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National Primary Drinking Water Regulations; Radon-222; Proposed Rule

Federal Register Document

Related Material





[Federal Register: November 2, 1999 (Volume 64, Number 211)]

[Proposed Rules]               

[Page 59245-59294]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr02no99-35]                         

 



[[Page 59245]]



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Part II











Environmental Protection Agency











_______________________________________________________________________







40 CFR Parts 141 and 142







National Primary Drinking Water Regulations; Radon-222; Proposed Rule





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ENVIRONMENTAL PROTECTION AGENCY



40 CFR Parts 141 and 142



[WH-FRL-6462-8]

RIN 2040-AA94



 

National Primary Drinking Water Regulations; Radon-222



AGENCY: Environmental Protection Agency (EPA).



ACTION: Notice of proposed rulemaking.



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SUMMARY: In this action, the Environmental Protection Agency (EPA) is 

proposing a multimedia approach to reducing radon risks in indoor air 

(where the problem is greatest), while protecting public health from 

the highest levels of radon in drinking water. Most radon enters indoor 

air from soil under homes and other buildings. Only approximately 1-2 

percent comes from drinking water. The Agency is proposing a Maximum 

Contaminant Level Goal (MCLG) and National Primary Drinking Water 

Regulations (NPDWR) for radon-222 in public water supplies. Under the 

framework set forth in the 1996 amendments to the SDWA, EPA is also 

proposing an alternative maximum contaminant level (AMCL) and 

requirements for multimedia mitigation (MMM) programs to address radon 

in indoor air. Public water systems (PWS) are defined in the Safe 

Drinking Water Act (SDWA). This proposed rule applies to community 

water systems (CWS), a subset of PWSs. Under the proposed rule, CWSs 

may comply with the AMCL if they are in States that develop an EPA-

approved MMM program or, in the absence of a State program, develop a 

State-approved CWS MMM program. This approach is intended to encourage 

States, Tribes, and CWSs to reduce the health risk of radon in the most 

cost-effective way. The Agency is also proposing a maximum contaminant 

level (MCL) for radon-222, to apply to CWSs in non-MMM States that 

choose not to implement a CWS MMM program. The proposal also includes 

monitoring, reporting, public notification, and consumer confidence 

report requirements for radon-222 in drinking water.



DATES: EPA must receive public comments, in writing, on the proposed 

regulations by January 3, 2000.



ADDRESSES: You may send written comments to the Radon-222, W-99-08 

Comments Clerk, Water Docket (MC-4101); U.S. Environmental Protection 

Agency; 401 M Street, SW., Washington, DC 20460. Comments may be hand-

delivered to the Water Docket, U.S. Environmental Protection Agency; 

401 M Street, SW., East Tower Basement, Washington, DC 20460. Comments 

may be submitted electronically to owdocket@epamail.epa.gov. Electronic 

comments must be submitted as an ASCII, WP6.1, or WP8 file avoiding the 

use of special characters and any form of encryption. Electronic 

comments must be identified by the docket number W-99-08. Comments and 

data will also be accepted on disks in WP6.1, WP8, or ASCII format. 

Electronic comments on this action may be filed online at many Federal 

Depository libraries.

    Please submit a copy of any references cited in your comments. 

Facsimiles (faxes) cannot be accepted. EPA would appreciate one 

original and three copies of your comments and enclosures (including 

any references). Commenters who would like EPA to acknowledge receipt 

of their comments should include a self-addressed, stamped envelope.

    The proposed rule and supporting documents, including public 

comments, are available for review in the Water Docket at the address 

listed previously. The Docket also has several of the key supporting 

documents electronically available as PDF files. For information on how 

to access Docket materials, please call (202) 260-3027 between 9 a.m. 

and 3:30 p.m. Eastern Time, Monday through Friday.



FOR FURTHER INFORMATION CONTACT: For general information on radon in 

drinking water, contact the Safe Drinking Water Hotline, phone (800) 

426-4791. The Safe Drinking Water Hotline is open Monday through 

Friday, excluding Federal holidays, from 9 a.m. to 5:30 p.m. Eastern 

Time. For technical inquiries regarding the proposed regulations, 

contact Sylvia Malm, Office of Ground Water and Drinking Water, U.S. 

Environmental Protection Agency (mailcode 4607), 401 M Street, SW, 

Washington DC, 20460. Phone: (202) 260-0417. E-mail: 

malm.sylvia@epa.gov. For inquiries regarding the proposed multimedia 

mitigation program, contact Anita Schmidt, Office of Radiation and 

Indoor Air, U.S. Environmental Protection Agency, (mailcode 6609J), 401 

M Street, S.W, Washington, DC, 20460. Phone: (202) 564-9452. E-mail: 

schmidt.anita@epa.gov. For general information on radon in indoor air, 

contact the Radon Hotline at 1-800-SOS-RADON (1-800-767-7236).



SUPPLEMENTARY INFORMATION:



Potentially Regulated Entities



    Potentially regulated entities include community water systems 

using ground water or mixed ground and surface water.

    The following table lists potentially regulated entities. This 

table is not intended to be exhaustive, but rather provides a guide for 

readers regarding entities likely to be regulated by this action. This 

table lists the types of entities that EPA is now aware of that could 

potentially be regulated by this action. Other entities not listed in 

the table could also be regulated. To determine whether your 

organization is affected by this action, you should carefully examine 

the proposed applicability criteria in section 40 CFR parts 

141.20(b)(1) and Section IV of the preamble. If you have questions 

regarding the applicability of this action to a particular entity, 

consult Sylvia Malm who is listed in the preceding FOR FURTHER 

INFORMATION CONTACT section.



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                                               Examples of potentially

                 Category                        regulated entities

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Industry..................................  Privately owned/operated

                                             community water supply

                                             systems using ground water

                                             or mixed ground water and

                                             surface water.

State, Tribal, and Local Government.......  State, Tribal, or local

                                             government-owned/operated

                                             water supply systems using

                                             ground water or mixed

                                             ground water and surface

                                             water.

Federal Government........................  Federally owned/operated

                                             community water supply

                                             systems using ground water

                                             or mixed ground water and

                                             surface water.

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



Abbreviations Used in This Proposal



AMCL: Alternative Maximum Contaminant Level

BAT: Best Available Technology

BEIR: Committee on the Biological Effects of Ionizing Radiation. The 

Committee on Health Risks of Exposure on Radon that conducted the 

National Research Council Biological Effects of Ionizing Radiation 

(BEIR) VI Study (NAS 1999a). The committee is formed by the Radiation 

Effect Research/Commission on Life Sciences/National Research Council/

National Academy of Sciences.

CFR: Code of Federal Regulations

CWS: Community Water System

EF: Equilibrium Factor

EPA: U.S. Environmental Protection Agency

FR: Federal Register

GAC: Granular Activated Carbon



[[Page 59247]]



HRRCA: Health Risk Reduction and Cost Analysis

IOC: Inorganic Contaminant

LSC: Liquid Scintillation Counting

MCL: Maximum Contaminant Level

MCLG: Maximum Contaminant Level Goal

MMM: Multimedia Mitigation

NAS: National Academy of Sciences

NAS Radon in Drinking Water Committee: The Committee on Risk Assessment 

of Exposure to Radon of the Drinking Water that conducted the National 

Research Council Risk Assessment of Radon in Drinking Water Study (NAS 

1999b). The committee is formed by the Board of Radiation Effect 

Research of the Commission on Life Sciences of the National Research 

Council, National Academy of Sciences.

NELAC: National Environmental Laboratory Accreditation Conference

NIST: National Institute of Standards and Technology

NIRS: National Inorganics and Radionuclides Survey

NPDWR: National Primary Drinking Water Regulation

NPRM: Notice of Proposed Rulemaking

NTNC: Non-Transient, Non-Community

OGWDW: Office of Ground Water and Drinking Water

OMB: Office of Management and Budget

PBMS: Performance-Based Measurement System

PE: Performance Evaluation

PT: Proficiency Testing

POE: Point-of-Entry

POU: Point-of-Use

PRA: Paperwork Reduction Act

PWS: Public Water System

pCi/L: Picocuries per Liter

RFA: Regulatory Flexibility Act

SAB: Science Advisory Board

SBA: Small Business Administration

SBO: Small Business Ombudsman

SBREFA: Small Business Regulatory Enforcement and Fairness Act

SDWA: Safe Drinking Water Act

SDWIS: Safe Drinking Water Information System

SIRG: State Indoor Radon Grant

SSCT: Small Systems Compliance Technology

SSVT: Small Systems Variance Technology

SMF: Standardized Monitoring Framework

UMRA: Unfunded Mandates Reform Act

URTH: Unreasonable Risks to Health

WL: Working Level

WLM: Working Level Month



Table of Contents



I. Summary: What Does Today's Proposed Rulemaking Mean for My Water 

System?

    A. Why is EPA Proposing to Regulate Radon in Drinking Water?

    B. What is Radon?

    C. What are the Health Concerns from Radon in Air and Water?

    D. Does this Regulation Apply to My Water System?

    E. How Will this Regulation Protect Public Health?

    F. How Will the Multimedia Mitigation (MMM) Program Work?

    G. What are the Proposed Limits for Radon in Drinking Water?

    H. What is the Proposed Best Available Technology (BAT) for 

Treating Radon in Drinking Water?

    I. What Analytical Methods are Recommended?

    J. Where and How Often Must I Test My Water for Radon?

    K. May I Use Point-of-Use (POU) Devices, Point-of-Entry (POE) 

Devices, or Bottled Water to Comply with this Regulation?

    L. May I Get More Time or Use a Cheaper Treatment? Variances and 

Exemptions

    M. What are State Primacy, Record Keeping, and Reporting 

Requirements?

    N. How are Tribes Treated in this Proposal?



Statutory Requirements and Regulatory History



II. What Does the Safe Drinking Water Act Require the EPA to Do When 

Regulating Radon in Drinking Water?

    A. Withdraw the 1991 Proposed Regulation for Radon

    B. Arrange for a National Academy of Sciences Risk Assessment.

    C. Set an MCLG, MCL, and BAT for Radon-222

    D. Set an Alternative MCL (AMCL) and Develop Multimedia 

Mitigation (MMM) Program Plan Criteria

    E. Evaluate Multimedia Mitigation Programs Every Five Years

III. What Actions Has EPA Taken on Radon in Drinking Water Prior to 

This Proposal?

    A. Regulatory Actions Prior to 1991

    B. The 1991 NPRM

    C. 1994 Report to Congress: Multimedia Risk and Cost Assessment 

of Radon

    D. 1997 Withdrawal of the 1991 NPRM for Radon-222

    E. 1998 SBREFA Small Business Advocacy Review Panel for Radon

    F. 1999 HRRCA for Radon in Drinking Water



Requirements



IV. To Which Water Systems Does this Regulation Apply?

V. What is the Proposed Maximum Contaminant Level Goal (MCLG) for 

Radon?

    A. Approach to Setting the MCLG

    B. MCLG for Radon in Drinking Water

VI. What Must a State or Community Water System Have In Its 

Multimedia Mitigation Program Plan?

    A. What are the Criteria?

    B. Why Will MMM Programs Get Risk Reduction Equal or Greater 

Than Compliance with the MCL?

    C. Implementation of an MMM Program in Non-Primacy States

    D. Implementation of the MMM Program in Indian Country

    E. CWS Role in State MMM Programs

    F. Local CWS MMM Programs in Non-MMM States and State Role in 

Approval of CWS MMM Program Plans

    G. CWS Role in Communicating to Customers

    H. How Did EPA Develop These Criteria?

    I. Background on the Existing EPA and State Indoor Radon 

Programs

VII. What are the Requirements for Addressing Radon in Water and 

Radon in Air? MCL, AMCL and MMM

    A. Requirements for Small Systems Serving 10,000 People or Less

    B. Requirements for Large Systems Serving More Than 10,000 

People

    C. State Role in Approval of CWS MMM Program Plans

    D. Background on Selection of MCL and AMCL

    E. Compliance Dates

VIII. What are the Requirements for Testing for and Treating Radon 

in Drinking Water?

