"After exhaustively analyzing the facts, the CSB investigation team found many ways that major refinery accidents like the Chevron fire could be made less likely by improving regulations," CSB Chairman Rafael Moure-Eraso said in a statement Monday. "Refinery safety rules need to focus on driving down risk to the lowest practicable level, rather than completing required paperwork."
Chevron briefly closed parts of its Richmond refinery following a fire in August 2012. CSB investigators said last year aging equipment at the refinery was in part to blame for the fire.
More than 15,000 area residents received medical attention in the wake of the blaze.
Don Holmstrom, director of the CSB's regional office, was quoted by the San Francisco Chronicle as saying state and federal regulations on refinery safety were poor compared with the rest of the world. The draft report found regulations were reactive and static.
"The regulatory system both in the U.S. and California for petroleum does not effectively prevent major accidents," he was quoted as saying.
Chevron has largely cooperated with the investigation into last year's fire.