.S. Court of Appeals for the District of Columbia Circuit on or before
February 17, 2004. Only those objections to the NESHAP which were
raised with reasonable specificity during the period for public comment
may be raised during judicial review. Under section 307(b)(2)of the
CAA, the requirements established by today's final action may not be
challenged separately in any civil or criminal proceeding we bring to
enforce these requirements.
Regulated Entities. Categories and entities potentially regulated
by this action include:

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Category SIC \1\ NAICS \2\ Regulated entities
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Industry.................... 2812 325181 Alkalies and Chlorine Manufacturing.
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\1\ Standard Industrial Classification.
\2\ North American Information Classification System.

This list is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be regulated by this
action. To determine whether your facility is regulated by this action,
you should examine the applicability criteria in Sec. 63.8182 of the
final rule. If you have questions regarding the applicability of this
action to a particular entity, consult your State or local agency (or
EPA Regional Office) described in the preceding FOR FURTHER INFORMATION
CONTACT section.
Worldwide Web (WWW). In addition to being available in the docket,
an

[[Page 70905]]

electronic copy of the final rule will also be available on the WWW
through the Technology Transfer Network (TTN). Following signature, a
copy of the final rule will be posted on the TTN's policy and guidance
page for newly proposed or promulgated rules http://www.epa.gov/ttn/oarpg.

Outline. The information in this preamble is organized as follows:

I. Introduction and Background
A. What Is the Source of Authority for Development of NESHAP?
B. What Is the Source Category?
C. What Criteria Are Used in the Development of NESHAP?
D. What Actions Were Proposed for This Source Category?
E. How Did the Public Participate in Developing the Rulemaking?
F. What Is a Mercury Cell Chlor-alkali Plant?
G. How Does This Action Relate to the 40 CFR Part 61 Mercury
NESHAP?
II. Summary of Changes Since Proposal
III. Summary of the Final Rule
A. What Is the Source Category?
B. What Are the Affected Sources and Emission Points To Be
Regulated?
C. What Are the Emissions Limitations?
D. What Are the Work Practice Standards?
E. What Are the Operation and Maintenance Requirements?
F. What Are the General Compliance Requirements?
G. What Are the Initial Compliance Requirements?
H. What Are the Continuous Compliance Requirements?
I. How Are Initial and Continuous Compliance With the Work
Practice Standards To Be Demonstrated?
J. What Are the Notification and Reporting Requirements?
K. What Are the Recordkeeping Requirements?
IV. Summary of Major Comments and Responses
A. What Issues Were Raised Regarding the Sources That Are
Subject to the Rule as Proposed?
B. What Issues Were Raised Regarding the HAP Addressed by the
Rule as Proposed?
C. What Issues Were Raised Regarding the Compliance Date?
D. What Issues Were Raised Regarding the Emission Limitations?
E. What Issues Were Raised Regarding the Work Practices?
F. What Issues Were Raised Regarding the Monitoring and
Continuous Compliance Requirements?
V. What Are the Environmental, Cost, and Economic Impacts of the
Final Rule?
A. What Are the Air Emission Impacts?
B. What Are the Non-air Health, Environmental, and Energy
Impacts?
C. What Are the Cost and Economic Impacts?
VI. Statutory and Executive Order Reviews
A. Executive Order 12866--Regulatory Planning and Review
B. Paperwork Reduction Act
C. Regulatory Flexibility Act
D. Unfunded Mandates Reform Act of 1995
E. Executive Order 13132--Federalism
F. Executive Order 13175--Consultation and Coordination With
Indian Tribal Governments
G. Executive Order 13045--Protection of Children From
Environmental Health Risks and Safety Risks
H. Executive Order 13211--Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
I. National Technology Transfer and Advancement Act of 1995
J. Congressional Review Act

I. Introduction and Background

A. What Is the Source of Authority for Development of NESHAP?

Section 112 of the CAA contains our authorities for reducing
emissions of hazardous air pollutants (HAP). Section 112(c)(1) of the
CAA requires us to list categories and subcategories of major sources
and area sources of HAP and to establish NESHAP for the listed source
categories and subcategories. Section 112(c)(6) requires us to list
source categories and subcategories assuring that sources accounting
for not less than 90 percent of the aggregate emissions of each of
seven specific pollutants (including mercury) are subject to standards
under section 112(d) of the CAA. Finally, section 112(c)(3) and
(k)(3)(B) require that we list source categories to ensure that area
sources representing 90 percent of the area source emissions of the 30
urban HAP are subject to regulation under section 112(d).

B. What Is the Source Category?

The chlorine production source category was initially listed as a
category of major sources of HAP pursuant to section 112(c)(1) of the
CAA on July 16, 1992 (57 FR 31576). At the time of the initial listing,
we defined the chlorine production source category as follows:

The Chlorine Production Source Category includes any facility
engaged in the production of chlorine. The category includes, but is
not limited to, facilities producing chlorine by the following
production methods: diaphragm cell, mercury cell, membrane cell,
hybrid fuel cell, Downs cell, potash manufacture, hydrochloric acid
decomposition, nitrosyl chloride process, nitric acid/salt process,
Kel-Chlor process, and sodium chloride/sulfuric acid process.

In our subsequent analysis of the chlorine production source
category, we did not identify any facilities that produce chlorine
using hybrid fuel cells, the nitrosyl chloride process, the Kel-Chlor
process, the sodium chloride/sulfuric acid process, or as a by-product
from potash manufacturing. The majority of the source category is made
up of chlor-alkali plants that produce chlorine and caustic (sodium
hydroxide) using mercury cells, diaphragm cells, or membrane cells. We
also identified operating plants that produce chlorine as a by-product:
one from the production of sodium metal in Down cells, another from the
production of potassium nitrate fertilizer that uses the nitric acid/
salt process, and a third that produces chlorine as a by-product from
primary magnesium refining (magnesium refining is a separately listed
source category and will be addressed on its own in a separate
rulemaking). In addition, at a site where a membrane cell process is
located, we have also identified a process that produces chlorine
through the decomposition of HCl. Our analysis shows that the only HAP
emitted from sources within this chlorine production source category
are chlorine, HCl, and mercury; and mercury is only emitted from
mercury cell chlor-alkali plants.
In addition to the listing pursuant to section 112(c)(1), chlor-
alkali production was among the categories of sources identified
pursuant to section 112(c)(6) to achieve the 90 percent goal for
mercury. While this category was titled ``chlor-alkali production,''
the only sources of mercury emissions are mercury cell chlor-alkali
plants. However, the mercury cell chlor-alkali subcategory was not
officially ``listed'' under section 112(c)(6) because the chlorine
production source category was already listed under section 112(c)(1),
and sources of mercury emissions at mercury cell chlor-alkali plants
would be subject to section 112(d)(2) standards via that chlorine
production source category listing.
Finally, on July 19, 1999 (64 FR 38706), we listed Mercury Cell
Chlor-Alkali Plants as an area source category. In this listing,
Mercury Cell Chlor-Alkali Plants were identified as one of the area
source categories that contribute at least 15 percent of the total area
source mercury emissions.
Because of the differences in the production methods and the HAP
emitted, we decided to divide the chlorine production category into two
subcategories: (1) Mercury cell chlor-alkali plants, and (2) chlorine
production plants that do not rely upon mercury cells for chlorine
production (diaphragm cell chlor-alkali plants, membrane cell chlor-
alkali plants, etc.). Thus, on July 3, 2002, we issued separate
proposals to address the emissions of mercury from the mercury cell
chlor-alkali plant subcategory

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sources (67 FR 44672) and the emissions of chlorine and HCl from both
non-mercury cell chlorine production subcategory sources and mercury
chlor-alkali plant subcategory sources (67 FR 44713).

C. What Criteria Are Used in the Development of NESHAP?

Section 112(d)(2) of the CAA specifies that NESHAP for new and
existing sources must reflect the maximum degree of reduction in HAP
emissions that is achievable, taking into consideration the cost of
achieving the emissions reductions, any non-air quality health and
environmental benefits, and energy requirements. This level of control
is commonly referred to as MACT.
Section 112(d)(3) defines the minimum level of control or floor
allowed for NESHAP. In essence, the MACT floor ensures that the
standards are set at a level that assures that all affected sources
achieve the level of control at least as stringent as that already
achieved by the better-controlled and lower-emitting sources in each
source category or subcategory. For new sources, the MACT floor cannot
be less stringent than the emission control that is achieved in
practice by the best-controlled similar source. The MACT standards for
existing sources cannot be less stringent than the average emission
limitation achieved by the best-performing 12 percent of existing
sources in the category or subcategory (or the best-performing five
sources for categories or subcategories with fewer than 30 sources).
In developing MACT, we also consider control options that are more
stringent than the floor. We may establish standards more stringent
than the floor based on the consideration of cost of achieving the
emissions reductions, any non-air quality health and environmental
impacts, and energy impacts.
The CAA includes exceptions to the general statutory requirement to
establish emission standards based on MACT. For pollutants for which a
threshold has been established, section 112(d)(4) allows us ``to
consider such threshold level, with an ample margin of safety, when
establishing emissions standards. * * *.''

D. What Actions Were Proposed for This Source Category?

As discussed above, we divided the chlorine production source
category into mercury cell chlor-alkali plants, and chlorine production
plants that do not rely upon mercury cells for chlorine production
(non-mercury cell chlorine production). On July 3, 2002, we proposed
one action to address mercury emissions from the mercury cell chlor-
alkali plant subcategory, and a separate action to address chlorine and
HCl emissions from both subcategories.
For mercury emissions from mercury cell chlor-alkali plant
subcategory sources, we issued a proposed rule based on MACT (67 FR
44672). Comments were received on the proposed rule and today's action
issues the final rule for the mercury emissions from the mercury cell
chlor-alkali plant subcategory.
We also proposed not to regulate chlorine and HCl emissions from
both the mercury cell chlor-alkali plant and non-mercury cell chlorine
production subcategories under our authority in section 112(d)(4) of
the CAA (67 FR 44713). We based this decision on our determination that
no further control is necessary because chlorine and HCl are ``health
threshold pollutants,'' and chlorine and HCl levels emitted from
chlorine production processes are below their threshold values within
an ample margin of safety. The basis for the determination was a series
of site-specific risk assessments for every chlorine production
facility in the United States that was located at a major source plant
site. In addition, we concluded, using a qualitative evaluation, that
chlorine and HCl emissions from these chlorine production facilities
did not result in adverse environmental effects. Background for this
action is contained in Docket OAR-2002-0016 or Docket A-2002-09. Public
comments on the proposed action were received, and we are finalizing
actions addressing chlorine and HCl emissions in today's Federal
Register. In today's final action, we are utilizing our authority under
section 112(d)(4) not to regulate chlorine and HCl emissions from the
mercury cell chlor-alkali plant subcategory. Final action addressing
the emissions of chlorine and HCl from the non-mercury cell chlorine
production subcategory is contained elsewhere in today's Federal
Register.

E. How Did the Public Participate in Developing the Rulemaking?

Prior to proposal, we met with industry representatives and State
regulatory authorities several times to discuss the data and
information used to develop the proposed standards. In addition, these
and other potential stakeholders, including equipment vendors and
environmental groups, had opportunity to comment on the proposed
standards.
The proposed rule was published in the Federal Register on July 3,
2002 (67 FR 44672). The preamble to the proposed rule discussed the
availability of technical support documents, which described in detail
the information gathered during the standards development process.
Public comments were solicited at proposal.
We received nine public comment letters on the proposed rule (two
of which were received well after the close of the comment period). The
commenters represent the following affiliations: Mercury cell chlor-
alkali companies, industrial trade associations, environmental/
conservation organizations, and a women's advocacy organization. In the
post-proposal period, we talked with commenters and other stakeholders
to clarify comments and to assist in our analysis of the comments.
Records of these contacts are found in Docket OAR-2002-0017 or Docket
A-2000-32. All of the comments have been carefully considered, and,
where appropriate, the final rule has been written to so reflect.
The proposed action not to regulate chlorine and HCl emissions was
published in the Federal Register on July 3, 2002 (67 FR 44713). The
preamble to the proposed action discussed the availability of technical
support documents, which described in detail the information gathered
during the standards development process. Public comments were
solicited at proposal.
We received eight public comment letters on the proposed action.
The commenters represent the following affiliations: Industry
representatives, governmental entities, and environmental groups. In
the post-proposal period, we talked with commenters and other
stakeholders to clarify comments and to assist in our analysis of the
comments. Records of these contacts are found in Docket OAR-2002-0016
or Docket A-2002-09. All of the comments have been carefully
considered.

F. What Is a Mercury Cell Chlor-alkali Plant?

Today's NESHAP apply to mercury emissions from mercury cell chlor-
alkali plants. Mercury cells are considerably larger than other types
of chlor-alkali cells. A mercury cell plant typically has scores of
individual cells (around 60 feet long and 9 feet wide) housed in one or
more cell buildings. Mercury cells are electrically connected together
in series with circuits of 30 or more cells.
In the mercury cell process, each cell actually involves two
distinct operations. The electrolytic cell

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produces chlorine gas, and a separate decomposer produces hydrogen gas
and caustic solution. There is one decomposer associated with each
cell, located directly underneath the cell. The cell and the decomposer
are linked at the two ends by an inlet end box and an outlet end box.
A stream of liquid mercury flows in a continuous loop between the
electrolytic cell and the decomposer. The mercury enters the cell at
the inlet end box and flows down a slight grade to the outlet end box.
At the outlet end box, the mercury flows out of the cell and falls down
to the decomposer. After being processed in the decomposer, the mercury
is pumped back up to the inlet end box of the electrolytic cell.
Saturated salt brine (using either sodium chloride or potassium
chloride) is fed to the electrolytic cell at the inlet end box and
flows toward the outlet end box on top of the mercury stream. The brine
and mercury flow under a dimensionally stable metal anode made of a
titanium substrate with a metal catalyst. The mercury forms the cathode
of the cell.
An electric current is applied between the anode and the mercury
cathode. The electric current causes a reaction producing chlorine gas
at the anode and a mercury:sodium (HgNa) or mercury:potassium (HgK)
amalgam at the cathode. Chlorine is collected at the top of the cell.
The amalgam ultimately exits at the outlet end box, falling into the
decomposer. Depleted brine also exits the cell at the outlet end box.
This brine is generally piped to a tank for resaturation and reuse.
The decomposer is a packed bed reactor where the mercury amalgam is
contacted with deionized water in the presence of a catalyst. The
amalgam reacts with the water, regenerating elemental mercury and
producing caustic (NaOH or KOH) and hydrogen. The caustic and mercury
are separated in a trap at the end of the decomposer. The caustic and
hydrogen are transferred to auxiliary processes for purification, and
the mercury is recycled back to the cell.
Chlorine is collected from the tops of the mercury cells by a
common header system which runs through the cell building. Hydrogen is
collected from the amalgam decomposers in a common header system. The
hydrogen stream contains a small amount of mercury vapor from the
liquid mercury processed in the decomposer. To remove the mercury
vapor, the hydrogen stream is typically cooled, passed through a mist
eliminator, and usually sent to a finishing device such as a carbon
adsorber. The hydrogen may then be discharged to the atmosphere, used
on-site, or sold for use off-site.
In a mercury cell process, a 50 percent caustic solution is
obtained directly from the amalgam decomposers. Thus, the mercury cell
caustic requires little further processing to yield a commercial
product.
Contaminated mercury and mercury-containing wastes are generated
from a number of sources at a mercury cell plant. These include the
hydrogen treatment operation, the brine and caustic treatment
operations, and mercury leaks or spills. Many plants recover mercury
from these wastes on-site in a mercury retort, or mercury thermal
recovery unit.
Mercury is emitted from two point sources associated with the
production of chlorine--the end box ventilation system and by-product
hydrogen system. Mercury is also emitted from mercury thermal recovery
units, which is also a point source. In addition, there are mercury
fugitive emissions from the cell rooms and from the waste recovery
areas.
In addition to mercury, chlorine and HCl are emitted from mercury
cell plants. Chlorine can be emitted from the tail gas stream from the
final liquefier, the cell room, and equipment in chlorine service.
Hydrochloric acid is used to pretreat feed brine prior to entering a
chlor-alkali cell, and at other locations throughout the process to
adjust pH. It can also be emitted from storage tanks and equipment in
HCl service.

G. How Does This Action Relate to the 40 CFR Part 61 Mercury NESHAP?

We promulgated the National Emission Standard for Mercury on April
6, 1973 (40 CFR part 61, subpart E).\1\ Those standards (hereafter
referred to as the Mercury NESHAP) limit mercury emissions from mercury
cell chlor-alkali plants as well as mercury ore processing facilities
and sludge incineration and drying plants. Specifically, the Mercury
NESHAP limit mercury emissions from mercury cell chlor-alkali plants to
2.3 kilogram (kg) (5.1 pound (lb)) of mercury per 24-hour period and
requires that mercury emissions be measured (in a one-time test) from
hydrogen streams, end box ventilation systems, and the cell room
ventilation system. As an alternative to measuring ventilation
emissions from the cell room to demonstrate compliance, the Mercury
NESHAP allow an owner or operator to assume a cell room ventilation
emission value of 1.3 kg (2.9 lb) per day of mercury providing the
owner/operator adheres to a suite of approved design, maintenance and
housekeeping practices. Every mercury cell chlor-alkali plant currently
in operation in the United States complies with the cell room
ventilation provisions by carrying out these practices rather than by
measuring mercury emissions discharged from the cell room. Since every
plant uses the 1.3 kg per day assumed value for its cell room
ventilation emissions, subtracting the 1.3 kg per day cell room value
from the 2.3 kg per 24-hour period plantwide standard effectively
creates an emission limit for the combined emissions from hydrogen
streams and end box ventilation systems of 1.0 kg per day (1,000 grams
per day).
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\1\ This regulatory program was originally set forth at 38 FR
8826; April 6, 1973; and amended at 40 FR 48302, October 14, 1975;
47 FR 24704, June 8, 1982; 49 FR 35770, September 12, 1984; 50 FR
46294, November 7, 1985; 52 FR 8726, March 19, 1987; and 53 FR
36972, September 23, 1988.
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The requirements in today's final standards are more stringent than
the requirements in the Mercury NESHAP. Using the 1,000 grams per day
value as the baseline, we estimate that mercury emissions will be
reduced to less than 60 grams per day (on average) by the final rule.
This represents about 94 percent reduction from the Mercury NESHAP
baseline for vents. In addition, the work practice standards in today's
final rule represent the most explicit compilation of practices
currently employed by the industry, along with detailed recordkeeping
and reporting requirements. While we cannot quantify the mercury
emissions reductions that would be achieved by the final work practice
standards, we are confident that their implementation would result in
additional reductions in mercury emissions beyond that currently
achieved by the existing Mercury NESHAP.
Every aspect of the Mercury NESHAP that applies to mercury cell
chlor-alkali plants is addressed in today's final rule (40 CFR part 63,
subpart IIIII). In fact, as discussed above, the requirements are more
stringent than the respective requirements in the Mercury NESHAP.
Consequently, when mercury cell chlor-alkali plants are required to
comply with the final rule, the requirements of the Mercury NESHAP that
apply to them will no longer be relevant or applicable. Therefore, upon
the compliance date as indicated in Sec. 63.8186 of the final rule,
mercury cell chlor-alkali plants will no longer have any obligation to
comply with the Mercury NESHAP, nor will they be allowed to comply with
the Mercury NESHAP instead of the applicable provisions in 40 CFR part
63, subpart IIIII. Specifically, affected sources

[[Page 70908]]

subject to the final rule would no longer be subject to Sec. Sec.
61.52(a), 61.53(b) and (c), and 61.55(b), (c) and (d) of 40 CFR part
61, subpart E, after the compliance date, which is December 19, 2006.

II. Summary of Changes Since Proposal

The proposed rule contained a compliance date 2 years from the date
that the final rule would appear in the Federal Register. In the final
rule, the compliance date has been changed to 3 years from December 19,
2006. However, unlike the proposed rule, which would have required that
performance tests be conducted within 180 days after the compliance
date, the final rule requires that all performance tests be conducted
on or before the compliance date.
For mercury cell chlor-alkali production facilities affected
sources, the proposed rule included a single emission limitation that
covered all mercury emissions from the two point sources associated
with chlorine production in mercury cells: the by-product hydrogen
stream and the end box ventilation system vent. The format of this
limitation was total grams of mercury per Megagram of chlorine
production (g Hg/Mg Cl₂). For the initial compliance
determination, the aggregate mercury emissions from all hydrogen by-
product streams and all end box ventilation system vents were divided
by the chlorine production for the same period and compared with the
applicable emission limitation. Continuous compliance would have then
been demonstrated by continuously monitoring the mercury concentration
in each stream and comparing the daily average mercury concentration
against a level determined during the initial compliance test.
Commenters objected to this daily averaging period for compliance
purposes when the emission limitations were based on annual average
emissions and chlorine production. In response to these comments, we
have written the averaging time for continuous compliance as a 52-week
period. Further, as discussed more below, rather than establishing
surrogate mercury concentration operating limits for each vent,
continuous compliance is determined by a direct comparison of the
emissions per unit of chlorine production (g Hg/Mg Cl₂) for
each 52-week compliance period and the emission limitation. This is a
rolling average compliance period that is determined each week. That
means a compliance determination is required each week for the previous
52-week period.
In addition to the averaging time for the by-product hydrogen/end
box ventilation system vent, we changed the value of the emission
limitation for plants with end box ventilation systems from the
proposed limit of 0.067 g Hg/Mg Cl₂ to 0.076 g Hg/Mg
Cl₂. The proposed limit of 0.033 g Hg/Mg Cl₂ for
plants without end box ventilation systems is retained in the final
rule.
In the final rule, we have written the method for determining
continuous compliance for the point sources of emissions in both types
of affected sources covered by the rule (by-product hydrogen streams
and end box ventilation system vents at mercury cell chlor-alkali
production facilities and mercury thermal recovery unit vents at
mercury recovery facilities). In the proposed rule, performance tests
would have been required to determine initial compliance with the
applicable emission limitation. The proposed rule also would have
required that the mercury concentration of each vent be monitored
during these performance tests, and that a mercury concentration
operating limit be established for each vent based on the monitoring
results obtained during the test. Compliance with the emission
limitation would have then been determined by comparing the results of
the continuous monitoring of mercury concentration against the
established operating limits. There were several comments received on
this approach.
In response to these comments, continuous compliance in the final
rule is determined via a direct comparison of emissions to the emission
limitation rather than using mercury concentration operating limits as
a surrogate. For by-product hydrogen streams and end box ventilation
system vents, the aggregate mercury emissions will be determined,
divided by the corresponding chlorine production, and compared with the
emission limitation for each 52-week compliance period (as discussed
above). For mercury thermal recovery unit vents, the measured mercury
concentration will be directly compared against the emission
limitations (which are in units of milligrams of mercury per dry
standard cubic meter, or mg/dscm). Also, the final rule contains two
options for measuring the mercury emissions for continuous compliance:
Continuous mercury emission monitoring systems, and periodic sampling
using EPA reference methods or approved alternative methods.
The proposed work practice provisions included a cell room
monitoring program, which would have required that the mercury
concentration be monitored in the cell room and corrective action taken
when a plant-specific action level was exceeded. The final rule retains
the cell room monitoring program, but it is as an alternative to the
work practices. The optional cell room monitoring provisions in the
final rule are more detailed and prescriptive than the requirements in
the proposed rule, and the final rule requires the preparation and
submittal of site-specific cell room monitoring plans. Since the cell
room monitoring program was made optional, the final rule requires (if
optional cell room monitoring is not chosen) the owner or operator to
institute a floor-level mercury vapor measurement program. This program
is designed to limit the amount of mercury vapor in the cell room
environment through periodic measurement of mercury vapor levels.
The final rule also requires that the owner of each mercury cell
chlor-alkali plant report the mass of virgin mercury added to the
cells. Initial compliance with this requirement is demonstrated by
reporting the mass of mercury added to cells for the 5 years preceding
the compliance date. This is a requirement requested by commenters.

III. Summary of the Final Rule

A. What Is the Source Category?

The chlorine production source category contains the mercury cell
chlor-alkali plant subcategory and includes all plants engaged in the
manufacture of chlorine and caustic in mercury cells. Other non-mercury
cell chlorine production plants used to produce chlorine and caustic,
such as diaphragm cell and membrane cell technologies, are not covered
by the final rule.

B. What Are the Affected Sources and Emission Points To Be Regulated?

The final rule defines two affected sources: Mercury cell chlor-
alkali production facilities, and mercury recovery facilities. The
former includes all cell rooms and ancillary operations used in the
manufacture of chlorine, caustic, and by-product hydrogen at a plant
site. The latter includes all processes and associated operations
needed for mercury recovery from wastes.
Emission points addressed within mercury cell chlor-alkali
production facilities include each mercury cell by-product hydrogen
stream, each mercury cell end box ventilation system vent, and fugitive
emission sources throughout each cell room and various areas. Emission
points addressed within mercury recovery facilities include each

[[Page 70909]]

mercury thermal recovery unit vent and fugitive emission sources
associated with storage areas for mercury-containing wastes.

C. What Are the Emission Limitations?

For new or reconstructed mercury cell chlor-alkali production
facilities, the final rule prohibits mercury emissions.
For existing mercury cell chlor-alkali production facilities with
end box ventilation systems, the final rule requires that aggregate
mercury emissions from all by-product hydrogen streams and end box
ventilation system vents not exceed 0.076 g Hg/Mg Cl₂ for
any consecutive 52-week period. For existing mercury cell chlor-alkali
production facilities without end box ventilation systems, the final
rule requires that mercury emissions from all by-product hydrogen
streams not exceed 0.033 g Hg/Mg Cl₂ for any consecutive 52-
week period.
For new, reconstructed, or existing mercury recovery facilities
with oven type mercury thermal recovery units, the final rule requires
that total mercury emissions not exceed 23 mg/dscm from each oven type
unit vent. For new, reconstructed, or existing mercury recovery
facilities with non-oven type mercury thermal recovery units, the limit
in the final rule is 4 mg/dscm.