    A. Best Available Technologies (BATs), Small Systems Compliance 

Technologies (SSCTs), and Associated Costs

    B. Analytical Methods

    C. Laboratory Approval and Certification

    D. Performance-Based Measurement System (PBMS)

    E. Proposed Monitoring and Compliance Requirements for Radon

IX. State Implementation

    A. Special State Primacy Requirements

    B. State Record Keeping Requirements

    C. State Reporting Requirements

    D. Variances and Exemptions

    E. Withdrawing Approval of a State MMM Program

X. What Do I Need to Tell My Customers? Public Information 

Requirements

    A. Public Notification

    B. Consumer Confidence Report



Risk Assessment and Occurrence



XI. What is EPA's Estimate of the Levels of Radon in Drinking Water?

    A. General Patterns of Radon Occurrence

    B. Past Studies of Radon Levels in Drinking Water

    C. EPA's Most Recent Studies of Radon Levels in Ground Water

    D. Populations Exposed to Radon in Drinking Water

XII. What Are the Risks of Radon in Drinking Water and Air?

    A. Basis for Health Concern

    B. Previous EPA Risk Assessment of Radon in Drinking Water

    C. NAS Risk Assessment of Radon in Drinking Water

    D. Estimated Individual and Population Risks

    E. Assessment by National Academy of Sciences: Multimedia 

Approach to Risk Reduction



Economics and Impacts Analysis



XIII. What is the EPA's Estimate of National Economic Impacts and 

Benefits?

    A. Safe Drinking Water Act (SDWA) Requirements for the HRRCA

    B. Regulatory Impact Analysis and Revised Health Risk Reduction 

and Cost Analysis (HRRCA) for Radon



[[Page 59248]]



    C. Baseline Analysis

    D. Benefits Analysis

    E. Cost Analysis

    F. Economic Impact Analysis

    G. Weighing the Benefits and Costs

    H. Response to Significant Public Comments on the February 1999 

HRRCA

XIV. Administrative Requirements

    A. Executive Order 12866: Regulatory Planning and Review

    B. Regulatory Flexibility Act (RFA)

    C. Unfunded Mandates Reform Act (UMRA)

    D. Paperwork Reduction Act (PRA)

    E. National Technology Transfer and Advancement Act (NTTAA)

    F. Executive Order 12898: Environmental Justice

    G. Executive Order 13045: Protection of Children from 

Environmental Health Risks and Safety Risks

    H. Executive Order on Federalism

    I. Executive Order 13084: Consultation and Coordination with 

Indian Tribal Governments

    J. Request for Comments on Use of Plain Language



Stakeholder Involvement



XV. How has the EPA Provided Information to Stakeholders in 

Development of this NPRM?

    A. Office of Ground Water and Drinking Water Website

    B. Public Meetings

    C. Small Entity Outreach

    D. Environmental Justice Initiatives

    E. AWWA Radon Technical Work Group



Background



XVI. How Does EPA Develop Regulations to Protect Drinking Water?

    A. Setting Maximum Contaminant Level Goal and Maximum 

Contaminant Level

    B. Identifying Best Available Treatment Technology

    C. Identifying Affordable Treatment Technologies for Small 

Systems

    D. Requirements for Monitoring, Quality Control, and Record 

Keeping

    E. Requirements for Water Systems to Notify Customers of Test 

Results if Not in Compliance

    F. Approval of State Drinking Water Programs to Enforce Federal 

Regulations

XVII. Important Technical Terms

XVIII. References



Appendix I to the Preamble: What are the Major Public Comments on the 

1991 NPRM and How has the EPA Addressed Them in this Proposal?



    A. General Issues

    B. Statutory Authority and Requirements

    C. Radon Occurrence

    D. Radon Exposure and Health Effects

    E. Maximum Contaminant Level

    F. Analytical Methods

    G. Treatment Technologies and Cost

    H. Compliance Monitoring



I. Summary: What Does Today's Proposed Rulemaking Mean for My Water 

System?



A. Why Is EPA Proposing To Regulate Radon in Drinking Water?



    The proposed National Primary Drinking Water Regulation (NPDWR) for 

radon in drinking water is based on a multimedia approach designed to 

achieve greater risk reduction by addressing radon risks in indoor air, 

with public water systems providing protection from the highest levels 

of radon in their ground water supplies. The framework for this 

proposal is set out in the Safe Drinking Water Act as amended in 1996 

(SDWA), which provides for a multimedia approach for addressing the 

public health risks from radon in drinking water and radon in indoor 

air from soil. This statutory-based framework reflects the 

characteristics uniquely specific to radon among drinking water 

contaminants: that the relative cost-effectiveness of reducing risk 

from exposure to this contaminant is substantially greater for a non-

drinking water source of exposure--indoor air--than it is from drinking 

water. Accordingly, SDWA directs the Environmental Protection Agency 

(EPA) to promulgate a maximum contaminant level (MCL) for radon in 

drinking water, but also to make available a higher alternative maximum 

contaminant level (AMCL) accompanied by a multimedia mitigation (MMM) 

program to address radon risks in indoor air. Further, in setting the 

MCL, EPA is to take into account the costs and benefits of programs 

that control radon in indoor air (SDWA 1412(b)(13)(E)).



B. What Is Radon?



Radon's Physical Properties

    Throughout this preamble, ``radon'' refers to the specific isotope 

radon-222. Radon is a naturally occurring gas formed from the 

radioactive decay of uranium-238. Low concentrations of uranium and its 

other decay products, specifically radium-226, occur widely in the 

earth's crust, and thus radon is continually being generated, even in 

soils in which there is no man-made radioactive contamination. Radon is 

colorless, odorless, tasteless, chemically inert, and radioactive. A 

portion of the radon released through radioactive decay moves through 

air or water-filled pores in the soil to the soil surface and enters 

the air, while some remains below the surface and dissolves in ground 

water (water that collects and flows under the ground's surface).

    Because radon is a gas, when water that contains radon is exposed 

to the air, the radon will tend to be released into the air. Therefore, 

radon is usually present in only low amounts in rivers and lakes. If 

ground water is supplied to a house, radon in the water will tend to be 

released into the air of the house via various water uses. Thus 

presence of radon in drinking water supplies leads to exposure via both 

oral route (ingesting water containing radon) and inhalation route 

(breathing air containing both radon and radon decay products released 

from water used in the house such as for cooking and washing).

    Radon itself also decays, emitting ionizing radiation in the form 

of alpha particles, and transforms into decay products, or ``progeny'' 

radioisotopes. It has a half-life of about four days and decays into 

short-lived progeny. Unlike radon, the progeny are not gases, and can 

easily attach to and be transported by dust and other particles in air. 

The decay of progeny continues until stable, non-radioactive progeny 

are formed. At each step in the decay process, radiation is released.



C. What Are the Health Concerns From Radon in Air and Water?



    National and international scientific organizations have concluded 

that radon causes lung cancer in humans. The primary risk is lung 

cancer from radon entering indoor air from soil under homes. Tap water 

is a smaller source of radon in air; however, breathing radon released 

to air from household water uses also increases the risk of lung 

cancer, and consumption of drinking water containing radon presents a 

smaller risk of internal organ cancers, primarily stomach cancer.

    In most cases, radon in soil under homes is the biggest source of 

exposure and radon from tap water will be a small source of radon in 

indoor air.

    The U.S. Surgeon General has warned that indoor radon (from soil) 

is the second leading cause of lung cancer (USEPA 1988b). The National 

Academy of Sciences (NAS 1999a) estimates that radon from soil causes 

about 15,000 to 22,000 (using two different approaches) lung cancer 

deaths each year in the U.S. If you smoke and your home has high indoor 

radon levels, your risk of lung cancer is especially high. EPA and the 

U.S. Surgeon General recommend testing all homes below the third floor.

    The NAS report mandated by the 1996 SDWA identifies the same unit 

risk associated with radon in drinking water compared with previous EPA 

analyses. Based on the NAS risk assessment and an updated EPA



[[Page 59249]]



occurrence analysis, the Agency estimates that uncontrolled levels of 

radon in public drinking water supplies cause 168 fatal cancers each 

year in the U.S. However, radon in domestic drinking water generally 

contributes a very small part (about 1-2 percent) of total radon 

exposure from indoor air. The NAS estimated that about 89 percent of 

the fatal cancers caused by radon in drinking water were due to lung 

cancer from inhalation of radon released to indoor air, and about 11 

percent were due to stomach cancer from consuming water containing 

radon (NAS 1999b).



D. Does This Regulation Apply to My Water System?



    The regulation for radon in drinking water and the multimedia 

approach proposed in this action would apply to all community public 

water systems (CWSs) that use ground water or mixed ground and surface 

water. The proposed regulation would not apply to non-transient non-

community (NTNC) public water supplies, nor to transient public water 

supplies.



E. How Will This Regulation Protect Public Health?



    Given the much greater potential for risk reduction in indoor air 

and years of experience with radon mitigation programs, EPA expects 

that greater overall risk reduction will result from this proposal than 

from an approach which solely addresses radon in public drinking water 

supplies. The proposed regulation for radon in drinking water is 

intended to promote a more cost-effective multimedia approach to reduce 

radon risks, particularly for small systems with limited resources, and 

to reduce the highest levels of radon in drinking water. This 

determination to have a strong and effective multimedia radon program 

to address radon in indoor air is consistent with the SDWA framework 

for multimedia radon programs and the SDWA expectation that EPA would 

give significant weight to the risk findings of the NAS report, which 

confirm the health risks of radon in drinking water, and the much 

greater risks from radon in indoor air arising from soil under homes.



F. How Will the Multimedia Mitigation (MMM) Program Work?



    The multimedia mitigation (MMM) program is modeled on the National 

Indoor Radon Program implemented by EPA, States and others. That 

program has achieved substantial risk reduction through voluntary 

public action since the release of the original ``A Citizen's Guide to 

Radon'' in 1986 (USEPA 1986, 1992b) and the U.S. Surgeon General's 

recommendation in 1988 that all homes be tested and elevated levels be 

reduced. The program has been successful in achieving indoor radon risk 

reduction through a variety of program strategies, which form the basis 

for EPA's proposed multimedia mitigation program plan criteria. Based 

on the estimated number of existing homes fixed and the number of new 

homes built radon-resistant since the national program began in 1986, 

EPA estimates that under existing Federal and State indoor radon 

programs, a total of more than 2,500 lives will be saved through indoor 

radon risk reduction efforts expected to take place through the year 

2000. Every year the rate of lives saved increases as more existing 

houses with elevated radon levels are fixed and as more new houses are 

built radon-resistant. For the year 2000, EPA estimates that the rate 

of radon-related lung cancer deaths that will be avoided from 

mitigation of existing homes and from homes built radon-resistant (in 

high radon areas) will be about 350 lives saved per year (USEPA 1999i).

    The MMM/AMCL approach is intended to provide a more cost-effective 

alternative to achieve radon risk reduction, by allowing States (or 

community water systems) to address radon in indoor air from the soil 

source, while reducing the highest levels of radon in drinking water. 

It is EPA's expectation that most States will develop State-wide 

multimedia mitigation programs as the most cost-effective approach. 

