The US Supreme Court will not hear appeals from energy giants BP and Anadarko Petroleum over the 2010 Gulf of Mexico oil spill.
Justices let stand a lower court ruling that said the owners of the blown-out Macondo well could not avoid federal fines for the spill by blaming another company's failed equipment.
The firms argued that the oil had not leaked from the well itself, but from the broken underwater pipe that connected the well to the rig owned by Transocean, a top drilling contractor.
That riser was ripped apart when the burning rig sank. The companies had argued that the rig's owners should be the only companies to pay.
A district judge and a federal appeals court rejected that argument.
The Deepwater Horizon drilling rig explosion and spill on April 20 2010 resulted in as much as 172 million gallons of oil getting into the Gulf of Mexico.