Safety Board Details BP Failures

BP Products North America Inc. failed to identify and remedy half-a-dozen key safety problems that ultimately led to the March 23 explosions and fire at the company’s Texas City, Texas, refinery, which killed 15 workers and injured 170 others, federal investigators said on Oct. 28.

Most notably, the Chemical Safety & Hazard Investigation Board (CSB) says the deadly blast could have been avoided if BP had installed a flare system on the unit that exploded. The incident involved a sudden release of flammable hydrocarbon liquid and vapor from an atmospheric vent stack in the refinery’s isomerization unit. Workers in nearby trailers were killed and injured in the subsequent explosions.

In preliminary findings, CSB says the 114-foot-tall stack, which dated from the 1950s and was not tied to a safety flare system, was overfilled with hydrocarbons during the start-up of a raffinate splitter tower, a 164-foot-tall distillation column that became flooded with at least 120 vertical feet of liquid. Normal operating levels in the tower are less than 10 vertical feet. The flooded tower experienced a sudden pressure increase, opening relief valves and venting hydrocarbon liquid and vapor that overwhelmed the vent stack and its associated blowdown drum.

“The first rule of oil refinery safety is to keep the flammable, hazardous materials inside piping and equipment,” CSB Lead Investigator Don Holmstrom says. “A properly designed and sized knockout drum and flare system would have safely contained the liquids and burned off the flammable vapors, preventing a release to the atmosphere.”

Instead, he says, the mix spewed onto the plant grounds, where it ignited and caused a series of explosions. According to Holmstrom, investigators found evidence that BP considered connecting the unit’s raffinate splitter tower to a flare system in 2002, but decided against it.

BP says some of the board’s findings “appear to be inconsistent with the evidence and analysis gathered by our own investigation team.” The company says it plans to meet with CSB officials to discuss their findings and supporting evidence.