Yesterday, EPA proposed to regulate certain PFAS under the Safe Drinking Water Act. EPA proposed Maximum Contaminant Level Goals for PFOA and PFOS of zero. It proposed Maximum Contaminant Levels for PFOA and PFOS of 4.0 parts per trillion.
EPA also proposed MCLGs and MCLs for PFNA, PFHxS, PFBS, and HFPO-DA (“GenX Chemicals”) based on a novel hazard index approach to these compounds as a group. Determining a violation will require use of a calculator that EPA will provide that will calculate the HI for each of of these PFAS compounds. The HI for each compound will be summed and the HI of all of them as a group will comply with the SDWA if the total HI does not exceed 1.0.
I’m not going to get into arguments concerning whether these limits are too stringent or not stringent enough. I will note, though, that anyone breathing a sigh of relief that EPA did not propose MCLs for PFOA and PFOS closer to the recently revised Health Advisories, which were in the low parts per quadrillion range, should read EPA’s explanation for the selection of the MCLs. EPA first notes that the SDWA calls for MCLs to be set as close to MCLGs as possible. EPA then states that:
Considering feasibility, including currently available analytical methods to measure and treat these chemicals in drinking water, EPA is proposing individual MCLs of 4.0 nanograms per liter (ng/L) or parts per trillion (ppt) for PFOA and PFOS. (Emphasis added.)
The proposal also notes that, in prior rules, establishment of limits at or near the practical quantitation limit drove laboratories to improve their technology. What happens when the PQL for PFOA and PFOS drops to 400 ppq or 40 ppq or 4 ppq? Will EPA revise the MCLs in order to approach the MCLG of zero?
I’ll also note that this proposal is limited to the SDWA. However, as practitioners know, MCLs are used at CERCLA sites to determine applicable or relevant and appropriate requirements. Once PFOA and PFOS are formally listed as hazardous substances and once this SDWA rule is finalized, CERCLA sites across the country are going to face pressure to attain 4.0 ppt in groundwater for PFOA and PFOS.
And given the ubiquity of PFAS generally and EPA’s proclivity towards reaching for the nearest deep pocket in cleanup situations, it’s not going to be long before EPA is asking PRPs at CERCLA sites to embark on expensive cleanups for PFAS contamination even in cases where there’s pretty solid evidence that the PFAS are not site-related.
Maybe that fine mess will be the straw that breaks the back of Congress’s inability or unwillingness to reform the worst-written statute in US legislative history – CERCLA. Don’t hold your breath.
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