LOS ANGELES (CBS/AP) — The California agency that investigates workplace accidents has cited and fined ExxonMobil $566,600 for workplace safety and health violations following a probe into February’s explosion at a Torrance refinery.

The California Division of Occupational Safety and Health said Thursday that 18 of the 19 citations are classified as serious because violations could potentially cause serious injury or death. Six of those serious violations were also classified as willful because Cal-OSHA found that Exxon did not take action to eliminate known hazardous conditions at the refinery.

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“Petroleum refineries have the responsibility to keep workers safe, and also to protect nearby communities and the environment,” Christine Baker, director of the Department of Industrial Relations, said in a statement. “This investigation revealed severe lapses in Exxon’s safety protocols.

ExxonMobil says it’s reviewing the citations.

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The Feb. 18 blast slightly injured four contractors, heavily damaged equipment and rained a fine white ash on nearby homes and cars.

Cal-OSHA, which is a division of the Department of Industrial Relations, says the explosion was caused by flammable vapor leakage from the refinery’s fluid catalytic cracker (FCC) unit into its electrostatic precipitator.

The FCC unit had not been working properly for as many as nine years prior to February’s explosion. On March 29, 2011, a worker working on the FCC unit suffered a fractured jaw and lost six teeth when a motor in a pump he was trying to shut down exploded.

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