Most of the States currently have indoor radon programs that are 

addressing radon risk from soil, and can be used as the foundation for 

development of MMM program plans. EPA expects that State indoor radon 

programs will implement MMM programs under agreements with the State 

drinking water programs. The regulatory expectation of community water 

systems serving 10,000 persons or less is that they meet the 

alternative maximum contaminant level (AMCL) and be associated with an 

approved MMM program plan--either developed by the State and approved 

by EPA or developed by the CWS and approved by the State. Tribal CWS 

MMM programs, as well as those in States and Territories that do not 

have drinking water primacy, will be approved by EPA. The same general 

criteria for State MMM program plans would apply to CWSs in developing 

local MMM programs in States that do not have such a program, albeit 

with a local perspective on such criteria and commensurate with the 

unique attributes of small CWSs. EPA expects that MMM program 

strategies for CWSs will be less comprehensive than those of State MMM 

programs, and will need to reflect the local character of the community 

served by the CWS. Strong public participation in the development of 

the CWS MMM program plans will help to ensure this, as well as 

community support for the MMM program. Figures I.1 and I.2 provide a 

conceptual model for the MCL, AMCL, and MMM programs for small and 

large systems.



BILLING CODE 6560-50-P



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[GRAPHIC] [TIFF OMITTED] TP02NO99.000







[[Page 59251]]



[GRAPHIC] [TIFF OMITTED] TP02NO99.001







BILLING CODE 6560-50-C



[[Page 59252]]



    To meet the requirements of SDWA, the risk reduction benefits 

expected to be achieved by MMM programs are to be equal to or greater 

than risk reduction benefits that would be achieved by CWSs complying 

with the MCL. Under SDWA, this means that if all States implemented MMM 

programs they would be expected to result in about 62 cancer deaths 

averted annually, equal to what would be achieved with universal 

compliance with the MCL at 300 pCi/L. Unlike health risk reduction 

benefits gained through water treatment, which remain constant from one 

year to the next, the rate of health benefits from reducing indoor 

radon is cumulative; that is, it steadily increases every year with 

every additional existing home that is mitigated and with every new 

home built radon-resistant. Therefore, MMM programs will use and build 

on the indoor radon program framework to achieve ``equal or greater'' 

risk reduction, rather than focusing efforts on precisely quantifying 

``equivalency'' to the much more limited risk reduction expected to 

occur if community water systems complied with the MCL.



G. What Are the Proposed Limits for Radon in Drinking Water?



    The proposed regulation provides that States may adopt State-wide 

MMM programs and the alternative maximum contaminant level (AMCL) of 

4000 pCi/L. This is the most effective approach for radon risk 

reduction and the one EPA expects the majority of States to adopt. If a 

State has an EPA-approved MMM program plan, CWSs in that State may 

comply with the AMCL. In the absence of an approved State MMM program 

plan the regulatory expectation for small CWSs (those serving 10,000 or 

fewer) is that they comply with a level of 4000 pCi/L in drinking 

water, and develop and implement a State-approved local MMM program 

plan to reduce indoor radon risks arising from soil and rock under 

homes and buildings. Small CWSs may also choose to comply with the MCL 

of 300 pCi/L (and not develop a local MMM program.)

    The AMCL/MMM approach is EPA's regulatory expectation for small 

CWSs because an MMM program and compliance with the AMCL is a much more 

cost-effective way to reduce radon risk than compliance with the 

maximum contaminant level (MCL) of 300 pCi/L. (While EPA believes that 

the MMM approach is preferable for small systems in a non-MMM State, 

small CWSs may, at their discretion, choose the option of meeting the 

MCL instead of developing a local MMM program). Large CWSs (serving a 

population of more than 10,000) must either comply with the proposed 

MCL or comply with the AMCL and implement a State-approved CWS MMM 

program plan (in the absence of an approved State MMM program plan).

    If a State has an approved MMM program plan, the standard for radon 

in drinking water that the State would adopt in order to obtain primacy 

would be 4000 pCi/L.

    Under the proposed requirements, an MMM program plan must address 

four criteria:



1. Public involvement in development of the MMM program plan

2. Quantitative goals for existing homes fixed and new homes built 

radon-resistant

3. Strategies for achieving goals

4. Plan to track and report results



    CWSs must monitor for radon in drinking water according to the 

requirements described in Section VIII of this preamble, and report 

their results to the State. If the State determines that the radon 

level in a CWS is below 300 pCi/L, the system need only continue to 

meet monitoring requirements and is not covered by the requirements 

described in Section VI of this preamble, regarding MMM programs.



H. What Is the Proposed Best Available Technology (BAT) for Treating 

Radon in Drinking Water?



Proposed BAT for Radon Under Section 1412 of the SDWA

    High-performance aeration, as described in Section VIII.A of this 

preamble, is the BAT for all systems. For systems serving 10,000 

persons or fewer, the BAT is high-performance aeration and the Small 

Systems Compliance Technologies, as described in Section VIII.A.

Proposed BAT for Radon Under Section 1415 of the SDWA

    BAT for purposes of variances is the same as BAT under Section 1412 

of the Act.



I. What Analytical Methods Are Recommended?



    EPA is proposing Liquid Scintillation Counting (Standard Method 

7500-Rn) and de-emanation (``Lucas Cell'') as the approved methods. The 

Liquid Scintillation Counting method designated ``D 5072-92'' by the 

American Society for Testing and Materials (ASTM) is being proposed as 

an alternate method.



J. Where and How Often Must I Test My Water for Radon?



    All CWSs that use ground water must monitor for radon. If your 

system relies on ground water or uses ground water to supplement 

surface water during low-flow periods, you must monitor for radon. If 

you are required to monitor for radon you must collect samples for 

analysis at each entry point to the distribution system, after 

treatment and storage. Initially all CWSs using ground water must 

monitor for radon at each entry point to the distribution system 

quarterly for one year. (See Section VII.E for discussion of compliance 

dates). If the results of analyses show that the average of all first 

year samples at any sample site is above the MCL/AMCL, you must 

continue monitoring quarterly at that sampling site until the average 

of four consecutive quarterly samples is below the MCL/AMCL. If the 

results of analyses show that the average of all first year samples at 

each sample site is below the MCL/AMCL, you may reduce monitoring to 

once a year at State discretion at each sample site. If the results 

indicate that the average of the four quarterly samples are close to 

the MCL/AMCL (as discussed next), the State may require you to continue 

monitoring quarterly.

    The State may allow you to reduce monitoring for radon to a 

frequency of once every three-years, if the average from four 

consecutive quarterly samples is less than \1/2\ the MCL/AMCL and the 

State determines that your system is reliably and consistently below 

the MCL/AMCL. However, if a sample collected while monitoring annually 

or less frequently exceeds the radon MCL/AMCL, the monitoring frequency 

must be increased to quarterly until the average of 4 consecutive 

quarterly samples is less than the MCL/AMCL. The State may require the 

collection of a confirmation sample(s) to verify the result of the 

initial sample. In the case of reduced monitoring, if the analytical 

results from any sampling point are found to exceed \1/2\ the MCL/AMCL, 

the State may require you to collect a confirmation sample at the same 

sampling point. The results of the initial sample and the confirmation 

sample(s) will be averaged and the resulting average will be used to 

determine compliance. States may, at their discretion, disregard 

samples that have obvious sampling errors.

    If, after initial monitoring, the State determines that it is 

highly unlikely that radon levels in your system will be above the MCL/

AMCL, the State may grant a waiver reducing monitoring frequency to 

once every nine years. In granting the waiver, the State must take into 

consideration factors such as the geological area of the source water 

and previous analytical results which demonstrate that radon levels do 

not



[[Page 59253]]



occur above the MCL/AMCL. If you are granted a waiver, it remains in 

effect for a nine year period.

    If you monitor for radon after proposal of this rule, you may use 

the data, at the State's discretion, toward satisfying the initial 

sampling requirements for radon. Your monitoring program and the 

methods used to analyze for radon must satisfy the regulations set out 

in the proposal.



K. May I Use Point-of-Use (POU) Devices, Point-of-Entry (POE) Devices, 

or Bottled Water To Comply With This Regulation?



    POE aeration or granular activated carbon (GAC) would be allowable 

for use to achieve compliance with MCLs. While these POE technologies 

are not considered BAT for large systems, they are considered small 

system compliance technologies (SSCTs), and thus may serve as BAT under 

Sections 1412 and 1415 of the Act for systems serving 10,000 persons or 

fewer. Since POU devices are used to treat water at a single tap, radon 

will be released at unacceptable levels from the other non-treated 

taps, including the shower head. For this reason, POU devices do not 

adequately address radon risks and will not be allowed to be used for 

compliance purposes. Likewise, although bottled water reduces ingestion 

risk from radon, it does not reduce radon-related inhalation risks from 

household water. For this reason, compliance determinations based on 

bottled water consumption cannot be used.



L. May I Get More Time or Use a Cheaper Treatment? Variances and 

Exemptions



Variances and Exemptions (Section 1415.a of the SDWA)

    States and Tribes with primary enforcement responsibility 

(``primacy'') may issue a variance under Section 1415(a)(1)(A) of the 

Act to a CWS that cannot comply with an MCL because of source water 

characteristics on condition that the system install the best available 

technology. Under Section 1416 of the Act, primacy entities may exempt 

a CWS from an NPDWR due to ``compelling factors'', subject to the 

restrictions described in the Act. Primacy entities may require systems 

to implement additional interim control measures such as installation 

of additional centralized treatment or POE devices for each customer as 

measures to reduce the health risk before granting a variance or 

exemption. The primacy entity must find that the variance or exemption 

will not pose an ``unreasonable risk to health'', as determined by the 

State or other primacy entity. Guidance for estimating ``unreasonable 

risk to health'' (URTH) values for contaminants, including radon, is 

being developed by EPA and will result in an upcoming publication (a 

draft of the guidance is expected in the Fall of 1999). Preliminary 

information regarding URTH values may be found elsewhere (Orme-Zavaleta 

1992, USEPA 1998f). States must require CWSs to provide POE devices or 

other means, as appropriate to the risks present (i.e., no POU or 

bottled water for volatile contaminants, such as radon), to reduce 

exposure below unreasonable risk to health values before granting a 

variance or exemption.

``Small Systems Variances'' (Section 1415(e) of the SDWA)

    For NPDWRs proposed after the 1996 Amendments to the Act, EPA is 

required to evaluate the affordability and technical feasibility of 

treatment technologies for use as compliance technologies for small 

systems. Three categories of small systems will be considered: those 

serving: (1) 25-500, (2) 501-3,300, and (3) 3,301-10,000 persons. If 

EPA determines that source water conditions exist for one or more small 

water system size categories such that typical small systems within a 

given category will not be able to afford and/or implement a technology 

capable of achieving compliance, then EPA will designate applicable 

``small systems variance technologies'' (SSVTs) capable of achieving 

contaminant levels that are ``protective of public health''. Primacy 

entities may issue small systems variances to eligible CWSs that 

install and properly maintain a listed SSVT. For a small system to be 

eligible for a small systems variance, the primacy entity must 

determine that the system cannot afford to comply through installing 

treatment, finding an alternate source of water, or restructuring/

consolidating.

    EPA has determined that affordable and technically feasible 

technologies exist for radon removal for all classes of small systems. 

Under the 1996 SDWA, if EPA lists at least one small systems compliance 

technology for a given system size category for all source water 

qualities, then it may not list any small systems variance technologies 

for that size category, i.e., small systems compliance technologies and 

variance technologies are mutually exclusive. For this reason, no small 

system will be eligible for a small systems variance for radon under 

the SDWA (Section 1415(e)). Small systems may be eligible for general 

variances (under Section 1415.a of the Act) and/or exemptions on a case 

by case basis. It is also important to emphasize that the presumptive 

regulatory expectation for small systems is an MMM program (in the 

absence of a State MMM program) and compliance with the AMCL of 4000 

pCi/L. Thus, for the vast majority of small systems (those with radon 

levels below 4000 pCi/L), compliance with this proposed rule will not 

involve any treatment of drinking water.



