A California regulatory agency has found that Exxon Mobil Corp. intentionally failed to comply with state safety standards prior to a February explosion that injured four workers at its Torrance refinery.

The Irving, Texas, energy giant will also be fined $566,600.

The California Division of Occupational Safety and Health, or Cal-Osha, uncovered 19 violations committed by Exxon, the fourth largest oil company in the world, which generated more than $394 billion in revenue last year.

“This investigation revealed severe lapses in Exxon’s safety protocols,” Christine Baker, director of the state Department of Industrial Relations which houses Cal-Osha, said in a statement.

Eighteen of those violations were considered serious because they could realistically result in death or serious injury. Six were also classified as willful because Exxon did not take action to eliminate known hazardous conditions at the refinery and intentionally failed to comply with state standards such as the replacement of defective parts and the implementation of safety procedures, according to a Cal-Osha statement.

The agency said the Feb. 18 explosion was caused by a release of hydrocarbon vapor. The agency has investigated Exxon’s Torrance facility twice in the last five years for accident-related incidents that resulted in serious workplace injuries.

Exxon has 15 working days to appeal the citations.

“We are reviewing the citations to determine the appropriate administrative and legal next steps,” Exxon spokesman Todd Spitler said in an email. “We have and will continue to work cooperatively with Cal-Osha.”