The US Occupational Safety and Health Administration today issued a record 87 million dollar (£52.88 million) fine against oil giant BP for failing to correct safety hazards after a 2005 explosion killed 15 workers and injured 170 at its Texas City refinery.

The fine - the largest in OSHA's history - comes after a 6-month inspection revealed hundreds of violations of a 2005 agreement to repair hazards at the refinery.

OSHA said the company also committed hundreds of new violations at the third largest US refinery by failing to follow industry controls on pressure relief safety systems and other precautions.

Labour Secretary Hilda Solis said BP failed to live up to the terms of its commitment to protect employees. If the problems are not addressed, Solis said it "could lead to another catastrophe".

"An 87 million dollar fine won't restore those lives, but we can't let this happen again," Ms Solis said. "Workplace safety is more than a slogan. It's the law."

BP spokesman Robert Wine said the company believed it was in "full compliance" with the settlement agreement, which included requirements that BP change working practices to improve safety, and it would demonstrate that to OSHA.

"We are disappointed that OSHA took this action in advance of the full consideration of the Review Commission," the London-based company said in an emailed statement, referring to an ongoing separate inquiry by a body separate to OSHA.

"While we strongly disagree with their conclusions, we will continue to work with the agency to resolve our differences," the company added.

BP will have 15 days to either agree to pay the penalties and take corrective action, or contest the fines through a hearing process.

The largest prior OSHA fine was 21 million dollars (£12.76 million), also levelled against BP in connection with the refinery explosion.

In the latest case, OSHA officials found 270 violations totalling 56.7 million dollars (£34.46 million) in penalties for BP's failure to take corrective action as required by terms of the 2005 settlement agreement with OSHA.

Agency inspectors also identified 439 new wilful violations totalling 30.7 million dollars (£18.66 million) in penalties for failure to repair pressure release safety devices.

OSHA officials said the 2005 explosion was caused by defective pressure relief systems.

Jordan Barab, acting assistant secretary of labour for OSHA, said the agency has found "some serious systemic safety problems within the corporation" and at the Texas refinery.

"The fact that there are so many still outstanding life-threatening problems at this plant indicates that they still have a systemic safety problem in this refinery." Mr Barab said.