M. What Are State Primacy, Record Keeping, and Reporting Requirements?



    The proposed Radon Rule requires States to adopt several regulatory 

requirements, including public notification requirements, MCL/AMCL for 

radon, and the requirements of Subpart R in the proposed rule. In 

addition, States and eligible Indian tribes will be required to adopt 

several special primacy requirements for the Radon Rule. The proposed 

rule includes additional reporting requirements for MMM program plans. 

The proposed rule also requires States to keep specific records in 

accordance with existing regulations. These requirements are discussed 

in more detail in Section IX of this preamble.



N. How Are Tribes Treated in This Proposal?



    The proposal provides Tribes the option of seeking ``treatment in 

the same manner as a State'' for the purposes of assuming enforcement 

responsibility for a CWS program, and developing and implementing an 

MMM program (see Section VI.C). If a Tribe chooses not to implement an 

EPA-approved MMM program, any tribal CWS may develop an MMM plan for 

EPA approval, under the same criteria described in Section VI.A.



Statutory Requirements and Regulatory History



II. What Does the Safe Drinking Water Act Require the EPA To Do 

When Regulating Radon in Drinking Water?



    The 1996 Amendments to the Safe Drinking Water Act (PL 104-182) 

establish a new charter for public water systems, States, Tribes, and 

EPA to protect the safety of drinking water supplies. (For an overview 

of the general requirements for all drinking water regulations, see 

Section XVI of this preamble). Among other mandates, Congress amended 

Section 1412 of the SDWA to direct EPA to take the following actions 

regarding radon in drinking water.



[[Page 59254]]



A. Withdraw the 1991 Proposed Regulation for Radon



    Congress specified that EPA should withdraw the drinking water 

standards proposed for radon in 1991 (see discussion in Section III.D).



B. Arrange for a National Academy of Sciences Risk Assessment



    The amendments in Section 1412(b)(13)(B) require EPA to arrange for 

the National Academy of Sciences (NAS) to conduct an independent risk 

assessment for radon in drinking water and an assessment of the health 

risk reduction benefits from various mitigation measures to reduce 

radon in indoor air.



C. Set an MCLG, MCL, and BAT for Radon-222



    Congress specified in Section 1412 (b)(13) that EPA should propose 

a new MCLG and NPDWR for radon-222 by August, 1999. EPA is also 

required to finalize the regulation by August, 2000. As a preliminary 

step, EPA was required to publish a radon health risk reduction and 

cost analysis (HRRCA) for possible radon MCLs for public comment by 

February, 1999. As required by SDWA, this analysis addressed: (1) 

Health risk reduction benefits that come directly from controlling 

radon; (2) health risk reduction benefits likely to come from 

reductions in contaminants that occur with radon; (3) costs; (4) 

incremental costs and benefits associated with each MCL considered; (5) 

effects on the general population and on groups within the general 

population likely to be at greater risk; (6) any increased health risk 

that may occur as the result of compliance; and (7) other relevant 

factors, including the quality and extent of the information, the 

uncertainties in the analysis, and factors with respect to the degree 

and nature of the risk.



D. Set an Alternative MCL (AMCL) and Develop Multimedia Mitigation 

(MMM) Program Plan Criteria



    The amendments in Section 1412(b)(13)(F) introduced two new 

elements into the radon in drinking water rule: (1) An Alternative 

Maximum Contaminant Level (AMCL), and (2) radon multimedia mitigation 

(MMM) programs. If the MCL established for radon in drinking water is 

more stringent than necessary to reduce the contribution to radon in 

indoor air from drinking water to a concentration that is equivalent to 

the national average concentration of radon in outdoor air, EPA is 

required to simultaneously establish an AMCL. The AMCL would be the 

standard that would result in a contribution of radon from drinking 

water to radon levels in indoor air equivalent to the national average 

concentration of radon in outdoor air. If an AMCL is established, EPA 

is to publish criteria for State multimedia mitigation (MMM) programs 

to reduce radon levels in indoor air. Section VI of this preamble 

describes what a State or public water system must have in their 

multimedia mitigation program plan.



E. Evaluate Multimedia Mitigation Programs Every Five Years



    Once the MMM programs are established, EPA must re-evaluate them no 

less than every five years (Section 1412(b)(13)(G)). EPA may withdraw 

approval of programs that are not expected to continue to meet the 

requirement of achieving equal or greater risk reduction.



III. What Actions Has EPA Taken on Radon in Drinking Water Prior to 

This Proposal?



A. Regulatory Actions Prior to 1991



    Section 1412 of the SDWA, as amended in 1986, required the EPA to 

publish Maximum Contaminant Level Goals (MCLGs) and to promulgate 

NPDWRs for contaminants that may cause an adverse effect on human 

health and that are known or anticipated to occur in public water 

supplies. On September 30, 1986, EPA published an advance notice of 

proposed rulemaking (ANPRM) (51 FR 34836) concerning radon-222 and 

other radionuclides. The ANPRM discussed EPA's understanding of the 

occurrence, health effects, and risks from these radionuclides, as well 

as the available analytical methods and treatment technologies, and 

sought additional data and public comment on EPA's planned regulation.

    EPA's Science Advisory Board (SAB) reviewed the ANPRM and the four 

draft criteria documents that supported it prior to publication of the 

ANPRM in the Federal Register. EPA subsequently revised the criteria 

documents and resubmitted them to the SAB for review during the summer 

of 1990. EPA then revised the criteria documents based on this 

additional round of SAB review and presented a summary of the SAB 

comments and the Agency's responses in a 1991 Notice of Proposed 

Rulemaking (NPRM).



B. The 1991 NPRM



    On July 18, 1991 (56 FR 33050), EPA proposed a NPDWR for radon and 

the other radionuclides addressed in the 1986 ANPRM. The 1991 notice, 

which built on and updated the information assembled for the 1986 

ANPRM, proposed an MCLG, an MCL, BAT, and monitoring, reporting, and 

public notification requirements for radon in public water supplies. 

The proposed MCLG was zero, the proposed MCL was 300 pCi/L, and the 

proposed BAT was aeration. Under the proposed rule, all CWSs and 

NTNCWSs relying on ground water would have been required to monitor 

radon levels quarterly at each point of entry to the distribution 

system. Compliance monitoring requirements were based on the arithmetic 

average of four quarterly samples. The 1991 proposed rule required 

systems with one or more points of entry out of compliance to treat 

influent water to reduce radon levels below the MCL or to secure water 

from another source below the MCL.

    The proposed rule was accompanied by an assessment of regulatory 

costs and economic impacts, as well as an assessment of the risk 

reduction associated with implementation of the MCL. EPA estimated the 

following potential impacts from the 1991 proposed MCL:

     An estimated lifetime cancer risk of about two cancers for 

every 10,000 persons exposed to radon in drinking water.

     Avoidance of about 80 cancer cases per year.

     About 27,000 public water systems affected.

     A total annual cost of about $180 million.

    The Agency received substantial comments on the proposal and its 

supporting analyses from States, water utilities, and other stakeholder 

groups. EPA has included in Appendix I of this preamble a summary of 

major public comments on the 1991 NPRM and how EPA subsequently 

addressed those comments.



C. 1994 Report to Congress: Multimedia Risk and Cost Assessment of 

Radon



    In 1992, Congress directed EPA to report on the multimedia risks 

from exposure to radon, the costs to control this exposure, and the 

risks from treating to remove radon. EPA's 1994 Report to Congress 

(USEPA 1994a) estimates the risk, fatal cancer cases, cancer cases 

avoided and costs for mitigating radon in water and in indoor air. The 

Report found that cancer risks from radon in both air and water are 

high. While radon risk in air typically far exceeds that in water, the 

cancer risk from radon in water is higher than the cancer risk 

estimated to result from any other currently regulated drinking water 

contaminant.

    EPA conducted a quantitative uncertainty analysis of the risks 

associated with exposure to radon in



[[Page 59255]]



drinking water. This analysis, reviewed by EPA's SAB at the direction 

of Congress, found that:

     People are exposed to waterborne radon in three ways: (1) 

From ingesting radon dissolved in water; (2) from inhaling radon gas 

released from water during household use; and (3) from inhaling radon 

progeny derived from radon released from water.

     The estimated total U.S. cancer fatalities per year from 

unregulated waterborne radon via all three routes of exposure were 192, 

with a range from about 51 to 620.

     The estimated annual cost was $272 million.

    The 1994 Report to Congress noted that the regulated industry 

estimated considerably higher costs than EPA for a 300 pCi/L MCL. For 

example, in October 1991 the American Water Works Association (AWWA) 

estimated national costs at $2.5 billion/year (for discussion of this 

issue, see Section G of the Appendix to this preamble). The final part 

of the report included the SAB's comments on each analysis presented 

and an EPA discussion of the issues raised by the SAB.



D. 1997 Withdrawal of the 1991 NPRM for Radon-222



    As required by the SDWA as amended, EPA withdrew the MCLG, MCL, and 

monitoring, reporting, and public notification requirements proposed in 

1991 for radon-222 on August 6, 1997 (62 FR 42221). No other provision 

of the 1991 proposal was affected by this withdrawal.



E. 1998 SBREFA Small Business Advocacy Review Panel for Radon



    In 1998, EPA convened a Small Business Advocacy Review Panel to 

address the radon rule, in accordance with the Regulatory Flexibility 

Act (RFA) as amended by the Small Business Regulatory Enforcement 

Fairness Act (SBREFA). The Panel of representatives from EPA, the 

Office of Management and Budget's Office of Information and Regulatory 

Affairs, and the Small Business Administration's Office of Advocacy 

reviewed technical background information related to this rulemaking, 

and reviewed comments provided by small business and government 

entities affected by this rule. The Panel made recommendations in a 

final report to the Administrator which included a discussion of how 

the Agency could accomplish its environmental goals while minimizing 

impacts to small entities. For additional details, see Section XIV.B of 

this proposal.



F. 1999 HRRCA for Radon in Drinking Water



    EPA published the Health Risk Reduction and Cost Analysis required 

by the SDWA on February 26, 1999 (64 FR 9559), and took public comment 

for 45 days. EPA held a one-day public meeting in Washington, D.C. on 

March 16, 1999, to present the HRRCA and the latest MMM framework, and 

discuss stakeholder questions and issues. For details of the contents 

of the HRRCA and EPA's response to significant public comment, see 

Section XIII of this preamble.



Requirements



IV. To Which Water Systems Does This Regulation Apply?



    The SDWA directs EPA to develop national primary drinking water 

regulations (NPDWRs) that apply to public water systems (PWSs). The 

statute defines a PWS as a system that provides water to the public for 

human consumption if such system has at least 15 service connections or 

regularly serves at least 25 individuals (Section 1401(4)(A)). EPA's 

regulations at 40 CFR 141.2 define different types of PWSs. A community 

water system (CWS) serves at least 15 service connections used by year 

round residents or regularly serves at least 25 year-round residents. A 

non-community system does not serve year-round residents; rather, it 

(1) regularly serves at least 25 of the same persons over 6 months of 

the year (a ``non-transient'' system such as a restaurant or church) or 

(2) does not serve at least 25 of the same persons over 6 months of the 

year (a ``transient'' system such as a campground or service station).

    The regulation for radon in drinking water and the multimedia 

approach for reduction of radon in indoor air (MMM program) proposed in 

this notice applies only to CWSs that use ground water or mixed ground 

and surface water (see following discussion regarding ``mixed'' 

supplies). The proposed regulation does not apply to transient water 

systems because most people who use such facilities do so only 

occasionally (e.g., travelers). There is no evidence that such short-

term exposure to radon would cause acute illness. The data on which 

health risks from radon were determined for this rulemaking reflect 

long-term exposure (see chapter 3 of the RIA (USEPA 1999f) HRRCA 

section that discusses calculation of risk). And, as discussed next in 

the context of non-transient non-community systems, even workers at 

transient facilities who regularly drink the water would be expected to 

have much less exposure than persons served by community water systems. 

For these reasons, the proposed rule does not cover transient systems.

