“The Trump administration has blocked a Centers for Disease Control study that is poised to recommend a safety level for PFAS exposure in drinking water that’s six times lower than the current benchmark guiding federal and state contamination response efforts in Michigan, according to emails reported by Politico.

According to one email, the Agency for Toxic Substances and Disease Registry (ATSDR) has yet to release new draft toxicological profiles for several per- and polyfluoroalkyl substances, or PFAS, after White House aides deemed the new levels a ‘public relations nightmare’ in January.

The Environmental Protection Agency’s current health advisory level for PFOS and PFOA — two PFAS compounds that ATSDR is studying — is 70 parts-per-trillion (ppt). It was set in 2016.

The ATSDR, the toxicological arm of the CDC, thinks the ‘minimal risk level’ should be dropped to less than 12-ppt for some PFAS chemicals, based on its finding that exposure above that level ‘could be dangerous for sensitive populations like infants and breastfeeding mothers.’

The ATSDR defines minimal risk levels as estimates of ‘the daily human exposure to a hazardous substance that is likely to be without appreciable risk of adverse non-cancer health effects over a specified duration of exposure.’

According to the emails, the agency’s report include toxicological profiles of PFNA and PFHxS in addition to PFOS and PFOA. The ATSDR says that PFHxS — a chemical closely associated with PFAS-laden firefighting foam — has the longest half-life in the human body of any PFAS compound…

According to the Environmental Working Group, the proposed ATSDR levels are is based on weakened immune systems among exposed populations. The levels are not legally binding standards, but rather screening levels intended to help toxicologists understand the risk at hazardous waste sites.

But even non-enforceable levels can have major real world impact.

The U.S. Defense Department will not supply long-term safe water to homes near current and former military bases contaminated by PFAS unless the well tests above 70-ppt…

The state of Michigan has convened a PFAS science panel to explore whether the state should adopt a PFAS drinking water standard below 70-ppt.”

Read the full article by Garret Ellison