EPA Finalizes Its Perchlorate Decision

The U.S. Environmental Protection Agency (EPA) issued a press release on June 18, 2020, indicating it has determined that perchlorate does not meet the criteria for regulation as a drinking water contaminant under the Safe Drinking Water Act (SDWA) and thus is withdrawing its 2011 Regulatory Determination and is making a final decision to not issue a national regulation for perchlorate at this time. Specifically, EPA has determined that perchlorate does not occur "with a frequency and at levels of public health concern" within the meaning of the SDWA. In addition, in the judgment of the EPA Administrator, regulation of perchlorate does not present a "meaningful opportunity for health risk reduction for persons served by public water systems."

As described in a previous Holland & Knight alert (see "EPA Proposes Perchlorate Rule After Years of Study," June 10, 2019), EPA specifically reevaluated the 2011 Regulatory Determination over many years, conducting multiple analyses. In its June 2019 proposal, EPA evaluated the occurrence data collected from the Unregulated Contaminant Monitoring Rule (UCMR) and other monitoring, including the data generated by Massachusetts and California, which each had previously adopted their own, much lower MCLs of 2 parts per billion (ppb) and 6 ppb, respectively. This data reevaluation was in response to a request for correction filed by a trade association under the Information Quality Act, challenging the data used in the Regulatory Determination that EPA issued in 2011. Based on this data reevaluation, EPA concluded that only 15 regulated water systems in the U.S. would exceed even the lowest proposed value under consideration of 18 micrograms per liter (ug/L). As a result, pursuant to SDWA Section 1412(b)(4)(C), "the EPA Administrator has determined based upon the available information that the benefits of establishing an NPDWR [National Primary Drinking Water Regulation] for perchlorate do not justify the associated costs." (p. 110 of 171)

This conclusion is consistent with EPA's earlier Preliminary Regulatory Determination on Perchlorate (Oct. 10, 2008) indicating that "a national primary drinking water regulation would not provide a meaningful opportunity to reduce health risk." (73 Fed. Reg. 60262) Thus, EPA concluded in its May 2020 Reductions of Perchlorate in Drinking Water that there is infrequent occurrence of perchlorate at the levels of public health concern and that perchlorate occurrence in the environment has decreased over time, due to several mitigation actions taken by the EPA and others, including Massachusetts, which has virtually eliminated perchlorate from most of its public drinking water supply based upon reported data. Under the Safe Drinking Water Act evaluation and rulemaking process, EPA Administrator Andrew Wheeler is required to determine that regulation of the contaminant presents a meaningful opportunity for health risk reductions served by public water systems before proceeding with regulation, and he is authorized to make this determination in his sole judgment. In this case, EPA concluded that the occurrence data does not support that requirement due, in part, to the reductions that occurred years ago when states imposed the type of regulation that EPA is now declining to institute.

Given that EPA is acting under a Consent Decree, it remains to be seen if this "final decision" is truly the last word.