The Chemical Safety & Hazard Investigation Board last week released an interim analysis of the Aug. 6, 2012 refinery fire at a Chevron refinery in Richmond, Calif. The fire started when a corroded pipe ruptured in a crude oil processing unit. CSB identified several failures that led to the fire: “Missed opportunities to apply inherently safer technologies, a failure to recognize and correct workplace hazards, and the lack of industrial safeguards,” reported C&EN’s Jeff Johnson on Friday. CSB’s report is available here, and a Chevron internal report is available here.
One notable set of images in the CSB report is on pdf page 11. The set includes four photographs taken from across the Bay that show the initial hydrocarbon vapor cloud that formed when the pipe burst, followed by the black smoke from the fire. Amazingly, no one was killed when the leaking material ignited. From CSB’s video about the incident and its findings:
A decision was finally made to begin an emergency shut down of the crude unit. But it was too late. Suddenly, the pipe ripped open. A vapor cloud formed and rapidly expanded, as the large inventory of hydrocarbons in the distillation tower started to vent through the ruptured pipe. The vapor cloud immediately spread over hundreds of feet, engulfing all 19 people who had gathered nearby. The firefighters and operators struggled to escape through the dense hydrocarbon cloud, unable to see. They had to feel their way out, some on their hands and knees. At approximately 6:30 p.m., two minutes after the huge vapor cloud formed, the hydrocarbons ignited. One firefighter was trapped inside a fire engine when it was suddenly engulfed in flames. He radioed for help. … But when he received no response, he assumed everyone else was dead. To escape the inferno, he fled through what witnesses described as a wall of fire.
That fire engine was destroyed by the fire.The Chevron report argues that the white vapor cloud itself was not flammable. Instead, material still leaking from the pipe either auto-ignited or dislodged a light fixture, exposing wiring that could have ignited the stream. Chevron’s internal report also says, “The response and assessment after the discovery of the leak did not fully recognize the risk of piping rupture and the possibility of auto-ignition” (Causal Factor 1, pdf page 21).
Last but not least, here’s CSB’s video: