(Reuters) – Philadelphia Energy Solutions was expected to report to government officials on Friday that the toxic chemical hydrofluoric acid may have been released from its refinery in June, when a series of blasts and fire damaged the plant, two sources familiar with the plan said.

It was unclear how much of the chemical might have been released from the refinery or if the PES report would be made public, the sources said. PES officials were not immediately available for comment.

PES filed for bankruptcy on July 21 and is winding down the 335,000 barrel-per-day refinery with no scheduled restart after the fire. City, state and federal agencies are investigating the June 21 fire.

Hydrofluoric acid, or HF, is a highly toxic chemical used to make high-octane gasoline and is used in more than one-third of U.S. refineries. Exposure can cause severe health problems, including death. PES used a modified version of the acid, which is intended to help contain an airborne release.

In the days immediately after the June 21 fire, PES said it did not detect elevated levels of HF in the area of the fire or in the nearby neighborhood, the U.S. Environmental Protection Agency said in a statement last month.

HF has been used in refinery operations for about seven decades, and labor unions and environmentalists have warned about its presence in densely populated areas.

There have been a number of fires in or around hydrofluoric acid alkylation units in recent years, including refineries in California, Texas and Wisconsin, according to safety officials.

The United Steelworkers union (USW), whose members work at major refineries, launched a campaign in 2010 to end the oil industry’s use of HF. In 2013, the USW found 26 million people in the United States were at risk of HF exposure from a refinery accident.

(Reporting by Laila Kearney; Editing by Cynthia Osterman)

*Original article online at https://in.reuters.com/article/us-pes-bankruptcy-exclusive-acid-idINKCN1US2DU