One worker died and another was injured after an equipment failure released a hazardous chemical inside the Memphis Valero refinery Monday.

The workers -- an employee and a contractor -- received chemical burns when a small glass window shattered in a production line, officials said.

Bill Day, spokesman for San Antonio-based Valero, said the employee died at the Regional Medical Center at Memphis after the 9:20 a.m. accident.

It was the second death caused by an accident at the South Memphis refinery this year. It highlighted the hazards of converting crude oil into fuel and concerns that worker advocates have about refinery safety.

Memphis Fire Department spokesman Wayne Cooke said the workers were exposed to a mixture of propane and hydrofluoric acid released from a ruptured sight glass.

Two firefighters also were hospitalized after responding to the Valero incident, Cooke said. They were taken to The Med in noncritical condition to be treated for chemical exposure.

Day said, The incident is under investigation, so any speculation at this point is premature.

Officials with the United Steelworkers were reluctant to comment specifically on what went wrong, but they characterized hydrofluoric acid as an extremely hazardous, and replaceable, component of many refining operations.

It's an extremely deadly material that has to be handled very carefully, said Kim Nibarger, USW's oil health and safety expert. We've had a number of incidents over the years with hydrofluoric acid.

The Steelworkers Union is coming out with a study next February advocating that refineries switch to sulfuric acid as a catalyst in the alkylation process.Sulfuric acid is more easily detected and dealt with if it leaks, Nibarger said.

Alkylation converts high-octane butane and propane gases into lower-octane fuels.

In September, an explosion that occurred while workers were unloading a tanker at a chemical factory in South Korea released eight tons of hydrofluoric acid. Five people were killed, 18 were injured and 3,000 were left complaining of symptoms from the toxic fumes.

Memphis Fire Department and on-site emergency personnel responded to Monday's accident, and appropriate regulatory agencies were notified, Valero said.

The company said it expected no environmental impact on the neighborhood, and refinery operations were not affected.

Monday's incident came about nine months after an accident at the refinery critically injured three contractors who were doing maintenance. One of the workers later died.

In the March 6 accident, a flash fire erupted while a five-person crew was working outside on a flare, a safety device that vents gases from the refinery.

The Memphis plant and industry in general have a history of accidents and complaints about safety violations. A multimillion-dollar wrongful death and injury lawsuit was filed in April in San Antonio, claiming negligence on the company's part. The lawsuit said it was the third fire at the facility in less than two years.

The lawsuit contended the company failed to ensure no hazardous or flammable gases were left in the flare line. It also alleged firefighting procedures and equipment were inadequate.

Staff reporter Scott Carroll contributed to this story.



Copyright 2012 The Commercial Appeal, Inc.

(Originally published Dec. 4, 2012, in The Commercial Appeal.)