    The proposed regulation also does not apply to non-transient non-

community (NTNC) water systems. EPA has determined that the risks posed 

to persons served by NTNC systems (such as factories, hospitals, and 

schools with their own drinking water wells) are substantially less 

than the risks to persons served by community water systems.

    The Agency recently completed a preliminary analysis of radon 

occurrence (using data provided by six States), exposure and risk at 

NTNC public water systems. Results from this preliminary analysis 

indicate that even though radon concentrations are likely to be about 

60 percent higher at NTNC locations than at locations served by a 

community water system, the lifetime average risk to individuals who 

work or attend school in buildings served by a groundwater-based NTNC 

system is probably about 17 percent of the average risk to a worker 

(and 6.7 percent of the average risk to a student) exposed in a home 

served by a community ground water system. The reason that risks are 

lower in the NTNC setting than the residential setting is that people 

who are exposed at NTNC locations spend a smaller fraction of their 

lifetime there than in the home. Further, in the particular case of 

students most do not spend their entire school years in the same 

school. EPA also notes that there is limited data in this area, and 

more information is needed on how water is used in NTNC facilities and 

on the contribution NTNC water use makes to radon inhalation risk. In 

addition, the overall population served by NTNC PWSs is relatively 

small (5.2 million vs. 89.7 million in homes served by CWSs using 

ground water (USEPA 1999b)).

    EPA acknowledges that the SDWA applies to all public water systems. 

However, EPA believes that limiting the applicability of the radon rule 

to community water systems where the risk from radon exposure is the 

greatest meets a major goal of Congress in enacting the 1996 amendments 

to the Act-to focus regulations on the most significant problems. In 

the Conference Report adopting the 1996 amendments, Congress finds that 

``more effective protection of public health requires--a Federal 

commitment to set priorities that will allow scarce Federal, State, and 

local resources to be targeted toward the drinking water problems of 

greatest public health concerns. `` H. Rep. 104-182, Sec. 3. Moreover, 

Congress specifically directed EPA in setting the NPDWRs for radon to 

take into



[[Page 59256]]



consideration the costs and benefits of control programs for radon from 

other sources. EPA has used this authority in this proposal to set the 

MCL at 300 pCi/L and to encourage small systems to implement the MMM 

program and comply with the AMCL. In both circumstances, EPA took into 

account the fact that programs to control radon in indoor air promise 

greater benefits at considerably less cost. EPA believes this cost-

effectiveness factor is also relevant in determining the applicability 

of the radon rule. EPA's preliminary analysis of the risk associated 

with exposure to radon from NTNC systems is that it is much less than 

the risk from exposure from CWSs. For this reason, EPA has determined 

that it is not cost-effective to regulate these systems.

    However, it is important to note that this analysis is based on 

limited occurrence and exposure data. In particular, relatively little 

is known about the transfer factor for release of radon from water into 

indoor air at NTNC locations, or about the equilibrium factor affecting 

the amount of radon in indoor air at such locations. The calculations 

done by EPA to date have assumed that certain values for these 

parameters at NTNC locations are similar to those in homes, although 

the data are limited.

    The EPA is soliciting comment on the proposal to exclude NTNC PWSs 

from the radon regulation. EPA is soliciting comments on the Agency's 

preliminary analysis of radon exposure in NTNC PWSs, as well as any 

additional data on key parameters, including data on the release of 

radon from drinking water in the types of buildings (e.g., restaurants, 

factories, churches, etc.) supplied by NTNC PWSs, and occurrence of 

radon in NTNC PWSs. If information by commenters shows a greater 

opportunity for risk reduction than identified in its initial analysis, 

EPA may make the final radon rule applicable to NTNC PWSs without 

further public comment.

    With regard to systems using mixed ground and surface water, 

current regulations require that all systems that use any amount of 

surface water as a source be categorized as surface water systems. This 

classification applies even if the majority of water in a system is 

from a ground water source. Data currently in SDWIS does not identify 

how many of these mixed systems exist although this information would 

help the Agency to better understand regulatory impacts. To the extent 

that systems correctly classified by SDWIS as surface water systems 

also use ground water that may exceed the MCL/AMCL for radon, the costs 

and benefits of the current proposal will be underestimated.

    EPA is investigating ways to identify how many mixed systems exist 

and how many mix their ground and surface water at the same entry point 

or at separate entry points within the same distribution systems. For 

example, a system may have several plants/entry points that feed the 

same distribution system. One of these entry points may mix and treat 

surface water with ground water prior to its entry into the 

distribution system. Another entry point might use ground water 

exclusively for its source while a different entry point would 

exclusively use surface water. However, all three entry points would 

supply the same system classified in SDWIS as surface water.

    One method EPA could use to address this issue would be to analyze 

Community Water System Survey (CWSS) data then extrapolate this 

information to SDWIS to obtain a national estimate of mixed systems. 

CWSS data, from approximately 1,900 systems, breaks down sources of 

supply at the level of the entry point to the distribution system and 

further subdivides flow by source type. The Agency could use the 

national estimate of mixed systems to regroup surface water systems for 

certain impact analyses when regulations only impact one type of 

source. The Agency requests comment on this methodology and its 

applicability for use in regulatory impact analyses.



V. What Is the Proposed Maximum Contaminant Level Goal for Radon?



A. Approach To Setting the Maximum Contaminant Level Goal (MCLG)



    Under Section 1412(b)(4) of the SDWA, the EPA must establish 

maximum contaminant level goals (MCLG) at the level at which no known 

or anticipated adverse effects on the health of persons occur, and 

which allow an adequate safety margin. Section 1412(b)(13) requires the 

Administrator to set an MCLG for radon in drinking water.



B. MCLG for Radon in Drinking Water



    As described in Section XII of this preamble, radon is a documented 

human carcinogen, classified by EPA as a Group A carcinogen (i.e., 

there is sufficient evidence of a causal relationship between exposure 

to radon and lung cancer in humans). Radon is classified as a known 

human carcinogen based on data from epidemiological studies of 

underground miners. This finding is supported by a consensus of opinion 

among national and international health organizations. The 

carcinogenicity of radon has been well established by the scientific 

community, including the Biological Effects of Ionizing Radiation (BEIR 

VI) Committee of the National Academy of Sciences (NAS 1999a), the 

National Institute of Environmental Health Sciences, U.S. Department of 

Health and Human Services, the World Health Organization's 

International Agency for Research on Cancer (IARC 1988), the 

International Commission on Radiological Protection (ICRP 1987), and 

the National Council on Radiation Protection and Measurement (NCRP 

1984). In addition, the Centers for Disease Control, the American Lung 

Association, the American Medical Association, the American Public 

Health Association and others have recognized radon as a significant 

public health problem.

    Based on the well-established human carcinogenicity of radon, and 

of ionizing radiation in general, the Agency is proposing an MCLG of 

zero for radon in drinking water. This decision is also supported by 

the NAS' current recommendation for a linear non-threshold relationship 

between exposure to radon and cancer in humans. In the BEIR VI report 

(NAS 1999a), the NAS concluded that there is good evidence that a 

single alpha particle (high-linear energy transfer radiation) can cause 

major genomic changes in a cell, including mutation and transformation 

that potentially could lead to cancer. They noted that even if 

substantial repair of the genomic damage were to occur, ``the passage 

of a single alpha particle has the potential to cause irreparable 

damage in cells that are not killed.'' Given the convincing evidence 

that most cancers originate from damage to a single cell, the committee 

went on to conclude that ``On the basis of these [molecular and 

cellular] mechanistic considerations, and in the absence of credible 

evidence to the contrary, the committee adopted a linear non-threshold 

model for the relationship between radon exposure and lung-cancer risk. 

However, the BEIR VI committee recognized that it could not exclude the 

possibility of a threshold relationship between exposure and lung 

cancer risk at very low levels of radon exposure.'' The NAS committee 

on radon in drinking water (NAS 1999b) reiterated the finding of the 

BEIR VI committee's comprehensive review of the issue, that a 

``mechanistic interpretation is consistent with linear non-threshold 

relationship between radon exposure and cancer risk''. The committee 

noted that the ``quantitative



[[Page 59257]]



estimation of cancer risk requires assumptions about the probability of 

an exposed cell becoming transformed and the latent period before 

malignant transformation is complete. When these values are known for 

singly hit cells, the results might lead to reconsideration of the 

linear no-threshold assumption used at present.'' EPA recognizes that 

research in this area is on-going but is basing its regulatory 

decisions on the best currently available science and recommendations 

of the NAS that support use of a linear non-threshold relationship. For 

additional information on this issue see Section XII.C.3. ``Biologic 

Basis of Risk Estimation'' of this preamble.



VI. What Must a State or Community Water System Have in Its 

Multimedia Mitigation Program Plan?



    Today's proposed rule provides States (as defined in Section 1401 

of the SDWA) with alternatives for controlling radon exposure. States 

can develop a MMM program for the reduction of the higher risk of radon 

in indoor air together with an alternative MCL (AMCL) of 4000 pCi/L to 

address the highest levels of exposure from radon in drinking water. If 

a State does not choose this option, the community water systems (CWS) 

in that State must develop and implement local MMM program plans or 

comply with an MCL of 300 pCi/L. See Section VII for information on the 

regulatory expectations for CWSs.



A. What Are the Criteria?



1. Overview

    EPA has identified four criteria that State MMM program plans are 

required to meet to be approved by EPA. MMM program plans developed by 

Indian tribes will be reviewed by EPA, according to these same 

criteria. CWSs developing local MMM programs are also subject to these 

criteria. These four criteria are: public participation, setting 

quantitative goals, strategies for achieving goals, and a plan to track 

and report results.

    The criteria are based on a number of factors. Foremost, the 

criteria reflect the elements found in successful voluntary action 

programs for radon in indoor air that have been underway for more than 

a decade. It is estimated that at the end of the year 2000, voluntary 

programs to test homes and mitigate elevated radon levels in indoor air 

and to encourage the construction of ``radon-resistant'' new homes will 

have saved some 2500 lives; and, there is much more that can be done. 

In the 1999 BEIR VI report (NAS 1999a), NAS concluded that 5,000 to 

7,000 cancer cases (using two different methods) could be avoided 

annually if all homes were below EPA's voluntary radon action level of 

4 pCi/L of air. Incorporating these program elements into the criteria 

required for the MMM programs builds on successful efforts and can be 

expected to result in an even greater number of lives saved as more 

States adopt programs and existing programs are strengthened and 

expanded.

    EPA has developed criteria that allow considerable flexibility for 

those developing and expanding programs. EPA was urged by States and 

other stakeholders to avoid prescribing the specific elements of the 

MMM program in a ``one size fits all'' approach. States and CWSs 

adopting MMM programs will be required to set quantitative goals for 

mitigating elevated levels of radon in indoor air of existing homes and 

building radon-resistant new homes, and to initiate strategies to 

promote and increase these activities. However, there are requirements 

that will be new to many of the State indoor radon programs. Those 

adopting MMM programs will be required to involve the public in a 

number of important (and on-going) ways, and to track and report 

results from the implementation of the programs. With these additional 

elements, both the affected public and EPA will be able to assess the 

success of the MMM programs. Stakeholder input and EPA's experience 

with the national voluntary program and the State indoor radon programs 

led EPA to conclude that these criteria will provide the basis for a 

program that meets the statutory directive for equal or greater risk 

reduction benefits.

