PARKERSBURG — The chemical that replaced C8 in the Teflon-manufacturing process may be more toxic than its predecessor, according to a recent report from the U.S. Environmental Protection Agency.

The EPA’s Human Health Toxicity Assessment for GenX Chemicals includes a reference dose for the chemicals, which have been found in some local water systems. A reference dose is an estimate of how much a person can ingest daily over a lifetime or less and be unlikely to experience adverse health effects.

The reference dose for chronic (lifetime) exposure is 0.000003 micrograms per kilogram per day, which is more than 25 times lower than the draft level issued in 2018.

“The decrease in the chronic RfD occurred because EPA took into account new studies and analyses published after the completion of the 2018 draft assessment,” the fact sheet for the 2021 assessment says.

Officials with Chemours, which owns the Washington Works plant where the chemical is used, are reviewing the assessment and accompanying information, said Robin Ollis Stemple, regional communications manager for the company.

“We are unaware of data that would support the conclusions drawn by the agency,” she said via email. “We’re reviewing the information for additional insight into the new review process used by the agency and the new data the agency utilized for the change from its 2018 draft assessment, including the application of revised uncertainty factors to reflect greater uncertainty even though the agency indicates there is additional data since the draft assessment.”

GenX is part of the same family of perfluorinated compounds as C8, whose presence in area water systems has been a source of concern and litigation for years. Due to the fact that they break down slowly and accumulate in people, animals and the environment, per- and polyfluoroalkyl substances are referred to as “forever chemicals.”

Chemours was spun off from DuPont, which settled a class-action lawsuit over C8 that resulted in the company installing activated carbon filtration systems at multiple water systems and establishing a science panel that found possible links between C8 and half a dozen diseases in humans.

C8 was replaced in the manufacturing process by GenX chemicals, specifically hexafluoropropylene oxide dimer and its ammonium salt, in 2012. GenX chemicals have been found in surface water, groundwater, drinking water, rainwater and air emissions, according to the EPA.

The recommended dose for GenX chemicals is lower than that issued for C8, also called perfluorooctanoic acid or PFOA, and other PFAS chemicals in 2016 and 2021.

“It would suggest that it’s (GenX) more toxic, or similarly toxic at the very least,” said David Andrews, senior scientist for the Environmental Working Group, a nonprofit advocacy group that has been studying PFAS for more than 20 years. “This was the replacement chemical that was billed as a safer alternative, and a decade later, we’re finding out … that it’s absolutely no safer.”

The recommended dose is one factor in determining a health advisory level for the chemical. Depending on how it’s calculated, Andrews said it could be 3 or 4 parts per trillion. That’s much lower than the provisional health goal of 140 parts per trillion set by the state of North Carolina in 2017.

The fact sheet says EPA plans to develop drinking water health advisories for PFAS chemicals by the spring and propose a PFAS drinking water regulation in the fall of 2022.

Although not required to, some area water systems already monitor for GenX.

Among these is the Little Hocking Water Association, which saw a 500 percent increase in GenX concentration in its untreated water from 2018 to 2019. The numbers have continued an upward trend as the water is tested every two weeks, said David Altman, environmental attorney for the water association. But the activated carbon filtration system installed as part of the lawsuit settlement appears to be keeping the substance out of the treated drinking water.

“There’s no evidence that it’s there at all,” Altman said.

The Parkersburg Utility Board tests for C8 and other PFAS chemicals once a year, Manager Eric Bennett said. Results from the 2021 tests were received Thursday, showing treated water below the health advisory level of 70 parts per trillion for C8, as well as four of the five wells, he said.

Well 1 had the highest concentration of PFAS chemicals of all types, at 83 parts per trillion, Bennett said. Wells 2 and 3 showed 32 and 18 ppt, respectively.

Wells 4 and 5 were 0.9 and 2.6 ppt after showing non-detectable results last year. Bennett that is likely due to improvements in testing so that lower levels can be measured, rather than an increase in the chemicals’ presence.

After treatment, the levels are 55 ppt when well 1 is in service and 12 ppt when it is not.

“We’ve reduced its operation,” Bennett said. “Even when we’re using it, it’s a reduced level.”

Specific tests for GenX over the last four years have come back as non-detectable, Bennett said.

“I’m pretty confident they hopefully will remain at that level, or decrease,” he said, adding the latter doesn’t appear likely and referencing the “forever chemicals” label.

Evan Bevins can be reached at ebevins@newsandsentinel.com.