D. What Are the Work Practice Standards?

The final rule contains a set of work practice standards to address
and mitigate fugitive mercury releases at mercury cell chlor-alkali
plants. These provisions include specific equipment standards such as
the requirement that end boxes either be closed (that is, equipped with
fixed covers), or that end box headspaces be routed to a ventilation
system. Other examples include requirements that piping in liquid
mercury service have smooth interiors, that cell room floors be free of
cracks and spalling (i.e., fragmentation by chipping) and coated with a
material that resists mercury absorption, and that containers used to
store liquid mercury have tight-fitting lids. The work practice
standards also include operational requirements. Examples of these
include requirements to allow electrolyzers and decomposers to cool
before opening, to keep liquid mercury in end boxes and mercury pumps
covered by an aqueous liquid at a temperature below its boiling point
at all times, to maintain end box access port stoppers in good sealing
condition, and to rinse all parts removed from the decomposer for
maintenance prior to transport to another work area.
A cornerstone of the work practice standards is the inspection
program for equipment problems, leaking equipment, liquid mercury
accumulations and spills, and cracks or spalling in floors and pillars
and beams. Specifically, the final rule requires that visual
inspections be conducted twice each day to detect equipment problems,
such as end box access port stoppers not securely in place, liquid
mercury in open containers not covered by an aqueous liquid, or leaking
vent hoses. If a problem is found during an inspection, the owner or
operator will need to take immediate action to correct the problem.
Monthly inspections for cracking or spalling in cell room floors are
also required as well as semiannual inspections for cracks and spalling
on pillars and beams. Any cracks or spalling found will need to be
corrected within 1 month.
Visual inspections for liquid mercury spills or accumulations are
also required twice per day. If a liquid mercury spill or accumulation
is identified during an inspection, the owner or operator will need to
initiate cleanup of the liquid mercury within 1 hour of its detection.
Acceptable cleanup methods include wet vacuum cleaning or a suitable
alternative method approved upon petition.
In addition to cleanup, the final rule requires that an inspection
of equipment in the area of the spill or accumulation be conducted to
identify the source of the liquid mercury. If the source is found, the
owner or operator is required to repair the leaking equipment as
discussed below. If the source is not found, the owner or operator will
be required to reinspect the area every 6 hours until the source is
identified or until no additional liquid mercury is found at that
location.
Inspections of specific equipment for liquid mercury leaks are
required once per day. If leaking equipment is identified, the final
rule requires that any dripping mercury be contained and covered by an
aqueous liquid, and that a first attempt to repair leaking equipment be
made within 1 hour of the time it is identified. The final rule
requires that leaking equipment be repaired within 4 hours of the time
it is identified, although there are provisions for delaying repair of
leaking equipment for up to 48 hours.
Inspections for hydrogen gas leaks are required twice per day. For
a hydrogen leak at any location upstream of a hydrogen header, a first
attempt at repair is required within 1 hour of detection of the leaking
equipment, and the leaking equipment is required to be repaired within
4 hours (with provisions for delay of repair if the leaking equipment
is isolated). For a hydrogen leak downstream of the hydrogen header but
upstream of the final control device, a first attempt at repair is
required within 4 hours, and complete repair required within 24 hours
(with delay provisions if the header is isolated).
The work practice standards in the final rule require you to
institute a floor-level mercury vapor measurement program. Under this
program, mercury vapor levels are periodically measured and compared to
an action level of 0.05 mg/m\3\. The final rule specifies the actions
to be taken when the action level is exceeded. If the action level is
exceeded during any floor-level mercury vapor measurement evaluation,
you are required to take specific actions to identify and correct the
problem.
As an alternative to the full set of work practice standards
(including the floor-level monitoring program), the final rule also
includes an optional requirement to institute a cell room monitoring
program whereby owners and operators continuously monitor mercury
concentrations in the upper portion of each cell room and take
corrective actions as soon as practicable when elevated mercury vapor
levels are detected.
The program is not designed to be a continuous monitoring system
inasmuch as the results would be used only to determine relative
changes in mercury vapor levels rather than compliance with a cell room
emission or operating limit. The owner or operator is required to
establish an action level for each cell room based on preliminary
monitoring to determine normal baseline conditions. The action level,
or levels if appropriate, will then be established as a yet-to-be-
determined multiple of the baseline values. Once the action level(s) is
established, continuous monitoring must be conducted. If an action
level is exceeded, actions to correct the situation are required to be
initiated as soon as possible. If the elevated mercury vapor level is
due to a maintenance activity, the owner or operator must ensure that
all work practices related to that maintenance activity are followed.
If a maintenance activity is not the cause, inspections and other
actions will be needed to identify and correct the cause of the
elevated mercury vapor level. Owners and operators utilizing this cell
room monitoring program option are required to develop site-specific
cell room monitoring plans describing their monitoring system and
quality assurance/quality control

[[Page 70910]]

procedures that will be used, along with their action level.
The final rule establishes the duty for owners and operators to
routinely wash surfaces throughout the plant where liquid mercury could
accumulate. Owners and operators are required to prepare and follow a
written washdown plan detailing how and how often specific areas
specified in the final rule are to be washed down to remove any
accumulations of liquid mercury.
Finally, the final rule requires owners or operators to record and
report the mass of virgin mercury added to cells. Virgin mercury is
defined as mercury that has not been processed in an onsite mercury
thermal recovery unit or otherwise recovered from mercury-containing
wastes onsite. In order to establish a baseline of mercury being added
to the cells, the final rule requires owners or operators to submit the
mass of virgin mercury added to cells for the 5 years preceding the
compliance date.

E. What Are the Operation and Maintenance Requirements?

The final rule requires that each owner and operator always operate
and maintain each affected source, including air pollution control and
monitoring equipment, in a manner consistent with good air pollution
control practices for minimizing air emissions, as required under 40
CFR 63.6(e)(1)(i) of the NESHAP General Provisions. The final rule
requires each owner and operator to prepare and implement a written
startup, shutdown, and malfunction plan according to the operation and
maintenance requirements in Sec. 63.6(e)(3) of the NESHAP General
Provisions.

F. What Are the General Compliance Requirements?

The final rule requires compliance with the emission limitations
and applicable work practice requirements at all times, except during
periods or startup, shutdown, and malfunction as defined in 40 CFR
63.2. The owner or operator must develop and implement a written
startup, shutdown, and malfunction plan according to the requirements
in 40 CFR 63.6(e)(3).

G. What Are the Initial Compliance Requirements?

The final rule requires compliance with emission limitations and
work practices by December 19, 2006.
To demonstrate initial compliance with the emission limits for by-
product hydrogen streams and end box ventilation system vents, the
final rule requires each owner or operator to conduct performance tests
using 40 CFR part 61, appendix A, Method 102 for by-product hydrogen
streams, and 40 CFR part 61, appendix A, Method 101 or 101A for end box
ventilation system vents. In addition, the final rule also includes
procedures for reducing the mercury emissions data collected during the
performance test to units of the standard (i.e., g Hg/Mg
Cl₂). Each performance test is required to consist of a
minimum of three 2-hour runs with a minimum sample volume of 1.7 dscm
and must be conducted in accordance with a site-specific test plan
prepared according to the performance test quality assurance program
requirements in Sec. 63.7(c)(2) of the NESHAP General Provisions.
Concurrent with each test run, each owner or operator is required
to determine the quantity of chlorine produced using an equation
contained in the final rule which calculates chlorine production based
on cell line electric current load.
Initial compliance is demonstrated by showing that the total
mercury emission rate from all by-product hydrogen streams and all end
box ventilation system vents for the test are less than 0.076 g Hg/Mg
Cl₂ for plants with end box ventilation systems, or 0.033 g
Hg/Mg Cl₂ for plants without end box ventilation systems.
In addition, if the final control device is not a nonregenerable
carbon adsorber and continuous compliance will be demonstrated using
the periodic monitoring option, the owner or operator is required to
monitor the following parameters during the performance test to
establish either a maximum or minimum monitoring value, as applicable
for the control device:

? Exit gas temperature from uncontrolled streams;
? Outlet temperature of the gas stream for the final cooling
system when no control devices other than coolers or demisters are
used;
? The outlet temperature of the gas stream from the final cooling
system when the cooling system is followed by a molecular sieve or
regenerative carbon adsorber;
? Outlet concentration of available chlorine, pH, liquid flow
rate, and inlet gas temperature of chlorinated brine scrubbers and
hypochlorite scrubbers;
? The liquid flow rate and exit gas temperature for water
scrubbers;
? The inlet gas temperature of regenerative carbon adsorption
systems; or
? The temperature during the heating phase of the regeneration
cycle for regenerative carbon adsorbers or molecular sieves.

As part of the initial compliance demonstration, the owner or
operator must determine the maximum or minimum monitoring value by
calculating the average of the data collected during the performance
test. The exception to this is when the final control device is a
regenerative carbon adsorber. In this case, the highest temperature
reading during the performance test must be used.
To demonstrate initial compliance with the mercury thermal recovery
unit emission limits, the final rule requires that owners or operators
conduct a performance test for each vent using 40 CFR part 61, appendix
A, Method 101 or 101A. The owner or operator is required to develop and
follow a site-specific test plan according to Sec. 63.7(c)(2) of the
NESHAP General Provisions. Three test runs would need to be conducted
at a point after the last control device for each vent.
Initial compliance is achieved if the average vent mercury
concentration is less than 23 mg/dscm for each oven type vent or 4 mg/
dscm for each non-oven type vent. In addition, if the final control
device is not a nonregenerable carbon adsorber and continuous
compliance will be demonstrated using the periodic monitoring option,
the owner or operator is required to monitor the same parameters as
required for by-product hydrogen streams and end box ventilation system
vents and to establish the appropriate minimum or maximum monitoring
value for the control device.

H. What Are the Continuous Compliance Requirements?

The final rule contains two options for continuous compliance with
the emission limit for by-product hydrogen streams and end box
ventilation system vents and the emission limit for mercury thermal
recovery unit vents: Continuous monitoring using mercury continuous
emissions monitors, or periodic monitoring using testing. Both of these
options will produce results in the units of the standard, so
continuous compliance will be demonstrated through a direct comparison
of monitoring system results.
If mercury continuous emission monitors are used to comply with the
final rule, a site-specific monitoring plan must be developed to ensure
proper control device evaluation, and a performance evaluation is
required according to the monitoring plan. For each monitor, the final
rule requires the site-specific monitoring plan to address installation
and siting, monitor performance specifications,

[[Page 70911]]

performance evaluation procedures and calibration criteria, ongoing
operation and maintenance procedures, ongoing data assurance
procedures, and ongoing recordkeeping and reporting procedures. It must
also address how other parameters (e.g., flow rate) needed to calculate
the mass of mercury emissions from each emission point are to be
monitored. If periodic weekly monitoring is the selected compliance
method, the owner or operator is required to conduct tests on a weekly
basis using either an EPA Reference Method (101, 101A, or 102) or an
alternative method that has been validated using Method 301, 40 CFR
part 63, appendix A. If the final control device is not a
nonregenerable carbon adsorber, in addition to periodic testing, the
final rule contains requirements for the continuous monitoring of
control device-specific parameters.
To demonstrate continuous compliance, the final rule requires the
owner or operator to reduce mercury emissions to 52-week averages and
to maintain the 52-week average below 0.076 g Hg/Mg Cl₂ for
plants with end box ventilation systems, or 0.033 g Hg/Mg
Cl₂ for plants without end box ventilation systems. For
mercury thermal recovery units, the owner or operator is required to
determine daily average mercury emissions and maintain the daily
average below 23 mg/dscm for each oven type vent or 4 mg/dscm for each
non-oven type vent. The final rule requires the owner or operator to
collect emissions data using either a continuous mercury emissions
monitor, or by collecting weekly samples using periodic monitoring. If
the periodic monitoring option is used and the final control device is
not a nonregenerable carbon adsorber, the owner or operator is required
to also monitor specific control device parameters and compare to the
maximum or minimum monitoring values developed during the performance
test. Continuous compliance is achieved if the monitoring values remain
either below the maximum monitoring value, or above the minimum
monitoring value, as appropriate.

I. How Are Initial and Continuous Compliance With the Work Practice
Standards To Be Demonstrated?

The final rule requires compliance with the work practice standards
within 3 years from December 19, 2003.
The final rule contains specific recordkeeping requirements related
to the work practice standards. These include records of when
inspections were conducted, problems identified, and actions taken to
correct problems. Continuous compliance with work practice standards
will be demonstrated by maintaining these required records.
Initial compliance with the washdown plan will be demonstrated by
submission of the plan by the owner or operator and certification that
they operate according to, or will operate according to, the plan.
Continuous compliance with the plan will be demonstrated by maintaining
related records. Records will also be required to demonstrate
compliance with the cell room monitoring program.

J. What Are the Notification and Reporting Requirements?

The final rule requires that owners or operators submit Initial
Notifications, Notifications of Intent to conduct a performance test,
Notification of Compliance Status (NOCS), and compliance reports.
For the Initial Notification, we are requiring that each owner or
operator notify us that their plant is subject to the NESHAP for
mercury cell chlor-alkali plants, and that they provide other basic
information about the plant. For existing sources, this notification
would need to be submitted no later than April 19, 2004.
For the Notification of Intent report, we are requiring that each
owner or operator notify us in writing of the intent to conduct a
performance test at least 60 days before the performance test is
scheduled to begin.
The NOCS for the work practice standards will be due 30 days after
the compliance date for existing sources. In this notification, the
owner or operator will need to certify that the work practice standards
are being or will be met. Furthermore, we are requiring that the
washdown plan be submitted as part of this notification, and that the
owner or operator certify that they operate or will operate according
to the plan.
For the emission limits where a performance test is required to
demonstrate initial compliance (that is, the emission limits for by-
product hydrogen streams and end box ventilation system vents and the
mercury thermal recovery unit vent limits), the tests will have to be
conducted no later than the compliance date, and the NOCS will be due
60 days after the completion of the performance test. The site-specific
monitoring plan addressing the use of mercury continuous emission
monitors for vents must be submitted as part of this notification.
Compliance reporting is required semiannually, with the first
report due within the first 6 months after initial compliance.

K. What Are the Recordkeeping Requirements?

Records required by the final rule related to by-product hydrogen
streams, end box ventilation system vents, and mercury thermal recovery
unit vents include the following: Performance test results, records
showing the establishment of the applicable mercury concentration
operating limits (including records of the mercury concentration
monitoring conducted during the performance tests), records of the
continuous mercury concentration monitoring data, records of the daily
average elemental mercury concentration values, and records associated
with site-specific monitoring plans.
With regard to the work practice standards, the final rule requires
that records be maintained to document when each required inspection
was conducted and the results of each inspection. Records noting
equipment problems (such as end box cover stoppers not securely in
place or mercury in an open container not covered by an aqueous liquid)
identified during a required inspection, and the corrective action
taken would also be required. If equipment that is leaking mercury
liquid or hydrogen/mercury vapor is identified during a required
inspection or at any other time, the final rule requires records of
when the leak was identified and when it was repaired. Similarly, if a
mercury spill or accumulation is identified at any time, the final rule
requires records of when the spill or accumulation was found and when
it was cleaned up.
A copy of the current version of the washdown plan would need to be
kept on-site and be available for inspection. Records of when washdowns
were conducted would be required.
The final rule requires that copies of each notification and report
that is submitted to comply with the final rule be kept and maintained
for 5 years, the first 2 of which must be on-site.

IV. Summary of Major Comments and Responses

This section includes discussion of significant comments on the
proposed rule. For a complete summary of all the comments received on
the proposed rule and our responses to them, refer to the ``Background
Information Document for Promulgation of National Emissions Standards
for Hazardous Air Pollutant (NESHAP): Mercury Emissions From Mercury
Cell Chlor-Alkali Plants'' EPA-453/R-03-012 (hereafter called the
``response to comments document'') in Docket OAR-2002-0017 or A-2000-
32.

[[Page 70912]]

The docket also contains the actual comment letters and supporting
documentation developed for the final rule.

A. What Issues Were Raised Regarding the Sources That Are Subject to
the Rule as Proposed?

There were no issues raised by commenters regarding the sources
subject to the proposed rule and the affected source, as a mercury cell
chlor-alkali plant is a distinct and easily identifiable entity. There
were, however, issues raised regarding the proposed requirement for all
affected sources to obtain a title V permit and regarding the specific
emission points that were addressed in the proposed rule.
Comment: Three commenters disagreed with the proposed requirements
for all mercury cell chlor-alkali plants to obtain a title V permit,
including area sources. The commenters requested that this provision be
deleted from the final rule. The commenters stated that the facilities
affected by the proposal are minor sources of HAP emissions. All three
commenters maintained that requiring minor source facilities to obtain
title V permits would be burdensome, e.g., due to duplicative
recordkeeping and reporting provisions, for the area sources; one
commenter further stated that this burden would not yield any
environmental benefit. Additionally, according to this commenter,
dropping the title V permit requirement for area sources would not
lessen any substantive requirements for monitoring, recordkeeping, or
operation of any and all air pollution control devices. Commenters
noted that the CAA allows EPA to exempt certain sources from obtaining
a title V permit ``* * * if the Administrator finds that compliance
with such requirements is impracticable, infeasible, or unnecessarily
burdensome * * *''.
One commenter noted that in previously promulgated area source MACT
standards (e.g., Dry Cleaning MACT and Halogenated Solvent Cleaning
MACT), EPA identified area sources as being subject to title V
permitting. However, EPA allowed the permitting authorities to defer
area sources from title V permitting requirements until December 9,
2004.
In contrast, another commenter supported the proposed requirement
to require all affected sources to obtain title V permits. The
commenter argued that title V permits are needed because they
consolidate sources' applicable requirements in a single place. The
commenter further noted that ``* * * given the detailed work practice
requirements, it is reasonable to expect significant source-specific
tailoring of the standard for each plant's individual configuration.''
See, e.g., 67 FR 44706-07. The commenter also stated that requiring
title V permits of area sources of mercury is especially appropriate
because a small quantity of mercury is as toxic as far greater amounts
of other HAP.
Response: Section 502(a) of the CAA requires any source, including
an area source, subject to standards or regulations under section 111
or 112 of the CAA to operate in compliance with a title V permit after
the effective date of any title V permits program. The Administrator
may not exempt any major source from the requirements of title V.
In order to exempt area sources under the final rule from title V
requirements, the test in section 502(a) of the CAA must be met.
Specifically, the Administrator must make a finding that title V
requirements are impracticable, infeasible, or unnecessarily burdensome
for the source category or categories in question. Commenters may
provide data which would help the Administrator make such a finding,
but the commenters who were opposed to area sources being permitted
under the final rule did not provide any such data. Commenters
providing supporting data for their arguments is consistent with what
the Agency stated in its final rule for the Municipal Solid Waste
Landfills NESHAP in reference to the test in section 502(a) of the CAA
(68 FR 2227, 2234, January 16, 2003).
In terms of the commenters' concern about title V adding
duplicative recordkeeping and reporting requirements, the only
potential duplicative requirement that we are aware of is in relation
to deviation reporting under the semiannual compliance report required
by Sec. 63.8254 of the final rule and the semiannual monitoring report
required by 40 CFR 70.6(a)(3)(iii)(A) or 40 CFR 71.6(a)(3)(iii)(A).
However, this potential duplication was addressed by Sec. 63.8254(d)
in the proposed rule and this has been clarified in the final rule.
As to the deferral for area sources subject to the Dry Cleaning
MACT and the Halogenated Solvent Cleaning MACT, the area sources
subject to these MACT standards were deferred from title V permitting
until December 9, 2004. See final deferral rulemaking (64 FR 69637,
December 14, 1999). This deferral was granted in part because of the
concern that area sources would not be able to obtain the technical and
procedural assistance from permitting authorities needed to file timely
and complete title V applications given that permitting authorities
would be focused on the permitting of major sources. However, as the
title V program is no longer in its initial stages and the initial
permitting of existing major sources is nearing completion, we would
not be justified in granting a deferral to area sources under the final
rule for the same reason.
In terms of the commenter who supported the permitting of affected
sources under the final rule, we agree that the consolidation of
requirements in a title V permit is one of the ways that title V helps
assure compliance with all applicable requirements. As this commenter
also pointed out, title V permits clarify which requirements in
standards apply to a source where requirements may vary due to various
factors, e.g., design of the facility. Additionally, the title V
regulations at 40 CFR part 70 and 40 CFR part 71 help a source assure
compliance with its applicable requirements by requiring that a source
self-certify to compliance initially and annually, by requiring that a
source promptly report deviations from its permit requirements, and by
requiring that a permit contain monitoring requirements. It is also
important to note that the title V permitting process provides an
opportunity for the public to comment on whether a source is complying
with its applicable requirements. In short, title V permits can enhance
the effectiveness of rules such as the final rule, and EPA, therefore,
disagrees that there are no environmental benefits to requiring title V
permits for area sources.
In conclusion, as the test in section 502(a) of the CAA has not
been met, EPA has retained the requirement in the final rule that
affected sources subject to the final rule must obtain title V permits.
Therefore, whether an affected source under the final rule is a part of
a major or area source, the major/area source is required to obtain a
title V permit.
Comment: One commenter believed that the proposed rule violated the
CAA because the Agency did not establish standards for some parts of
chlor-alkali plants that emit mercury. The commenter noted that under
the proposed rule, EPA defined two affected sources: Mercury cell
chlor-alkali production facilities and mercury recovery facilities. The
commenter did not agree with EPA's determination that within mercury
cell chlor-alkali production facilities, chlorine purification, brine
preparation and wastewater treatment operations should not be subject
to emission standards

[[Page 70913]]

because they have low mercury air emissions. Similarly, the commenter
did not agree with EPA's decision not to regulate chemical mercury
recovery and recovery in batch purification stills at mercury recovery
facilities. According to the commenter, the CAA does not allow the
Agency to exempt certain classes, types and sizes of sources from
emission standards, unless EPA finds no potential for emissions.
Therefore, the commenter stated that EPA had a legal obligation to
establish standards that cover all mercury-emitting parts of chlor-
alkali facilities, and the Agency must re-visit and set emission
standards for the parts of the production and recovery facilities with
low mercury emissions.
Response: During development of the proposed rule, we did not
receive any data to indicate that mercury was emitted from chlorine
purification, brine preparation, or wastewater treatment operations,
and our knowledge of the process indicated that any potential emissions
would be very limited (67 FR 44674). Furthermore, we did not receive
any data indicating that control measures designed to reduce HAP were
in use at existing facilities that had these units. The same holds true
for chemical mercury recovery and recovery in batch purification stills
at mercury recovery facilities. Therefore, with no reported emissions
and process evidence that any emissions would be very limited, we
concluded that there was no potential for emissions. Adding to this the
existence of a MACT floor of no control (because none are controlled),
we did not regulate these processes.
The commenter did not provide emissions data that would indicate
that these sources emit significant amounts of mercury, or emit mercury
at all. Therefore, the final rule does not contain standards for
mercury emissions from chlorine purification, brine preparation,
wastewater treatment operations, chemical mercury recovery and recovery
in batch purification stills.
We point out that the final rule does contain very stringent
emission limitations for all point sources that have been demonstrated
to be sources of mercury emissions. Further, the work practice
requirements in the final rule address fugitive mercury emissions in
all areas of the facility, including the chlorine purification, brine
preparation, wastewater treatment areas, as well as areas where
chemical mercury recovery processes and batch purification stills are
located.

B. What Issues Were Raised Regarding the HAP Addressed by the Rule as
Proposed?

As noted earlier, we divided the chlorine production category into
two subcategories: Mercury cell chlor-alkali plants and chlorine
production plants that do not rely upon mercury cells for chlorine
production (diaphragm cell chlor-alkali plants, membrane cell chlor-
alkali plants, etc.). On July 3, 2002, we issued separate proposals to
address the emissions of mercury from the mercury cell chlor-alkali
plant subcategory sources (67 FR 44672) and the emissions of chlorine
and HCl from both the non-mercury cell chlorine production subcategory
sources and the mercury cell chlor-alkali subcategory sources (67 FR
44713). Specifically, we proposed a rule for mercury emissions from
mercury cell chlor-alkali plants, and we proposed not to regulate
chlorine and HCl emissions from mercury cell chlor-alkali plants and
non-mercury cell chlorine production plants under our authority in
section 112(d)(4) of the CAA.
Comments were received regarding the proposed action not to
regulate chlorine and HCl emissions (see Air Docket OAR-2002-0016 or
Air Docket A-2002-09). The aspects of these comments related to the
mercury cell chlor-alkali plant subcategory can be generally classified
into two basic categories: Our statutory authority under section
112(d)(4); and the site-specific risk assessments that formed the basis
for our decision.

Comments Related to the Section 112(d)(4) Authority

Comment: Several comments were received related to our decision not
to regulate chlorine and HCl emissions from chlorine production under
the authority of section 112(d)(4). Some commenters supported this
decision and stated the interpretation of our authority under section
112(d)(4) was appropriate and supported by the legislative history. In
contrast, other commenters disagreed with EPA's interpretation of
section 112(d)(4). Finally, some of the commenters stated that EPA
should use its authority under section 112(c)(9)(B)(ii).
One commenter stated that EPA conducted an appropriate analysis to
determine that human exposures from ambient concentrations are well
below threshold values with an ample margin of safety. According to
another commenter, any further regulation of chlorine and HCl emissions
from the chlorine production industry would have no environmental
benefits, but would result in costs for monitoring, recordkeeping, and
reporting efforts to certify compliance with any requirements. The
commenter was concerned that a regulation would also stretch EPA's
limited resources in monitoring for compliance. Three commenters stated
that EPA's interpretation of their authority under section 112(d)(4)
was supported by the legislative history, which emphasizes that
Congress included section 112(d)(4) in the CAA to prevent unnecessary
regulation of source categories. The commenter agreed that under
section 112(d)(4), once EPA establishes that a pollutant has a health
threshold and that exposure to that pollutant's emissions are below the
health threshold, EPA should refrain from setting MACT standards for
that pollutant. The commenter further suggested that EPA should use
section 112(d)(4) whenever setting emission standards under section
112(d).
Three commenters disagreed with EPA's interpretation of section
112(d)(4). They did not believe that section 112(d)(4) could be used as
an alternative to setting MACT standards under section 112(d)(3). One
commenter noted that the phrase ``in lieu of'' was not included in the
section 112(d)(4) provisions and that its absence was intentional. In
support of their claim, the commenter pointed to section 112(d)(5),
which does contain the phrase ``in lieu of.'' The commenter interpreted
section 112(d)(4) to mean that health-based thresholds can be
considered when establishing the degree of MACT requirements, but not
in place of the requirement to establish a MACT floor pursuant to
section 112(d)(3).
The commenter also pointed to the provisions of section 112(c)(2)
which require the Administrator to establish NESHAP for listed source
categories and subcategories. The commenter was concerned that EPA
evaluated emissions from chlorine production plants and concluded that
since they do not pose a threat to human health and the environment,
the Administrator is relieved of her responsibilities to establish a
MACT standard. The commenter maintained that this position is not
supported by section 112(c)(2).
The commenter also referred to section 112(d)(1), stating that EPA
did not have the authority to ``make a determination of no regulation
for a listed source category or pollutant.''
Finally, the commenter referred to section 112(d)(3), which
contains the MACT floor provisions. According to the commenter, the
intent of the NESHAP program is to develop a MACT

[[Page 70914]]

floor, and EPA is not fulfilling the requirements of the CAA by not
performing such an analysis. The commenter stated that a majority of
facilities identified in the analysis have adequate controls due to
State regulations and these controls should be incorporated into the
MACT floor evaluation. The commenter was particularly concerned that by
not developing a MACT floor, no new-source MACT standards were created.
The commenter requested that EPA perform a MACT floor analysis and
develop a NESHAP for new sources.
Two of the commenters stated that EPA should support its decision
not to regulate the chlorine production source category by citing the
provisions of section 112(c)(9)(B)(ii) in addition to the provisions of
section 112(d)(4). The commenters stated that the evaluation performed
by EPA would also be sufficient for deleting sources under section
112(c)(9)(B)(ii) and that EPA's proposal to not regulate chlorine
production is similar to deleting a subcategory of the Chlorine
Production source category. Therefore, in addition to using the
authority under section 112(d)(4), the commenters suggested that EPA
delete the subcategory using the authority under section
112(c)(9)(B)(ii) to avoid any uncertainty over the use of its authority
under section 112(d)(4).
Response: The EPA has the authority under CAA section 112(d)(4) to
decide not to establish a NESHAP for chlorine and HCl emissions from
certain chlorine production facilities. We have decided to limit our
use of section 112(d)(4) to the emissions of chlorine and HCl from
sources within the mercury cell chlor-alkali subcategory. While we have
decided to establish no standards for the emissions of these two HAP
from sources in the mercury cell chlor-alkali plant subcategory, we are
establishing standards for the mercury emissions from the sources
within that subcategory. As explained elsewhere in today's Federal
Register, we have decided to delete the non-mercury cell chlorine
production plants subcategory under CAA section 112(c)(9)(B)(ii). The
only HAP emitted by the non-mercury cell chlorine production sources
are chlorine and HCl.
Contrary to other commenters claims that our use of section
112(d)(4) is inappropriate, both the statutory language and the
legislative history of the provision support our decision not to set
limitations for chlorine and HCl emissions from sources in the mercury
cell chlor-alkali plant subcategory. The language of section 112(d)(4)
provides the Agency with ample discretion to utilize a risk-based
approach in determining whether to establish emission standards for
those HAP where we determine that the HAP are ``threshold pollutants''
and that the standard (or no standard) will achieve an ``ample margin
of safety.''
The statutory language in section 112(d)(4) is ambiguous. Thus,
under the Supreme Court's decision in Chevron v. NRDC, 467 U.S. 837
(1984), the Agency has the discretion to interpret the language to
allow us to establish NESHAP that do set limitations on certain HAP
emitted from sources (``when establishing standards'') but to also
decide not to set limitations on other HAP emitted from these same
sources if the other HAP are threshold pollutants and the risk from the
emissions are so low that no standard for that second set of HAP is
necessary to protect the public and the environment with ``an ample
margin of safety.''
This approach is consistent with prior decisions EPA has made in
the context of two other NESHAP. First, in the NESHAP for combustion
sources at pulp mills (40 CFR part 63, subpart MM), we chose not to set
a standard for HCl emissions from recovery furnaces, while we did set
standards for other HAP emitted from the same sources within the
category. We explained this decision in the preamble to the proposed
MACT standard and received no adverse comment on the approach (63 FR
18754, 18765-68, April 15, 1998). Second, we proposed to set no
standard under section 112(d)(4) for HCl emitted from lime kilns, while
we also proposed to set standards for other HAP emitted by these same
sources (67 FR 78046 December 20, 2002). We also received no adverse
comment on that proposed decision. While we originally proposed to
utilize section 112(d)(4) to set no standard for chlorine and HCl from
chlorine production sources in a separate notice of the Federal
Register (67 FR 44713, July 3, 2002), we made it clear that the
proposed use of section 112(d)(4) would apply to emissions of these two
HAP from mercury cell chlor-alkali sources (as well as the emissions of
chlorine and HCl from other chlorine production sources).
We do not agree that Congress' use of the phrase ``in lieu of'' in
CAA section 112(d)(5) so clearly restricts any possible interpretation
of CAA section 112(d)(4) such that some form of a MACT standard must
always be set even when the criteria of section 112(d)(4) are met.
Instead, we interpret that Congress enacted section 112(d)(4) to
provide EPA with the discretion to take risk into account and decide
that standards need not be set when the HAP are threshold pollutants
and levels being emitted are below the threshold value with an ample
margin of safety. Moreover, in each case where we have exercised
authority under section 112(d)(4), we have established standards in
each category (or subcategory, as here) for those pollutants that do
not satisfy the threshold pollutant and ample margin of safety
statutory criteria.
We also disagree with the commenter who argued that the provision
in section 112(c)(2), which requires the Administrator to establish
emission standards for listed categories and subcategories, has much
bearing on our use of section 112(d)(4) in this circumstance. By
setting a standard for the emission of mercury from the mercury cell
chlor-alkali plant subcategory, we are fulfilling our obligations under
section 112(c)(2). As stated earlier, we have utilized the same
approach in our other uses of section 112(d)(4), e.g., HCl emissions
from combustion sources at pulp mills and lime production sources.
The statutory language in section 112(d)(1) and (3) does not
prevent us from deciding that no emission standard is necessary for a
particular threshold pollutant which is being emitted at levels well
below the ample margin of safety when we are also establishing
standards for HAP emitted from sources in that same category or
subcategory. This approach to our use of section 112(d)(4) is
consistent with the statutory language of section 112(d)(1) and (3). We
are establishing emission standards for the listed category or
subcategory, but are deciding that no MACT floor need be established
and no emission standard set for those HAP that meet the criteria of
``threshold pollutant'' and ``ample margin of safety.''
With regard to the concerns the commenter raised about the failure
to set a standard for new sources, our review of the mercury cell
subcategory indicates that no new mercury cell chlor-alkali plants will
be constructed. Given that our emission standard for new sources in the
mercury cell chlor-alkali subcategory prohibits the emission of
mercury, we do not believe any new sources using mercury cells for
chlorine production will ever be constructed (or reconstructed).
Therefore, this no-mercury emissions requirement in the final rule
will, in effect, also ensure that there are no chlorine or HCl
emissions from new mercury cell facilities.
In response to other commenters' suggestion that we utilize the
authority of section 112(c)(9)(B)(ii) to delete the chlorine production
category, we have

