CSB: Fire at Chevron's Richmond Refinery

The U.S. Chemical Safety and Hazard Investigation Board (CSB) has released its final investigation report and incident animation for An August 6, 2012, release of flammable vapor led to a fire at the Chevron Refinery in Richmond, California.

On August 6, 2012, the Chevron U.S.A. Inc. Refinery in Richmond, California, (“the Chevron Richmond Refinery”) experienced a catastrophic pipe failure in the #4 Crude Unit (“the crude unit”). The pipe, a 52-inch long carbon steel piping component of the #4 sidecut line, ruptured and released flammable, hydrocarbon process fluid, which partially vaporized into a large vapor cloud that engulfed 19 Chevron employees and ignited. All of the employees escaped, narrowly avoiding serious injury. The ignition of the flammable portion of the vapor cloud and subsequent continued burning of the hydrocarbon process fluid resulted in a large plume of particulates and vapor traveling across the Richmond, California area. Approximately 15,000 people from the surrounding area sought medical treatment due to the release.

Corrosion Finding. Testing conducted on the ruptured pipe determined that it had experienced extreme thinning near the rupture location due to sulfidation corrosion. Sulfidation corrosion is a damage mechanism that causes thinning in iron-containing materials, such as steel, due to the reaction between sulfur compounds and iron at temperatures ranging from 450 °F to 800 °F. This damage mechanism causes pipe walls to gradually thin over time, and is common in crude oil distillation where naturally occurring sulfur and sulfur compounds found in crude oil feed, such as hydrogen sulfide, are available to react with steel piping and equipment. Sulfidation corrosion can cause thinning to the point of pipe failure when not properly monitored and controlled.

The final investigation report:

https://www.csb.gov/chevron-richmond-refinery-fire/

The animation: