Officials with the U.S. Chemical Safety Board said they were focusing on whether an explosion inside a piece of equipment caused BP employee William Joseph Gracia to die of head injuries on Jan. 14. Gracia was the third worker to be killed at the refinery since the deadly blast.
The accident happened as a water filtration unit was being restarted. Lead investigator Don Holmstrom said a possible explosion inside the filter tank was just one of several scenarios CSB officials were looking into.
"Root causes that are determined by the board are typically safety system deficiencies that lead to these types of incidents and we are going to be examining them thoroughly," he said. "At this point it's too early to speculate what systems may have been involved."
The CSB's final report on the 2005 accident concluded that "organizational and safety deficiencies at all levels of BP" caused the accident. The agency also blamed BP for cost cutting that left the plant vulnerable to catastrophe.
The blast occurred after a piece of equipment called a blowdown drum overfilled with highly flammable liquid hydrocarbons. Alarms and gauges that were supposed to warn of the overfilled equipment didn't work properly.
CSB board member William Wark said BP has made safety improvements since the accident.
"How much further they have to go is a matter of speculation," he said.
BP has said it's spent more than $1 billion upgrading the refinery, about 40 miles southeast of Houston. The company says it also has more than doubled the refinery's staff responsible for safety and environmental issues and nearly tripled the number of employees in the process safety management group.
BP spokesman Neil Chapman did not comment when asked whether the safety culture might have contributed to Gracia's death.
"Our own investigation continues, and until we know the facts we really can't comment on safety issues," he said.
Tony Buzbee, the attorney for Gracia's family, which is suing BP, said his clients believe there has been no change in the safety culture since 2005.
"We hope the Chemical Safety Board will not only just focus on this one filtration unit but will also focus on the plant as a whole because there is a major problem with the physical plant that would allow something like this to occur," he said.
Gracia's family also questioned BP's commitment to improving safety during a court hearing earlier this week on whether a federal judge should accept the company's guilty plea for criminal conduct related to the 2005 blast. The plea has been criticized by victims of the accident. A decision by the judge is pending.
Holmstrom, CSB's lead investigator of the 2005 blast, said the accident involving Gracia happened in a water filtration tank that is part of what's called an ultracracker unit, which helps convert petroleum products similar to diesel fuel into high-octane gasoline.
This section of the ultracracker unit, which had been shut down since 2005, was in the beginning stages of a start-up when the accident occurred. Gracia was standing next to the filtration tank when the 500-pound lid, held down by 24 large steel bolts, was suddenly blown off the tank.
Holmstrom said he could not say if Gracia was killed by the flying lid because officials were still waiting for a final autopsy report. But Buzbee said he believes the lid caused the fatal head injury. Gracia, a supervisor who had worked at the plant for 32 years, also suffered burns to his head.
CSB officials are looking at whether combustible substances such as hydrogen were in the water inside the filtration tank when the restart was occurring, if the bolts holding down the lid might have been corroded and if proper safety procedures were followed.
The agency's probe is expected to take several months. The U.S. Occupational Safety and Health Administration is also investigating.