[[Page 70915]]

decided to exercise our authority under that statutory provision for
the non-mercury cell chlorine production subcategory. That decision is
discussed in a separate notice in today's Federal Register. However, we
are not deleting the mercury cell chlor-alkali plant subcategory
because the sources within the category also emit mercury, and we are
establishing emissions standards for mercury emissions in today's final
rule.
Comment: Some commenters concluded that we did not establish either
cancer or noncancer thresholds for HCl and chlorine and, therefore, it
is illegal for EPA to attempt to use section 112(d)(4) to set
standards.
Response: The ``threshold level'' in section 112(d)(4) refers to
the level of concentration of a chemical under which no health effects
are expected from exposure, although this term is not defined in
section 112. Further, section 112 does not address the process that
must be followed to ``establish'' a threshold level.
The reference concentration (RfC) is a ``long-term'' threshold,
defined as an estimate of a daily inhalation exposure that, over a
lifetime, would not likely result in the occurrence of noncancer health
effects in humans. We have determined that the RfC for HCl of 20
micrograms per cubic meter ([mu]g/m3) is an appropriate
threshold value for assessing risk to humans associated with exposure
to HCl through inhalation http://www.epa.gov/iris/subst/0396.htm.
In cases where we have not studied a chemical itself, we rely on
the studies of other governmental agencies, such as the Agency for
Toxic Substances and Disease Registry (ATSDR) or the Office of Health
Hazard Assessment of California's Environmental Protection Agency (CAL
EPA), for RfC values. The CAL EPA developed an RfC value of 0.2 [mu]g/
m3 for chlorine based on a large inhalation study with rats.
Acute exposure guideline level (AEGL) toxicity values are estimates
of adverse health effects due to a single exposure lasting 8 hours or
less. The confidence in the AEGL (a qualitative rating of either low,
medium, or high) is based on the number of studies available and the
quality of the data. Consensus toxicity values for effects of acute
exposures have been developed by several different organizations, and
we are beginning to develop such values. A national advisory committee
organized by EPA has developed AEGL's for priority chemicals for 30-
minute, 1-hour, 4-hour, and 8-hour airborne exposures. They have also
determined the levels of these chemicals at each exposure duration that
will protect against discomfort (AEGL1), serious effects (AEGL2), and
life-threatening effects or death (AEGL3). Hydrogen chloride has been
assigned AEGL values (65 FR 39264, June 23, 2000), including the 1-
hour, AEGL1 of 2,700 [mu]g/m3 used in our revised analysis.
Chlorine has also been assigned AEGL values (62 FR 58840), including
the 1-hour AEGL1 of 1,500 [mu]g/m3 used in our revised
analysis.
We maintain that the listing of health thresholds by EPA and other
organizations in the public domain as discussed above has
``established'' health thresholds for HCl and chlorine. Further, the
recognition of these levels by EPA, ASTDR, and CAL EPA indicates that
chlorine and HCl are threshold pollutants.
Moreover, we provided the public an opportunity to comment on the
thresholds for chlorine and HCl that we used in our original analysis
for the proposed action (67 FR 44716). We used the same threshold level
for HCl for both the proposed and final NESHAP for the pulp and paper
mill category. We have also used the same threshold for HCl in the
proposed and final NESHAP for lime production (67 FR 78046; final
action is anticipated in August 2003). There is no requirement in
section 112(d)(4) that EPA develop or finalize a threshold for a
particular HAP in a certain manner. The thresholds we have used for
both HCl and chlorine are consistent with the statutory language in
section 112(d)(4).

Comments Related to the Risk Assessment

Comment: In the analysis for the proposed action (67 FR 44713), we
used the HCl RfC to determine the long-term health effects of chlorine
emissions, since chlorine photolyzes very quickly to HCl in sunlight.
Two comments supported this methodology and stated that our decision
was based on sound scientific knowledge of the pollutants of concern.
In contrast, two other commenters did not agree with our use of the
HCl RfC as a threshold level for chlorine. The commenters stated that
not all of the annual chlorine emissions can be considered as HCl and,
therefore, the chlorine exposure was underestimated. The commenters
argued that chlorine emissions will not undergo photolysis to convert
to HCl when there is not bright sunshine (i.e., at night or on cloudy
days).
Response: The widely accepted fact that chlorine is photolyzed in
sunlight formed the basis for the assumption in the original risk
assessment that chronic exposure to chlorine would not occur. As a
result of this comment, we re-examined the literature on the
atmospheric fate of chlorine to validate our original assumption.
The additional information obtained from the literature confirmed
our earlier information. There are several different pathways that
molecular chlorine can take, including photolysis (reaction with
light), reactions with hydroxyl radicals, reactions with oxygen atoms,
and reactions with water vapor. Each pathway results in different
amounts of Cl₂ being removed from the troposphere, and
different pathways are predominant at different times of the day.
However, photolysis is the primary pathway.
Therefore, this information did not fundamentally change the
assumption made in the original risk assessment, which was that on a
long-term basis, individuals will be exposed more to HCl formed from
the photolysis of chlorine than to chlorine. However, the commenters
are correct that there will be situations where individuals will be
exposed to chlorine. Therefore, in addition to the assessment where we
considered only acute exposure to chlorine, we concluded that it was
appropriate to consider the effects of chronic exposure to chlorine
emissions from chlor-alkali plants. In order to provide an upper bound
estimate of the chronic risks to compare with the lower bound estimates
assuming that all chlorine was converted to HCl, we conducted modeling
assuming that no chlorine is photolyzed.
In general, we consider an exposure concentration which is below
the RfC concentration (what we call a hazard quotient of less than 1)
to be ``safe.'' This is based on the definition of RfC. The RfC is a
peer reviewed value defined as an estimate (with uncertainty spanning
perhaps an order of magnitude) of a daily inhalation exposure to the
human population (including sensitive subgroups) that is likely to be
without appreciable risk of deleterious noncancer effects during a
lifetime (i.e., 70 years).
As discussed above, we conducted additional modeling for major
source facilities within the subcategory using the same model used for
the proposed action (ISCST3) to estimate chronic chlorine exposure
using the assumption that no chlorine is photolyzed to HCl. The hazard
quotients resulting from this additional modeling defined the upper
bound of our risk assessment. The highest upper-bound hazard quotient
estimated by the model is just over 0.3. (For more details regarding
this revised risk assessment, refer to table 2 of the responses to
comment document, available in the docket.) Given the health protective
assumptions used in

[[Page 70916]]

this analysis, the value of 0.3 represents a hypothetical exposure that
is well above what we would expect actual exposures to be. This is
because chlorine is converted to HCl in the presence of sunlight within
a few minutes. In addition, the hazard quotient of 0.3, which results
from this exposure scenario is well below the safe value of 1. Thus, we
have concluded that, even assuming that some chronic exposure to
chlorine may occur, that none of the major sources included in this
subcategory will have emissions of chlorine or HCl that exceed a level
of exposure which is adequate to protect public health and the
environment with an ample margin of safety.
Comment: Two commenters did not support EPA's use of the AEGL2 for
use as a short-term exposure limit for chlorine and HCl. One commenter
stated that the AEGL2 values would not sufficiently protect public
health because they would allow emissions at levels that cause
``discomfort,'' and according to the commenter, discomfort is an
adverse health effect. The commenter also complained that EPA did not
explain why it chose to use AEGL2 rather than AEGL1 or AEGL3. The
commenter explained that although emissions from chlorine plants did
not exceed AEGL2 values, the emissions may exceed AEGL1 values, and if
they did, the proposed action would not meet the statutory
requirements. Another commenter stated that AEGL limits are not
appropriate for assessing daily human exposure scenarios because they
were developed for emergency planning. The commenter recommended that
EPA use the American Conference of Governmental Industrial Hygienists
(ACGIH), which has a 1-hour Short Term Exposure Limit (STEL) similar to
the AEGL1 value of 1 part per million (ppm) for chlorine and is used to
protect against eye and mucous membrane irritation. The commenter
stressed that EPA must use conservative benchmarks before concluding
that an ample margin of safety exists.
Response: The AEGL values represent short-term threshold or ceiling
exposure values intended for the protection of the general public,
including susceptible or sensitive individuals, but not
hypersusceptible or hypersensitive individuals. The AEGL values
represent biological reference values for this defined human population
and consist of three biological endpoints for each of four different
exposure periods of 30 minutes, l hour, 4 hours, and 8 hrs.
As utilized in the proposed action, the AEGL2 1-hour concentrations
for chlorine and HCl are 5,800 [mu]g/m3 and 33,000 [mu]g/
m3, respectively.
The 1-hour AEGL1 concentration for chlorine is 2,900 [mu]g/
m3 and the corresponding value for HCl is 2,700 [mu]g/
m3. The ACGIH short term exposure limit (STEL) for chlorine,
which is 1 ppm is approximately equal to the AEGL1 value of 2,900
[mu]g/m3.
Although we stand by our original analysis, which used the AEGL2
level, we have incorporated the commentor's suggested use of the AEGL1
values (possibly with a safety factor) for determining whether an ample
margin of safety has been obtained. Therefore, we simply compared the
short term (1-hour average) modeling results from the original acute
risk assessment to the AEGL1 values. These results were obtained by
modeling the maximum allowable hourly emissions reported in the section
114 responses for each of the sources. For plants that did not report
fugitive emissions, fugitive emissions were estimated using worst-case
emission factors.
The maximum modeled 1-hour chlorine concentration for two of the
three plants with the mercury cell chlor-alkali process is less than 5
percent of the AEGL1 (and ACGIH) value for chlorine. Further, the
highest modeled concentration for any plant, 155 [mu]g/m\3\, is less
than 6 percent of the AEGL1 values. The highest modeled 1-hour HCl
concentration for any plant, 32 [mu]g/m\3\, is less than 2 percent of
the AEGL1 value for HCl. Furthermore, all of the mercury cell chlor-
alkali facilities also produce chlorine using a non-mercury chlorine
production process (i.e., diaphragm cells). The modeled emissions
represent chlorine and HCl emissions from both processes. Therefore,
the chlorine and HCl emissions from the mercury cell chlor-alkali
process would be even lower.
Based on this comparison, we conclude that the chlorine and HCl
emissions from mercury cell chlor-alkali production plants do not
represent an unsafe level of acute exposure. We further maintain that,
along with the chlorine exposure assessment, this proves that an ample
margin of safety is provided with no additional control.
Comment: Two commenters supported EPA's method of selecting a risk
assessment approach to meet the unique needs of the chlorine production
industry. The commenters agreed that the risk assessment methodology
should not be interpreted as a standardized approach that would set a
precedent for how EPA will apply CAA section 112(d)(4) in future cases.
Furthermore, the commenters stated that the degree of conservatism
built into all aspects of the risk assessment conducted for the
chlorine production source category could vary greatly in future risk
assessments for other source categories. The commenters stressed that
the conservative assumptions made in the health effects assessment,
emissions estimates, and exposure assessment were appropriate for the
proposed action.
In contrast, one commenter stated that the risk assessment fell
short of the Agency's prior practice. According to the commenter,
whenever EPA has made determinations to regulate a specific pollutant
based on health considerations (e.g., national ambient air quality
standards (NAAQS) for ozone and PM), the Agency evaluated health
effects and exposure in great detail. The commenter contended that in
this case, EPA appears to be content with ``the bare and unsupported
assumptions about what health levels are safe.'' The commenter argued
that it was not appropriate for EPA to use a rigorous approach when
setting standards and a more cursory approach when making a decision
not to regulate.
Response: We disagree with the one commenter's characterization of
the assessment that forms the basis for this decision, and we strongly
dispute the characterization of the assessment as ``bare and
unsupported.'' As discussed elsewhere in this preamble, we maintain
that the RfC and AEGL values used as benchmarks for this assessment are
scientifically sound and appropriate. The emissions data and other
inputs used for this analysis, which were provided by the industry and
checked by our staff, are representative of the industry.
In this assessment, the predicted health effects estimated, using
very conservative inputs and assumptions, were well below the
recognized health thresholds. While our approach in this particular
action may not be the same as an approach for a NAAQS, we believe that
it has been certainly more than ``cursory.'' We have looked at
emissions and exposure data for each of the major sources in the
subcategory. We have established hazard indices for chlorine and HCl
for each major source in the subcategory. We performed a qualitative
ecological assessment. Moreover, in response to comment received, we
have revised our analyses and taken into account comments that we have
received when performing these reassessments. We will base each risk
assessment for this and future regulatory action on sound scientific
principles.
Comment: In the proposed action, the risk assessment modeling was
conducted by placing receptors at the

[[Page 70917]]

geographic center of census blocks within 2 kilometers of the site and
in the population-weighted centers of census block groups or census
tracks out to 50 kilometers. Two commenters did not agree with this
methodology for determining receptor location for threshold pollutants.
One commenter stated that EPA's methodology would be more appropriate
for cancer causing agent, where the risk is based on probabilities of
health effects. The commenter argued that for noncancer (i.e.,
threshold pollutants) compounds, placing the receptors at the center of
census tracks would not properly identify the highest impacts close to
the facility. They felt that it was more appropriate to measure the
exposure of the most exposed individual (e.g., someone living at the
fence line of a facility or directly downwind).
Response: We certainly agree with the commenters that the greatest
impacts will likely occur near the facility for this source
subcategory. However, we do not agree with the commenters that our
approach fails to meet statutory requirements. We do not feel that
considering an ``ample margin of safety'' means that we must
demonstrate no risk or adverse health effects for a theoretical person
living at the fence line. Rather, it is appropriate to assess the risks
at locations where people most likely reside. A census block is the
smallest geographic unit for which the Census Bureau tabulates 100
percent data. While census blocks in rural areas may be larger, many
blocks correspond to individual city blocks in more populated areas.
The commenter is correct in that an individual could live closer to the
plant than the center of the census block and our approach would have
slightly underestimated risk. It is just as likely, however, that the
closest individual could live farther from the plant than the center of
the census block causing our risk estimates to be slightly
overestimated. By placing receptors at the center of populated census
blocks on all sides of a facility, we have evaluated people living
``downwind.'' In conclusion, we continue to feel that placing a
receptor in the geographic center of populated census blocks near a
facility is a well established approach to exposure modeling which
results in a reasonable approximation of estimating the risks where
people actually live, and we maintain that this methodology is
appropriate for actions taken under the authority of section 112(d)(4).
Comment: One commenter stated that all chlorine emissions from
chlorine production facilities that are collocated with other source
categories need to be reviewed as a whole when evaluating public health
risk, adverse environmental effects, and possible control strategies.
The commenter stressed that other sources of chlorine and HCl should be
included in the risk assessment under section 112(d)(4). The commenter
was concerned that not accounting for all chlorine and HCl emissions
from a facility would provide the community with a false sense of
assurance of protection and is not consistent with the legislative
intent of the CAA to consider cumulative HAP exposure issues through an
integrated approach under section 112(d), 112(f), and 112(k).
Therefore, the commenter requested that EPA evaluate the potential for
adverse health and environmental impacts using conservative risk
assessment methodology that incorporates all known chlorine and HCl
emissions from a contiguous facility.
Response: Section 112 of the CAA requires us to list categories and
subcategories of major sources and area sources of HAP and to establish
NESHAP for the listed source categories and subcategories. In directing
us how to establish MACT emission limits, section 112(d)(3) of the CAA
requires us to set the emission limitation at a level that assures that
all major sources achieve the level of control at least as stringent as
that already achieved by the better-controlled and lower-emitting
sources in each source category or subcategory. Therefore, the entire
MACT program is structured on a source category-specific basis. All
MACT standards developed to date have addressed emissions from specific
source categories.
There are instances where mercury cell chlor-alkali facilities are
collocated with other source categories. However, based on the risk
assessment for chlorine and HCl emissions from mercury cell chlor-
alkali plants, the predicted impacts from chlorine and HCl at these
plants are extremely low. We believe that the human health and
environmental impacts from all sources in the subcategory even when
collocated with other chlorine and HCl emissions will still be within
an ample margin of safety to protect the public health, and will not
cause adverse environmental effects. Moreover, as indicated in the
preamble to the proposed action, most major processes at the sites
where mercury cell chlor-alkali facilities are located are subject to,
or will be subject to, NESHAP to reduce HAP emissions (67 FR 44714,
July 3, 2002). Therefore, it would be inappropriate to include
emissions from those sources in an assessment for the mercury cell
chlor-alkali subcategory conducted under the authority of section
112(d)(4).
Comment: Two commenters stated that the environmental effects
analysis was not adequate. One commenter stated that potential
ecological effects of HCl emissions have not been properly referenced.
One commenter stated that EPA's proposed action falls short of its
obligation to protect against environmental effects. According to the
commenter, EPA has understated its statutory obligation in the proposed
action. The commenter referred to the legislative history, which
indicates that CAA section 112(d)(4) requires standards that ``would
not result in adverse environmental effects which would otherwise be
reduced or eliminated.'' The commenter listed the several shortcomings
in the EPA's environmental assessment.
The commenter concluded that although EPA acknowledged that it had
an obligation to ensure that any standards set under section 112(d)(4)
did not have any adverse environmental effects, the Agency did not
properly consider the issue. Therefore, the commenter stated that EPA
could not promulgate standards under section 112(d)(4) without
contravening the CAA.
Response: While CAA section 112(d)(4) makes no mention of
environmental effects, we took the potential of such adverse effects
into account when we issued our proposed action. The level of our
analysis at proposal was adequate to satisfy the requirements of
section 112(d)(4). The commenters did not suggest that they believed
there was the potential for adverse environmental effects from HCl or
chlorine emissions from mercury cell chlor-alkali plants. Were there
any evidence that such adverse effects were likely, or even possible,
we would have conducted a more intensive ecological risk assessment.
The commenters are correct, however, that we did not discuss the
ecological effects of chlorine. This was because, as was stated in the
proposal preamble, we did not perform a separate evaluation of chronic
chlorine exposure because chlorine is converted to HCl in the
atmosphere so rapidly.
Atmospheric exposure is the primary pathway for environmental
effects from chlorine emissions. However, since most chlorine is
converted to HCl, studies have focused on the effects of HCl on
vegetation. Although plant exposures to elevated levels of chlorine can
cause plant injury, it tends to be converted to other, less toxic forms
rather rapidly in plants and may not result in the direct accumulation
of

[[Page 70918]]

toxic pollutant residuals important in the food chain.
Plant studies have found foliar damage due to chlorine emissions,
decreased levels of chlorphyll a and b, decreased leaf areas, obvious
chlorosis, and a decline in fruit production due to chlorine emissions.
There is evidence of effects to animals due to accidental and/or
catastophic exposures, but the chlorine concentrations of these
exposures are unknown. However, there are no data on exposure to
historic or atmospheric concentrations.
More information is available on the effects of chlorine from
aquatic exposures. However, there is no evidence that suggests that
emissions of chlorine from industrial sources in the air contribute
significantly to aquatic concentrations of chlorine.
One study reported a significant decrease in phytoplankton activity
following exposure to 0.1 ppm chlorine in cooling tower water.
Additional laboratory studies showed that continuous exposure to 0.002
milligrams per liter (mg/L) total residual chlorine (TRC) resulted in
depressed algal biomass in naturally-derived microcosms.
When exposed continuously for 96 hours to 0.05 mg/L TRC, the
Eurasian water milfoil showed a significant reduction in shoot and dry
weights, shoot length, and chlorophyll content.
Aquatic invertebrates are very sensitive to chlorine and reaction
products of chlorine, with early life stages showing the most
sensitivity. For example, free chlorine, monochloramine, and
dichloroamine have been shown to reduce the rate of oyster larvae
survival. Many studies have been performed, and the results are highly
variable depending on the chlorine species, the lifestage of the
invertebrate, and other factors such as salinity. The most sensitive
aquatic species appears to be molluscan larvae, with lethal
concentration 50% (LC₅₀) of 0.005 mg/L. Sublethal effects
have also been studied, including reduced growth, reduced motility, and
reproductive failure.
The effects on fish also vary depending on the life stage and fish
species and environmental factors, such as the pH, temperature, and
type of chlorine species. Larval stages are more susceptible to
effects, and freshwater species are more sensitive than marine species.
Free chlorine is generally more toxic than residual chlorine; where the
form of chlorine is dependent on the pH of the water. Sublethal effects
such as avoidance, reduction of diversity in chlorinated effluents,
reduction or elimination of spawning, abnormal larvae, reduced oxygen
consumption, and gill damage have been noted. Many LC₅₀
values were reported, ranging from 0.08 mg/L after 24 hours of exposure
to TRC to 2.4 mg/L after 0.5 hours of exposure to TRC.
Acute and chronic exposures to predicted chlorine and HCl
concentrations around the sources are not expected to result in adverse
toxicity effects. These pollutants are not persistent in the
environment. The chlorine and HCl emitted should not significantly
contribute to aquatic chlorine concentrations and are not likely to
accumulate in the soil. Chlorine rapidly converts to HCl in the
atmosphere, and chlorine and HCl are not believed to result in
biomagnification or bioaccumulation in the environment. Therefore, we
do not feel there will be adverse ecological effects due to chlorine
and HCl emissions from mercury cell chlor-alkali plants.

C. What Issues Were Raised Regarding the Compliance Date?

Comment: Commenters requested an extension of the compliance date,
which was proposed to be 2 years from the effective date of the final
rule. The commenters recommended that the compliance date should be
changed to 3 years after promulgation. The commenters stated that
affected facilities are being required to install costly, complex
control and monitoring equipment, as well as establish additional
operating and maintenance procedures at their facilities in order to
ensure compliance with the emission limitations and work practice
requirements of the proposed rule. The commenters believed that 2 years
was not a sufficient period of time to complete such tasks,
specifically the continuous monitoring requirements.
Response: We agree that since the existing sources are required to
install complex monitoring equipment and to establish additional
operating and maintenance procedures, it is reasonable to allow more
time than the proposed 2-year compliance period. Section 63.6(c)(1) of
the NESHAP General Provisions states that ``* * * in no case will the
compliance date * * * exceed 3 years after the effective date of * *
*.'' Therefore, the final rule specifies that the compliance date for
existing sources is 3 years after the effective date of the final rule.

D. What Issues Were Raised Regarding the Emission Limitations?

Comment: One commenter, which submitted comments after the close of
the comment period, recommended that EPA re-define MACT to ban the use
of mercury cell technology. The commenter explained that this would be
easily achievable because the majority of the chlorine production
industry already uses other, superior technologies such as membrane
cells and diaphragm cells. The commenter claimed that EPA abused its
authority to establish subcategories of emission sources by creating a
subcategory of ``mercury cell chlor-alkali plants'' within the chlorine
production source category which limits the pool of facilities upon
which the MACT floor is based to those who create dangerous pollution,
as opposed to those industry leaders that use non-polluting and readily
available equipment.
The commenter further listed a lack of confidence that the mercury
cell process could be adequately controlled. The commenter explained
that the work practice requirements which are proposed to address
fugitive emissions, the largest source of emissions from this process,
are too weak.
Finally, the commenter stated that converting all mercury cell
plants to membrane cells would still be cost-effective, and that their
estimate of the cost to convert all mercury cell plants to other
technologies ($920 million) was justifiable given the significant
threat to public health and the environment posed by mercury.
Response: We disagree with the commenter that we abused our
authority to create subcategories by subcategorizing the chlorine
production industry and only including mercury cell plants in the MACT
floor analysis. It is our general policy to subcategorize when there
are technical distinctions among classes, types, or sizes of sources,
and manufacturing processes of sources, that would impact setting an
appropriate emission limit even when creating the subcategories leads
to some with a small number of sources. This policy is supported by the
broad discretion provided to the Agency to establish subcategories
under CAA section 112(c), the legislative history, and EPA's prior
rulemakings.
In general, EPA has previously taken the position that
subcategorization is appropriate where types of emissions and/or types
of operation make use of the same air pollution control technology
infeasible. The EPA's rulemakings reflect this general understanding
and provide criteria for subcategorization that focus on the
appropriateness of applying similar technology-based requirements at
different sources.

