On July 13, 2020 the US Environmental Protection Agency (EPA) posted a pre-publication Federal Register notice indicating that the Agency will not establish a Maximum Contaminant Level (MCL) for perchlorate. The final notice was published in today’s Federal Register (EPA_Fed Reg_Perchlorate Final No MCL_2020-07-21).
In February 2011 EPA made a determination to regulate perchlorate in drinking water. In October 2016, the US District Court for the Southern District of New York entered a consent decree (with EPA and the Natural Resources Defense Council, NRDC) requiring EPA to “sign for publication in the Federal Register” a proposed Maximum Contaminant Level Goal (MCLG) and NPDWR by the end of October 2018. The consent decree requires EPA to publish a final MCLG and MCL by December 19, 2019.
On June 26, 2019 EPA proposed the perchlorate MCLG and MCL at 56 ppb. The 60-day public comment period closed on August 26, 2019. In addition, EPA requested public comment on the following three alternatives:
- MCLG and MCL at 18 ppb.
- MCLG and MCL at 90 ppb
- Withdrawing EPA’s February 2011 determination to regulate perchlorate in drinking water “…based on new information that indicates that perchlorate does not occur in public water systems with a frequency and at levels of public health concern and there may not be a meaningful opportunity for health risk reduction through drinking water regulation.”