By OGJ editors
HOUSTON, Apr. 13 -- Investigations continue into the causes of a Mar. 23 explosion and fire in an isomerization unit at BP America Inc.'s Texas City, Tex., refinery that killed 15 contractors and injured more than 100 other persons (OGJ Online, Mar. 23, 2005).
Preliminary data point to the ignition of excess vapors from a blowdown drum's vent stack—possibly by a vehicle parked too close to the unit. Many of the victims killed were attending a meeting in a contractor's office trailer located within 150 ft of the isomerization unit, which was being restarted after a maintenance turnaround.
A spokesman from the US Chemical Safety and Hazard Investigation Board (CSB), which is investigating the accident, said, "In this case we know that there was a catastrophic release of hydrocarbons from a vent stack." He also said that trailers have been "considered a major issue since day one."
The location of the trailers was in violation of BP best practices, which in this case apparently were not enforced.
BP said the investigation is far from complete.
"The explosion and fire at the isomerization unit was a result of a very complex process upset that BP America is still striving to understand," the company said in a statement Apr. 10 outlining progress of its own internal investigation.
The BP PLC unit said it has turned over to CSB and the US Occupational Safety and Health Administration (OSHA) more than 8,500 pages of information related to the accident, including maintenance records, engineering documents, computerized plant control data, and eyewitness accounts of the incident.
BP said it "has thoroughly inspected the isomerization unit to verify positions of key valves and other visible indicators." It said it will obtain fluid samples and complete further inspections of the unit "in order to actively manage safety concerns related to benzene, asbestos, and other potential hazards."
BP said it is building process data and information gleaned from the investigation site to model the accident and the subsequent explosion, a process expected to take several weeks.
In the interim, the company has taken measures to reinforce safety at the refinery. BP said it has completed a comprehensive review of every process unit's safety protection system and has immediately addressed any issues it identified or has shut down work until those issues can be resolved.
By Apr. 8, BP had moved all personnel to locations more than 500 ft from any blowdown stack or flare. It also is in the process of removing any temporary trailers that may be within these areas.
BP said it "also is relocating people whose jobs do not require them to be located near refinery equipment, improving internal emergency communication planning, and beginning a review of all safety emergency systems, including blowdown drums and flares."
