A vapor cloud from a pipeline servicing a unit at Chevron's refinery in Richmond, Calif., ignited, causing a fire that forced a partial shutdown of the facility.
The San Francisco Chronicle reports that Chevron, in a federally mandated analysis in 2009, drafted a plan meant to avoid a theoretical disaster similar to the August incident.
The newspaper cites meetings from a county safety audit that documented company engineers as taking note of the risk of a "leak/rupture due to corrosion/erosion in overhead piping."
Riffat Maqbool Qadir, a risk management expert from safety consulting company Enpro Solutions, told the Chronicle the Richmond incident was similar to a 2005 explosion at BP's refinery in Texas City, Texas.
"This has been the case in a number of accidents, where companies have failed to act on recommendations" he was quoted as saying.
Chevron announced this week it opened a second center in Richmond to help assist residents who may wish to file a claim related to the refinery fire.
Randy Sawyer, head of materials safety for Contra Costa County, told the newspaper that "for whatever reason" Chevron's 2009 plan "was not adequate." Ben Sloan, a maintenance specialist for Chevron, told regulators in 2010 that vapor cloud ignition "could never happen in California."
The U.S. Chemical Safety Board said it was investigating the incident with the help of California regulators and Chevron.