A South Coast Air Quality Management District committee on April 28 ordered agency staff to develop rules or reach an agreement to reduce the risk of accidental releases of a toxic chemical at two local refineries.

The chemical, modified hydrofluoric acid (MHF), is used at Torrance Refining Co., owned by PBF Energy, and at Valero Energy Corp.’s Wilmington Refinery, as a chemical catalyst to produce high-octane gasoline.

In 2015, an explosion at the Torrance refinery, then owned by ExxonMobil Corp., occurred near a container of MHF; had that container ruptured, the highly toxic chemical gas could have drifted over nearby communities containing tens of thousands of residents. As a condition of approving the refinery to reopen last year, the air quality agency said it would look at banning the chemical entirely.

But oil refiners and the business community opposed a ban, saying it would force the refineries to close, cost thousands of jobs and cause gasoline prices to rise in the region.

After a contentious hearing on April 28, the agency opted for a middle course, ordering staff to look at steps that could reduce the risk of an accidental release of MHF.

“If released during a refinery accident, MHF could pose a serious health threat to the community,” Clark Parker, chairman of the air district’s refinery Committee, said in a statement following a contentious hearing April 28. “We are directing staff to identify potential further mitigations to benefit public health and safety.”

Economy, education, energy and transportation reporter Howard Fine can be reached at [email protected]. Follow him on Twitter @howardafine