The United Steelworkers Union is pressing the U.S. refining industry to cease using hydrogen fluoride, a toxic chemical that can pose a danger to workers and surrounding communities, in favor of less dangerous alkylation methods.

The union gathered a variety of speakers knowledgeable on the subject to discuss the dangers of hydrogen fluoride and its other form as hydrofluoric acid, and some safer alternatives, such as sulfuric acid, at a press conference on Nov. 12.

When used by refineries in alkylation, hydrogen fluoride can potentially be released as a vapor cloud that can travel for up to 17 miles and cause a host of symptoms ranging from nose and throat irritation to liver, lung and kidney damage. Brief exposure to concentrations above 50 parts per million can be fatal.

Just this year, three refinery releases of hydrogen fluoride across the U.S. injured 16 workers. One small spill of the chemical in Wind Gap, Pennsylvania, spurred the evacuation of 5,000 residents after a truck carrying hydrofluoric acid overturned, according to the union.

On the other hand, sulfuric acid cannot create a vapor cloud that would affect other areas, and produces the same alkylation effect that hydrogen fluoride does, said Jim Lefton, a subdirector for the union in Corpus Christi, Texas. Modified hydrofluoric acid, while still able release and travel offsite, has less damaging affects as regular hydrofluoric acid.

Also, pilot tests are currently taking place for a new, completely non-toxic solid state catalyst called Exact, developed by Excellent Inc. in Livingston, N.J. So far, testing shows that Exact produces the same quality of alkylate as hydrogen fluoride, Lefton said.

It would take about $4 million for a refinery to test out Exact, a cost that is relative to “$5 to someone like you or me,” he said. Retrofitting an 8,500 bpd alkylation unit to use the solid state catalyst would cost about $16 million.

Of the close to 100 refineries in the U.S. that produce alkylate, about 50 use sulfuric acid, with the remainder using hydrogen fluoride. Hydrogen fluoride is technically cleaner and more efficient than sulfuric acid, which is why some refineries risk its dangerous effects.

But groups like the USW and the Sierra Club think it should be banned.

“This chemical is used in high volume in refineries,” said Neil Carman, a former investigator with the Texas Commission on Environmental Quality who now works with the Sierra Club on industrial air pollution.

“Because it is so corrosive and acidic and dangerous to human health it is definitely a chemical we want phased out,” he added.

Carman said TCEQ has no capability to measure the chemical’s use or releases, and that groups who want the chemical phased out can’t depend on regulators to fix the problem.

Corpus Christi, Texas, is the city with the highest rate of hydrogen fluoride use in the nation, with Valero, Citgo and Flint Hill refineries using it in large quantities, Lefton said. The community with the most concentrated use of hydrogen fluoride is in Texas City, Texas, which is home to two BP refineries and one Valero refinery, all of which use the chemical.