BP has accepted responsibility for a "series of failures" by staff which it said led to the fatal explosion at its largest US refinery in March.
Proper procedures were not followed before the explosion
The blast and subsequent fire at the Texas City refinery near Houston claimed 15 lives and injured 170.
An interim report into the tragedy has found that failure to follow the proper procedures and poor supervision at the plant contributed to the explosion.
BP said it would discipline staff found to have made mistakes.
An investigation into the explosion on 23 March found that it was caused by a huge build-up in fluid in a unit used to produce octane for petrol.
It concluded that managers failed to supervise the unit properly while operators were absent at crucial periods and failed to take corrective action early enough, thus contributing to the disaster.
The death toll was exacerbated by the presence of temporary trailers near the processing unit used to house workers.
Staff also failed to sound the alarm to evacuate when it became clear that pressure in the unit was at unsustainable levels.
"The mistakes made during the start-up of this unit were surprising and deeply disturbing," said Ross Pillari, president of BP Products North America.
"We regret that our mistakes have caused so much suffering."
BP has begun the process of evaluating and settling claims against the company.
It stressed that it wanted to offer "fair compensation" to the families of the deceased and injured without the need for litigation.
The company has begun to take disciplinary action against staff responsible for the operation and supervision of the processing unit, measures which it said would include sackings.
"The failure of unit managers to provide appropriate leadership and of hourly workers to follow written procedures are among the root causes of this incident," Mr Pillari added.
"We cannot ignore these failures."
BP has also launched a comprehensive review of operations at the refinery which employs 1600 permanent staff.
The Texas City complex pumps out 460,000 barrels of oil a day, providing about 3% of the US' annual oil supply.
It has suffered previous safety problems.
In March 2004, it was evacuated after an explosion that cost the company $63,000 in fines.
Last September, two workers died and another was seriously injured when they were scalded by superheated water that escaped from a high-pressure pipe.