[[Page 70919]]

The EPA feels that the subcategorization scheme it has used for
this category of sources (as described above and in the proposed rule)
is consistent with the statute, the legislative history, and EPA's past
implementation of section 112(c) and the MACT program. The HAP emitted
by the two subcategories (mercury cell chlor-alkali plants and non-
mercury cell chlorine production) plants are different--while plants in
both categories emit chlorine and HCl, only plants in the mercury cell
subcategory emit mercury. The processes used to produce chlorine that
the plants in the two subcategories used are generally different
(because of the use of the mercury cells). Thus, no change was made in
response to this comment and the final rule does not ban mercury cells
(except the final rule does prohibit the emission of mercury from new
or reconstructed chlor-alkali production facility sources).
With regard to the cost effectiveness of a ban of mercury cell
chlor-alkali facilities, the commenter did not provide any basis for
their estimate so we could not verify these costs. Further, we do not
feel that ``conversion'' accurately describes the replacement of a
mercury cell plant to another technology. There is little salvageable
from a mercury cell plant that can be used in the construction of a
membrane cell plant, so the demolition of the mercury cell plant
followed by the construction of a membrane cell plant is a more
accurate characterization.
Therefore, we did not promulgate a final rule that requires non-
mercury technology for chlorine production.
Comment: Two commenters did not agree with the proposed ``beyond-
the-floor'' emission limitations. They stated that there is no
justification for EPA to set emission limits beyond the floor, as
proposed. The commenters stressed that EPA is required to assess the
cost-benefit relationship when considering ``beyond the MACT floor''
limitations. According to the commenters, the Agency did not set forth
an accurate basis for costs associated with meeting the MACT floor or
cost/benefits associated with meeting the ``beyond the MACT floor''
emission limitations.
These commenters were also concerned that the very low emission
limits required by EPA's beyond-the-floor determination cannot be
obtained by the industry as a whole. Specifically, the commenters
stated that the Agency lacks high quality point source emission data
upon which to base their ``beyond-the-floor'' limits. The commenters
pointed out that the mercury emission limitations for hydrogen vent gas
streams are based on limited data provided by a single facility in
Maine that has been closed for nearly 2 years. The commenters
maintained that for all of the eleven plants combined (ten affected
plants plus the closed Maine plant), there was very little high quality
point source emission data. Due to the significant chance that the data
used to develop the standard are biased and quantitatively non-
representative, the commenters stated that the Agency was not justified
in moving beyond the floor to the most stringent value ever obtained by
the industry.
The commenters further argued that EPA's conclusion that the
``beyond-the-floor'' emission limitations can be met with existing,
commercially available control equipment is not supported and thereby
seriously flawed. The commenters pointed out that EPA presented no data
in the preamble or elsewhere in support of their decision that the
proposed standards could be met with commercially available control
systems.
Response: First, we disagree with the commenters' assertions that
we did not have justification for going beyond the floor, and that we
did not have an accurate basis for costs associated with meeting the
MACT floor or meeting beyond-the-floor emission limitations. We
conducted a very detailed plant-specific cost impacts analysis which is
available in the docket. The commenters did not provide any specific
comments on this detailed analysis or any specific data or rationale to
refute our cost analysis. Therefore, we stand by our original analysis
and have not made any changes to the cost impacts approach. Based on
our analysis, we concluded that the costs/benefits of going beyond the
floor are warranted. Given the persistent nature of mercury in the
environment and its associated health and welfare impacts, we continue
to feel that the additional emission reductions that will be achieved
by the beyond-the-floor option are warranted considering the associated
costs.
However, in the proposal preamble (67 FR 44682), we acknowledged
that there was uncertainty associated with the level of control
associated with the beyond-the-floor option proposed because the
molecular sieve adsorption control technology is no longer commercially
available, and because the plant representing this level of control is
no longer operating. We did not receive any comments indicating that
the molecular sieve control technology is commercially available.
Further, since the plant has closed, we were unable to obtain
additional information to further scrutinize the data to ensure that
they were not biased and quantitatively non-representative. Therefore,
we have concluded that we cannot fully demonstrate that the proposed
beyond-the-floor standard is achievable using commercially available
technology.
In the proposal preamble, however, we also stated that we were
retaining the option of setting the standard at the next lowest
normalized emission value of 0.076g Hg/Mg Cl₂ for plants
with end box ventilation systems. The plant with this emissions level
controls its by-product hydrogen system with a series of iodine and
potassium iodide impregnated carbon adsorbers, and their end box
ventilation system vent with a condenser and demister, which are
commercially available technologies. Further, in the documentation for
the proposed standard, we determined on a plant-specific basis which
commercially available technologies could be made to comply with the
proposed standard. The commenters provided no comment on why the
application of the very specific application of these technologies
could not achieve the emission limitations.
The emissions estimates for the facility with normalized emissions
of 0.076 g Hg/Mg Cl₂ are based on weekly testing using
methods that are modifications of EPA Methods 101A and 102. The primary
difference between the methods used by the facility and the EPA
Reference Methods is that the sampling is not isokinetic. We discussed
our opinion that data obtained using this type of modified method were
acceptable to use in MACT standards in the proposal BID. Therefore, it
can be considered that the emission estimates used to establish the
level of 0.076 grams Hg/Mg Cl₂ are based on weekly
performance tests. We do not consider such data to be of low quality.
Therefore for the final rule, we have selected the 0.076 grams Hg/Mg
Cl₂ beyond-the-floor option as MACT for plants with end box
ventilation systems.
For the by-product hydrogen stream for plants without end box
ventilation systems and mercury thermal recovery unit vents, there were
no questions raised regarding the availability of the control
techniques used at the lowest emitting plants that formed the basis for
the proposed emission limitations. Further, at proposal, we examined
the data used to establish the emission limitations and determined that
they were of adequate quality to be used to establish standards.
Therefore, the final rule retains the proposed emission limitations for
these emission sources.
Comment: Commenters were concerned that the proposed mercury

[[Page 70920]]

emission limitation for by-product hydrogen had a daily averaging
period for continuous compliance. According to the commenters, the
Agency developed the proposed standard using annual average emissions
and actual annual production and then interpolated to a daily limit
without regard to statistical error. Therefore, the commenters
requested either an annual average emission rate limit or that the
daily limit be set at not less than two times the annual limit divided
by 365 (days).
Response: The commenters are correct in that the normalized mercury
emissions used to establish the standards were based on annual average
emissions and annual actual chlorine production. Therefore, the
commenters' concerns about the variability of the control systems over
a year and the ability to comply on a daily basis with this limit have
merit. We considered the two options offered by the commenters (a 365-
day compliance period and adjustments to account for daily variations).
We do not feel that it would be appropriate to apply a generic
multiplier to the limit for mercury cell chlor-alkali plants to account
for short-term variation. In addition, mercury cell emissions data were
not available to assess the variability in emissions from these
emission points. Therefore, we concluded that the emission limitation
should reflect an annual average. This would be consistent with the
data used to create the emission limitation and would allow for short-
term variations in operations and control device performance.
The final rule is allowing weekly monitoring/testing as an
alternative method to determine continuous compliance with the emission
limitations. In order to be consistent with the continuous compliance
approach, we concluded that the by-product hydrogen/end box ventilation
emission limitation in the final rule should be annualized on a 52-week
rolling basis. Specifically, the final rule requires that mercury
emissions from all by-product hydrogen streams and end box ventilation
system vents not exceed 0.076 grams Hg/Mg Cl₂ for any
consecutive 52-week period.

E. What Issues Were Raised Regarding the Work Practices?

Comment: One commenter recommended that EPA establish numerical
standards for fugitive emissions. The commenter maintained that, absent
published information on good mass balance analyses performed at chlor-
alkali facilities, one can only assume that significant mercury losses
are occurring through fugitive emissions. Accordingly, the commenter
felt it is crucial that the EPA step up efforts to address all
potential release routes from such facilities, including fugitive
emissions.
Another commenter, which submitted comments after the close of the
comment period, expressed the view that the mercury consumed cannot be
accounted for in material balances. This commenter asserted that the
proposed rule failed to address the majority of the true annual mercury
emissions from the mercury cell chlor-alkali industry. The commenter
explained that the mercury used in this industry is not incorporated
into final products or consumed in the process, so all mercury
purchased is used to replenish mercury that has been lost from the
manufacturing process. The commenter compared the amount of mercury
purchased by the industry in 1994 (136 tons) to EPA's estimate of
annual emissions (22,200 pounds or 11.1 tons) and concluded that the
proposed rule fails to account for nearly 90 percent of the true
mercury emissions from this industry. The commenter drew this
conclusion based on the assumption that most of the mercury would be
released to the air rather than transferred off-site as solid waste or
accumulated in on-site tanks and ponds. The commenter noted that EPA's
estimate of annual emissions was based on outdated and inadequate
estimates of fugitive emissions which were based on short-term
measurements taken when fugitive emissions were non-representatively
low.
One of these commenters, who submitted comments after the comment
period, recommended that EPA require both monitoring of fugitive
emissions from cell rooms and waste storage areas and establish a
reduction goal for such emissions. According to the commenter,
technologies are available to quantify airborne mercury concentrations
continuously, and in combination with estimates of air flow rates,
estimates of fugitive loss rates under selected conditions could be
made and could serve as the basis for reduction targets.
Response: The issue of unaccounted for mercury has been the subject
of intense scrutiny from other groups within EPA and the indusry. As
part of the Great Lakes Binational Toxics Strategy, mercury cell
chlorine producers annually report the total mercury consumption for
the industry. From the baseline consumption of 160 tons per year (tpy)
for the years 1990-1995, the industry reported an 81 percent reduction
of mercury consumed in 2001 (30 tpy). One of the commenters
characterized the 2001 consumption as an outlier, but the 79 tpy
consumed in 2000 still represents a significant decrease from the
baseline level.
Even with this decrease in consumption, significant mercury remains
unaccounted for by the industry. The mercury releases reported to the
air, water, and solid wastes in the 2000 Toxics Release Inventory (TRI)
totaled around 14 tons. This leaves around 65 tons of consumed mercury
that is not accounted for in the year 2000.
While it may appear to the commenters that the discrepancy in the
mercury material balance is the result of fugitive emissions, there is
little empirical evidence to support this conclusion. The commenters
did not provide any emissions data to support their assertion.
Furthermore, industry personnel claim that mercury which condenses and
accumulates in pipes, tanks, and other plant equipment makes up a large
component of the unaccounted for mercury. While the commenters
completely discount this claim by the industry, it is relevant to
consider the very high density of mercury. For instance, the 65 tons of
unaccounted for mercury in 2000 averages just over 7 tons per plant.
One gallon of mercury weighs around 113 pounds, meaning that around 124
gallons of mercury would be unaccounted for per plant. This is a very
small percentage (less than 2 percent) of the amount of mercury
typically on site at most facilities. However, the industry is also
unable to fully substantiate their theory. Therefore, the fate of all
the mercury consumed at mercury cell chlor-alkali plants remains
somewhat of an enigma.
We agree that work practice standards should only be set when it is
not feasible to prescribe or enforce an emission standard. Indeed, our
reasons for establishing work practices instead of numerical limits are
based on factors associated with the practicality and feasibility of
setting a realistic limit against which compliance can be measured and
enforced.
First, data are not available to establish a numerical emission
standard for fugitive emissions. As stated in the proposal preamble (67
FR 44680), emissions data for fugitives from cell rooms and waste
storage areas are very limited. Second, we do not agree with the
commenter's implication that available measurement technologies could
support enforcing a numerical emission standard for the following
reasons:

? Mercury emission monitors have not been used to monitor
fugitive

[[Page 70921]]

emissions at mercury chlor-alkali facilities for compliance
demonstrations;
? The variability in the number of and location of exhaust vents
at each facility affects the amount of air moved through the cell rooms
and thus affects the mass emission rate of the fugitives; and
? The variability of the cell room roof configuration affects the
feasibility of using the continuous emissions monitors at each
facility.

Therefore, the establishment of numerical emission limitations for
fugitive emissions from the cell room and other areas is ``not
feasible,'' as defined in CAA section 112(h)(2)(B). Thus, the final
rule retains the work practice elements of the proposed rule.
However, in response to the concerns about unaccounted for mercury,
we did add a provision in the final rule that requires each facility to
record and report the mercury consumed each year. While there are no
mercury consumption reduction targets in the final rule, we believe
that reporting mercury consumption on a plant-specific basis will
encourage additional action to identify unaccounted for mercury and
reduce mercury consumption.
Comment: A commenter that submitted comments well after the close
of the comment period expressed the opinion that there was a
fundamental flaw in the proposed rule because the proposal will weaken
existing sources' obligations to limit mercury emissions from the cell
room. They cited 42 U.S.C. Sec. 7412(d)(7), which prohibits emission
standards from weakening existing standards. This commenter summarized
the 40 CFR part 61 mercury NESHAP, which requires mercury cell chlor-
alkali plants to not emit more than 2,300 grams per day of mercury from
the entire facility, including the cell room, the by-product hydrogen
streams, the end box ventilation system vents, and other sources of
mercury. The commenter stated that even if emissions from all other
points were zero, emission from the cell room cannot exceed 2,300 grams
per day. The commenter acknowledged that an owner or operator may
forego cell room emission testing and assume that cell room emissions
are 1,300 grams/day, but pointed out that complying with these work
practices does not absolve the owner or operator of the obligation to
meet the applicable numeric emission standard.
The commenter contrasted this with the proposed rule, which
established numerical emission standards for by-product hydrogen
streams, end box ventilation systems, and mercury thermal recovery unit
vents, but not for cell room fugitive emissions. The commenter claimed
that emissions from the cell room will be able to exceed 2,300 grams/
day so long as the work practices are followed, when the rule as
proposed prohibits such a result.
The commenter concluded that it is not sufficient to say that the
work practices that have been proposed are more stringent than the
existing requirements, because neither the existing nor proposed work
practices by themselves require any given numeric level to be achieved.
They argued that the existing numeric limit provides EPA and the public
with an enforceable limit of performance to which owners and operators
can be held. The commenter went on to indicate that such a numerical
standard is particularly necessary, as plants are currently emitting
far more than 2,300 grams per day of mercury. To support this
assertion, the commenter provided information indicating that mercury
cell plants add much more mercury to their cells than 2,300 grams per
day, and they concluded that cell room emissions is a very likely way
that mercury is lost. In conclusion, the commenter stated that it would
be inappropriate for EPA to rely entirely on a work practice standard
and eliminate stricter provisions that would enable the Agency to
insist that facilities keep their emissions below a set level.
Response: The 40 CFR part 61, Mercury NESHAP, Sec. 61.53(c)(1),
contains requirements for stack sampling to determine emission levels
for cell room ventilation systems at mercury chlor-alkali plants. If an
owner or operator meets the prescribed work practice standards, they
can assume a mercury emission rate from the cell room of 1,300 grams
per day.
While the final rule does not retain the numerical emission
limitation from the 40 CFR part 61 Mercury NESHAP, the requirements in
the final rule for fugitive mercury emissions from the cell room are
far more stringent than the design, maintenance, and housekeeping
practices allowed by the Mercury NESHAP in lieu of meeting the
numerical limit. In addition, the Mercury NESHAP contained only 18 work
practice requirements as compared to the more than 80 design,
operation, maintenance, inspection, and required actions for repair
contained in tables 1 through 4 to the final rule. The work practice
standards specify the equipment and areas to be inspected along with
the frequency of the inspections and conditions that trigger corrective
action. Response time intervals for when the corrective actions must
occur are also specified. Furthermore, some types of inspections are
required at more frequent intervals than required by the Mercury NESHAP
(e.g., inspecting decomposers for hydrogen leaks twice per day rather
than once each day). In addition, the detailed recordkeeping procedures
and reporting provisions are more fully developed than those in the
Mercury NESHAP, as well as requirements for storage of mercury-
containing wastes.
Finally, the work practice standards contain a requirement for
owners and operators to develop and implement a plan for the routine
washdown of accessible surfaces in the cell room and other areas. The
standards establish the duty for owners or operators to prepare and
implement a written plan for washdowns and specify elements to be
addressed in the plan. A requirement for washdowns is an important part
of an overall approach to reducing cell room fugitive emissions.
Along with a floor-level periodic mercury monitoring program
(discussed later), not only will the work practice standards in the
final rule result in reduced mercury fugitive emissions (and,
therefore, mercury consumption), but provide much more enforceable
provisions so that an inspector can verify that they are being met.
In addition, we have calculated emission reductions for the final
rule. Assuming that every facility is complying with the 1,000 grams
per day limit from point sources (this value assumes that 1,300 grams
per day of the 2,300 grams per day facility limit are being used for
fugitive emissions), we estimate that baseline emissions from all nine
existing facilities (relative to the Mercury NESHAP) are 3,285 kg/yr.
We estimate that annual emissions after the application of MACT to be
217 kg/yr. Therefore, the final rule will result in emission reductions
of 3,068 kg/yr, or approximately 93 percent from the existing Mercury
NESHAP. This supports our position that we are not setting a standard
that allows backsliding. Therefore, once the final rule compliance date
ensues, sources subject to the provisions of the final rule will no
longer be subject to the Mercury NESHAP.
Comment: Commenters disagreed with EPA's proposal to institute a
continuous mercury monitoring program whereby owners and operators
would be required to continuously monitor mercury concentration in the
upper portion of each cell room and take corrective actions when
elevated mercury vapor levels are detected. The commenters stated that
the proposed

[[Page 70922]]

monitoring program was seriously flawed and should be deleted from the
final rule. The commenters noted that periodic monitoring done in
various areas of the cell room (as currently practiced to ensure
compliance with Occupational Health & Safety Administration (OSHA)
permissible exposure limits) was an appropriate substitute. Several
commenters stated that they would not be opposed to the continuous
mercury monitoring program if the technology were field demonstrated.
In contrast, one commenter, which submitted comments after the
close of the comment period, ``enthusiastically'' supported the
proposed cell room monitoring program. Nonetheless, the commenter felt
that it was unwise for the EPA to allow each owner/operator to set his/
her own cell room action level.
Some commenters stated that cell room monitoring is redundant to
the housekeeping requirements, and that the work practices required in
Tables 1-5 to the proposed rule allow for sufficient opportunity to
quickly detect abnormal sources of mercury emissions. Another commenter
stated that the final rule should either require continuous monitoring
or detailed work practice standards but not both. The commenter argued
that cell room designs vary greatly. Given this variability, the
commenter urged EPA to enable facilities to select the appropriate
compliance strategy for individual circumstances.
Response: With regard to technical feasibility, a cell room mercury
monitoring system was tested in 2000 at a mercury cell facility in
Augusta, Georgia, that demonstrated that the monitoring technology can
be effectively installed and operated in mercury cell chlor-alkali
plant cell rooms, and this technology, along with other measures, can
be an effective mechanism to identify leaking equipment and other
problems that result in fugitive mercury emissions from the cell room.
We acknowledge that this success, which occurred in a limited and
very controlled situation for a short time period, does not necessarily
prove that similar monitoring at every mercury cell room would prove to
be an effective long-term method to reduce mercury fugitive emissions.
In fact, the design and operation of the Augusta facility probably
represented the optimum circumstances for a mercury cell room
monitoring program to be successful. We are aware that cell room
designs vary greatly and recognize that the design affects the location
and number of monitors necessary to accurately monitor each individual
cell room. In addition, depending on the design of the roof, it may be
possible that installation of monitors that adequately monitor mercury
concentration would not even be possible.
Even with these limitations, a well designed and implemented cell
room monitoring program can effectively reduce mercury fugitive
emissions on a long-term basis. Therefore, we included this concept in
the final rule.
However, we do agree with the commenters that a comprehensive
continuous cell room monitoring program should be sufficient to reduce
fugitive mercury emissions from the cell room without imposing the
overlapping requirements of the detailed work practices. Therefore, we
have concluded that it is appropriate to allow facilities to implement
the continuous cell room monitoring program as an alternative to, and
not in addition to, the work practice requirements. In the final rule,
facilities are given the option to implement the cell room continuous
monitoring program in lieu of the work practice requirements. We do,
however, feel there is a need to outline more specifically the elements
that must be included in the cell room monitoring program to ensure
that it provides at least the same level of control as the work
practices and cell room monitoring program would have provided
together. Therefore, there are more prescriptive requirements in the
final rule for the cell room monitoring plan option. The final rule
dictates how the action level is to be established, what measures must
be followed when the action level is exceeded, and what records must be
kept.
Although the continuous cell room monitoring provisions are
optional, some mercury monitoring to detect elevated mercury levels in
the cell room is appropriate. Therefore, we have included a periodic
monitoring program to be performed throughout the cell room as a
substitute for continuous monitoring. The final rule contains a floor-
level periodic monitoring program as part of the work practice
standards.

F. What Issues Were Raised Regarding the Monitoring and Continuous
Compliance Requirements?

Comment: Three commenters questioned EPA's intent in establishing
emission limitations based on the initial performance test. These
commenters felt that the proposed standards amounted to changing the
emission limit based on the emissions observed during the performance
test which amounted to ignoring the emission limit established through
the rulemaking process. Two of the commenters stated that the amount of
mercury emissions measured during the initial compliance performance
test should be used only to verify compliance with the MACT standards,
and not to establish new emission limits. The commenters were concerned
that the emission limits would become floating limits based on the most
recent performance test, as opposed to being MACT standards.
The commenters indicated that variations around the concentrations,
above and below, measured during the performance test can be expected.
Treatment systems employed to obtain compliance (e.g., carbon) would be
expected to show some slight deterioration after a period of operation.
Therefore, a performance test conducted just after a carbon change
would result in an unrealistically low operating limit. Finally, the
commenters were concerned that different facilities would have
different operating limits, depending on variables like the type of
control equipment installed, the operating conditions on the day of the
emission test (i.e., mercury volatility changes significantly with
temperature), and other factors. One commenter was concerned that,
given the wide variability in emission constituents, operators would
not be able to assure that their facilities will consistently emit
within the limits established during an ideally controlled initial
performance test.
Two of the commenters acknowledged that other MACT standards
require the gathering of data for surrogate parameters (e.g., scrubber
liquor pH, scrubber liquor flow) when direct measurement of a control
parameter is not required or feasible. These surrogate parameters are
used to establish performance requirements for the control device. The
commenters went on to say that in cases where performance requirements
based on surrogate parameters were established during the performance
test, the emission limitation was not modified to reflect the actual
emissions experience during the test. However, the commenters stated
that they felt that this is exactly what is required under the proposed
rule.
One of the commenters argued that EPA's required installation of
instruments directly in the vent stream to continuously monitor actual
concentration of mercury and, therefore, actual mercury emissions,
means that there is no need to rely on operating parameters which have
been calculated for only one set of conditions.
One commenter was concerned about the cost-benefits of continuous

[[Page 70923]]

monitoring systems (CMS) in the by-product hydrogen, end box
ventilation system, and mercury thermal recovery unit vent streams.
According to the commenter, the types of control devices likely to be
used for controlling mercury emissions from these streams (i.e., carbon
or molecular sieve units) have very good performance characteristics
and are not likely to incur short-term upsets. The commenter noted that
performance is subject to normal variations, and the ability of these
systems to absorb mercury does degrade over time. The commenter stated
that before emissions reach the permit limits due to reduced
performance, the beds must be replaced. The commenter requested that in
lieu of CMS, facilities should be allowed to rely on the known
capability of the systems to operate reliably. The commenter stated
that the Agency could delete the requirement for CMS without any real
harm to the environment.
Response: In general, we disagree with the premise of the
commenters' argument. The proposed rule would have required that
continuous compliance for each vent be determined by monitoring mercury
concentration as an operating limit. The measured concentrations would
not have been used to compare directly with the emission limitations.
Rather, they would have provided an indication that the control device
was performing in a manner consistent with the operation during the
initial performance test. Therefore, the proposed requirements to
establish operating limits would have established emission limitations,
or resulted in changing emission limits, based on the initial
performance test.
However, we do acknowledge that there is a difference in a mercury
concentration operating limit and an operating limit based on surrogate
parameters because the mercury concentration is obviously a direct
measure of mercury emissions. In fact, we agree with the point made by
the one commenter that there is no need to rely on operating parameters
when a direct measurement of emissions is being required.
As discussed at length in the proposal preamble (67 FR 44690), we
considered requiring mercury continuous emission monitors (CEM) that
would directly measure in units of the standard. Although monitoring
that directly measures compliance is preferred, we decided to propose
mercury concentration operating limits based on the uncertainties
associated with the cost and reliability of the mercury monitoring
devices. Commenters did not provide any information to alleviate these
concerns. In fact, they shared our basic concerns even if the
monitoring devices were only used for operating limits.
We weighed the comments related to the mercury concentration
operating limits against the concerns associated with using mercury
concentration monitors as CEM. Our preference continues to be to
require mercury CEM. With sufficient evaluation, analysis, and
refinement, the industry will find these devices acceptable. However,
we could not require these devices in the final rule without a fallback
alternative if sources found that these monitoring devices were not
acceptable for use within the industry.
During the development of the proposed standards, we learned that
many mercury cell chlor-alkali facilities conducted periodic (e.g.,
weekly, monthly) tests to determine the mercury content in vent
streams. This is done to assess control device performance or, for the
by-product hydrogen stream, to ensure product quality. These tests are
not typically conducted using EPA-approved test methods, but are
usually conducted using modified methods. Since this periodic testing
is already being conducted at many mercury cell plants, we evaluated
whether a continuous compliance option could be included in the final
rule based on such periodic testing. Since such testing directly
measures mercury emissions, we concluded that it would be an acceptable
alternative to mercury CEM. The only question was how often such
testing would be needed to ensure continuous compliance with the
emission limitations. Daily testing would certainly be adequate, but we
were concerned about the costs and burden associated with 365 tests
each year for each process vent.
The most common final control device is (or will be)
nonregenerative carbon adsorption. These fixed bed carbon devices can
operate for long periods of time before a carbon change is needed. The
carbon replacement frequency is often more than a year. Weekly testing
would be more than sufficient to represent the emissions for the entire
week and to indicate when breakthrough (i.e., the point at which the
carbon has become saturated with mercury emissions) is approaching.
Because breakthrough does not occur instantaneously, but is slowly
approached over time, weekly testing is sufficient to detect the point
at which breakthrough is approaching.
However, there is the possibility that non-carbon devices such as
condensers, absorbers, or regenerative molecular sieves could be used
as the final control device to comply with the emission limits in the
final rule. Since improper operation of these devices could result in
higher emissions for short periods, we had concerns about utilizing
weekly testing for these devices. However, we concluded that if
parametric monitoring of surrogate parameters (e.g., condenser
temperature) were conducted to ensure consistent and proper operation
of these devices, weekly testing would be acceptable.
Therefore, the final rule includes two options for continuous
compliance for the by-product hydrogen stream, the end box ventilation
system vent, and the mercury thermal recovery unit vent. The first
option is continuous emissions monitoring using a mercury continuous
emissions monitoring system. The second is periodic testing using
Method 101, 101A, or 102 or an approved alternative method.
Specifically, this second option requires that at least three
acceptable test runs be conducted each week. As part of the periodic
testing option, if the final control device is not a nonregenerative
carbon adsorber, surrogate parameter monitoring is required.

V. What Are the Environmental, Cost, and Economic Impacts of the Final
Rule?

A. What Are the Air Emission Impacts?

The level of mercury emissions allowed by the Mercury NESHAP is
2,300 grams per day. If one assumes that all nine plants in the source
category emit mercury at this level, and that each operates 365 days a
year, total annual potential-to-emit baseline emissions would be 7,556
kg/yr (16,658 lb/yr). Annual potential-to-emit baseline emissions for
fugitive emission sources would be 4,271 kg/yr (9,416 lb/yr), based on
1,300 grams per day assumed for each plant's cell room ventilation
system when the 18 design, maintenance, and housekeeping practices
referenced in the Mercury NESHAP are followed. Annual potential-to-emit
baseline emissions for by-product hydrogen streams, end box ventilation
system vents, and mercury thermal recovery unit vents would be 3,285
kg/yr (7,242 lb/yr), based on the remaining 1,000 grams per day
allowed. We estimate that the final rule will reduce industrywide
mercury emissions for by-product hydrogen streams, end box ventilation
system vents, and mercury thermal recovery unit vents from this annual
potential-to-emit baseline to around 217 kg/yr (478 lb/yr), which is
equivalent to about 93 percent reduction.

[[Page 70924]]

While the level of mercury emissions allowed by the Mercury NESHAP
defines the potential-to-emit baseline, the sum of annual mercury
emission releases from by-product hydrogen streams, end box ventilation
system vents, and mercury thermal recovery vents, as estimated by
mercury cell chlor-alkali plants, defines an annual actual baseline for
vents of about 800 kg/yr (1,764 lb/yr). We estimate that the final rule
will reduce industrywide mercury emissions for vents from this annual
actual baseline to around 217 kg/yr (478 lb/yr), which is equivalent to
about 73 percent reduction.
We estimate that secondary air pollution emissions will result from
the production of electricity required to operate new control devices
and new monitoring equipment assumed for plant vents. Assuming
electricity production as based entirely on coal combustion for a
worst-case scenario, we estimated plant-specific impacts for sulfur
dioxide, nitrogen oxides, particulate matter, and carbon monoxide
emissions. The total estimated secondary air impacts of the final
requirements for point sources at the nine mercury cell chlor-alkali
plants is around 2.12 mg/yr (4.67 tpy) for all pollutants combined.
We are unable to quantify the primary air emission impacts
associated with the final work practice standards, so no mercury
emission reduction is assumed for fugitive emission sources. However,
we feel strongly that the new and more explicit requirements contained
in the final standards will in fact result in mercury emission
reductions beyond baseline levels. Relative to secondary impacts, we
expect that secondary air pollution emissions will result from the
production of electricity required to operate new monitoring equipment
assumed for plant cell rooms. We estimate the secondary air impacts of
the final rule for fugitive emission sources to be 0.112 mg/yr (0.124
tpy).

