PFAS Playbook

On November 16, EPA asked its Science Advisory Board (SAB) to review draft scientific documents re-evaluating EPA’s 2016 analysis of potential health effects of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). The review could lead to EPA lowering its existing drinking water health advisory levels and inform development of National Primary Drinking Water Regulations for the two compounds.

EPA sent four draft documents with recent scientific data and analyses to its SAB that indicate adverse health effects may occur at lower levels of exposure to PFOA and PFOS than it previously thought. The reports also point to PFOA being a possible carcinogen.

This review follows EPA’s release of an updated risk assessment for GenX last month. In its final human health toxicity assessment for hexafluoropropylene oxide (HFPO) dimer acid and its ammonium salt (referred to as "GenX chemicals"), EPA set a lower reference dose than was proposed in 2018.

Once the SAB reviews EPA’s draft documents through the peer review process, EPA intends that the information will be used to develop drinking water health advisories, Maximum Contaminant Level Goals, and National Primary Drinking Water Regulations.

Effect on Drinking Water Standards

Drinking Water Health Advisories are non-enforceable standards that provide technical information to states, agencies, and other public health officials about potential drinking water contaminants that may cause human health effects. EPA’s current Health Advisory standards for PFOA and PFOS are set at 70 parts per trillion (ppt). This will likely be replaced with a more restrictive standard following SAB review of new scientific data on PFOA and PFOS and will impact states that rely on EPA’s Drinking Water Health Advisories to set standards.

Maximum Contaminant Level Goals (MCLGs) represent the maximum level of a contaminant, with a margin of safety, in drinking water at which no known or anticipated adverse effects will occur in humans. MCLGs are non-enforceable public health goals. If PFOA is a carcinogen as indicated in EPA’s preliminary analysis, the MCLG would be set at zero.

National Primary Drinking Water Regulations are legally enforceable maximum contaminant levels (MCLs) and treatment techniques that apply to public water systems. EPA sets MCLs as close to the health goal as possible, but weighs the technical and financial barriers with public health protection. As part of EPA’s PFAS Roadmap, EPA plans to establish national primary drinking water regulations for PFOA and PFOS. EPA aims to have a proposed rule by fall of 2022 and a final rule setting the standards by fall 2023.

The increased scrutiny of PFAS compounds in drinking water follows EPA’s PFAS Strategic Roadmap which sets forth the agency’s timeline and goals for action on the compounds through 2024.