Read the full article by Pat Rizzuto (Bloomberg Law)

“Thyroid function and children’s developing immune systems may be impaired following exposure to a particular PFAS, the EPA said in a draft analysis it released on Monday for public comment and scientific critique.

When finalized, the Environmental Protection Agency’s Toxicological Review of perfluorohexanesulfonic acid (PFHxS) and related salts will be used by the agency and states to inform regulatory and other decisions about when the amounts of the chemical in soil, water, or other parts of the environment need to be reduced.

‘The available evidence indicates that PFHxS exposure is likely to cause thyroid and developmental immune effects in humans, given sufficient exposure conditions,’ the EPA’s analysis said.

Ingestion of less than 0.0000000004 PFHxS milligrams per kilogram of body weight per day (mg/kg-day) should be low enough to avoid thyroid problems or reduced responses to antitetanus and antidiphtheria shots for children, according to the EPA’s analysis. The document contains a variety of these ingestion levels, called ‘reference doses,’ that risk assessors can use as they decide whether particular exposure scenarios might be harmful.

Studies suggest the PFHxS chemicals may harm heart function, fetal development, and babies’ developing neurological systems, but that information isn’t strong enough to estimate potentially harmful doses, the EPA said.

There’s inadequate evidence to determine whether PFHxS can contribute to cancer, reproductive problems, or other harms, the agency said.

Breast Milk, Umbilical Cords

PFHxS is among the per- and polyfluoroalkyl substances (PFAS) that has been found in people’s bodies including breast milk, the EPA said.

A team of academic and California EPA scientists reported finding PFHxS in umbilical cord blood suggesting another way babies can be exposed, according to their study published in the Environmental Health Perspectives (EHP) journal earlier this month.

The chemical also is commonly detected in water and soil by states including California, Maryland, and Massachusetts, which have set advisory or regulatory levels for it.

The EPA’s proposed reference dose for PFHxS is the lowest the agency has suggested for any of the PFAS it’s examined, said the American Chemistry Council.

But, the analysis ‘appears to rely on the same flawed Faroe Islands study’ that the agency has used in other PFAS evaluation, the trade association said in a statement.

A review of that study published in April by an international team of scientists and industry consultants agreed that the Faroe Islands cohort data ‘should not be used as the primary basis for deriving PFAS risk assessment values.’

Yet PFHxS was among the chemicals a team of California EPA and academic scientists consistently found in mothers who had pregnancy complications, according to the EHP study.

‘The draft assessment for PHFxS is a stark reminder of just how toxic this chemical family is to human health at very low levels,’ said Olga Naidenko, vice president for science investigations at the Environmental Working Group. ‘This is further evidence that we must move much faster to dramatically reduce exposures to PFAS and phase-out all nonessential uses.’

The substance has been found in people’s bodies including breast milk, the EPA said. And the chemical is found in umbilical cord blood suggesting another way babies can be exposed, according to a study published earlier this month by academic and California EPA scientists.

PFHxS is among six PFAS that the EPA has proposed to limit through a drinking water rule.

Water utilities are required to monitor for PFHxS starting this year and through 2025 to comply with the fifth Unregulated Contaminant Monitoring Rule (UCMR 5) that the EPA finalized in 2021.” …