B. What Are the Non-Air Health, Environmental, and Energy Impacts?

We do not expect that there will be any significant adverse non-air
health impacts associated with the final standards for mercury-cell
chlor-alkali plants.
We estimate that an increase in the amount of mercury-containing
waters will result from the heightened use of packed tower scrubbing
assumed for several plant vents. The total estimated water pollution
impact of the final rule for point sources is about 1.5 million liters
(404 thousand gallons) of additional wastewater per year. We estimate
that an increase in the amount of mercury-containing solid wastes will
result with the heightened use of carbon adsorption assumed for several
plant vents. The total estimated solid waste impact of the final rule
for point sources is about 8.8 mg/yr (9.7 tpy) of additional mercury-
containing spent carbon.
We are unable to quantify non-air environmental impacts associated
with the final work practice standards, so no wastewater and solid
waste impacts are assumed for fugitive emission sources.
We estimate that the final requirements for point sources will
result in increased energy consumption, specifically additional fan
power in conveying gas streams through new carbon adsorbers and new
packed scrubbers assumed for certain plant vents and additional power
consumed by new vent monitoring equipment. The total estimated energy
impacts of the final requirements for point sources is about 772
thousand kW-hr/yr.
We estimate that the final requirements for fugitive emission
sources will result in increased energy consumption required to operate
new monitoring equipment assumed for plant cell rooms. The total
estimated energy impacts of the final requirements for fugitive
emission sources is about 39 thousand kW-hr/yr.

C. What Are the Cost and Economic Impacts?

For projecting cost impacts of the final rule on the mercury cell
chlor-alkali industry, we estimate that all nine plants will incur
costs to meet the final work practice standards and the final
monitoring, recordkeeping, and reporting requirements. We estimate that
seven plants will incur costs to meet the final emission limits for by-
product hydrogen streams and end box ventilation system vents, and two
plants will incur costs to meet the final emission limits for mercury
thermal recovery units. The total estimated capital cost of the final
rule for the nine mercury cell chlor-alkali plants is around $1.6
million, and the total estimated annual cost is about $1.4 million per
year. Plant-specific annual costs in our estimate range from about
$130,000 for the least-impacted plant to about $260,000 for the worst-
impacted plant.
The purpose of the economic impact analysis is to estimate the
market response of chlor-alkali production facilities to the final
standards and to determine the economic effects that may result due to
the final NESHAP. Chlor-alkali production jointly creates both chlorine
and caustic, usually sodium hydroxide, in fixed proportions. Being
joint commodities, the economic analysis considers the impacts of the
final NESHAP on both the chlorine and sodium hydroxide markets.
The chlor-alkali production source category contains 43 facilities,
but only nine facilities using mercury cells are directly affected by
the final standards. These nine facilities are located at nine plants
that are owned by seven companies.
Chlor-alkali production in mercury cells leads to potential mercury
emissions from hydrogen streams, end box ventilation system vents,
mercury thermal recovery units, and fugitive emission sources. The
compliance costs for the final standards, therefore, relate to the
purchase, installation, operation, and maintenance of pollution control
equipment at the point sources, as well as the labor costs and
overheads associated with observing work practices addressing fugitive
emissions. The estimated total annual costs for the final NESHAP are
$1.8 million. This cost estimate represents about 0.30 percent of the
1997 chlorine sales revenue for the mercury cell chlor-alkali
production facilities. Furthermore, the total annual costs represent
less than 0.01 percent of the revenues of owning the directly affected
mercury cell chlor-alkali plants.
The economic analysis predicts minimal changes in industry outputs
and the market prices of chlorine and sodium hydroxide as a result of
the estimated control costs. The new market equilibrium quantities of
chlorine and sodium hydroxide decrease by less than 0.1 percent.
Equilibrium prices of chlorine and sodium hydroxide both rise by less
than 0.1 percent due to the final standards. Based on these estimates,
we conclude that the final standards are not likely to have a
significant economic impact on the chlorine production industry as a
whole or on secondary markets such as the labor market and foreign
trade.
We performed an economic analysis to determine facility- and
company-specific impacts. These economic impacts are measured by
calculating the ratio of the estimated annualized compliance costs of
emissions control for each entity to its revenues (i.e., cost-to-sales
ratio). After the cost-to-sales ratio is calculated for each entity, it
is then multiplied by 100 to convert the ratio into percentages. Actual
revenues at the facility level are not available, therefore, estimated
facility revenues received from the sale of chlorine are used. Some of
these facilities also produce caustic as potassium hydroxide, but the
revenues from the sale of this product are not estimated. The nine
mercury cell chlor-alkali

[[Page 70925]]

plants have positive cost-to-sales ratios. The ratio of costs to
estimated chlorine sales revenue for these facilities range from a low
of 0.16 percent to a high of 1.00 percent. The average cost-to-sales
ratio for the nine mercury process chlorine production facilities is
0.46 percent. More detailed economic analysis predicted minimal changes
in chlorine production at each facility. Thus, overall, the economic
impact of the final standards is minimal for the facilities producing
chlorine.
The share of compliance costs to company sales are calculated to
determine company level impacts. Since seven companies own the nine
affected facilities, all seven firms face positive compliance costs
from the final NESHAP. The ratio of costs to estimated revenues range
from a low of less than 0.01 percent to a high of 0.22 percent, and the
average ratio of costs to company revenues is 0.06 percent. Again, more
detailed economic analysis at the company level predicts little change
in company output or revenues. So, at the company level, the final
standards are not anticipated to have a significant economic impact on
companies that own and operate the chlorine production facilities.
No facility or company is expected to close as a result of the
final standards, and the economic impacts to consumers are anticipated
to be minimal. The generally small scale of the impacts suggests that
there will also be no significant impacts on markets for the products
made using chlorine or sodium hydroxide. For more information, consult
the economic impact analysis report entitled ``Economic Impact Analysis
for the Final Mercury Cell Chlor-Alkali Production NESHAP,'' which is
available in the docket for this rulemaking.

VI. Statutory and Executive Order Reviews

A. Executive Order 12866--Regulatory Planning and Review

Under Executive Order 12866 (58 FR 51735, October 4, 1993), the
Agency must determine whether the regulatory action is ``significant''
and therefore subject to Office of Management and Budget (OMB) review
and the requirements of the Executive Order. The Executive Order
defines ``significant regulatory action'' as one that is likely to
result in a rule 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 the rights and obligation of 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
the Executive Order.
It has been determined that the final rule is not a ``significant
regulatory action'' under the terms of Executive Order 12866 and is,
therefore, not subject to OMB review.

B. Paperwork Reduction Act

The information collection requirements in the final rule have been
submitted for approval to OMB under the requirements of the Paperwork
Reduction Act, 44 U.S.C. 3501 et seq. The information requirements are
not enforceable until OMB approves them.
The information requirements are based on notifications, records,
and reports required by the General Provisions (40 CFR part 63, subpart
A), which are mandatory for all operators subject to national emission
standards. These recordkeeping and reporting requirements are
specifically authorized under section 114 of the CAA (42 U.S.C. 7414).
All information submitted to the EPA pursuant to the recordkeeping and
reporting requirements for which a claim of confidentiality is made
will be safeguarded according to Agency policies in 40 CFR part 2,
subpart B, Confidentiality of Business Information.
According to the ICR, the total 3-year monitoring, reporting, and
recordkeeping burden for this collection is 6,692 labor hours, and the
annual average burden is 2,231 labor hours. The total annualized cost
of monitoring, reporting, and recordkeeping is approximately $628,212.
The labor cost over the 3-year period is $295,928 or $98,643 per year.
The annualized capital cost for monitoring equipment is $262,458.
Annual operation and maintenance costs are $365,754 over 3 years,
averaging $121,918 per year. This estimate includes a one-time plan for
demonstrating compliance, annual compliance certificate reports,
notifications, and recordkeeping.
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 utilize
technology and systems for the purpose of collecting, validating, and
verifying information; process and maintain information and disclose
and provide information; adjust the existing ways to comply with any
previously applicable instructions and requirements; train personnel to
respond to a collection of information; search existing 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. The OMB
control number(s) for the information collection requirements in the
final rule will be listed in an amendment to 40 CFR part 9 or 48 CFR
chapter 15 in a subsequent Federal Register document after OMB approves
the ICR.

C. Regulatory Flexibility Act

The EPA has determined that it is not necessary to prepare a
regulatory flexibility analysis in connection with the final rule. The
EPA has also determined that the final rule will not have a significant
economic impact on a substantial number of small entities. For purposes
of assessing the impacts of today's final rule on small entities, small
entity is defined as: (1) A small business according to the Small
Business Administration (SBA) size standards by NAICS code, a maximum
of 1,000 employees for the alkalies and chlorine manufacturing
industry; (2) a small governmental jurisdiction that is a government of
a city, county, town, school district or special district with a
population of less than 50,000; and (3) a small organization that is
any not-for-profit enterprise which is independently owned and operated
and is not dominant in its field.
After considering the economic impacts of today's final rule on
small entities, EPA has concluded that this action will not have a
significant economic impact on a substantial number of small entities.
We have determined that two of the seven companies that own mercury
chlor-alkali plants are small entities. Although small businesses
represent 30 percent of the companies within the source category, they
are expected to incur 18 percent of the total industry annual
compliance costs. There are no companies with compliance costs equal to
or greater than 1 percent of their sales. No firms are expected to
close rather than incur the costs of compliance with the final rule.

[[Page 70926]]

Furthermore, firms are not projected to close their facilities due to
the final rule.
Although the final rule will not have significant economic impact
on a substantial number of small entities, we have nonetheless worked
aggressively to minimize the impact of the final rule on small
entities, consistent with our obligation under the CAA. The two
companies have been active participants in the rulemaking process
through their association with the industry trade organization, the
Chlorine Institute. Therefore, we met with representatives of these
small entities on numerous occasions. In addition, we conducted an
extended visit to a mercury cell chlor-alkali plant owned by one of
these companies to understand their process and emission control
techniques, along with any unique impacts that might occur due to the
fact that their company was a small entity. In general, the provisions
of the rule were deigned to achieve the maximum emission reduction
while also incorporating as many of the existing practices currently
being employed by the industry. The input received from these small
entities was duly considered in this evaluation.

D. Unfunded Mandates Reform Act of 1995

Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public
Law 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, we
generally must prepare a written statement, including cost-benefit
analysis, for proposed and final rules with ``Federal mandates'' that
may result in expenditures to State, local, and Tribal governments, in
the aggregate, or to the private sector, of $100 million or more in any
1 year. Before promulgating an EPA rule for which a written statement
is needed, section 205 of the UMRA generally requires us 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 us to adopt an alternative other than the least
costly, most cost-effective, or least burdensome alternative if we
publish with the final rule an explanation why that alternative was not
adopted.
Before we establish any regulatory requirements that may
significantly or uniquely affect small governments, including Tribal
governments, we 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 our regulatory proposals with significant Federal
intergovernmental mandates, and informing, educating, and advising
small governments on compliance with the regulatory requirements.
We have determined that the final rule does not contain a Federal
mandate that may result in expenditures of $100 million or more for
State, local, or tribal governments, in the aggregate, or the private
sector in any 1 year. The total annualized cost of the final rule has
been estimated to be $1,390,000. Thus, today's final rule is not
subject to the requirements of sections 202 and 205 of the UMRA. In
addition, we have determined that the final rule contains no regulatory
requirements that might significantly or uniquely affect small
governments because it contains no regulatory requirements that apply
to such governments or impose obligations upon them. Therefore, the
final rule is not subject to the requirements of section 203 of the
UMRA.

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.''
``Policies that have federalism implications'' are defined in the
Executive Order 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.''
The 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. The standards apply only to
mercury cell chlor-alkali plants and do not pre-exempt States from
adopting more stringent standards or otherwise regulate State or local
governments. Thus, Executive Order 13132 does not apply to the final
rule.
Although section 6 of Executive Order 13132 does not apply to the
final rule, EPA did consult with State and local officials in
developing the final rule. No concerns were raised by these officials
during this consultation.

F. Executive Order 13175--Consultation and Coordination With Indian
Tribal Governments

Executive Order 13175, entitled ``Consultation and Coordination
with Indian Tribal Governments'' (59 FR 22951, November 6, 2000),
requires EPA to develop an accountable process to ensure ``meaningful
and timely input by tribal officials in the development of regulatory
policies that have tribal implications.'' ``Policies that have tribal
implications'' are defined in the Executive Order to include
regulations that have ``substantial direct effects on one or more
Indian tribes, on the relationship between the Federal government and
the Indian tribes, or on the distribution of power and responsibilities
between the Federal government and Indian tribes.''
The final rule does not have tribal implications. It will not have
substantial direct effects on tribal governments, on the relationship
between the Federal government and Indian tribes, or on the
distribution of power and responsibilities between the Federal
government and Indian tribes, as specified in Executive Order 13175.
This is because no tribal governments own or operate a mercury cell
chlor-alkali plant. Thus, Executive Order 13175 does not apply to the
final 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 Executive Order 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 rule is preferable to other potentially effective and
reasonably feasible alternatives that we considered.
The final rule is not subject to Executive Order 13045 because it
is not an economically significant regulatory action as defined by
Executive Order 12866. In addition, EPA interprets Executive Order
13045 as applying only to those regulatory actions that are based on
health and safety risks, such that the analysis required under section

[[Page 70927]]

5-501 of the Executive Order has the potential to influence the
regulation.
As with most rulemakings developed under section 112(d) of the CAA,
the final rule is based on MACT. Risks to public health and impacts on
the environment are not typically considered in the development of
emissions standards under section 112(d). Rather, these risks and
impacts are considered later (within 8 years after promulgation of the
MACT rule) under the residual risk program as required by section
112(f) of the CAA. While we do not believe the final rule to be
``economically significant,'' as defined under Executive Order 12866,
we do believe that it addresses environmental health or safety risks
that may have a disproportionate effect on children.
Mercury has been identified as a priority pollutant under EPA's
National Agenda to Protect Children's Health from Environmental Threats
and by the Federal Children's Health Protection Advisory Committee
(CHPAC). The CHPAC was formed to advise, consult with, and make
recommendations to EPA on issues associated with the development of
regulations to address the prevention of adverse health effects to
children. One of the CHPAC's primary missions was to identify five
existing EPA regulations, which if reevaluated, could lead to better
protection for children. The CHPAC recommended the Mercury NESHAP for
chlor-alkali plants as one of the regulations to be reevaluated
considering impacts on children. We adopted the CHPAC recommendation.
Therefore, we considered the impacts on children in the development of
the final rule. A qualitative assessment of the potential impacts on
children's health due to mercury emissions from chlor-alkali plants was
presented in the preamble to the proposed rule (67 FR 44693).
Because the final rule does not meet both criteria for
applicability, it is not subject to Executive Order 13045. However,
based on our assessment, the final rule will help reduce the mercury
exposures to humans, including children.

H. Executive Order 13211--Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use

The final rule is not subject to Executive Order 13211, ``Actions
Concerning Regulations That Significantly Affect Energy Supply,
Distribution, or Use'' (66 FR 28355, May 22, 2001) because it is not a
significant regulatory action under Executive Order 12866.

I. National Technology Transfer and Advancement Act of 1995

Section 12(d) of the National Technology Transfer and Advancement
Act (NTTAA) of 1995 (Public Law No. 104-113; 15 U.S.C. 272 note)
directs EPA to use voluntary consensus standards in their regulatory
and procurement 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, business practices) developed or adopted by one or
more voluntary consensus bodies. The NTTAA directs EPA to provide
Congress, through annual reports to the OMB, with explanations when an
agency does not use available and applicable voluntary consensus
standards.
The final rule involves technical standards. The EPA cites in the
final rule EPA Methods 1, 1A, 2, 2A, 2C, 2D, 3, 3A, 3B, 4, 5, 101,
101A, 102, and any method to measure mercury (validated with EPA Method
301). Consistent with the NTTAA, EPA conducted searches to identify
voluntary consensus standards in addition to these EPA methods. No
applicable voluntary consensus standards were identified for EPA
Methods 1A, 2A, 2D, and 102. The search and review results have been
documented and are placed in the docket (OAR-2002-0017 or A-2000-32)
for the final rule.
This search for emissions monitoring procedures identified 14
voluntary consensus standards and five draft standards. The EPA
determined that the 14 standards were impractical alternatives to EPA
test methods for the purposes of this rulemaking. Therefore, EPA will
not adopt these standards today. The reasons for this determination for
these 14 standards are in the docket.
The 14 voluntary consensus standards are as follows: ASME C00031 or
PTC 19-10-1981, ``Part 10 Flue and Exhaust Gas Analyses,'' for EPA
Method 3; ASME PTC-38-80 R85 or C00049, ``Determination of the
Concentration of Particulate Matter in Gas Streams,'' for EPA Method 5;
ASTM D3154-91 (1995), ``Standard Method for Average Velocity in a Duct
(Pitot Tube Method),'' for EPA Methods 1, 2, 2C, 3, 3B, and 4; ASTM
D3464-96, ``Standard Test Method Average Velocity in a Duct Using a
Thermal Anemometer,'' for EPA Method 2; ASTM D3685/D3685M-98, ``Test
Methods for Sampling and Determination of Particulate Matter in Stack
Gases,'' for EPA Method 5; ASTM D3796-90 (1998), ``Standard Practice
for Calibration of Type S Pitot Tubes,'' for EPA Method 2; ASTM D5835-
95, ``Standard Practice for Sampling Stationary Source Emissions for
Automated Determination of Gas Concentration,'' for EPA Methods 3A;
ASTM E337-84 (Reapproved 1996), ``Standard Test Method for Measuring
Humidity with a Psychrometer (the Measurement of Wet- and Dry-Bulb
Temperatures),'' for EPA Method 4; CAN/CSA Z223.1-M1977, ``Method for
the Determination of Particulate Mass Flows in Enclosed Gas Streams,''
for EPA Method 5; CAN/CSA Z223.2-M86 (1986), ``Method for the
Continuous Measurement of Oxygen, Carbon Dioxide, Carbon Monoxide,
Sulphur Dioxide, and Oxides of Nitrogen in Enclosed Combustion Flue Gas
Streams,'' for EPA Methods 3A; CAN/CSA Z223.26-M1987, ``Measurement of
Total Mercury in Air Cold Vapour Atomic Absorption Spectrophotometeric
Method,'' for EPA Methods 101 and 101A; ISO 9096:1992 (in review 2000),
``Determination of Concentration and Mass Flow Rate of Particulate
Matter in Gas Carrying Ducts--Manual Gravimetric Method,'' for EPA
Method 5; ISO 10396:1993, ``Stationary Source Emissions: Sampling for
the Automated Determination of Gas Concentrations,'' for EPA Method 3A;
ISO 10780:1994, ``Stationary Source Emissions--Measurement of Velocity
and Volume Flowrate of Gas Streams in Ducts,'' for EPA Method 2.
The following five standards identified in this search were not
available at the time the review was conducted for the purposes of this
rulemaking because they are under development by a voluntary consensus
body: ASME/BSR MFC 12M, ``Flow in Closed Conduits Using Multiport
Averaging Pitot Primary Flowmeters,'' for EPA Method 2; ASME/BSR MFC
13M, ``Flow Measurement by Velocity Traverse,'' for EPA Method 2 (and
possibly 1); ISO/DIS 12039, ``Stationary Source Emissions--
Determination of Carbon Monoxide, Carbon Dioxide, and Oxygen--Automated
Methods,'' for EPA Method 3A; PREN 13211 (1998), ``Air Quality--
Stationary Source Emissions--Determination of the Concentration of
Total Mercury,'' for EPA Methods 101, 101A (and mercury portion of EPA
Method 29); and ASTM Z6590Z, ``Manual Method for Both Speciated and
Elemental Mercury'' is a potential alternative for portions of EPA
Methods 101A and Method 29 (mercury portion only).
Section 63.8232 of the final rule lists the EPA testing methods
included in the final rule. Under 40 CFR 63.7(f) and 63.8(f), a source
may apply to EPA for

[[Page 70928]]

permission to use alternative test methods or alternative monitoring
requirements in place of any of the EPA testing methods, performance
specifications, or procedures.

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. The 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. This action is not
a ``major rule'' as defined by 5 U.S.C. 804(2). The final rule will be
effective on December 19, 2003.

List of Subjects in 40 CFR Part 63

Environmental protection, Administrative practice and procedure,
Air pollution control, Hazardous substances, Intergovernmental
relations, Recordkeeping and reporting requirements.

Dated: August 25, 2003.
Marianne Lamont Horinko,
Acting Administrator.

? For the reasons stated in the preamble, title 40, chapter I, part 63 of
the Code of Federal Regulations is amended as follows:

PART 63--[AMENDED]

? 1. The authority citation for part 63 continues to read as follows:

Authority: 42 U.S.C. 7401, et seq.

? 2. Part 63 is amended by adding subpart IIIII to read as follows:

Subpart IIIII--National Emission Standards for Hazardous Air
Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants

Sec.

What This Subpart Covers

63.8180 What is the purpose of this subpart?
63.8182 Am I subject to this subpart?
63.8184 What parts of my plant does this subpart cover?
63.8186 When do I have to comply with this subpart?

Emission Limitations and Work Practice Standards

63.8190 What emission limitations must I meet?
63.8192 What work practice standards must I meet?

Operation and Maintenance Requirements

63.8222 What are my operation and maintenance requirements?

General Compliance Requirements

63.8226 What are my general requirements for complying with this
subpart?

Initial Compliance Requirements

63.8230 By what date must I conduct performance tests or other
initial compliance demonstrations?
63.8232 What test methods and other procedures must I use to
demonstrate initial compliance with the emission limits?
63.8234 What equations and procedures must I use for the initial
compliance demonstration?
63.8236 How do I demonstrate initial compliance with the emission
limitations and work practice standards?

Continuous Compliance Requirements

63.8240 What are my monitoring requirements?
63.8242 What are the installation, operation, and maintenance
requirements for my continuous monitoring systems?
63.8243 What equations and procedures must I use to demonstrate
continuous compliance?
63.8244 How do I monitor and collect data to demonstrate continuous
compliance?
63.8246 How do I demonstrate continuous compliance with the emission
limitations and work practice standards?
63.8248 What other requirements must I meet?

Notifications, Reports, and Records

63.8252 What notifications must I submit and when?
63.8254 What reports must I submit and when?
63.8256 What records must I keep?
63.8258 In what form and how long must I keep my records?

Other Requirements and Information

63.8262 What parts of the General Provisions apply to me?
63.8264 Who implements and enforces this subpart?
63.8266 What definitions apply to this subpart?

Tables to Subpart IIIII of Part 63

Table 1 to Subpart IIIII of Part 63--Work Practice Standards--
Design, Operation, and Maintenance Requirements
Table 2 to Subpart IIIII of Part 63--Work Practice Standards--
Required Inspections
Table 3 to Subpart IIIII of Part 63--Work Practice Standards--
Required Actions for Liquid Mercury Spills and Accumulations and
Hydrogen and Mercury Vapor Leaks
Table 4 to Subpart IIIII of Part 63--Work Practice Standards--
Requirements for Mercury Liquid Collection
Table 5 to Subpart IIIII of Part 63--Required Elements of Floor-
Level Mercury Vapor Measurement and Cell Room Monitoring Plans
Table 6 to Subpart IIIII of Part 63--Examples of Techniques for
Equipment Problem Identification, Leak Detection and Mercury Vapor
Measurements
Table 7 to Subpart IIIII of Part 63--Required Elements of Washdown
Plans
Table 8 to Subpart IIIII of Part 63--Requirements for Cell Room
Monitoring Program
Table 9 to Subpart IIIII of Part 63--Required Records for Work
Practice Standards
Table 10 to Subpart IIIII of Part 63--Applicability of General
Provisions to Subpart IIIII

What This Subpart Covers

Sec. 63.8180 What is the purpose of this subpart?

This subpart establishes national emission standards for hazardous
air pollutants (NESHAP) for affected sources of mercury emissions at
mercury cell chlor-alkali plants. This subpart also establishes
requirements to demonstrate initial and continuous compliance with all
applicable emission limitations and work practice standards in this
subpart.

Sec. 63.8182 Am I subject to this subpart?

(a) You are subject to this subpart if you own or operate a mercury
cell chlor-alkali plant.
(b) You are required to obtain a title V permit, whether your
affected source is a part of a major source of hazardous air pollutant
(HAP) emissions or a part of an area source of HAP emissions. A major
source of HAP is a source that emits or has the potential to emit any
single HAP at a rate of 10 tons or more per year or any combination of
HAP at a rate of 25 tons or more per year. An area source of HAP is a
source that has the potential to emit HAP but is not a major source.
Nothing in this subpart revises how affected sources are aggregated for
purposes of determining whether an affected source is a part of an
area, nonmajor, or major source under any provisions of the Clean Air
Act (CAA) or EPA's regulations. For information on aggregating affected
sources to determine what is a source under title V, see the definition
of major source in 40 CFR 70.2, 71.2 and 63.2.
(c) Beginning on December 19, 2006, the provisions of subpart E of
40 CFR part 61 that apply to mercury chlor-alkali plants, which are
listed in paragraphs (c)(1) through (3) of this section, are no longer
applicable.
(1) Sec. 61.52(a);
(2) Sec. 61.53(b) and (c); and

[[Page 70929]]

(3) Sec. 61.55(b), (c) and (d).

Sec. 63.8184 What parts of my plant does this subpart cover?

(a) This subpart applies to each affected source at a plant site
where chlorine and caustic are produced in mercury cells. This subpart
applies to two types of affected sources: the mercury cell chlor-alkali
production facility, as defined in paragraph (a)(1) of this section;
and the mercury recovery facility, as defined in paragraph (a)(2) of
this section.
(1) The mercury cell chlor-alkali production facility designates an
affected source consisting of all cell rooms and ancillary operations
used in the manufacture of product chlorine, product caustic, and by-
product hydrogen at a plant site. This subpart covers mercury emissions
from by-product hydrogen streams, end box ventilation system vents, and
fugitive emission sources associated with cell rooms, hydrogen systems,
caustic systems, and storage areas for mercury-containing wastes.
(2) The mercury recovery facility designates an affected source
consisting of all processes and associated operations needed for
mercury recovery from wastes at a plant site. This subpart covers
mercury emissions from mercury thermal recovery unit vents and fugitive
emission sources associated with storage areas for mercury-containing
wastes.
(b) An affected source at your mercury cell chlor-alkali plant is
existing if you commenced construction of the affected source before
July 3, 2002.
(c) A mercury recovery facility is a new affected source if you
commence construction or reconstruction of the affected source after
July 3, 2002. An affected source is reconstructed if it meets the
definition of ``reconstruction'' in Sec. 63.2.

Sec. 63.8186 When do I have to comply with this subpart?

(a) If you have an existing affected source, you must comply with
each emission limitation, work practice standard, and recordkeeping and
reporting requirement in this subpart that applies to you no later than
December 19, 2006.
(b) If you have a new or reconstructed mercury recovery facility
and its initial startup date is on or before December 19, 2003, you
must comply with each emission limitation, work practice standard, and
recordkeeping and reporting requirement in this subpart that applies to
you by December 19, 2003.
(c) If you have a new or reconstructed mercury recovery facility
and its initial startup date is after December 19, 2003, you must
comply with each emission limitation, work practice standard, and
recordkeeping and reporting requirement in this subpart that applies to
you upon initial startup.
(d) You must meet the notification and schedule requirements in
Sec. 63.8252. Several of these notifications must be submitted before
the compliance date for your affected source(s).

Emission Limitations and Work Practice Standards

Sec. 63.8190 What emission limitations must I meet?

(a) Emission limits. You must meet each emission limit in
paragraphs (a)(1) through (3) of this section that applies to you.
(1) New or reconstructed mercury cell chlor-alkali production
facility. Emissions of mercury are prohibited from a new or
reconstructed mercury cell chlor-alkali production facility.
(2) Existing mercury cell chlor-alkali production facility. During
any consecutive 52-week period, you must not discharge to the
atmosphere total mercury emissions in excess of the applicable limit in
paragraph (a)(2)(i) or (ii) of this section calculated using the
procedures in Sec. 63.8243(a).
(i) 0.076 grams of mercury per megagram of chlorine produced (1.5 x
10-4 pounds of mercury per ton of chlorine produced) from
all by-product hydrogen streams and all end box ventilation system
vents when both types of emission points are present.
(ii) 0.033 grams of mercury per megagram of chlorine produced (6.59
x 10-5 pounds of mercury per ton of chlorine produced) from
all by-product hydrogen streams when end box ventilation systems are
not present.
(3) New, reconstructed, or existing mercury recovery facility. You
must not discharge to the atmosphere mercury emissions in excess of the
applicable limit in paragraph (a)(3)(i) or (ii) of this section.
(i) 23 milligrams per dry standard cubic meter from each oven type
mercury thermal recovery unit vent.
(ii) 4 milligrams per dry standard cubic meter from each non-oven
type mercury thermal recovery unit vent.
(b) [Reserved]

Sec. 63.8192 What work practice standards must I meet?