    The Agency also considered equity-related issues concerning the 

potential impacts of MMM program implementation. There is no factual 

basis to indicate that minority and low income or other communities are 

more or less exposed to radon in drinking water than the general 

public. However, some stakeholders expressed more general concerns 

about equity in radon risk reduction that could arise from the MMM/AMCL 

framework outlined in SDWA. One concern is the potential for an uneven 

distribution of risk reduction benefits across water systems and 

society. Under the proposed framework for the rule, customers of CWSs 

complying with the AMCL could be exposed to a higher level of radon in 

drinking water than if the MCL were implemented, though this level 

would not be higher than the background concentration of radon in 

ambient air. However, these CWS customers could also save the cost, 

through lower water rates, of installing treatment technology to comply 

with the MCL. Under the proposed regulation, CWSs and their customers 

have the option of complying with either the AMCL (associated with a 

State or local MMM program) or the MCL. EPA believes it is important 

that these issues and choices be considered in an open public process 

as part of the development of MMM program plans. Therefore, EPA has 

incorporated requirements into the proposed rule that provide a 

framework for consideration of equity concerns with the MMM/AMCL. 

First, the proposed rule includes requirements for public participation 

in the development of MMM program plans, as well as for notice and 

opportunity for public comment. EPA believes that the requirement for 

public participation will result in State and CWS program plans that 

reflect and meet their different constituents' needs and concerns and 

that equity issues can be most effectively dealt with at the State and 

local levels with the participation of the public. In developing their 

MMM program plans, States and CWSs are required to document and 

consider all significant issues and concerns raised by the public. EPA 

expects and strongly recommends that States and CWSs pay particular 

attention to addressing any equity concerns that may be raised during 

the public participation process. In addition, EPA believes that 

providing CWS customers with information about the health risks of 

radon and on the AMCL and MMM program option will help to promote 

understanding of the health risks of radon in indoor air, as well as in 

drinking water, and help the public to make informed choices. To this 

end, EPA is requiring CWSs to alert consumers to the MMM approach in 

their State in consumer confidence reports issued between publication 

of the final radon rule and the compliance dates for implementation of 

MMM programs. This will include information about radon in indoor air 

and drinking water and where consumers can get additional information.

    EPA is encouraging the States to elect to develop and implement 

State-wide MMM program plans. Since almost all States currently have 

State indoor radon programs, EPA considers the States to be best 

positioned to develop strong MMM program plans that, when implemented, 

will be expected to achieve equal or greater radon risk reduction when 

compared to compliance with the MCL. For example, a State-wide plan can 

take into account the within-State variations in indoor radon 

potential, the differences in radon



[[Page 59258]]



levels in drinking water, the experienced coalitions and cooperative 

partners that have been working to promote public action on indoor 

radon, the technical expertise of State drinking water and indoor radon 

programs, and many other factors. EPA expects that the States will be 

best positioned to develop MMM program plans that are robust and 

credible in terms of the level of public participation in the 

development and review process, the goals that are to be achieved from 

implementation of MMM, and the program strategies to be used.

    In the development of State MMM program plans meeting EPA's 

criteria and in the implementation of the State's MMM program plan, EPA 

expects and strongly recommends that the State's programs responsible 

for drinking water and for indoor radon coordinate and collaborate on 

their efforts. This is particularly important because of the uniqueness 

of the MMM/AMCL approach which addresses radon risk reduction in 

drinking water and in indoor air in a multimedia manner that is outside 

the normal regulatory structure for drinking water. Both programs have 

important responsibilities and roles in making the AMCL and MMM program 

approach successful in achieving optimal radon risk reduction. To this 

end, EPA has included as a special primacy requirement (see Section 

142.16 of the proposed rule) that States include in their primacy 

revision application for the AMCL a description of the extent and 

nature of coordination between the State's interagency programs (i.e., 

indoor radon and drinking water programs) on development and 

implementation of the MMM program plan, including the level of 

resources that will be made available for implementation and 

coordination between these agencies.

    CWSs developing local MMM program plans are also subject to these 

criteria. CWS MMM program plans developed in the absence of a State 

program are deemed to be approved by EPA if they meet the same criteria 

and are approved by the State. States without a MMM program, as a 

special condition of primacy (see Section 142.16 of the proposed rule), 

will be required to review and approve local CWS MMM program plans and 

to submit their process for approving such plans to EPA. The Agency 

considered an approach under which it would directly review and approve 

CWS MMM program plans. However, for several reasons, EPA is proposing 

that States review local MMM program plans. EPA believes that 

responsibility for such reviews is an appropriate and natural extension 

of the States' primacy responsibilities for oversight and enforcement 

of drinking water regulations. State review and approval of local MMM 

program plans will ensure that all elements of the radon rulemaking--

both the MMM program as well as implementation of the AMCL/MCL--are 

enforced through the State, rather than separating elements of the rule 

between the Federal and State governments. Dividing responsibility in 

such a way may complicate implementation of both elements of the radon 

rule and be confusing to both CWSs and the public. EPA also believes 

that the States are best positioned to assist CWSs, especially small 

systems, in the development of local MMM programs plans to review and 

approve local plans that meet the four criteria. States have a direct 

and ongoing regulatory relationship with CWSs as a part of their 

primacy authorities, as well as a major responsibility for public 

health related policy and programs in the State. In addition, States 

are aware of and sensitive to local public health needs and concerns, 

as well as other issues, that may need to be considered in the 

development and implementation of local MMM programs. For all these 

reasons, EPA is proposing an approach today that would require the 

States to review and approve local MMM program plans in accordance with 

the same criteria used in EPA's review of State MMM program plans. 

However, EPA solicits comments on other approaches, such as EPA review 

and approval of local MMM program plans or other options intermediate 

between sole State or sole Federal responsibility.

    EPA anticipates, and recommends, that States would assist CWSs in 

developing their local MMM program plans and would approve program 

plans that meet the criteria and that reflect local radon 

implementation issues as discussed in Section VI.F. In non-MMM States, 

EPA is also including as a special primacy requirement that States 

include in their primacy revision application for the MCL a description 

of the extent and nature of coordination between interagency programs 

(i.e., indoor radon and drinking water programs) on development and 

implementation of the State's review and approval process for CWS MMM 

program plans, including the level of resources will be made available 

for implementation and coordination between these agencies.

2. Criteria for MMM Program Plans

    The following four criteria are required for approval of State MMM 

program plans by EPA. Local MMM program plans developed by community 

water systems are deemed to be approved by EPA if they meet these 

criteria (as appropriate for the local level) and are approved by the 

State. The term ``State'', as referenced next, includes States, Indian 

tribes and community water systems. EPA is requesting comment on each 

of the criteria for approval of State, and CWS, MMM program plans. In 

particular, EPA is requesting comment on whether the criteria need to 

be more or less stringent, and the supporting rationale for EPA's 

consideration of other potentially credible approaches.

    (a) Description of Process for Involving the Public. (1) States are 

required to involve community water system customers, and other sectors 

of the public with an interest in radon, both in drinking water and in 

indoor air, in developing their MMM program plan. The MMM program plan 

must include:



A description of processes the State used to provide for public 

participation in the development of its MMM program plan, including the 

components identified in the following paragraphs b, c, and d;

A description of the nature and extent of public participation that 

occurred, including a list of groups and organizations that 

participated;

A summary describing the recommendations, issues, and concerns arising 

from the public participation process and how these were considered in 

developing the State's MMM program plan; and,

A description of how the State made information available to the public 

to support informed public participation, including information on the 

State's existing indoor radon program activities and radon risk 

reductions achieved, and on options considered for the MMM program plan 

along with any analyses supporting the development of such options.

    (2) Once the draft program plan has been developed, the State must 

provide notice and opportunity for public comment on the draft plan 

prior to submitting it to EPA.

    (b) Quantitative Goals. (1) States are required to establish and 

include in their plans quantitative goals, to measure the effectiveness 

of their MMM program, for the following:

    (i) Existing houses with elevated indoor radon levels that will be 

mitigated by the public; and,

    (ii) New houses that will be built radon-resistant by home 

builders.

    EPA is proposing to require establishing quantitative goals in 

these



[[Page 59259]]



two areas because they represent the most direct link to the risk 

reduction benefits that are the ultimate objective of the MMM programs. 

In addition, EPA analyses indicate that it is very cost-effective to 

test and mitigate existing homes with elevated indoor radon levels. It 

is also very cost-effective to build new homes radon-resistant, 

especially in higher radon potential areas. In the existing indoor 

radon program, EPA has been encouraging the States to promote testing 

and mitigation in all areas of a State. EPA has also encouraged the 

States to focus on their activities to promote radon-resistant new 

construction on the highest radon potential areas (Zone 1) where 

building homes radon-resistant is most cost-effective. However, it is 

also cost-effective to build homes in medium potential areas (Zone 2), 

as well as in ``hot'' spots found in most lower radon potential areas 

(Zone 3).

    EPA recognizes the States' (and CWSs') need for flexibility in 

designing MMM programs reflecting their needs and circumstances, in 

particular the extent to which opportunities are available for risk 

reduction in mitigation of existing homes with elevated indoor radon 

levels or in construction of new homes built radon-resistant. Some 

States, in particular those with a preponderance of lower radon 

potential areas (and for CWSs in lower radon potential areas), may find 

it preferable to focus more heavily on testing and mitigation of 

existing housing than on radon-resistant new construction.

    EPA is requesting comment on whether there are alternative goals 

that achieve radon risk reduction and the rationale for those goals. 

EPA is also soliciting comments on the goals outlined in paragraph (b), 

in particular on the appropriateness of the goals and whether the goals 

need to be more or less stringent.

    (2) These goals must be defined quantitatively either as absolute 

numbers or as rates. If goals are defined as rates, a detailed 

explanation of the basis for determining the rates must be included.

    EPA is proposing to provide this option, in part, because 

opportunities available for risk reduction in mitigation of existing 

homes with elevated indoor radon levels or in construction of new homes 

built radon-resistant may vary between States and within States. In 

addition, the level of new home construction may vary from year to year 

in different parts of a State or in a local jurisdiction. In this 

situation, it may be more appropriate to set goals for radon-resistant 

new construction as a rate, rather than absolute numbers, to account 

for this variability. This may be especially true for CWS developing 

local MMM program plans where no new home construction is currently 

taking place but may in the future.

    (3) States are required to establish goals for promoting public 

awareness of radon health risks, for testing of existing homes by the 

public, for testing and mitigation of existing schools, and for 

construction of new public schools to be radon-resistant, or to include 

an explanation of why goals were not established in these program 

areas.

    EPA is proposing that States have this option of defining goals as 

absolute numbers or as rates because, while awareness of radon health 

risks is a necessary element and a first step in getting the public to 

take action on indoor radon, public awareness, in and of itself, does 

not constitute radon exposure reduction. It does, however, help to 

facilitate informed choice by the public regarding radon testing and 

mitigation. Since the level of awareness on the health effects of radon 

is already high in many States, EPA is proposing to give flexibility to 

the States on this goal. In the case of radon in schools, many States 

have undertaken a range of activities to address radon in schools and 

some have done extensive testing, in some cases passing State 

legislation requiring the State to test public schools. Therefore, EPA 

is proposing to give States the option of setting these goals for 

schools. Although this approach provides flexibility in goal setting, 

EPA strongly encourages those States which do not have high levels of 

public awareness on radon and where there has been limited testing of 

public schools across the State to set goals in these areas. EPA is 

soliciting comment on whether States should be required to set 

quantitative goals in all or some of these areas in paragraph (b)(3).

    (c) Implementation Plans. (1) States are required to include in 

their MMM program plan implementation plans outlining the strategic 

approaches and specific activities the State will undertake to achieve 

the quantitative goals identified in paragraphs (b)(1) and (b)(2). This 

must include implementation plans in the following two key areas:

    (i) Promoting increased testing and mitigation of existing housing 

by the public through public outreach and education and during 

residential real estate transactions.

    (ii) Promoting increased use of radon-resistant techniques in the 

construction of new homes.

    (2) If a State has included goals for promoting public awareness of 

radon health risks; promoting testing of existing homes by the public; 

promoting testing and mitigation of existing schools; and promoting 

construction of new public schools to be radon resistant, then the 

State is required to submit a description of the strategic approach 

that will be used to achieve the goals.

