A federal study shows toxic chemicals used at DuPont’s Washington Works plant south of Parkersburg are dangerous at a lower level of exposure than the U.S. Environmental Protection Agency had previously warned.

The study on PFOA and PFOs, referred to as per- and polyfluoroalkyl substances (PFAS) was previously blocked because the Trump administration worried the study would result in a “public relations nightmare,” Politico reported in May.

The U.S. Department of Health and Human Services’ Agency for Toxic Substances and Disease Registry’s study was finally released Wednesday and shows the chemicals are dangerous at about 10 times lower than the EPA’s 70-parts-per-trillion advisory levels.

Perfluorooctanoate acid (PFOA), known as C8, was used at DuPont’s Washington Works plant beginning in the 1950s to make Teflon and other nonstick products, oil-resistant paper packaging and stain-resistant textiles.

The chemicals have been linked to cancer, immune effects and adverse developmental effects on fetuses during pregnancy, and DuPont has faced thousands of lawsuits from residents who lived in the area.

Other states have opted to lower their levels, but Ohio and West Virginia never adopted state drinking water guidelines, said Robert Bilott, a lawyer for residents living in Ohio and West Virginia communities affected by C8.

“It suggests those numbers ought to be coming down,” Bilott said. The ATSDR’s study looks into the effects of a handful of PFAS, but Bilott said the next step should involve looking at many more chemicals in the PFA family.

The ATSDR’s study mentions different research into the effect of C8 in the DuPont Washington Works Facility, including the C8 Health Project, funded by DuPont as part of a class action settlement agreement. The study looked into the serum perfluoroalkyl levels of 69,000 Ohio and West Virginia residents who lived near the DuPont facility. One study found the average level of C8 was 1,000 nanograms per milliliter in workers between 2004 and 2005, compared with 432 nanograms per milliliter in community members who lived near the facility. The country’s mean geometric mean serum level, meanwhile, was about 3.92 nanograms per milliliter in 2005 to 2006.

Before it was released, Sens. Shelley Moore Capito, R-W.Va., and Joe Manchin, D-W.Va., urged the EPA to come forward with the study.

In a statement Wednesday, Manchin said the study paved the way for “additional steps to address these issues in West Virginia and continue to pursue a definitive rule that sets maximum limits on these chemicals.”

A spokeswoman for Manchin said they were waiting for the 30-day public comment window to close before considering legislative decisions “but it’s not out of the question.”

Capito, too, issued a statement that said the report was “critical to ensuring the health of West Virginians.”

The EPA held a “National Leadership Summit” in Washington, D.C., in May to talk about strategies to clean up areas affected by PFAS and promised to visit states with communities affected by PFAS.

On Thursday, the only community session listed on the EPA’s website was one for Exeter, New Hampshire. A spokeswoman for the EPA said the agency is finalizing plans and will post more information soon.