You must meet the work practice requirements specified in
paragraphs (a) through (f) of this section. As an alternative to the
requirements specified in paragraphs (a) through (d) of this section,
you may choose to comply with paragraph (g) of this section.
(a) You must meet the work practice standards in Tables 1 through 4
to this subpart, except as specified in paragraph (g) of this section.
(b) You must adhere to the response intervals specified in Tables 1
through 4 to this subpart at all times. Nonadherence to the intervals
in Tables 1 through 4 to this subpart constitutes a deviation and must
be documented and reported in the compliance report, as required by
Sec. 63.8254(b), with the date and time of the deviation, cause of the
deviation, a description of the conditions, and time actual compliance
was achieved.
(c) As provided in Sec. 63.6(g), you may request to use an
alternative to the work practice standards in Tables 1 through 4 to
this subpart.
(d) You must institute a floor-level mercury vapor measurement
program to limit the amount of mercury vapor in the cell room
environment through periodic measurement of mercury vapor levels and
actions to be taken when a floor-level mercury concentration action
level is exceeded. The program must meet the requirements listed in
paragraphs (d)(1) through (4) of this section. As specified in Sec.
63.8252(e)(1)(i) to implement this program, you must prepare and submit
to the Administrator a floor-level mercury vapor measurement plan which
must contain the elements listed in Table 5 to this subpart.
(1) You must utilize a mercury measurement device described in of
Table 6 to this subpart to measure the level of mercury vapor in the
cell room at floor-level.
(2) You must conduct at least one floor-level mercury vapor
measurement evaluation each half day. This evaluation must include
three measurements of the mercury concentration at locations
representative of the entire cell room floor area. The average of these
measurements must be recorded as specified in Sec. 63.8156(c)(1). At a
minimum, you must measure the level of mercury vapor above mercury-
containing cell room equipment, as well as areas around the cells,
decomposers, or other mercury-containing equipment.
(3) You must establish a floor-level mercury concentration action
level that is no higher than 0.05 milligrams per cubic meter (mg/m\3\).
(4) If a mercury concentration greater than the action level is
measured during any floor-level mercury vapor measurement evaluation,
you must meet the requirements in either paragraph (d)(4)(i) or (ii) of
this section.
(i) If you determine that the cause of the elevated mercury
concentration is an open electrolyzer, decomposer, or

[[Page 70930]]

other maintenance activity, you must record the information specified
in paragraphs (d)(4)(i)(A) through (C) of this section.
(A) A description of the maintenance activity resulting in elevated
mercury concentration;
(B) The time the maintenance activity was initiated and completed;
and
(C) A detailed explanation how all the applicable requirements of
Table 1 to this subpart were met during the maintenance activity.
(ii) If you determine that the cause of the elevated mercury
concentration is not an open electrolyzer, decomposer, or other
maintenance activity, you must follow the procedures specified in
paragraphs (d)(4)(ii)(A) and (B) of this section until the floor-level
mercury concentration falls below the floor-level mercury concentration
action level. You must also keep all the associated records for these
procedures as specified in Table 9 to this subpart.
(A) Within 1 hour of the time the floor-level mercury concentration
action level was exceeded, you must conduct each inspection specified
in Table 2 to this subpart in the area where the concentration higher
than the floor-level mercury concentration action level was measured,
with the exception of the cell room floor and the pillars and beam
inspections. (B) You must also inspect all decomposers, hydrogen system
piping up to the hydrogen header, and other potential locations of
mercury vapor leaks in the area using a technique specified in Table 6
to this subpart. You must correct any problem identified during these
inspections according to the requirements in Tables 2 and 3 to this
subpart.
(e) You must prepare, submit, and operate according to a written
washdown plan designed to minimize fugitive mercury emissions through
routine washing of surfaces where liquid mercury could accumulate. The
written plan must address the elements contained in Table 7 to this
subpart.
(f) You must keep records of the mass of all virgin mercury added
to cells on an annual basis.
(g) As an alternative to the work practice standards in paragraphs
(a) through (d) of this section, you may institute a cell room
monitoring program to continuously monitor the mercury vapor
concentration in the upper portion of each cell room and to take
corrective actions as quickly as possible when elevated mercury vapor
levels are detected. As specified in Sec. 63.8252(e)(1)(iv), if you
choose this option, you must prepare and submit to the Administrator, a
cell room monitoring plan containing the elements listed in Table 5 to
this subpart and meet the requirements in paragraphs (g)(1) through (4)
of this section.
(1) You must utilize mercury monitoring systems that meet the
requirements of Table 8 to this subpart.
(2) You must establish an action level according to the
requirements in paragraphs (g)(2)(i) through (iii) of this section.
(i) Beginning on the compliance date specified for your affected
source in Sec. 63.8186, measure and record the mercury concentration
for at least 30 days using a system that meets the requirements of
paragraph (g)(1) of this section.
(ii) Using the monitoring data collected according to paragraph
(g)(1)(i) of this section, establish your action level at the 75th
percentile of the data set.
(iii) Submit your action level as part of your Notification of
Compliance Status report according to Sec. 63.8252(e)(1).
(3) Beginning on the compliance date specified for your affected
source in Sec. 63.8186, you must continuously monitor the mercury
concentration in the cell room. Failure to monitor and record the data
according to Sec. 63.8256(c) (4)(ii) for 75 percent of the time in any
6-month period constitutes a deviation.
(4) If the average mercury concentration for any 1-hour period
exceeds the action level established according to paragraph (g)(2) of
this section, you must meet the requirements in either paragraph
(g)(4)(i) or (ii) of this section.
(i) If you determine that the cause of the elevated mercury
concentration is an open electrolyzer, decomposer, or other maintenance
activity, you must record the information specified in paragraphs
(g)(4)(i)(A) through (C) of this section.
(A) A description of the maintenance activity resulting in elevated
mercury concentration;
(B) The time the maintenance activity was initiated and completed;
and
(C) A detailed explanation how all the applicable requirements of
Table 1 to this subpart were met during the maintenance activity.
(ii) If you determine that the cause of the elevated mercury
concentration is not an open electrolyzer, decomposer, or other
maintenance activity, you must follow the procedures specified in
paragraphs (g)(4)(ii)(A) and (B) of this section until the mercury
concentration falls below the action level. You must also keep all the
associated records for these procedures as specified in Table 9 to this
subpart.
(A) Within 1 hour of the time the action level was exceeded, you
must conduct each inspection specified in Table 2 to this subpart, with
the exception of the cell room floor and the pillars and beam
inspections. You must correct any problem identified during these
inspections in accordance with the requirements in Table 2 and 3 to
this subpart.
(B) If the Table 2 inspections and subsequent corrective actions do
not reduce the mercury concentration below the action level, you must
inspect all decomposers, hydrogen system piping up to the hydrogen
header, and other potential locations of mercury vapor leaks using a
technique specified in Table 6 to this subpart. If a mercury vapor leak
is identified, you must take the appropriate action specified in Table
3 to this subpart.

Operation and Maintenance Requirements

Sec. 63.8222 What are my operation and maintenance requirements?

As required by Sec. 63.6(e)(1)(i), you must always operate and
maintain your affected source(s), including air pollution control and
monitoring equipment, in a manner consistent with safety and good air
pollution control practices for minimizing emissions.

General Compliance Requirements

Sec. 63.8226 What are my general requirements for complying with this
subpart?

(a) You must be in compliance with the applicable emission
limitations for by-product hydrogen streams, end box ventilation system
vents, and mercury thermal recovery unit vents in Sec. 63.8190 at all
times, except during periods of startup, shutdown, and malfunction. You
must be in compliance with the applicable work practice standards in
Sec. 63.8192 at all times, except during periods of startup, shutdown,
and malfunction.
(b) You must develop and implement a written startup, shutdown, and
malfunction plan (SSMP) according to the provisions in Sec.
63.6(e)(3).

Initial Compliance Requirements

Sec. 63.8230 By what date must I conduct performance tests or other
initial compliance demonstrations?

(a) You must conduct a performance test no later than the
compliance date that is specified in Sec. 63.8186 for your affected
source to demonstrate initial compliance with the applicable emission
limit in Sec. 63.8190(a)(2) for by-product hydrogen streams and end
box ventilation system vents and the

[[Page 70931]]

applicable emission limit in Sec. 63.8190(a)(3) for mercury thermal
recovery unit vents.
(b) For the applicable work practice standards in Sec. 63.8192,
you must demonstrate initial compliance within 30 calendar days after
the compliance date that is specified for your affected source in Sec.
63.8186.

Sec. 63.8232 What test methods and other procedures must I use to
demonstrate initial compliance with the emission limits?

You must conduct a performance test for each by-product hydrogen
stream, end box ventilation system vent, and mercury thermal recovery
unit vent according to the requirements in Sec. 63.7(e)(1) and the
conditions detailed in paragraphs (a) through (d) of this section.
(a) You may not conduct performance tests during periods of
startup, shutdown, or malfunction, as specified in Sec. 63.7(e)(1).
(b) For each performance test, you must develop a site-specific
test plan in accordance with Sec. 63.7(c)(2).
(c) You must conduct at least three test runs to comprise a
performance test, as specified in Sec. 63.7(e)(3) and in either
paragraph (c)(1) or (2) of this section.
(1) The sampling time and sampling volume for each run must be at
least 2 hours and 1.70 dry standard cubic meters (dscm). Mercury
results below the analytical laboratory's detection limit must be
reported using the reported analytical detection limit to calculate the
sample concentration value and, in turn, the emission rate in the units
of the standard; or
(2) The sampling time for each test run must be at least 2 hours
and the mercury concentration in each field sample analyzed must be at
least two times the reported analytical detection limit.
(d) You must use the test methods specified in paragraphs (d)(1)
through (4) of this section and the applicable test methods in
paragraphs (d)(5) through (7) of this section.
(1) Method 1 or 1A in appendix A of 40 CFR part 60 to determine the
sampling port locations and the location and required number of
sampling traverse points.
(2) Method 2, 2A, 2C, or 2D in appendix A of 40 CFR part 60 to
determine the stack gas velocity and volumetric flow rate.
(3) Method 3, 3A, or 3B in appendix A of 40 CFR part 60 to
determine the stack gas molecular weight.
(4) Method 4 in appendix A of 40 CFR part 60 to determine the stack
gas moisture content.
(5) For each by-product hydrogen stream, Method 102 in appendix A
of 40 CFR part 61 to measure the mercury emission rate after the last
control device.
(6) For each end box ventilation system vent, Method 101 or 101A in
appendix A of 40 CFR part 61 to measure the mercury emission rate after
the last control device.
(7) For each mercury thermal recovery unit vent, Method 101 or 101A
in appendix A of 40 CFR part 61 to measure the mercury emission rate
after the last control device.
(e) During each test run for a by-product hydrogen stream and each
test run for an end box ventilation system vent, you must continuously
measure the electric current through the operating mercury cells and
record a measurement at least once every 15 minutes.
(f) If the final control device is not a nonregenerable carbon
adsorber and if you are demonstrating compliance using periodic
monitoring under Sec. 63.8240(b), you must continuously monitor the
parameters listed in paragraph (f)(1) of this section and establish
your maximum or minimum monitoring value (as appropriate for your
control device) using the requirements in paragraph (f)(2) of this
section.
(1) During the performance test specified in paragraphs (a) through
(d) of this section, you must continuously monitor the control device
parameters in paragraphs (f)(1)(i) through (vii) of this section and
record a measurement at least once every 15 minutes.
(i) The exit gas temperature from uncontrolled streams;
(ii) The outlet temperature of the gas stream for the final (i.e.,
the farthest downstream) cooling system when no control devices other
than coolers or demisters are used;
(iii) The outlet temperature of the gas stream from the final
cooling system when the cooling system is followed by a molecular sieve
or regenerative carbon adsorber;
(iv) Outlet concentration of available chlorine, pH, liquid flow
rate, and inlet gas temperature of chlorinated brine scrubbers and
hypochlorite scrubbers;
(v) The liquid flow rate and exit gas temperature for water
scrubbers;
(vi) The inlet gas temperature of regenerative carbon adsorption
systems; and
(vii) The temperature during the heating phase of the regeneration
cycle for carbon adsorbers or molecular sieves.
(2) To establish a maximum monitoring value or minimum monitoring
value, as appropriate for your final control device, you must average
the recorded parameters in paragraphs (f)(1)(i) through (vi) of this
section over the test period. If your final control device is a
regenerative carbon adsorber, you must use the highest temperature
reading measured in paragraph (f)(1)(vii) as the reference temperature
in Sec. 63.8244(b)(2)(v).

Sec. 63.8234 What equations and procedures must I use for the initial
compliance demonstration?

(a) By-product hydrogen streams and end box ventilation system
vents. You must determine the total grams of mercury per Megagram of
chlorine production (g Hg/Mg Cl₂) of chlorine produced from
all by-product hydrogen streams and all end box ventilation system
vents, if applicable, at a mercury cell chlor-alkali production
facility, and you must follow the procedures in paragraphs (a)(1)
through (6) of this section.
(1) Determine the mercury emission rate for each test run in grams
per day for each by-product hydrogen stream and for each end box
ventilation system vent, if applicable, from Method 101, 101A, or 102
(40 CFR part 61, appendix A).
(2) Calculate the average measured electric current through the
operating mercury cells during each test run for each by-product
hydrogen stream and for each end box ventilation system vent, if
applicable, using Equation 1 of this section as follows:
[GRAPHIC]
[TIFF OMITTED]
TR19DE03.000

Where:
CL_{avg, run} = Average measured cell line current load during
the test run, amperes;
CL_{i, run} = Individual cell line current load measurement
(i.e., 15 minute reading) during the test run, amperes; and
n = Number of cell line current load measurements taken over the
duration of the test run.

(3) Calculate the amount of chlorine produced during each test run
for each by-product hydrogen stream and for each end box ventilation
system vent, if applicable, using Equation 2 of this section as
follows:

[[Page 70932]]
[GRAPHIC]
[TIFF OMITTED]
TR19DE03.001

Where:
P_Cl2_,run = Amount of chlorine produced during the
test run, megagrams chlorine (Mg Cl₂);
1.3 x 10 -6 = Theoretical chlorine production rate factor,
Mg Cl₂ per hour per ampere per cell;
CL_avg,run = Average measured cell line current load during
test run, amperes, calculated using Equation 1 of this section;
n_cell,run = Number of cells on-line during the test run; and
t_run = Duration of test run, hours.

(4) Calculate the mercury emission rate in grams of mercury per
megagram of chlorine produced for each test run for each by-product
hydrogen stream and for each end box ventilation system vent, if
applicable, using Equation 3 of this section as follows:
[GRAPHIC]
[TIFF OMITTED]
TR19DE03.002

Where:
E_Hg,run = Mercury emission rate for the test run, g Hg/Mg
Cl₂;
R_run = Measured mercury emission rate for the test run from
paragraph (a)(1) of this section, grams Hg per day;
t_run = Duration of test run, hours;
24 = Conversion factor, hours per day; and
P_Cl2_,run = Amount of chlorine produced during the
test run, calculated using Equation 2 of this section, Mg
Cl₂.

(5) Calculate the average mercury emission rate for each by-product
hydrogen stream and for each end box ventilation system vent, if
applicable, using Equation 4 of this section as follows:
[GRAPHIC]
[TIFF OMITTED]
TR19DE03.003

Where:
E_Hg,avg = Average mercury emission rate for the by-product
hydrogen stream or the end box ventilation system vent, if applicable,
g Hg/Mg Cl₂;
E_Hg,run = Mercury emission rate for each test run for the
by-product hydrogen stream or the end box ventilation system vent, if
applicable, g Hg/Mg Cl₂, calculated using Equation 3 of this
section; and
n = Number of test runs conducted for the by-product hydrogen stream or
the end box ventilation system vent, if applicable.

(6) Calculate the total mercury emission rate from all by-product
hydrogen streams and all end box ventilation system vents, if
applicable, at the mercury cell chlor-alkali production facility using
Equation 5 of this section as follows:
[GRAPHIC]
[TIFF OMITTED]
TR19DE03.004

Where:
E_Hg,H2_EB = Total mercury emission rate from all
by-product hydrogen streams and all end box ventilation system vents,
if applicable, at the affected source, g Hg/Mg Cl₂;
E_Hg,avg = Average mercury emission rate for each by-product
hydrogen stream and each end box ventilation system vent, if
applicable, g Hg/Mg Cl₂, determined using Equation 4 of this
section; and
n = Total number of by-product hydrogen streams and end box ventilation
system vents at the affected source.

(b) Mercury thermal recovery vents. You must determine the
milligrams of mercury per dscm exhaust discharged from mercury thermal
recovery unit vents, using the procedures in paragraphs (b)(1) and (2)
of this section.
(1) Calculate the concentration of mercury in milligrams of mercury
per dscm of exhaust for each test run for each mercury thermal recovery
unit vent using Equation 6 of this section as follows:
[GRAPHIC]
[TIFF OMITTED]
TR19DE03.005

Where:
C_Hg,run = Mercury concentration for the test run, milligrams
of mercury per dry standard cubic meter of exhaust;
m_Hg = Mass of mercury in test run sample, from Method 101,
101A, or 102, micrograms;
10-3 = Conversion factor, milligrams per microgram; and
V_m(std) = Dry gas sample volume at standard conditions, from
Method 101, 101A, or 102, dry standard cubic meters.

(2) Calculate the average concentration of mercury in each mercury
thermal recovery unit vent exhaust using Equation 7 of this section as
follows:
[GRAPHIC]
[TIFF OMITTED]
TR19DE03.006

Where:
C_Hg,avg = Average mercury concentration for the mercury
thermal recovery unit vent, milligrams of mercury per dry standard
cubic meter exhaust;
C_Hg,run = Mercury concentration for each test run,
milligrams of mercury per dry standard cubic meter of exhaust,
calculated using Equation 6 of this section; and
n = Number of test runs conducted for the mercury thermal recovery unit
vent.

Sec. 63.8236 How do I demonstrate initial compliance with the
emission limitations and work practice standards?

(a) For each mercury cell chlor-alkali production facility, you
have demonstrated initial compliance with the applicable emission limit
for by-product hydrogen streams and end box ventilation system vents in
Sec. 63.8190(a)(2) if you comply with paragraphs (a)(1) and (2) of
this section:
(1) Total mercury emission rate from all by-product hydrogen
streams and all end box ventilation system vents, if applicable, at the
affected source, determined according to Sec. Sec. 63.8232 and
63.8234(a), did not exceed the applicable emission limit in Sec.
63.8190(a)(2)(i) or (ii); and
(2) If you have chosen the periodic monitoring option specified in
Sec. 63.8240(b) and your final control device is not a nonregenerable
carbon adsorber, you have established a parameter value according to
Sec. 63.8232(f)(2).
(b) For each mercury recovery facility, you have demonstrated
initial compliance with the applicable emission limit for mercury
thermal recovery unit vents in Sec. 63.8190(a)(3) if you comply with
paragraphs (b)(1) and (2) of this section.
(1) Mercury concentration in each mercury thermal recovery unit
vent exhaust, determined according to Sec. Sec. 63.8232 and
63.8234(b), did not exceed the applicable emission limit in Sec.
63.8190(a)(3)(i) or (ii); and
(2) If you have chosen the periodic monitoring option in Sec.
63.8240(b) and have a final control device that is not a nonregenerable
carbon adsorber, you

[[Page 70933]]

have established a maximum or minimum monitoring value, as appropriate
for your control device according to Sec. 63.8232(f)(2).
(c) For each affected source, you have demonstrated initial
compliance with the applicable work practice standards in Sec. 63.8192
if you comply with paragraphs (c)(1) through (7) of this section.
(1) You certify in your Notification of Compliance Status that you
are operating according to the work practice standards in Sec.
63.8192(a) through (d).
(2) You choose the continuous cell room monitoring program option,
you certify in your Notification of Compliance Status that you are
operating according to the continuous cell room monitoring program
under Sec. 63.8192(g) and you have established your action level
according to Sec. 63.8192(g)(2).
(3) You certify in your Notification of Compliance Status that you
are operating according to your washdown plan.
(4) You have submitted your washdown plan as part of your
Notification of Compliance Status.
(5) You have submitted your continuous cell room monitoring plan,
if applicable, as part of your Notification of Compliance Status.
(6) You have submitted your floor-level cell room monitoring plan,
if applicable, as part of your Notification of Compliance Status.
(7) You have submitted records of the mass of virgin mercury added
to cells for the 5 years preceding the applicable compliance date for
your affected source as a part of the Notification of Compliance
Status.
(d) You must submit the Notification of Compliance Status
containing the results of the initial compliance demonstration
according to the requirements in Sec. 63.8252(e).

Continuous Compliance Requirements

Sec. 63.8240 What are my monitoring requirements?

For each by-product hydrogen stream, each end box ventilation
system vent, and each mercury thermal recovery unit vent, you must
monitor the mercury emissions using the procedures in paragraph (a) or
(b) of this section.
(a) You must continuously monitor the mercury concentration using a
mercury continuous emissions monitor according to the requirements in
Sec. Sec. 63.8242(a) and 63.8244(a); or
(b) You must periodically monitor the mercury emissions according
to the requirements in Sec. Sec. 63.8242(b) and 63.8244(b).

Sec. 63.8242 What are the installation, operation, and maintenance
requirements for my continuous monitoring systems?

(a) If you choose the continuous mercury monitoring option under
Sec. 63.8240(a), you must install, operate, and maintain each mercury
continuous emissions monitor according to paragraphs (a)(1) through (5)
of this section.
(1) Each mercury continuous emissions monitor must sample, analyze,
and record the concentration of mercury at least once every 15 minutes.
(2) Each mercury continuous emissions monitor analyzer must have a
detector with the capability to detect a mercury concentration at or
below 0.5 times the mercury concentration level measured during the
performance test conducted according to Sec. 63.8232.
(3) In lieu of a promulgated performance specification as required
in Sec. 63.8(a)(2), you must develop a site-specific monitoring plan
that addresses the elements in paragraphs (a)(3)(i) through (vi) of
this section.
(i) Installation and measurement location downstream of the final
control device for each by-product hydrogen stream, end box ventilation
system vent, and mercury thermal recovery unit vent.
(ii) Performance and equipment specifications for the sample
interface, the pollutant concentration analyzer, and the data
collection and reduction system.
(iii) Performance evaluation procedures and acceptance criteria
(i.e., calibrations).
(iv) Ongoing operation and maintenance procedures according to the
requirements of Sec. 63.8(c)(1), (3), and (4)(ii).
(v) Ongoing data quality assurance procedures according to the
requirements of Sec. 63.8(d).
(vi) Ongoing recordkeeping and reporting procedures in accordance
with the general requirements of Sec. 63.10(c), (e)(1), and (e)(2)(i).
(4) You must conduct a performance evaluation of each mercury
continuous emissions monitor according to your site-specific monitoring
plan.
(5) You must operate and maintain each mercury continuous emissions
monitor in continuous operation according to the site-specific
monitoring plan.
(b) If you choose the periodic monitoring option and your final
control device is not a nonregenerable carbon adsorber, you must
install, operate, and maintain a continuous parameter monitoring system
(CPMS) for each parameter specified in Sec. 63.8232(f)(1), according
to Sec. 63.8(c).

Sec. 63.8243 What equations and procedures must I use to demonstrate
continuous compliance?

(a) By-product hydrogen streams and end box ventilation system
vents. For each consecutive 52-week period, you must determine the g
Hg/Mg Cl₂ produced from all by-product hydrogen streams and
all end box ventilation system vents, if applicable, at a mercury cell
chlor-alkali production facility using the procedures in paragraphs
(a)(1) through (3) of this section. You must begin collecting data on
the compliance date that is specified in Sec. 63.8186 for your
affected source and calculate your first 52-week average mercury
emission rate at the end of the 52nd week after the compliance date.
(1) Each week, you must determine the weekly mercury emission rate
in grams per week for each by-product hydrogen stream and for each end
box ventilation system vent, if applicable, using one of the monitoring
options in paragraph (a)(1)(i) or (ii) of this section.
(i) Continuous mercury monitoring according to Sec. Sec. 63.8242
and 63.8244(a).
(ii) Periodic monitoring according to Sec. 63.8244(b).
(2) Each week, you must determine the chlorine production and keep
records of the production rate as required under Sec. 63.8256(b)(6).
(3) Beginning 52 weeks after the compliance date specified in Sec.
63.8186 for your affected source, you must calculate the 52-week
average mercury emission rate from all by-product hydrogen steam and
all end box ventilation system vents, if applicable, using Equation 1
of this section as follows:
[GRAPHIC]
[TIFF OMITTED]
TR19DE03.007

Where:
E_Hg = 52-week average mercury emission rate for
week_i, g Hg/Mg Cl₂;
R_{week, i} = Mercury emission rate for week_i from
paragraph (a)(1) of this section, g Hg per week;
P_{Cl2, weeki} = Amount of chlorine produced during
week_i, from paragraph (a)(2) of this section, Mg
Cl₂ per week.

(b) Mercury thermal recovery units. If you choose the continuous
monitoring option in Sec. 63.8240(a), you must demonstrate continuous
compliance using paragraph (b)(1) of this section. If you choose the
periodic monitoring option in Sec. 63.8240(b), you must demonstrate
continuous compliance using paragraph (b)(2) of this section.

[[Page 70934]]

(1) You must calculate the daily average mercury concentration
using Equation 2 of this section as follows:
[GRAPHIC]
[TIFF OMITTED]
TR19DE03.008

Where:
C_{Hg, dailyavg} = Average mercury concentration for the
operating day, milligrams per dry standard cubic meter;
C_Hg,i = Concentration of mercury measured at the interval i
(i.e., 15 minute reading) using a mercury continuous emission monitor,
milligrams per dry standard cubic meter; and
n = Number of concentration measurements taken during the operating
day.

(2) You must calculate the daily average mercury concentration
using the procedures in Sec. 63.8234(b).

Sec. 63.8244 How do I monitor and collect data to demonstrate
continuous compliance?

(a) Continuous monitoring option. You must monitor mercury
concentration according to Sec. 63.8242(a) at all times that the
affected source is operating with the exception of paragraphs (a)(1)
and (2) of this section.
(1) Except for monitor malfunctions, associated repairs, and
required quality assurance or control activities (including, as
applicable, calibration checks and required zero and span adjustments),
you must monitor mercury emissions continuously (or collect data at all
required intervals) at all times that the affected source is operating.
A monitoring malfunction is any sudden, infrequent, not reasonably
preventable failure of the monitoring to provide valid data. Monitoring
failures that are caused in part by poor maintenance or careless
operation are not malfunctions.
(2) You may not use data recorded during monitoring malfunctions,
associated repairs, and required quality assurance or control
activities in data averages and calculations used to report emission or
operating levels or to fulfill a minimum data availability requirement,
if applicable. You must use all the data collected during all other
periods in assessing compliance.
(b) Periodic monitoring option. If you choose the periodic
monitoring option under Sec. 63.8240(b), you must monitor according to
the procedures in paragraph (b)(1) or (2) of this section.
(1) If your final control device is a nonregenerable carbon
adsorber, then you must conduct at least three test runs per week
meeting the criteria specified in Sec. 63.8232(c)(1) and (2) to
measure mercury emissions using the test methods specified in Sec.
63.8232(d). Alternatively, you may use any other method that has been
validated using the applicable procedures in Method 301, 40 CFR part
63, appendix A.
(2) If your final control device is anything other than a
nonregenerable carbon adsorber, you must monitor according to the
requirements of paragraphs (b)(2)(i) through (v) of this section.
(i) You must conduct at least three test runs per week meeting the
criteria specified in Sec. 63.8232(c)(1) and (2) to measure mercury
emissions using the test methods specified in Sec. 63.8232(d).
Alternatively, you may use any other method that has been validated
using the applicable procedures in Method 301, 40 CFR part 63, appendix
A.
(ii) Except as specified in paragraph (b)(2)(iii) of this section,
you must continuously collect data at least once every 15 minutes using
a CPMS installed and operated according to Sec. 63.8242(b) and record
each 1-hour average from all measured data values during each 1-hour
period for the applicable parameter identified in Sec. 63.8232(f)(1)
using the methods specified in Sec. 63.8244(a).
(iii) As appropriate, you must continuously monitor the temperature
specified in Sec. 63.8232(f)(1)(vii) during each heating phase of the
regeneration cycle of your carbon adsorber.
(iv) If the hourly average monitoring value of any applicable
parameter recorded under paragraph (b)(2)(ii) of this section is below
the minimum monitoring value or above the maximum monitoring value of
that same parameter established under Sec. 63.8232(f)(2) for 24
consecutive hours, your monitoring value is out of range and you must
take corrective action as soon as practicable. The hourly average
monitoring value must be above the minimum monitoring value or below
the maximum monitoring value as appropriate for that parameter, within
48 hours of the period that the monitoring value is out of range.
(v) If your final control device is a regenerative carbon adsorber,
when the maximum hourly value of the temperature measured according to
paragraph (b)(2)(iii) of this section is below the reference
temperature determined according to Sec. 63.8232(f)(2) for three
consecutive regeneration cycles, your monitoring value is out of range
and you must take corrective action as soon as practicable. During the
first regeneration cycle following the period that your monitoring
value is out of range, the maximum hourly value must be above the
reference temperature recorded according to Sec. 63.8232(f)(2).