    (3) States are required to provide the overall rationale and 

support for why their proposed quantitative goals identified in 

paragraphs (b)(1) and (b)(2), in conjunction with their program 

implementation plans, will satisfy the statutory requirement that an 

MMM program be expected to achieve equal or greater risk reduction 

benefits to what would have been expected if all public water systems 

in the State complied with the MCL.

    (d) Plans for Measuring and Reporting Results. (1) States are 

required to include in the MMM plan submitted to EPA a description of 

the approach that will be used to assess the results from 

implementation of the State MMM program, and to assess progress towards 

the quantitative goals in paragraphs (b)(1) and (b)(2). This 

specifically includes a description of the methodologies the State will 

use to determine or track the number of existing homes with elevated 

levels of radon in indoor air that are mitigated and the number or the 

rate of new homes built radon-resistant. This must also include a 

description of the approaches, methods, or processes the State will use 

to make the results of these assessment available to the public.

    (2) If a State includes goals in paragraph (b)(3) for promoting 

public awareness of radon health risks; testing of existing homes by 

the public; testing and mitigation of existing schools; and, 

construction of new public schools to be radon-resistant; the State is 

required to submit a description of how the State will determine or 

track progress in achieving each of these goals. This must also include 

a description of the approaches, methods, or processes the State will 

use to make these results available to the public.



B. Why Will MMM Programs Get Risk Reduction Equal or Greater Than 

Compliance With the MCL?



    The National Indoor Radon Program implemented by EPA, States and 

others, has achieved substantial risk reduction through voluntary 

public action since the release of the original ``A Citizen's Guide to 

Radon'' in 1986 (USEPA 1986) (updated: USEPA 1992b) and the U.S. 

Surgeon General's recommendation in 1988 (US EPA, 1988b) that all homes 

be tested and elevated radon levels be reduced. The program has been



[[Page 59260]]



successful in achieving voluntary risk reduction on indoor radon 

through a variety of program strategies. It is important to keep in 

perspective the comparatively large potential for risk reduction that 

can be achieved if all existing homes with indoor radon levels at or 

above EPA's voluntary action level for indoor radon of 4 pCi/L in the 

U.S. were mitigated (approximately 6 million homes). In addition there 

is the potential for significant risk reduction potential if the 

approximately 1 million new homes built annually in the U.S. were built 

radon-resistant. Based on the estimated number of existing homes fixed 

and the number of new homes built radon-resistant since the national 

program began in 1986, EPA estimates that a total of more than 2,500 

lives will be saved through voluntary indoor radon risk reduction 

efforts expected to take place up through the year 2000. Every year the 

rate of lives saved increases as more existing houses with elevated 

radon levels are fixed and as more new houses are built radon-

resistant. On average this rate of lives that will be saved from these 

risk reduction actions increases by about 30 additional lives per year. 

EPA estimates that for the year 2000, the rate of radon-related lung 

cancer deaths that will be avoided from mitigation of existing homes 

and from homes built radon-resistant in high radon areas will be about 

350 lives saved per year (USEPA 1999i).

    Under the radon provision of SDWA, if all States adopted the AMCL, 

all State MMM programs together must be expected to result in at 

minimum about 62 cancer deaths averted annually; equal to what would be 

achieved with universal compliance with the MCL. Unlike these health 

risk reduction benefits which remain constant from one year to the 

next, the rate of health benefits from reducing radon in indoor air, as 

noted previously, steadily increases every year with every additional 

existing home that is mitigated and with every new home built radon-

resistant. This steady incremental risk reduction offered by mitigation 

of existing homes with elevated indoor radon and building homes radon-

resistant, especially during real estate transactions and through 

builder and consumer education and State and local adoption of radon-

resistant building codes, holds the potential for substantial long-term 

risk reduction. NAS in their 1999 BEIR VI Report, concluded that up to 

one third (i.e., 5,000 to 7,000) of their estimated 15,000 to 22,000 

annual radon-related lung cancer deaths in the U.S. could be avoided if 

all homes were below EPA's voluntary radon action level of 4 pCi/L of 

air (NAS 1999a). This does not include the risk reduction that is 

achieved from new homes built radon-resistant. The one million new 

homes on average being built every year represent a significant radon 

risk reduction opportunity. Therefore, a critical element for MMM is to 

utilize and build on the indoor radon program framework to achieve 

``equal or greater'' risk reduction rather than focusing efforts on 

precisely quantifying the much more limited risk reduction that will 

not occur in community water systems complying with the AMCL (i.e., the 

difference in the risk reduction between the MCL and the AMCL).

C. Implementation of an MMM Program in Non-Primacy States

    A State that does not have primary enforcement responsibility for 

the Public Water System Program under Section 1413 of the SDWA 

(``primacy'') and where EPA administers the CWS program may still 

develop a State-wide MMM program plan. EPA would not expect to develop 

an MMM program plan where the State elects not to develop a State-wide 

MMM program plan. Accordingly, CWSs in such jurisdictions would be 

required to comply with the more stringent MCL or develop local MMM 

program plans for approval by EPA.

    The SDWA authorizes all States to develop and submit a MMM program 

plan to mitigate radon levels in indoor air for approval by the 

Administrator under Section 1412(b)(13)(G). EPA is proposing that 

States that do not have primacy may submit a plan to EPA that meets the 

criteria of 40 CFR 141.302. If the State's plan is approved, the State 

would be subject to all reporting and compliance requirements of 40 CFR 

141.303. Community water systems in States with approved MMM programs 

would comply with the AMCL of 4000 pCi/L, and would be subject to the 

requirements for monitoring and analytical methods in 40 CFR 141.20. 

EPA would continue to administer compliance with the MCL/AMCL, and with 

monitoring and methods requirements.



D. Implementation of the MMM Program in Indian Country



    Under this proposal, States can develop State-wide MMM programs for 

the reduction of radon in indoor air, and community water systems in 

such States can then comply with an AMCL of 4000 pCi/L (rather than an 

MCL of 300 pCi/L). Under Section 1451 of the SDWA, the Administrator of 

EPA is authorized to treat Indian Tribes in the same manner as States. 

The proposal provides tribes the option of seeking ``treatment in the 

same manner as a State'' for the purposes of assuming enforcement 

responsibility for a community water system program, and developing and 

implementing an MMM program. If a tribe does not choose to implement an 

MMM program, any tribal CWS may develop an MMM program plan for EPA 

approval, under the same criteria described previously.

    EPA is proposing to amend the ``treatment as a State'' regulations 

to allow tribes to be treated in the same manner as States for purposes 

of carrying out the MMM program. Under this proposal, a tribe would not 

need to demonstrate that it qualified for treatment in the same manner 

as a State for any other purpose other than the MMM provisions. Tribes 

may want to seek treatment in the same manner as a State for this 

limited purpose to the extent that radon is a significant problem on 

tribal lands because the MMM program provides an opportunity to focus 

resources on reducing the higher risk exposure--indoor air--and 

addressing radon in drinking water at the highest levels of exposure. 

EPA is proposing to amend the treatment in the same manner as State 

regulations (40 CFR 142.72 and 40 CFR 142.78) to obtain treatment as a 

State status solely for the purpose of implementing the MMM 

authorities. Tribes can, of course, always apply to be treated in the 

same manner as a State for primacy over the Public Water Supply Program 

under 40 CFR 142.72.

    A tribe applying for authority to develop and implement an MMM 

program plan that has met the criteria under 40 CFR 142. 72 to be 

treated in the same manner as a State for any purpose will not need to 

reestablish that it meets the first two criteria (40 CFR 142.72 (a) and 

(b)) and needs to provide only information in 40 CFR 142.76 that is 

necessary to demonstrate that the criteria in 40 CFR 142.72 (c) and (d) 

are met for the MMM program plan. A tribe whose application for 

authority to carry out the MMM program is approved must develop and 

implement a MMM program plan in accordance with 40 CFR 141.302 and 

141.303.



E. CWS Role in State MMM Programs



    EPA anticipates that CWSs, especially small systems, would have a 

limited role in State-wide MMM programs. For example, States may 

develop information brochures on radon that could be distributed 

locally by CWSs. EPA expects that States will want to consult with 

CWSs, small and large, in



[[Page 59261]]



making a determination about the nature and scope of the role, if any, 

of CWSs in implementing a State-wide MMM program. During EPA's 

stakeholder process, many States and CWSs agreed that States were best 

positioned to design and implement effective State-wide MMM programs 

and that it was not apparent what role CWSs might take in such a 

program. However, CWSs do have important responsibilities for 

communicating information on radon to their customers (see Section 

VI.G).



F. Local CWS MMM Programs in Non-MMM States and State Role in Approval 

of CWS MMM Program Plans



    The regulatory expectation of small community public water systems 

(CWSs) is that they meet the AMCL and be associated with a MMM program-

either developed by the State and approved by EPA or developed by the 

CWS and approved by the State. EPA strongly recommends that States 

choose to develop and implement State-wide MMM programs as the most 

cost-effective approach to manage the health risks from radon. In those 

cases where States do not elect to do a State-wide MMM program, CWSs 

would need to notify the State of its intention to develop and submit a 

local MMM program plan to the State (4 years after publication of the 

final rule in the Federal Register). EPA believes that, in all cases, 

the regulatory burden of complying with AMCL and implementing a MMM 

program will be considerably less than complying with the more 

stringent regulatory level for radon in drinking water. EPA believes 

that the MMM/AMCL is the appropriate standard for CWSs, especially for 

small systems, because it results in greater radon risk reduction and 

makes better use of limited resources. EPA believes that the four 

criteria for plan approval can be applied to CWS local MMM program 

plans (as appropriate for the local level), commensurate with the 

unique attributes of these CWSs and their service areas. As previously 

discussed in more detail, these four criteria are: public 

participation, setting quantitative goals, strategies for achieving 

goals, and a plan to track and report results.

    In general, EPA expects that CWSs would be able to meet the four 

criteria by carrying out a wide range of diverse activities, many of 

which are well within the expertise of CWSs. However, small CWSs would 

not necessarily be expected to perform some of the activities entirely 

on their own. In carrying out certain activities, small CWSs would be 

expected to seek help from others in order to build upon and take 

advantage of existing CWS and State networks. The existing State indoor 

radon programs, for example, operate in large measure through a network 

of State and local partners such as the American Lung Association, the 

National Association of Counties, the National Environmental Health 

Association, the National Safety Council, consumer advocacy groups, 

non-government organizations, and other local and county governmental 

organizations. CWSs should be able to use the same networks and their 

capabilities, and State radon in indoor air programs should help 

facilitate these contacts. The following provides some additional 

perspective on the four criteria relative to CWS MMM programs.

    Public Participation: Thorough public participation is certainly 

within the capability of CWSs. Systems are often required in the course 

of CWS activities, such as operation, maintenance, water bill 

collection, violation notification, and planning for new facilities, to 

involve, communicate with, inform, and in other ways interact with the 

public. Thus, these systems already engage, to a significant degree, in 

public outreach and communication. EPA expects that such expertise can 

readily be directed toward the particular public participation 

requirements associated with MMM programs. Public participating during 

development of local MMM plans will help ensure greater local support 

for and implementation of the CWS MMM programs.

    Quantitative Goals: EPA notes that the quantitative goals that 

CWSs, especially small CWSs, typically will need to establish may be 

rather modest compared to those that would be expected for State-wide 

programs. The level of risk reduction needed to ensure ``equal or 

greater'' risk reduction be achieved (as if the MCL were being met) 

from a local MMM program plan is a function of and takes into account 

factors such as the size of the population served, level of radon in 

drinking water, and most importantly, the needs and goals of the 

community.

