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07/16/12 Conference Call - Report to Congress: Radon in Drinking Water Regulations

On July 16, 2012, EPA's offices of Radiation and Indoor Air (http://www.epa.gov/iaq/) and Groundwater and Drinking Water (http://water.epa.gov/drink/) co-hosted a conference call regarding the recently released Report to Congress: Radon in Drinking Water Regulations. Approximately 50 people participated in the call. The audience was almost evenly split between state drinking water and state radon program managers. A few individuals from the private sector also called in.

Lisa Christ, Assistant Chief of the Targeting and Analysis Branch of OGDW provided a brief history of the proposed regulation. She said that in developing this Report to Congress, EPA explored various options for a single radon in drinking water standard. The existing statutory requirements of the 1996 amendments to the Safe Drinking Water Act, directed EPA to propose an MCL and, if that MCL is less than the national average concentration of radon in outdoor air, also propose an AMCL equivalent to this concentration combined with a program to mitigate radon in indoor air.

To address these requirements, EPA proposed: (1) an MCL of 300 pCi/L in water and (2) an AMCL of 4,000 pCi/L in water, which represents the average natural background levels of radon in outdoor air, combined with requirements for an MMM program to address radon in indoor air.

Most of the one hour call was spent discussing the three options for a single drinking water standard: A) an MCL equal to 4,000 pCi/L, B) an MCL equal to 1,000 pCi/L, and C) an MCL equal to 300 pCi/L. Christ explained that consistent with Congressional directive to evaluate options for a single standard, none of these options included a provision for an AMCL combined with requirements for MMM programs. She stated that only Option A, an MCL of 4,000 pCi/L, could be adopted under the current statute because this MCL is not less than atmospheric background and thus would not trigger the statutory requirements for an AMCL. Options B and C would require a change to the current provisions of SDWA. Christ referred the audience to Table 1 on page 9 of the Report for a succinct estimate of risks, annual national costs and associated benefits.

To view the report, please click here.