Sec. 63.8246 How do I demonstrate continuous compliance with the
emission limitations and work practice standards?

(a) By-product hydrogen streams and end box ventilation system
vents. (1) For all by-product hydrogen streams and all end box
ventilation system vents, if applicable, you must demonstrate
continuous compliance with the applicable mercury emission limit by
reducing the mercury emissions data to 52-week averages using Equation
1 of Sec. 63.8243 and maintaining the 52-week average mercury
emissions no higher than the applicable mercury emissions limit in
Sec. 63.8190(a)(2). To obtain the data to calculate these 52-week
averages, you must monitor in accordance with paragraph (a)(1)(i) or
(ii) of this section.
(i) Continuous monitoring option. You must collect mercury
emissions data according to Sec. 63.8244(a), representing at least 75
percent of the 15-minute periods in each operating day of the 52-week
compliance period (with data recorded during monitoring malfunctions,
associated repairs, and required quality assurance or control
activities not counting toward the 75 percent requirement);
(ii) Periodic monitoring option. You must conduct at least three
test runs per week to collect mercury emissions samples according to
Sec. 63.8244(b)(1) and (2)(i) and, if your final control device is not
a nonregenerable carbon adsorber, you must collect data for monitoring
values according to Sec. 63.8244(b)(2)(ii) through (v).
(2) You must maintain records of mercury emissions and 52-week
average values, as required in Sec. 63.8256(b)(3) and (4). If your
final control device is not a nonregenerable carbon adsorber, you must
maintain records according to Sec. 63.8256(d).
(b) Mercury thermal recovery unit vents. (1) For each mercury
thermal recovery unit vent, you must demonstrate continuous compliance
with the applicable emission limit specified in Sec. 63.8190(a)(3) by
maintaining the outlet mercury hourly-average concentration no higher
than the applicable limit. To determine the outlet mercury
concentration, you must monitor according to paragraph (b)(1)(i) or
(ii) of this section.
(i) Continuous monitoring option. You must collect mercury
concentration data according to Sec. 63.8244(a), representing at least
75 percent of the 15-minute periods in the operating day (with data

[[Page 70935]]

recorded during monitoring malfunctions, associated repairs, and
required quality assurance or control activities not counting toward
the 75 percent requirement).
(ii) Periodic monitoring option. You must conduct at least three
test runs per week to collect mercury emissions samples according to
Sec. 63.8244(b)(1) and (2)(i) and, if your final control device is not
a nonregenerable carbon adsorber, you must collect data for monitoring
values according to Sec. 63.8244(b)(2)(ii) through (v).
(2) You must maintain records of mercury emissions and daily
average values as required in Sec. 63.8256(b)(3). If your final
control device is not a nonregenerable carbon adsorber, you must
maintain records according to Sec. 63.8256(d).
(c) You must demonstrate continuous compliance with the applicable
work practice standards in Sec. 63.8192 by maintaining records in
accordance with Sec. 63.8256(c).

Sec. 63.8248 What other requirements must I meet?

(a) Deviations. The instances specified in paragraphs (a)(1)
through (4) of this section are deviations and must be reported
according to the requirements in Sec. 63.8254.
(1) You must report each instance in which you did not meet each
emission limitation in Sec. 63.8190 that applies to you. This includes
periods of startup, shutdown, and malfunction.
(2) You must report each instance in which you did not meet each
work practice standard in Sec. 63.8192 that applies to you. This
includes periods of startup, shutdown, and malfunction.
(3) You must report each instance in which the corrective actions
taken according to Sec. 63.8244(b)(2)(iv) did not result in average
monitoring values being within range within 48 hours of the period that
the monitoring value is out of range.
(4) You must report each instance in which the corrective action
taken according to Sec. 63.8244(b)(2)(v) did not result in the maximum
hourly temperature being above the reference temperature during the
first regeneration cycle following the period that the monitoring value
was out of range.
(b) Startups, shutdowns, and malfunctions. During periods of
startup, shutdown, and malfunction, you must operate in accordance with
your startup, shutdown, and malfunction plan that satisfies the
requirements in Sec. 63.6(e) and as required in Sec. 63.8226(b).
(1) Consistent with Sec. Sec. 63.6(e) and 63.7(e)(1), deviations
that occur during a period of startup, shutdown, or malfunction are not
violations if you demonstrate to the Administrator's satisfaction that
you have an adequate startup, shutdown, or malfunction plan that
satisfies the requirements of Sec. 63.6(e), and you have complied with
the startup, shutdown, and malfunction plan.
(2) The Administrator will determine whether deviations that occur
during a period of startup, shutdown, or malfunction are violations,
according to the provisions in Sec. 63.6(e).
(3) By-passing the control device for maintenance activities is not
considered a startup, shutdown, or malfunction event.

Notification, Reports, and Records

Sec. 63.8252 What notifications must I submit and when?

(a) You must submit all of the notifications in Sec. Sec. 63.7(b)
and (c), 63.8(e) and (f) and 63.9(b) through (h) that apply to you by
the dates specified.
(b) As specified in Sec. 63.9(b)(2), if you start up your affected
source before December 19, 2003, you must submit your initial
notification not later than April 19, 2004.
(c) As specified in Sec. 63.9(b)(3), if you start up your new or
reconstructed mercury recovery facility on or after December 19, 2003,
you must submit your initial notification not later than 120 days after
you become subject to this subpart.
(d) For each performance test that you are required to conduct for
by-product hydrogen streams and end box ventilation system vents and
for mercury thermal recovery unit vents, you must submit a notification
of intent to conduct a performance test at least 60 calendar days
before the performance test is scheduled to begin as required in Sec.
7(b)(1).
(e) You must submit a Notification of Compliance Status according
to paragraphs (e)(1) and (2) of this section.
(1) For each initial compliance demonstration that does not include
a performance test, you must submit the Notification of Compliance
Status before the close of business on the 30th calendar day following
the completion of the initial compliance demonstration. The
Notification of Compliance Status must contain the items in paragraphs
(e)(1)(i) through (iv) of this section:
(i) If you choose not to implement a cell room monitoring program
according to Sec. 63.8192(g), a certification that you are operating
according to the applicable work practice standards in Sec. 63.8192(a)
through (d) and your floor-level mercury vapor measurement plan
required by Sec. 63.8192(d).
(ii) The washdown plan, and you must certify that you are operating
according to the washdown plan specified in Sec. 63.8192(f).
(iii) The mass of virgin mercury added to cells for the 5 years
preceding the compliance date.
(iv) If you choose to implement a cell room monitoring program
according to Sec. 63.8192(g), your cell room monitoring plan.
(2) For each initial compliance demonstration that does include a
performance test, you must submit the Notification of Compliance
Status, including the performance test results, before the close of
business on the 60th calendar day following the completion of the
performance test according to Sec. 63.10(d)(2). The Notification of
Compliance Status must contain the information in Sec.
63.9(h)(2)(ii)(A) through (G). The site-specific monitoring plan
required in Sec. 63.8242(a)(3) must also be submitted.

Sec. 63.8254 What reports must I submit and when?

(a) Compliance report due dates. You must submit a semiannual
compliance report to your permitting authority according to the
requirements in paragraphs (a)(1) through (4) of this section.
(1) The first compliance report must cover the period beginning on
the compliance date that is specified for your affected source in Sec.
63.8186 and ending on June 30 or December 31, whichever date comes
first after the compliance date that is specified for your affected
source in Sec. 63.8186.
(2) The first compliance report must be postmarked or delivered no
later than July 31 or January 31, whichever date comes first after your
first compliance reporting period.
(3) Each subsequent compliance report must cover the semiannual
reporting period from January 1 through June 30 or the semiannual
reporting period from July 1 through December 31.
(4) Each subsequent compliance report must be postmarked or
delivered no later than July 31 or January 31, whichever date comes
first after the end of the semiannual reporting period.
(b) Compliance report contents. Each compliance report must contain
the information in paragraphs (b)(1) through (3) of this section, and
as applicable, paragraphs (b)(4) through (12) of this section.
(1) Company name and address.
(2) Statement by a responsible official, with that official's name,
title, and signature, certifying the truth, accuracy, and completeness
of the report.

[[Page 70936]]

(3) Date of report and beginning and ending dates of the reporting
period.
(4) If you had a startup, shutdown or malfunction during the
reporting period and you took actions consistent with your startup,
shutdown, and malfunction plan, the compliance report must include the
information in Sec. 63.10(d)(5)(i).
(5) If there were no deviations from the continuous compliance
requirements in Sec. 63.8246 that apply to you, a statement that there
were no deviations from the emission limitations, work practice
standards, and operation and maintenance standards during the reporting
period.
(6) If there were no periods during which the mercury continuous
emission monitor or CPMS (if applicable) were out-of-control as
specified in Sec. 63.8(c)(7), a statement that there were no periods
during the which the mercury continuous emissions monitor or CPMS (if
applicable) were out-of-control during the reporting period.
(7) For each deviation from the requirements for work practice
standards in Tables 1 through 4 to this subpart that occurs at an
affected source (including deviations where the response intervals were
not adhered to as described in Sec. 63.8192(b)), the compliance report
must contain the information in paragraphs (b)(1) through (4) of this
section and the information in paragraphs (b)(7)(i) and (ii) of this
section. This includes periods of startup, shutdown, and malfunction.
(i) The total operating time of each affected source during the
reporting period.
(ii) Information on the number, duration, and cause of deviations
(including unknown cause, if applicable), as applicable, and the
corrective action taken.
(8) For each deviation from an emission limitation occurring at an
affected source where you are using a mercury continuous emission
monitor, according to the site-specific monitoring plan required in
Sec. 63.8242(a)(3), to comply with the emission limitation in this
subpart, you must include the information in paragraphs (b)(1) through
(4) of this section and the information in paragraphs (b)(8)(i) through
(xii) of this section. This includes periods of startup, shutdown, and
malfunction.
(i) The date and time that each malfunction started and stopped.
(ii) The date and time of each instance in which a continuous
monitoring system was inoperative, except for zero (low-level) and
high-level checks.
(iii) The date, time, and duration of each instance in which a
continuous monitoring system was out-of-control, including the
information in Sec. 63.8(c)(8).
(iv) The date and time that each deviation started and stopped, and
whether each deviation occurred during a period of startup, shutdown,
or malfunction or during another period.
(v) A summary of the total duration of the deviation during the
reporting period and the total duration as a percent of the total
source operating time during that reporting period.
(vi) A breakdown of the total duration of the deviations during the
reporting period including those that are due to startup, shutdown,
control equipment problems, process problems, other known causes, and
other unknown causes.
(vii) A summary of the total duration of continuous monitoring
system downtime during the reporting period and the total duration of
monitoring system downtime as a percent of the total source operating
time during the reporting period.
(viii) An identification of each hazardous air pollutant that was
monitored at the affected source.
(ix) A brief description of the process units.
(x) A brief description of the continuous monitoring system.
(xi) The date of the latest continuous monitoring system
certification or audit.
(xii) A description of any changes in monitoring system, processes,
or controls since the last reporting period.
(9) For each deviation from an operation and maintenance standard
occurring at an affected source where you are using the periodic
monitoring option specified in Sec. 63.8240(b) and your final control
device is not a nonregenerable carbon adsorber, the compliance report
must include the information in paragraphs (b)(1) through (4) of this
section and the information in paragraphs (b)(9)(i) through (x) of this
section. This includes periods of startups, shutdowns and malfunctions.
(i) The total operating time of each affected source during the
reporting period.
(ii) Information on the number, duration, and cause of deviations
(including unknown cause, if applicable), as applicable, whether the
deviation occurred during a period of startup, shutdown, or
malfunction, or other period, and the corrective action taken.
(iii) The date and time of each instance in which a CPMS was
inoperative, except for zero (low-level) and high-level checks.
(iv) The date, time, and duration of each instance in which a CPMS
was out-of-control, including the information specified in Sec.
63.8(c)(8).
(v) A summary of the total duration of the deviation during the
reporting period and the total duration as a percent of the total
source operating time during that reporting period.
(vi) A breakdown of the total duration of the deviations during the
reporting period including those that are due to startup, shutdown,
control equipment problems, process problems, other known causes, and
other unknown causes.
(vii) A summary of the total duration of continuous monitoring
system downtime during the reporting period and the total duration of
monitoring system downtime as a percent of the total source operating
time during the reporting period.
(viii) A brief description of the CPMS.
(ix) The date of the latest CPMS certification or audit.
(x) A description of any changes in monitoring system, processes,
or controls since the last reporting period.
(10) The compliance report must contain the mass of virgin mercury
added to cells for the reporting period.
(11) The compliance report must contain each instance in which
corrective actions taken under Sec. 63.8244(b)(2)(iv) did not result
in average monitoring values being within range within 48 hours of the
period that the monitoring value is out of range.
(12) The compliance report must contain each instance in which
corrective action taken according to Sec. 63.8244(b)(2)(v) did not
result in the maximum hourly temperature being above the reference
temperature during the first regeneration cycle following the period
that the monitoring value was out of range.
(c) Immediate startup, shutdown, and malfunction report. If you
took an action during a startup, shutdown, or malfunction during the
semiannual reporting period that was not consistent with your startup,
shutdown, and malfunction plan required in Sec. 63.8226(b), and the
source exceeded any applicable emission limitation in this subpart, you
must submit an immediate startup, shutdown, and malfunction report
according to the requirements in Sec. 63.10(d)(5)(ii).
(d) Title V monitoring report. After your affected source has been
issued a title V operating permit pursuant to 40 CFR part 70 or 40 CFR
part 71, you must report all deviations from permit requirements and
provide reports of any required monitoring in your semiannual
monitoring report as required by 40 CFR 70.6(a)(3)(iii)(A) or 40 CFR
71.6(a)(3)(iii)(A). If you submit a

[[Page 70937]]

semiannual compliance report for an affected source as required by this
subpart as part of the semiannual monitoring report required by 40 CFR
70.6(a)(3)(iii)(A) or 40 CFR 71.6(a)(3)(iii)(A), and the semiannual
compliance report includes all information required by the 40 CFR part
70 or 40 CFR part 71 semiannual monitoring report for the deviations
that are reported in the semiannual compliance report, submission of
the semiannual compliance report satisfies your obligation to report
the same deviation information in the semiannual monitoring report.
However, in such situations, the semiannual monitoring report must
cross-reference the semiannual compliance report, and submission of a
semiannual compliance report does not otherwise affect any obligation
you may have to report deviations from permit requirements for an
affected source to your permitting authority under 40 CFR part 70 or 40
CFR part 71.

Sec. 63.8256 What records must I keep?

(a) General records. You must keep the records in paragraphs (a)(1)
and (2) of this section.
(1) A copy of each notification and report that you submitted to
comply with this subpart, including all documentation supporting any
initial notification or Notification of Compliance Status that you
submitted, according to the requirements in Sec. 63.10(b)(2)(xiv).
(2) The records in Sec. 63.6(e)(3)(iii) through (v) related to
startup, shutdown, and malfunction.
(b) Records associated with the by-product hydrogen stream and end
box ventilation system vent emission limitations and the mercury
thermal recovery unit vent emission limitations. You must keep the
records in paragraphs (b)(1) through (5) of this section related to the
emission limitations in Sec. 63.8190(a)(2) through (3) and (b).
(1) Records of performance tests as required in Sec.
63.10(b)(2)(viii).
(2) Records of the mercury emissions monitoring conducted during
the performance tests.
(3) Records of the continuous or periodic mercury emissions
monitoring data.
(4) Records of the 52-week rolling average mercury emissions.
(5) Records associated with your site-specific monitoring plan
required in Sec. 63.8242(a)(3) (i.e., results of inspections,
calibrations, and validation checks of each mercury concentration
continuous monitoring system (CMS)).
(6) Records of chlorine production on a weekly basis.
(c) Records associated with the work practice standards.
(1) If you choose not to institute a cell room monitoring program
according to Sec. 63.8192(g) of this subpart, you must keep the
records specified in paragraphs (c)(1)(i) through (v) of this section.
(i) Records specified in Table 9 to this subpart related to the
work practice standards in Tables 1 through 4 of this subpart.
(ii) Your current floor-level mercury vapor measurement plan.
(iii) Records of the average value calculated from at least three
measurements taken according to your floor-level mercury vapor
measurement plan.
(iv) Records indicated in Sec. 63.8192(d)(4)(i) for maintenance
activities that cause the floor-level mercury concentration to exceed
the action level.
(v) Records of all inspections and corrective actions taken in
response to a non-maintenance related situation in which the mercury
vapor concentration exceeds the floor-level mercury concentration
action level.
(2) You must maintain a copy of your current washdown plan and
records of when each washdown occurs.
(3) You must maintain records of the mass of virgin mercury added
to cells for each reporting period.
(4) If you choose to institute a cell room monitoring program
according to Sec. 63.8192(g) of this subpart, you must keep your
current cell room monitoring plan and the records specified in
paragraphs (c)(4)(i) through (v) of this section.
(i) Records of the monitoring conducted in accordance with Sec.
63.8192(g)(2)(i) to establish your action level, and records
demonstrating the development of this action level.
(ii) Records of the cell room mercury concentration monitoring data
collected.
(iii) Instances when the action level is exceeded.
(iv) Records specified in Sec. 63.8192(g)(4)(i) for maintenance
activities that cause the mercury vapor concentration to exceed the
action level.
(v) Records of all inspections and corrective actions taken in
response to a non-maintenance related situation in which the mercury
vapor concentration exceeds the action level.
(d) Records associated with the periodic monitoring option if your
final control device is not a nonregenerable carbon adsorber. You must
keep the records in paragraph (d)(1) through (3) of this section.
(1) Records of the CPMS data collected during the performance test
as specified in Sec. 63.8232(f)(1).
(2) Records documenting the development of the maximum monitoring
value or minimum monitoring value, as appropriate, according to Sec.
63.8232(f)(2).
(3) Records of hourly average values of applicable parameters
monitored as specified in Sec. 63.8244(b)(2)(ii) or (iii).

Sec. 63.8258 In what form and how long must I keep my records?

(a) Your records must be in a form suitable and readily available
for expeditious inspection and review, according to Sec. 63.10(b)(1).
(b) As specified in Sec. 63.10(b)(1), you must keep each record
for 5 years following the date of each occurrence, measurement,
maintenance, corrective action, report, or record.
(c) You must keep each record on site for at least 2 years after
the date of each occurrence, measurement, maintenance, corrective
action, report, or record, according to Sec. 63.10(b)(1). You can keep
the records offsite for the remaining 3 years.

Other Requirements and Information

Sec. 63.8262 What parts of the General Provisions apply to me?

Table 10 to this subpart shows which parts of the General
Provisions in Sec. Sec. 63.1 through 63.13 apply to you.

Sec. 63.8264 Who implements and enforces this subpart?

(a) This subpart can be implemented and enforced by us, the United
States Environmental Protection Agency (U.S. EPA), or a delegated
authority such as your State, local, or tribal agency. If the EPA
Administrator has delegated authority to your State, local, or tribal
agency, then that agency has the authority to implement and enforce
this subpart. You should contact your EPA Regional Office to find out
if this subpart is delegated to your State, local, or tribal agency.
(b) In delegating implementation and enforcement authority of this
subpart to a State, local, or tribal agency under subpart E of this
part, the authorities contained in paragraph (c) of this section are
retained by the EPA Administrator and are not transferred to the State,
local, or tribal agency.
(c) The authorities in paragraphs (c)(1) through (4) of this
section will not be delegated to State, local, or tribal agencies.
(1) Approval of alternatives under Sec. 63.6(g) to the non-opacity
emission limitations in Sec. 63.8190 and work practice standards in
Sec. 63.8192.

[[Page 70938]]

(2) Approval of major alternatives to test methods under Sec.
63.7(e)(2)(ii) and (f) and as defined in Sec. 63.90.
(3) Approval of major alternatives to monitoring under Sec.
63.8(f) and as defined in Sec. 63.90.
(4) Approval of major alternatives to recordkeeping and reporting
under Sec. 63.10(f) and as defined in Sec. 63.90.

Sec. 63.8266 What definitions apply to this subpart?

Terms used in this subpart are defined in the CAA, in Sec. 63.2,
and in this section as follows:
Aqueous liquid means a liquid mixture in which water is the
predominant component.
Brine means an aqueous solution of alkali metal chloride, as sodium
chloride salt solution or potassium chloride salt solution, that is
used in the electrolyzer as a raw material.
By-product hydrogen stream means the hydrogen gas from each
decomposer that passes through the hydrogen system and is burned as
fuel, transferred to another process as raw material, or discharged
directly to the atmosphere.
Caustic means an aqueous solution of alkali metal hydroxide, as
sodium hydroxide or potassium hydroxide, that is produced in the
decomposer.
Caustic basket means a fixture adjacent to the decomposer that
contains a serrated funnel over which the caustic from the decomposer
passes, breaking into droplets such that electric current is
interrupted.
Caustic system means all vessels, piping, and equipment that convey
caustic and remove mercury from the caustic stream. The caustic system
begins at the decomposer and ends after the primary filters.
Cell room means a building or other structure in which one or more
mercury cells are located.
Continuous parameter monitoring system, or CPMS, means the total
equipment that may be required to meet the data acquisition and
availability requirements of this subpart, used to sample, condition
(if applicable), analyze, and provide a record of process of control
system parameters.
Control device means a piece of equipment (such as condensers,
coolers, chillers, heat exchangers, mist eliminators, absorption units,
and adsorption units) that removes mercury from gaseous streams.
Decomposer means the component of a mercury cell in which mercury
amalgam and water react in bed of graphite packing (within a
cylindrical vessel), producing caustic and hydrogen gas and returning
mercury to its elemental form for re-use in the process.
Deviation means any instance in which an affected source subject to
this subpart, or an owner or operator of such a source:
(1) Fails to meet any requirement or obligation established by this
subpart including, but not limited to, any emission limitation
(including any operating limit) or work practice standard;
(2) Fails to meet any term or condition that is adopted to
implement an applicable requirement in this subpart and that is
included in the title V operating permit for any affected source
required to obtain such a permit;
(3) Fails to meet any emission limitation (including any operating
limit) or work practice standard in this subpart during startup,
shutdown, or malfunction, regardless of whether or not such failure is
allowed by this subpart; or
(4) Fails to take corrective actions within 48 hours that result in
parameter monitoring values being within range.
Electrolyzer means the main component of the mercury cell that
consists of an elongated, shallow steel trough that holds a layer of
mercury as a flowing cathode. The electrolyzer is enclosed by side
panels and a top that suspends metal anodes. In the electrolyzer, brine
is fed between a flowing mercury cathode and metal anodes in the
presence of electricity to produce chlorine gas and an alkali metal-
mercury amalgam (mercury amalgam).
Emission limitation means any emission limit or operating limit.
End box means a component of a mercury cell for transferring
materials between the electrolyzer and the decomposer. The inlet end
box collects and combines raw materials at the inlet end of the cell,
and the outlet end box separates and directs various materials either
into the decomposer or out of the cell.
End box ventilation system means all vessels, piping, and equipment
that evacuate the head space of each mercury cell end box (and possibly
other vessels and equipment) to the atmosphere. The end box ventilation
system begins at the end box (and other vessel or equipment which is
being evacuated) and terminates at the end box ventilation system vent.
The end box ventilation system includes all control devices.
End box ventilation system vent means the discharge point of the
end box ventilation system to the atmosphere after all control devices.
Hydrogen leak means hydrogen gas (containing mercury vapor) that is
escaping from the decomposer or hydrogen system.
Hydrogen system means all vessels, piping, and equipment that
convey a by-product hydrogen stream. The hydrogen system begins at the
decomposer and ends at the point just downstream of the last control
device. The hydrogen system includes all control devices.
In liquid mercury service means containing or coming in contact
with liquid mercury.
Liquid mercury accumulation means one or more liquid mercury
droplets, or a pool of liquid mercury, present on the floor or other
surface exposed to the atmosphere.
Liquid mercury leak means the liquid mercury that is dripping or
otherwise escaping from process equipment.
Liquid mercury spill means a liquid mercury accumulation resulting
from a liquid mercury that leaked from process equipment or that
dripped during maintenance or handling.
Mercury cell means a device consisting of an electrolyzer and
decomposer, with one or more end boxes, a mercury pump, and other
components linking the electrolyzer and decomposer.
Mercury cell amalgam seal pot means a compartment through which
mercury amalgam passes from an outlet end box to a decomposer.
Mercury cell chlor-alkali plant means all contiguous or adjoining
property that is under common control, where mercury cells are used to
manufacture product chlorine, product caustic, and by-product hydrogen
and where mercury may be recovered from wastes.
Mercury cell chlor-alkali production facility means an affected
source consisting of all cell rooms and ancillary operations used in
the manufacture of product chlorine, product caustic, and by-product
hydrogen at a mercury cell chlor-alkali plant.
Mercury concentration CMS, or mercury concentration continuous
monitoring system, means a CMS, as defined in Sec. 63.2, that
continuously measures the concentration of mercury.
Mercury-containing wastes means waste materials containing mercury,
which are typically classified under Resource Conservation and Recovery
Act (RCRA) solid waste designations. K071 wastes are sludges from the
brine system. K106 are wastewater treatment sludges. D009 wastes are
non-specific mercury-containing wastes, further classified as either
debris or nondebris (i.e., cell room sludges and carbon from
decomposes).
Mercury pump means a component of a mercury cell for conveying
elemental mercury re-created in the decomposer to

[[Page 70939]]

the beginning of the mercury cell. A mercury pump is typically found
either as an in-line mercury pump (near a mercury suction pot or
mercury seal pot) or submerged mercury pump (within a mercury pump tank
or mercury pump seal).
Mercury recovery facility means an affected source consisting of
all processes and associated operations needed for mercury recovery
from wastes at a mercury cell chlor-alkali plant.
Mercury thermal recovery unit means the retort(s) where mercury-
containing wastes are heated to volatilize mercury and the mercury
recovery/control system (control devices and other equipment) where the
retort off-gas is cooled, causing mercury to condense and liquid
mercury to be recovered.
Mercury thermal recovery unit vent means the discharge point of the
mercury thermal recovery unit to the atmosphere after all recovery/
control devices. This term encompasses both oven type vents and non-
oven type vents.
Mercury vacuum cleaner means a cleanup device used to draw a liquid
mercury spill or accumulation (via suction pressure) into a closed
compartment.
Non-oven type mercury thermal recovery unit vent means the
discharge point to the atmosphere after all recovery/control devices of
a mercury thermal recovery unit in which the retort is either a rotary
kiln or single hearth retort.
Open-top container means any container that does not have a tight-
fitting cover that keeps its contents from being exposed to the
atmosphere.
Oven type mercury thermal recovery unit vent means the discharge
point to the atmosphere after all recovery/control devices of a mercury
thermal recovery unit in which each retort is a batch oven retort.
Responsible official means responsible official as defined in 40
CFR 70.2.
Retort means a furnace where mercury-containing wastes are heated
to drive mercury into the gas phase. The types of retorts used as part
of mercury thermal recovery units at mercury cell chlor-alkali plants
include batch oven retorts, rotary kilns, and single hearth retorts.
Spalling means fragmentation by chipping.
Sump means a large reservoir or pit for wastewaters (primarily
washdown waters).
Trench means a narrow channel or depression built into the length
of a cell room floor that leads washdown materials to a drain.
Vent hose means a connection for transporting gases from the
mercury cell.
Virgin mercury means mercury that has not been processed in an
onsite mercury thermal recovery unit or otherwise recovered from
mercury-containing wastes onsite.
Washdown means the act of rinsing a floor or surface with a stream
of aqueous liquid to cleanse it of a liquid mercury spill or
accumulation, generally by driving it into a trench.
Week means any consecutive seven-day period.
Work practice standard means any design, equipment, work practice,
or operational standard, or combination thereof, that is promulgated
pursuant to section 112(h) of the CAA.

