Radon in Drinking Water Proposed Rule: Background and Status

1
Radon in Drinking Water Proposed RuleBackground
and Status

• Presentation for the Workshop on Radon
  Occurrence, Health Risks, and Policy
• October 4, 2006
• Rebecca Allen
• U.S. Environmental Protection Agency
• Office of Ground Water and Drinking Water

2
Background Radon Health Effects

• Radon (Rn-222) is a colorless and odorless
  naturally occurring gas
• Well-known human carcinogen since 1940s World
  Health Organization, National Cancer Institute,
  National Academy of Sciences and other national
  and international organizations
• Well studied and agreed upon science MCLG of
  zero
• Well-known linear non-threshold carcinogen
  extensive epidemiological and biological evidence
  of human lung cancer risks from residential radon
  exposure
• Indoor radon (from soil) is second
• leading cause of lung cancer
• From drinking water NAS (1999)
• estimates 168 fatal cancer cases each year
• From indoor air NAS-BEIR VI (1999)
• estimates 15,000 to 22,000 lung
• cancer deaths each year

3
Regulating Radon in Drinking Water

• Important opportunity for public health
  protection
• NAS Report on Radon in Drinking Water (1999)
• Risks associated with waterborne radon are large
  in comparison with other regulated contaminants
  in drinking water
• radon in drinking water causes 168 fatal cancers
  per year in absence of regulation 89 from lung
  cancer due to inhalation of radon released from
  water, and 11 primarily from stomach cancer due
  to ingestion

4
What is unique about the radon proposed framework?

• Proposed Rule published in Federal Register
  November 1999
• Statutory deadline for final rule August 2000
• Based on SDWA and multimedia radon exposure
• Two regulatory options
• MCL 300 pCi/L, based on SDWA MCL and
  radon-specific language. MCL is within EPAs
  traditional risk range of 10-4 to 10-6
• Alternative MCL 4000 pCi/Lwater, based on NAS
  guidance and SDWA direction
• AND
• Multimedia Mitigation (MMM) program highly
  flexible, least-cost and cost-effective, not
  prescriptive proposed 4 criteria viewed as
  enhancement of existing state radon programs
• Regulation applies to all CWSs using ground water
  and mixed water

WITH
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Proposed Radon Framework for States CWSs

NO
YES
Potential for up to 5,000 to 7,000 Lives
Saved/Year
Maximum 62 Lives Saved/Year
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Multimedia Mitigation Program Requirements

• EPA approvable program plans (State or CWS)
  provide information on
• Public participation that occurred in development
  of MMM plan
• Quantitative goals set by State that achieve risk
  reduction from
• Mitigation of existing homes
• New homes built radon-resistant
• Program strategy in 2 key areas
• Testing/mitigation of existing homes (outreach
  and real estate sales
• Construction of radon-resistant homes
• Measure and report results 2-year reports (used
  for 5-year EPA reviews)
• State/CWS must demonstrate equal or greater
  benefits

7
How did EPA set the proposed MCL for Radon?

• MCLG of zero
• Analyzed relative risk to human health at various
  levels (100 4,000 pCi/L) and associated
  benefits
• Adjusted from 100 pCi/L to 300 pCi/L using
  radon-specific SDWA language
• Proposed MCL is within Agencys risk range of
  10-4 to 10-6
• Administrator determination that benefits
  justify costs
• Another key consideration was spread between
  MCL and AMCL relatively low MCL increase
  incentive for States and/or systems to adopt AMCL
  and MMM option
• An MCL of 4,000 pCi/L obviates need for MMM
  program under SDWA

8
Total National Benefits and Costs at Various
Radon Levels(Proposal Estimates)
Millions, 1997
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Goals for Radon Rule

• For States to choose AMCL/MMM option
• Historically, many States expressed interest in
  MMM programs
• For States to continue and enhance existing State
  indoor air radon programs
• To achieve higher rates of risk reduction
• Considerations underlying MMM program criteria
• Voluntary for States
• Criteria provide each State flexibility to tailor
  specific needs
• Not much risk reduction needed from MCL to
  achieve equal or greater benefits (compared to
  300 MCL)
• Can choose to use non-regulatory and regulatory
  approaches
• Current indoor air programs reducing risk with
  approaches outlined in SDWA
• MMM builds on and enhances existing radon
  programs (infrastructure, networks, new
  opportunities)

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Key Issues and Stakeholder Concerns on the
Proposed Rule

• 775 commenters on proposed rule
• MCL and Rule Structure
• State and utility comments mixed, but generally
  didnt support proposed MCL
• Higher MCLs ranging from 500 to 4,000 pCi/L were
  suggested
• Inclusion of smokers in risk estimates
• State Resource Drain
• Resources needed to implement MMM option
• AMCL/MMM option complex and requires tight
  coordination between air and water programs
  within State
• Tort Liability
• Concern over dual MCL
• Equity
• Appearance of unequal risk reduction to consumers
  from AMCL and MMM

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What are some options that EPA can consider for
the final Radon Rule?

• Maintain option outlined in 1999 proposed rule
• Set MCL between 300 and 4,000 pCi/L with AMCL/MMM
  alternative available
• Set MCL 4,000 pCi/L AMCL with mandatory MMM
  program
• Would require statutory change
• Set MCL 4,000 AMCL with no MMM program
• Approximately 4 Lives Saved per year
• Other alternatives would require Legislative
  changes

12
EPAs Current Activities on Radon in Drinking
Water

• January 2009 current projected date for final
  Radon in Drinking Water Rule
• Interim activities and remaining work
• GAO 2002 analysis of EPAs cost estimates
• GAO recommendations include
• Inclusion of mixed water systems in cost analysis
  
• Update off-gas risk estimates and assess impact
  on cost estimates
• Expand range of assumptions for estimating
  compliance costs with AMCL/MMM option
• Majority of recommendations have been
  incorporated remaining await MCL decision
• Competing Drinking Water priorities Final GWR,
  recently finalized Stage 2 and LT2 rules, CCL 3
  process, Lead and Copper revisions

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Report to CongressRadon in Drinking Water
Regulations

• FY03 Appropriations Language, Congress directed
  EPA to
• Consult with State drinking water, air, and
  radiation programs, and
• Evaluate options to implement a single drinking
  water standard for radon
• EPA interprets single drinking water standard
  as a single MCL for all systems (no MMM)
• EPA consulted with ASDWA and CRCPD in 2003
• Anticipate Final report to be sent to Congress by
  end of 2006

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Any Questions?

• Rebecca Allen
• Office of Ground Water and Drinking Water
• U.S. Environmental Protection Agency
• [phone]
• allen.rebeccak_at_epa.gov