Prompted by the Husky refinery explosion in Superior, Wis., federal chemical safety investigators are advocating a review of the oil refining industry's use of hydrogen fluoride, a highly toxic chemical.
The fiery accident a year ago this week led to an evacuation of large parts of Superior, as public-safety officials feared a release of hydrogen fluoride. In the end, storage tanks full of the chemical were never breached.
The U.S. Chemical Safety Board this week said it "strongly encourages" the federal Environmental Protection Agency (EPA) to review whether refineries' risk-management plans are sufficient to prevent "catastrophic releases" of hydrogen fluoride.
The letter also asks the EPA to determine if there are "commercially viable" alternatives to using hydrofluoric acid in the oil refining process. The Chemical Safety Board essentially wants the EPA to review and update the agency's 1993 study on the hazards of hydrogen fluoride, which was done at the behest of Congress.
Accidents involving hydrogen fluoride are rare. But the chemical can cause severe burns and, in a worst-case scenario, create a deadly gas cloud.
Hydrofluoric acid, which is hydrogen fluoride dissolved in water, is used as a catalyst to boost octane in gasoline at about half of the nation's refineries. The other half use sulfuric acid for the same purpose — which poses its own hazards but doesn't vaporize as fast hydrofluoric acid.
Marathon Petroleum's refinery in St. Paul Park uses hydrofluoric acid; Flint Hills Resources' oil refinery in Rosemount uses sulfuric acid.
The Chemical Safety Board's request to the EPA came after its investigations of the conflagration at Husky Energy's refinery and a 2015 explosion at the former Exxon Mobil refinery in Torrance, Calif.