Tables to Subpart IIIII of Part 63

Table 1 to Subpart IIIII of Part 63.--Work Practice Standards--Design,
Operation, and Maintenance Requirements
[As stated in Sec. 63.8192, you must meet the work practice standards
in the following table]
------------------------------------------------------------------------
For * * * You must * * *
------------------------------------------------------------------------
1. Cell rooms..................... a. For new or modified cell rooms,
construct each cell room interior
using materials that are resistant
to absorption of mercury, resistant
to corrosion, facilitate the
detection of liquid mercury spills
or accumulations, and are easy to
clean.
b. Limit access around and beneath
mercury cells in each cell room to
prevent liquid mercury from being
tracked into other areas.
c. Provide adequate lighting in each
cell room to facilitate the
detection of liquid mercury spills
or accumulations.
d. Minimize the number of items
stored around and beneath cells in
each cell room.
2. Mercury cells and electrolyzers a. Operate and maintain each
electrolyzer, decomposer, end box,
and mercury pump to minimize
leakage of mercury.
b. Prior to opening an electrolyzer
for maintenance, do the following:
(1) Complete work that can be done
before opening the electrolyzer in
order to minimize the time required
to complete maintenance when the
electrolyzer is open; (2) fill the
electrolyzer with an aqueous
liquid, when possible; (3) allow
the electrolyzer to cool before
opening; and (4) schedule and staff
maintenance of the electrolyzer to
minimize the time the electrolyzer
is open.
c. When the electrolyzer top is
raised and before moving the top
and anodes, thoroughly flush all
visible mercury from the top and
the anodes with an aqueous liquid,
when possible.
d. While an electrolyzer is open,
keep the bottom covered with an
aqueous liquid or maintain a
continuous flow of aqueous liquid,
when possible.
e. During an electrolyzer side panel
change, take measures to ensure an
aqueous liquid covers or flows over
the bottom, when possible.
f. Each time an electrolyzer is
opened, inspect and replace
components, as appropriate.
g. If you step into an electrolyzer
bottom, either remove all visible
mercury from your footwear or
replace them immediately after
stepping out of the electrolyzer.
h. If an electrolyzer is
disassembled for overhaul
maintenance or for any other
reason, chemically clean the bed
plate or thoroughly flush it with
an aqueous liquid.
i. Before transporting each
electrolyzer part to another work
area, remove all visible mercury
from the part or contain the part
to prevent mercury from dripping
during transport.
j. After completing maintenance on
an electrolyzer, check any mercury
piping flanges that were opened for
liquid mercury leaks.
k. If a liquid mercury spill occurs
during any maintenance activity on
an electrolyzer, clean it up in
accordance with the requirements in
Table 3 to this subpart.

[[Page 70940]]

3. Vessels in liquid mercury If you replace a vessel containing
service. mercury that is intended to trap
and collect mercury after December
19, 2003, replace it with a vessel
that has a cone shaped bottom with
a drain valve or other design that
readily facilitates mercury
collection.
4. Piping and process lines in a. To prevent mercury buildup after
liquid mercury service. December 19, 2003, equip each new
process line and piping system with
smooth interiors and adequate low
point drains or mercury knock-out
pots to avoid liquid mercury
buildup within the pipe and to
facilitate mercury collection and
recovery.
5. Cell room floors............... a. Maintain a coating on cell room
floors that is resistant to
absorption of mercury and that
facilitates the detection of liquid
mercury spills or accumulations.
b. Maintain cell room floors such
that they are smooth and free of
cracking and spalling.
c. Maintain the cell room floor to
prevent mercury accumulation in the
corners.
d. Maintain a layer of aqueous
liquid on liquid mercury contained
in trenches or drains and replenish
the aqueous layer at least once per
day.
e. Keep the cell room floor clean
and free of debris.
f. If you step into a liquid mercury
spill or accumulation, either
remove all visible mercury from
your footwear or replace your
footwear immediately.
6. End boxes...................... a. Either equip each end box with a
fixed cover that is leak tight, or
route the end box head space to an
end box ventilation system.
b. For each end box ventilation
system: maintain a flowof aqueous
liquid over the liquid mercury in
the end box and maintain the
temperature of the aqueous liquid
below its boiling point, maintain a
negative pressure in the end box
ventilation system, and maintain
the end box ventilation system in
good condition.
c. Maintain each end box cover in
good condition and keep the end box
closed when the cell is in service
and when liquid mercury is flowing
down the cell, except when
operation or maintenance activities
require short-term access.
d. Keep all bolts and C-clamps used
to hold the covers in place when
the cell is in service and when
liquid mercury is flowing down the
cell.
e. Maintain each access port stopper
in an end box cover in good sealing
condition and keep each end box
access port closed when the cell is
in service and when liquid mercury
is flowing down the cell.
7. Decomposers.................... a. Maintain each decomposer cover in
good condition and keep each
decomposer closed and sealed,
except when maintenance activities
require the cover to be removed.
b. Maintain connections between the
decomposer and the corresponding
cell components, hydrogen system
piping, and caustic system piping
in good condition and keep the
connections closed/tight, except
when maintenance activities require
opening/loosening these
connections.
c. Keep each mercury cell amalgam
seal pot closed and sealed, except
when operation or maintenance
activities require short-term
access.
d. Prior to opening a decomposer, do
the following: fill the decomposer
with an aqueous liquid or drain the
decomposer liquid mercury into a
container that meets requirements
in Table 1, Item 9 or 10, allow the
decomposer to cool before opening,
and complete work that can be done
before opening the decomposer.
e. Take precautions to avoid mercury
spills when changing graphite grids
or balls in horizontal decomposers
or graphite packing in vertical
decomposers. If a spill occurs, you
must clean it up in accordance with
the requirements in Table 3 to this
subpart.
f. After each maintenance activity,
use an appropriate technique (Table
6 to this subpart) to check for
hydrogen leaks.
g. Before transporting any internal
part from the decomposer (such as
the graphite basket) to another
work area, remove all visible
mercury from the part or contain
the part to prevent mercury from
dripping during transport.
h. Store carbon from decomposers in
accordance with the requirements in
40 CFR part 265, subparts I and CC,
until the carbon is treated or is
disposed.
8. Submerged mercury pumps........ a. Provide a vapor outlet connection
from each submerged pump to an end
box ventilation system. The
connection must be maintained under
negative pressure.
b. Keep each mercury pump tank
closed, except when maintenance or
operation activities require the
cover to be removed.
c. Maintain a flow of aqueous liquid
over the liquid mercury in each
mercury pump tank and maintain the
aqueous liquid at a temperature
below its boiling point.
9. Open-top containers holding Maintain a layer of aqueous liquid
liquid mercury. over liquid mercury in each open-
top container. Replenish the
aqueous layer at least once per day
and, when necessitated by operating
procedures or observation, collect
the liquid mercury from the
container in accordance with the
requirements in Table 4 to this
subpart.
10. Closed containers used to a. Store liquid mercury in
store liquid mercury. containers with tight fitting
covers.
b. Maintain the seals on the covers
in good condition.
c. Keep each container securely
closed when mercury is not being
added to, or removed from, the
container.
11. Caustic systems............... a. Maintain the seal between each
caustic basket cover and caustic
basket by using gaskets and other
appropriate material.
b. Do not allow solids and liquids
collected from back-flushing
primary caustic filters to contact
floors or run into open trenches.
c. Collect solids and liquids from
back-flushing each primary caustic
filter and collect these mercury-
containing wastes in process
vessels or in accordance with the
requirements in 40 CFR part 265,
subparts I and CC.

[[Page 70941]]

d. Keep each caustic basket closed
and sealed, except when operation
or maintenance activities require
short term access.
12. Hydrogen systems.............. a. Collect drips from each hydrogen
seal pot and compressor seal in
containers meeting the requirements
in this table for open containers.
These drips should not be allowed
to run on the floor or in open
trenches.
b. Minimize purging of hydrogen from
a decomposer into the cell room by
either sweeping the decomposer with
an inert gas or by routing the
hydrogen to the hydrogen system.
c. Maintain hydrogen piping gaskets
in good condition.
d. After any maintenance activities,
use an appropriatetechnique (Table
6 to this subpart) to check all
hydrogen piping flanges that were
opened for hydrogen leaks.
------------------------------------------------------------------------

Table 2 to Subpart IIIII of Part 63.--Work Practice Standards--Required Inspections
[As stated in Sec. 63.8192, you must meet the work practice standards in the following table]
----------------------------------------------------------------------------------------------------------------
At least once each * * *
You must inspect * . * And if you find * * * You must * * *
----------------------------------------------------------------------------------------------------------------
1. Each vent hose on each mercury Half day................ A leaking vent hose.... Take action immediately
cell. to correct the leak.
2. Each open-top container holding Half day................ Liquid mercury that is Take action immediately
liquid mercury. not covered by an to cover the liquid
aqueous liquid. mercury with an
aqueous liquid.
3. Each end box..................... Half day................ a. An end box cover not Take action immediately
securely in place. to put the end box
cover securely in
place.
b. An end box stopper Take action immediately
not securely in place. to put the end box
stopper securely in
place.
c. Liquid mercury in an Take action immediately
end box that is not to cover the liquid
covered by an aqueous mercury with an
liquid at a aqueous liquid.
temperature below
boiling.
4. Each mercury amalgam seal pot.... Half day................ A seal pot cover that Take action immediately
is not securely in to put the seal pot
place. cover securely in
place.
5. Each mercury seal pot............ Half day................ A mercury seal pot Take action immediately
stopper not securely to put the mercury
in place. seal pot stopper
securely in place.
6. Cell room floors................. Month................... Cracks, spalling, or Repair the crack,
other deficiencies spalling, or other
that could cause deficiency within 1
liquid mercury to month from the time
become trapped. you identify the
deficiency.
7. Pillars and beams................ 6 months................ Cracks, spalling, or Repair the crack,
other deficiencies spalling, or other
that could cause deficiency within 1
liquid mercury to month from the time
become trapped. you identify the
deficiency.
8. Each caustic basket.............. Half day................ A caustic basket cover Take action immediately
that is not securely to put the caustic
in place. basket cover securely
in place.
9. All equipment and piping in the Day..................... Equipment that is Initiate repair of the
caustic system. leaking caustic. leaking equipment
within 72 hours from
the time that you
identify the caustic
leak.
10. All floors and other surfaces Half day................ A liquid mercury spill Take the required
where liquid mercury could or accumulation. action specified in
accumulate in cell rooms and other Table 3 to this
production facilities and in subpart.
mercury recovery facilities.
11. Each electrolyzer bottom, Day..................... Equipment that is Take the required
electrolyzer side panel, end box, leaking liquid mercury. action specified in
mercury amalgam seal pot, Table 3 to this
decomposer, mercury pump, and subpart.
hydrogen cooler, and all other
vessels, piping, and equipment in
liquid mercury service in the cell
room.
12. Each decomposer and all hydrogen Half day................ Equipment that is Take the required
piping up to the hydrogen header. leaking hydrogen and/ action specified in
or mercury vapor. Table 3 to this
subpart.
13. All equipment in the hydrogen 3 months................ Equipment that is Take the required
system from the start of the header leaking hydrogen and/ action specified in
to the last control device. or mercury vapor. Table 3 to this
subpart.
----------------------------------------------------------------------------------------------------------------

[[Page 70942]]

Table 3 to Subpart IIIII of Part 63.--Work Practice Standards--Required
Actions for Liquid Mercury Spills and Accumulations and Hydrogen and
Mercury Vapor Leaks
[As stated in Sec. 63.8192, you must meet the work practice standards
in the following table]
------------------------------------------------------------------------
During a required inspection or at
any other time, If you find * * * You must * * *

------------------------------------------------------------------------
1. A liquid mercury spill or a. Initiate clean up of the liquid
accumulation. mercury spill or accumulation as
soon as possible, but no later than
1 hour from the time you detect it.
b. Clean up liquid mercury using a
mercury vacuum cleaner or by using
an alternative method. If you use
an alternative method to clean up
liquid mercury, you must submit a
description of the method to the
Administrator in your Notification
of Compliance Status report.
c. If you use a mercury vacuum
cleaner, the vacuum cleaner must be
designed to prevent generation of
airborne mercury; you must cap the
ends of hoses after each use; and
after vacuuming, you must wash down
the area.
d. Inspect all equipment in liquid
mercury service in the surrounding
area to identify the source of the
liquid mercury within 1 hour from
the time you detect the liquid
mercury spill or accumulation.
e. If you identify leaking equipment
as the source of the spill or
accumulation, contain the dripping
mercury, stop the leak, and repair
the leaking equipment as specified
below.
f. If you cannot identify the source
of the liquid mercury spill or
accumulation, re-inspect the area
within 6 hours of the time you
detected the liquid mercury spill
or accumulation, or within 6 hours
of the last inspection of the area.
2. Equipment that is leaking a. Contain the liquid mercury
liquid mercury. dripping from the leaking equipment
by placing a container under the
leak within 30 minutes from the
time you identify the liquid
mercury leak.
b. The container must meet the
requirement for open-top containers
in Table 1 to this subpart.
c. Make a first attempt at stopping
the leak within 1 hour from the
time you identify the liquid
mercury leak.
d. Stop the leak and repair the
leaking equipment within 4 hours
from the time you identify the
liquid mercury leak.
e. You can delay repair of equipment
leaking liquid mercury if you
either isolate the leaking
equipment from the process so that
it does not remain in mercury
service; or determine that you
cannot repair the leaking equipment
without taking the cell off line,
provided that you contain the
dripping mercury at all times as
described above, and take the cell
off line as soon as practicable,
but no later than 48 hours from the
time you identify the leaking
equipment. You cannot place the
cell back into service until the
leaking equipment is repaired.
3. A decomposer or hydrogen system a. Make a first attempt at stopping
piping up to the hydrogen header the leak within 1 hour from the
that is leaking hydrogen and/or time you identify the hydrogen and/
mercury vapor. or mercury vapor leak.
b. Stop the leak and repair the
leaking equipment within 4 hours
from the time you identify the
hydrogen and/or mercury vapor leak.
c. You can delay repair of a
equipment leaking hydrogen and/or
mercury vapor if you isolate the
leaking equipment or take the cell
off line until you repair the
leaking equipment.
4. Equipment in the hydrogen a. Make a first attempt at stopping
system, from the start of the the leak within 4 hours from the
hydrogen header to the last time you identify the hydrogen and/
control device, that is leaking or mercury vapor leak.
hydrogen and/or mercury vapor.
b. Stop the leak and repair the
header within 24 hours from the
time you identify the hydrogen and/
or mercury vapor leak.
c. You can delay repair of equipment
leaking hydrogen and/or mercury
vapor if you isolate the leaking
equipment.
------------------------------------------------------------------------

Table 4 to Subpart IIIII of Part 63.--Work Practice Standards--Requirements for Mercury Liquid Collection
[As stated in Sec. 63.8192, you must meet the work practice standards in the following table]
----------------------------------------------------------------------------------------------------------------

-------------------------------------------------------------------------
You must collect liquid mercury At the following When collecting the mercury, you must meet these
from * * * intervals requirements
----------------------------------------------------------------------------------------------------------------
1. Open-top containers.......... a. At least once i. If you spill ii. From the time iii. Within 4
each 72 hours. liquid mercury that you collect hours from the
during collection liquid mercury time you` collect
or transport, you into a temporary the liquid
must take the container until mercury, you must
action specified the time that you transfer it from
in Table 3 to store the liquid each temporary
this subpart for mercury, you must container to a
liquid mercury keep it covered storage container
spills and by an aqueous that meets the
accumulations. liquid. specifications in
Table 1 to this
subpart.
2. Vessels, low point drains, a. At least once See 1.a.i through
mercury knock-out pots, and each week. iii above.
other closed mercury collection
points.

[[Page 70943]]

3. All other equipment.......... a. Whenever See 1.a.i. through
maintenance iii above.
activities
require the
opening of the
equipment.
----------------------------------------------------------------------------------------------------------------

Table 5 to Subpart IIIII.--Required Elements of Floor-Level Mercury
Vapor Measurement and Cell Room Monitoring Plans
[Your Floor-Level Mercury Vapor Measurement Plan required by Sec.
63.8192(d) and Cell Room Monitoring Plan required by Sec. 63.8192(g)
must contain the elements listed in the following table]
------------------------------------------------------------------------
You must specify in your plan * *
* Additional requirements
------------------------------------------------------------------------
Floor-Level Mercury Vapor Measurement Plan
------------------------------------------------------------------------
1. Locations in the cell room The locations must be representative
where you will measure the level of the entire cell room floor area.
of mercury vapor. At a minimum you must measure the
level of mercury vapor above
mercury-containing cell room
equipment, as well as areas around
the cells, decomposes, or other
mercury-containing equipment.
2. Equipment or sampling and If an instrument or other equipment
analytical methods that you will is used, the plan must include
use to measure the level of manufacturer specifications and
mercury vapor. calibration procedures. The plan
must also include a description of
how you will ensure that the
instrument will be calibrated and
maintained according to
manufacturer specifications.
3. Measurement frequency.......... Measurements must take place at
least once each half day.
4. Number of measurements......... At least three readings must be
taken at each sample location and
the average of these readings must
be recorded.
5. A floor-level mercury The action level may not be higher
concentration action level. than 0.05 mg/m3.
------------------------------------------------------------------------
Cell Room Monitoring Plan
------------------------------------------------------------------------
1. Details of your mercury
monitoring system.
2. How representative sampling Include some pre-plan measurements
will be conducted. to demonstrate the profile of
mercury concentration in the cell
room and how the selected sampling
locations ensure conducted
representativeness.
3. Quality assurance/quality Include a description of how you
control procedures for your will keep records or other means to
mercury monitoring system. demonstrate that the system is
operating properly.
4. Your action level.............. Include the background data used to
establish your level.
------------------------------------------------------------------------

Table 6 to Subpart IIIII of Part 63.--Examples of Techniques for
Equipment Problem Identification, Leak Detection and Mercury Vapor
Measurements
[As stated in Tables 1 and 2 of Subpart IIIII, examples of techniques
for equipment problem identification, leak detection and mercury vapor
measurements can be found in the following table]
------------------------------------------------------------------------
You could use * * Principle of
To detect * * * * detection * * *
------------------------------------------------------------------------
1. Leaking vent hoses; liquid Visual inspections
mercury that is not covered by
an aqueous liquid in open-top
containers or end boxes; end
box covers or stoppers, amalgam
seal pot stoppers, or caustic
basket covers not securely in
place; cracks or spalling in
cell room floors, pillars, or
beams; caustic leaks; liquid
mercury accumulations or
spills; and equipment that is
leaking liquid mercury.
2. Equipment that is leaking a. Auditory and
hydrogen and/or mercury vapor visual
during inspections required by inspections
Table 2 to this subpart.
b. Portable A sample of gas is
mercury vapor drawn through a
analyzer--ultravi detection cell
olet light where ultraviolet
absorption light at 253.7
detector. nanometers (nm)
is directed
perpendicularly
through the
sample toward a
photodetector.
Elemental mercury
absorbs the
incident light in
proportion to its
concentration in
the air stream.
c. Portable A sample of gas is
mercury vapor drawn through a
analyzer--gold detection cell
film amalgamation containing a gold
detector. film detector.
Elemental mercury
amalgamates with
the gold film,
changing the
resistance of the
detector in
proportion to the
mercury
concentration in
the air sample.

[[Page 70944]]

d. Portable short- Ultraviolet light
wave ultraviolet is directed
light, toward a
fluorescent fluorescent
background--visua background
l indication. positioned behind
a suspected
source of mercury
emissions.
Elemental mercury
vapor absorbs the
ultraviolet
light, projecting
a dark shadow
image on the
fluorescent
background.
e. Portable
combustible gas
meter.
3. Level of mercury vapor in the a. Portable See Item 2.b.
cell room and other areas. mercury vapor
analyzer--ultravi
olet light
absorption
detector.
b. Portable See Item 2.c.
mercury vapor
analyzer--gold
film amalgamation
detector.
c. Permanganate A known volume of
impingement. gas sample is
absorbed in
potassium
permanganate
solution.
Elemental mercury
in the solution
is determined
using a cold
vapor adsorption
analyzer, and the
concentration of
mercury in the
gas sample is
calculated.
------------------------------------------------------------------------

Table 7 to Subpart IIIII of Part 63.--Required Elements of Washdown
Plans
[As stated in Sec. 63.8192, your written washdown plan must address
the elements contained in the following table]
------------------------------------------------------------------------
You must establish the
For each of the following areas * * * following as part of your plan
* * *
------------------------------------------------------------------------
1. Center aisles of cell rooms......... A description of the manner of
washdown of the area, and the
washdown frequency for the
area.
2. Electrolyzers
3. End boxes and areas under end boxes
4. Decomposers and areas under
decomposers
5. Caustic baskets and areas around
caustic baskets
6. Hydrogen system piping
7. Basement floor of cell rooms
8. Tanks
9. Pillars and beams in cell rooms
10. Mercury cell repair areas
11. Maintenance shop areas
12. Work tables
13. Mercury thermal recovery units
14. Storage areas for mercury-
containing wastes
------------------------------------------------------------------------

Table 8 to Subpart IIIII of Part 63.--Requirements for Cell Room
Monitoring Program
[As stated in Sec. 63.8192(g)(1), your mercury monitoring system must
meet the requirements contained in the following table]
------------------------------------------------------------------------
If you utilize an * * * Your * * * Must * * *
------------------------------------------------------------------------
1. Extractive cold vapor a. Mercury vapor Be capable of
spectroscopy system. analyzer. continuously
monitoring the
elemental mercury
concentration
with a detection
level at least
two times lower
than the baseline
mercury
concentration in
the cell room.
b. Sampling system Obtain
measurements at
three or more
locations along
the center aisle
of the cell room
at a height
sufficient to
ensure that
sample is
representative of
the entire cell
room. One
sampling location
must be above the
midpoint of the
center aisle, and
the other two an
equidistance
between the
midpoint and the
end of the cells.
2. Open path differential a. Mercury vapor Be capable of
optical absorption spectroscopy analyzer. continuously
system. monitoring the
elemental mercury
concentration
with a detection
level at least
two times lower
than the baseline
mercury
concentration in
the cell room.
b. Path........... Be directed along
the center aisle
at a height
sufficient to
ensure that the
sample is
representative of
the entire cell
room.
------------------------------------------------------------------------

[[Page 70945]]

Table 9 to Subpart IIIII of Part 63.--Required Records for Work Practice
Standards
[As stated in Sec. 63.8256(c), you must keep the records (related to
the work practice standards) specified in the following table]
------------------------------------------------------------------------
You must record the following
For each * * * information * * *
------------------------------------------------------------------------
1. Inspection required by Table 2 to Date and time the inspection
this subpart. was conducted.
2. Situation found during an inspection a. Description of the
required by Table 2 to this subpart: condition.
leaking vent hose; open-top container b. Location of the condition.
where liquid mercury is not covered by c. Date and time you identify
an aqueous liquid; end box cover that the condition.
is not securely in place; end box d. Description of the
stopper that is not securely in place; corrective action taken.
end box where liquid mercury is not e. Date and time you
covered by an aqueous liquid at a successfully complete the
temperature below boiling; seal pot corrective action.
cover that is not securely in place;
open or mercury seal pot stopper that
is not securely in place; crack,
spalling, or other deficiency in a
cell room floor, pillar, or beam that
could cause liquid mercury to become
trapped; or caustic basket that is not
securely in place.
3. Caustic leak during an inspection a. Location of the leak.
required by Table 2 to this subpart. b. Date and time you identify
the leak.
c. Date and time you
successfully stop the leak and
repair the leaking equipment.
4. Liquid mercury spill or accumulation a. Location of the liquid
identified during an inspection mercury spill or accumulation.
required by Table 2 to this subpart or b. Estimate of the weight of
at any other time. liquid mercury.
c. Date and time you detect the
liquid mercury spill or
accumulation.
d. Method you use to clean up
the liquid mercury spill or
accumulation.
e. Date and time when you clean
up the liquid mercury spill or
accumulation.
f. Source of the liquid mercury
spill or accumulation.
g. If the source of the liquid
mercury spill or accumulation
is not identified, the time
when you reinspect the area.
5. Liquid mercury leak or hydrogen leak a. Location of the leak.
identified during an inspection b. Date and time you identify
required by Table 2 to this subpart or the leak.
at any other time. c. If the leak is a liquid
mercury leak, the date and
time that you successfully
contain the dripping liquid
mercury.
d. Date and time you first
attempt to stop the leak.
e. Date and time you
successfully stop the leak and
repair the leaking equipment.
f. If you take a cell off line
or isolate the leaking
equipment, the date and time
you take the cell off line or
isolate the leaking equipment,
and the date and time you put
the cell or isolated equipment
back into service.
6. Occasion for which it is not a. Reason for not being able to
possible to perform the design, perform each procedure
operation and maintenance procedures determined to be not possible.
required by Item 2 of Table 1 to this b. Actions taken to reduce or
subpart. prevent mercury emissions, in
lieu of the requirements in
Table 1 to this subpart.
------------------------------------------------------------------------

Table 10 to Subpart IIIII of Part 63.--Applicability of General Provisions to Subpart IIIII
[As stated in Sec. 63.8262, you must comply with the applicable General Provisions requirements according to
the following table]
----------------------------------------------------------------------------------------------------------------
Applies to Subpart
Citation Subject IIIII Explanation
----------------------------------------------------------------------------------------------------------------
Sec. 63.1.......................... Applicability.......... Yes....................
Sec. 63.2.......................... Definitions............ Yes....................
Sec. 63.3.......................... Units and Abbreviations Yes....................
Sec. 63.4.......................... Prohibited Activities.. Yes....................
Sec. 63.5.......................... Construction/ Yes....................
Reconstruction.
Sec. 63.6(a)-(g), (i), (j)......... Compliance with Yes....................
Standards and
Maintenance
Requirements.
Sec. 63.6(h)....................... Compliance with Opacity No..................... Subpart IIIII does not
and Visible Emission have opacity and
Standards. visible emission
standards.
Sec. 63.7(a)(1), (b)-(h)........... Performance Testing Yes.................... Subpart IIIII specifies
Requirements. additional
requirements related
to site-specific test
plans and the conduct
of performance tests.
Sec. 63.7(a)(2).................... Applicability and No..................... Subpart IIIII requires
Performance Test Dates. the performance test
to be performed on the
compliance date.
Sec. 63.8(a)(1), (a)(3); (b); Monitoring Requirements Yes....................
(c)(1)-(4), (6)-(8); (d); (e); and
(f)(1)-(5).
Sec. 63.8(a)(2).................... Continuous Monitoring No..................... Subpart IIIII requires
System (CMS) a site-specific
Requirements. monitoring plan in
lieu of a promulgated
performance
specification for a
mercury concentration
CMS.

[[Page 70946]]

Sec. 63.8(a)(4).................... Additional Monitoring No..................... Subpart IIIII does not
Requirements for require flares.
Control Devices in
Sec. 63.11.
Sec. 63.8(c)(5).................... COMS Minimum Procedures No..................... Subpart IIIII does not
have opacity and
visible emission
standards.
Sec. 63.8(f)(6).................... Alternative to Relative No..................... Subpart IIIII does not
Accuracy Test. require CEMS.
Sec. 63.8(g)....................... Data Reduction......... No..................... Subpart IIIII specifies
mercury concentration
CMS data reduction
requirements.
Sec. 63.9(a)-(e), (g)-(j).......... Notification Yes....................
Requirements.
Sec. 63.9(f)....................... Notification of VE/ No..................... Subpart IIIII does not
Opacity Test. have opacity and
visible emission
standards.
Sec. 63.10(a); (b)(1); (b)(2)(i)- Recordkeeping/Reporting Yes....................
(xii), (xiv); (b)(3); (c);(d)(1)-
(2), (4)-(5); (e); (f).
Sec. 63.10(b)(2)(xiii)............. CMS Records for RATA No..................... Subpart IIIII does not
Alternative. require CEMS.
Sec. 63.10(d)(3)................... Reporting Opacity or VE No..................... Subpart IIIII does not
Observations. have opacity and
visible emission
standards.
Sec. 63.11......................... Flares................. No..................... Subpart IIIII does not
require flares.
Sec. 63.12......................... Delegation............. Yes....................
Sec. 63.13......................... Addresses.............. Yes....................
Sec. 63.14......................... Incorporation by Yes....................
Reference.
Sec. 63.15......................... Availability of Yes....................
Information.
----------------------------------------------------------------------------------------------------------------

[FR Doc. 03-22926 Filed 12-18;-03; 8:45 am]
BILLING CODE 6560-50-P

Notices For
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National Emission Standards for Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants

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