    Strategies for Achieving Goals: EPA recognizes that promoting 

public action in the areas of new homes built radon-resistant and 

mitigation of existing homes with elevated levels of radon in indoor 

air will be entirely new ventures for CWSs. However, EPA believes CWSs, 

including small CWSs, will be capable of conducting various activities 

designed to promote testing and mitigation of existing homes with 

elevated levels of radon in indoor air and building of new homes to be 

radon-resistant. Such activities include public education programs, 

provision of radon test kits, establishing networks with local health 

and government officials to gain their support and involvement in MMM 

implementation, meeting with community leaders, customers, local real 

estate and home building officials and organization, utilizing existing 

information distribution network employed by CWSs, and other types of 

activities to promote public action on indoor radon. EPA expects that 

MMM program strategies for CWSs will be less comprehensive and far 

reaching than those of State MMM programs, and will need to reflect the 

local character of the community served by the CWS.

    Tracking and Reporting of Results: EPA recognizes that assessing or 

tracking progress towards meeting these goals also represents a new 

responsibility for CWSs. However, CWSs may be able to build upon their 

experience and networks for communicating with customers and 

identifying their needs or concerns and find ways to collect 

information about actions taking place in the community. To track homes 

built or modified to be radon resistant, CWSs may be able to obtain 

needed information from various local and State programs and offices 

and other organizations in its network. CWS may also choose to employ 

contractor support or consultant services to obtain this information or 

to help track other MMM related activities. EPA also expects the States 

to provide assistance to CWSs in developing their tracking and 

assessment approach based on State experience in determining the 

results of their State indoor radon programs. EPA recognizes that CWSs' 

options for tracking results may be more limited than those available 

to the States, and that States should consider such limitations in 

their five-year review of local programs.

    CWSs may find it useful to combine efforts with adjacent CWSs for 

purpose of developing and implementing joint MMM programs, thereby 

broadening their combined expertise, local infrastructure and 

institutional bases, and network of partners. EPA also expects that 

privately-owned, as well as publicly owned, CWSs can avail themselves 

of these same kinds of networks, partnership, and consultant services. 

Private systems will generally also be well connected to the municipal 

entities in the jurisdictions in which they operate.

    The report of the Small Business Advocacy Review Panel included a 

discussion of the concept of a ``model MMM program'' for small systems 

which would not be required but could



[[Page 59262]]



provide a workable option for small systems. It might address potential 

concerns of the smallest systems that anticipate they may lack the 

resources and expertise to develop an MMM program. As discussed 

subsequently in Section VI. H., EPA has concerns in general about the 

appropriateness and applicability of a ``one-size-fits-all'' approach 

for MMM programs. A model approach, even for small CWSs, would not 

address the unique, site-specific needs of different CWSs and their 

associated communities. EPA is requesting public comment on the concept 

of a model MMM program for CWSs.

    As noted previously, EPA is strongly recommending that States 

choose to develop and implement State-wide MMM programs as the most 

cost-effective approach to manage the health risks from radon which 

would preclude the need for water systems to develop such programs on 

their own. EPA also believes the States which choose not to do an MMM 

program have an important role, and are the best positioned, to assist 

CWSs in development of local MMM program plans. EPA will also be 

providing guidance to assist CWSs, including small CWSs, in the 

development of local MMM programs. This section has discussed the 

manner in which the four criteria could be applied to CWSs in non-MMM 

States. EPA is requesting comment on approaches to applying these 

criteria to CWSs, especially the smallest CWSs, in view of the 

capabilities of these systems and their ability to get assistance from 

others. EPA is also requesting comment on options that may be available 

to CWSs, particularly, small systems, to develop and implement an MMM 

program plan.

    In summary, EPA recognizes that CWSs do not have the same 

institutional base and infrastructure, legislative authority, 

proportionate resource base, or indoor radon program experience as 

States on which to base development of a local MMM program plan. 

However, EPA believes that the four criteria for approval are equally 

applicable to both States and CWSs, and can be applied to CWSs 

(particularly small CWSs) in a manner that recognizes and accounts for 

these differences. As discussed previously, the manner in which these 

criteria are addressed by CWSs in local MMM program plans, and the 

level and scope of effort, will necessarily differ from that embodied 

in State plans. States should consider these differences in evaluating 

CWS MMM program plans and in their five-year review of CWS MMM program 

implementation. EPA believes that States, in particular, are best 

positioned to assist CWSs, especially small systems, in the development 

of local MMM programs that satisfy the four criteria, and expects them 

to provide such assistance. In evaluating CWS plans, States should 

exercise flexibility in their review and approval process, especially 

for small CWSs, recognizing that they will not have the same 

institutional and resource base or experience and may need to obtain 

assistance from others.

    The Agency expects that most systems in non-MMM States with radon 

levels between 4,000 pCi/L and 300 pCi/L will develop and submit MMM 

program plans. However, the Agency recognizes that some CWSs in non-MMM 

States may elect not to develop a MMM program plan for a variety of 

reasons. In these cases, certain options are available to small CWSs. 

They may consider working with one or more other systems for the 

purposes of developing and implementing an MMM program plan, in order 

to take advantage of greater institutional capabilities. If a system 

does not develop an MMM program plan on its own or together with other 

systems, the system must comply with the MCL of 300 pCi/L through any 

available means (e.g., blending, use of alternate sources, and 

treatment).

    From a risk communication standpoint, EPA wishes to convey to 

customers of small CWSs that its regulatory expectation for these 

systems is that they meet the AMCL and implement an MMM program. 

However, CWSs can choose to meet the MCL rather than take the MMM 

approach. If a CWS opts for the MMM/AMCL approach but is unable to 

develop and successfully implement a State-approved MMM program plan, 

it may be required as part of an enforcement order, to meet the MCL 

rather than comply with the MMM/AMCL. The Agency requests comment on 

this approach for small system MMM programs.

    The SDWA provides that EPA will approve local water system MMM 

program plans and EPA has developed the criteria to be used for 

approving MMM program plans, as discussed in (A). EPA will review and 

approve State MMM program plans. CWS MMM program plans that address the 

criteria and are approved by the State are deemed approved by EPA. The 

proposed rule requires States that do not have a State-wide MMM 

program, as a condition of primacy for the radon regulation, to review 

MMM program plans submitted by CWSs and to approve plans meeting the 

four criteria for MMM program plans discussed in Section VI.A. of this, 

including providing notice and opportunity for public comment on CWS 

MMM program plans. EPA solicits comment on this approach to reviewing 

and approving local MMM plans. Under SDWA, MMM program plans submitted 

by CWSs are to be subject to the same criteria and conditions as State 

MMM program plans. EPA believes that the States are best positioned to 

assist CWSs, especially small systems, in the development and review of 

local MMM program plans that meet the four criteria, and to have public 

health oversight of the progress of the implementation of these local 

radon risk reduction programs. EPA encourages those States not choosing 

to develop a State-wide MMM program plan to exercise flexibility in 

their review and approval of local MMM program plans, especially for 

small CWSs, recognizing that CWSs will not have the same institutional 

base, nor the State's program experience on indoor radon, on which to 

base to local development of a MMM program plan. EPA expects that the 

State drinking water programs and indoor radon programs will work 

collaboratively in assisting CWSs that elect to develop and implement 

local CWS MMM program plans and comply with the AMCL. In non-primacy 

states, EPA will review and approve local CWS MMM program plans and 

oversee compliance with the AMCL if the state chooses not to do a 

state-wide MMM program plan. MMM program plans developed by Indian 

Tribes or tribal community water systems will be reviewed by EPA. The 

specific requirements of a CWS in a State with a State-wide MMM program 

are addressed in Section VI.E. CWSs may choose to meet the MCL.

    For those CWSs (both large and small) in non-MMM States that 

develop local MMM program plans, the State would review the MMM program 

at least once every 5 years and provide progress reports to the EPA in 

keeping with the statutory requirements of the SDWA and this Section. 

(States may also establish interim reporting requirements for the CWS 

under a MMM program to help ensure adequate progress toward the goals 

set forth in the local MMM program plan.) Failure of a CWS to develop 

its MMM program plan by the required regulatory deadline or failure of 

a CWS to implement its approved MMM program plan (5 years and 5\1/2\ 

years, respectively after the final rule is published) would be a 

violation of this regulation unless the CWS is complying with the MCL. 

It is expected that a CWS would be given time to correct any violations 

relating to its MMM program



[[Page 59263]]



through an appropriate enforcement action.



G. CWS Role in Communicating to Customers



    At a minimum, CWSs have important responsibilities for 

communicating information on radon to their customers. Under the 

requirements of the Consumer Confidence Rule (CCR), CWSs will be 

required to provide key information on the health effects of radon 

should the level of radon in drinking water exceed the MCL (or AMCL in 

States with MMM programs). Today's action also updates the standard CCR 

rule requirements and adds special requirements that reflect the 

multimedia approach of this rule. The intent of these provisions is to 

assist in clearer communication of the relative risks of radon in 

indoor air from soil and from drinking water, and to encourage public 

participation in the development of the State or CWS MMM program plans. 

Today's action also proposes to require CWSs to add information to the 

mandatory yearly report which would inform their customers on how to 

get involved in developing their State or local CWS MMM program plan. 

This information would include a brief educational statement on radon 

risks, explaining that the principal radon risk comes from radon in 

indoor air, rather than drinking water, and for that reason, radon risk 

reduction efforts may be focused on indoor air rather than drinking 

water. This information will also note that many States and systems are 

in the process of creating programs to reduce exposure to radon, and 

encourage readers to call for more information. This information would 

be provided every year until the compliance date for implementation of 

State MMM programs (or CWS local MMM programs in States without a 

State-wide MMM program. (See Section X of this preamble for more 

information on CCR and public notice requirements for radon). EPA is 

also planning to develop public information materials on radon in 

drinking water and indoor air as ``tools'' to assist CWSs, as well as 

the States, Indian tribes, and others, with the risk communication 

issues associated with the MCL, AMCL, and MMM.



H. How Did EPA Develop These Criteria?



    EPA obtained extensive stakeholder input in developing the 

regulatory criteria for State MMM program plans. Stakeholders 

participating in this process represented many diverse groups and 

organizations with an interest in radon, both from the perspective of 

radon in drinking water and of radon in indoor air. This included State 

drinking water and State radon program representatives, municipal and 

privately owned public water system suppliers, local government 

officials, environmental groups, and organizations representing State 

health officials, county governments, public interest groups, and 

others.

    As part of the process of getting stakeholder input on development 

of MMM guidelines and criteria, EPA presented several conceptual 

framework options for MMM for discussion and consideration. Three 

preliminary approaches were discussed: (1) To set specific numerical 

targets in mitigations of existing houses and houses built radon-

resistant (as surrogates for lives saved) for each State to meet; (2) 

to set a level of effort that States must demonstrate would be achieved 

under their MMM plan; and (3) to set minimum core indoor radon program 

elements required for all plans.

    Under the first approach, specific targets to achieve ``equal'' 

risk reduction could be set using a variety of approaches and tools and 

based on a number of factors, such as the level of radon in the 

drinking water, the number of people served by that system, and other 

factors. It would also require allocating among the States the total 

number of lives saved nationally by universal compliance with the MCL 

(estimated to be about 62 lives saved yearly). The allocation of lives 

saved by States would likely lead to some State targets being fractions 

of a life saved yearly, depending on the number of systems, radon 

levels, and people served. Many stakeholders thought that significant 

attention would need to be paid to the risk communication challenges of 

communicating this approach to the public. Although some stakeholders 

thought this approach might be workable, others did not consider it 

universally applicable or workable and that it might preclude 

flexibility and innovation.

    The second approach, ``level of effort'', would focus more on a 

plan for implementation of risk reduction strategies using a point 

system where different risk reduction strategies (such as public 

education, radon-resistant new construction code adoption, etc.) would 

be assigned a specific number of points based on potential to achieve 

health risk reduction. The number of State-specific points that a MMM 

program plan would have to meet to be approved would require 

determining the number of systems complying with the AMCL rather than 

the MCL, the radon levels in their drinking water, and