West Virginia’s U.S. senators want the Trump administration to publish a high-profile study on toxic chemicals that were used at DuPont’s Washington Works plant south of Parkersburg.

The study from the U.S. Department of Health and Human Services’ Agency for Toxic Substances and Disease Registry examined the chemicals PFOA and PFOS, referred to as per- and polyfluoroalkyl substances (PFAS).

But the Environmental Protection Agency and White House attempted to block the study because it would become a “public relations nightmare,” according to a Politico article published this week.

In response, Sen. Joe Manchin wrote to Mick Mulvaney, director of the Office of Management and Budget, asking that he release the data in the study.

“As you must know, the adverse effects of contamination due to these chemicals continue to plague communities around the country,” he wrote in a letter Wednesday. “And they will continue to do so if not properly addressed.”

Perfluorooctanoate acid (PFOA), known as C8, was used at DuPont since 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.

DuPont and other companies phased out PFAS, but researchers remain worried about the lasting effects of the chemicals. The EPA’s advisory level of PFAS is 70 parts per trillion, but the study might suggest people can be affected by as little as 12 parts per trillion to 516 parts per trillion, according to internal emails published in Politico.

The EPA will host a “National Leadership Summit” in Washington, D.C., next week to talk about efforts to monitor and clean up areas affected by PFAS and find ways to address public concern about the chemicals. After the summit, the EPA said, it will visit states with communities affected by PFAs.

A spokeswoman for the EPA said the agency hasn’t finalized its list of communities to visit, or who would be traveling.

On Wednesday, Sen. Shelley Moore Capito, R-W.Va., told EPA Administrator Scott Pruitt that she appreciated taking the “regulatory boot off American workers” but pressed him on the study.

“What is your response to the question on this report? Will it be published? Will we see it before your stakeholder meeting next week?” she asked during a Senate Interior Appropriations subcommittee hearing on the EPA’s 2019 budget.

“Again, HHS is a participant in that summit next week, and I was not aware that there had been some holding back of the report,” Pruitt responded.