BP will pay a record $50.6m (£32.5m) fine for continuing safety problems at its Texas City refinery, where an explosion in 2005 killed 15 workers and injured around 180.
The energy giant, still reeling from the Gulf oil spill, has settled 270 of the 709 cases brought against it by the US Operational Safety and Health Administration (OSHA) over chronic safety issues.
It will also pay up to $500m over the next six years to improve the hazardous conditions at the Texas plant. OSHA is still pursuing a $30.6m fine for more recent safety violations.
BP has already paid a $50m fine to settle the criminal charges stemming from the explosion, and spent more than $2.1bn settling hundreds of lawsuits brought by victims.
Iain Conn from BP said: “BP has a stated goal to become a leader in process safety and we look forward to working collaboratively with OSHA.”