A federal appeals court narrowly upheld a 2012 ruling Monday that found BP and Anadarko Petroleum can face civil fines under federal pollution laws for the Deepwater Horizon spill.
The 5th Circuit Court of Appeals let stand a decision by U.S. District Judge Carl Barbier that found the two companies can be fined under the Clean Water Act. The appeals panel decided by a 7-6 vote against BP and Anadarko, Reuters said.
BP owned a 65 percent interest in the Macondo well where a 2010 blowout killed 11 people and caused the largest oil spill in U.S. history.
Texas-based Anadarko held a 25 percent stake in the well.
The two companies argued that they should not face federal fines because the blowout was caused by a riser belonging to Switzerland-based Transocean, the owner of the Deepwater Horizon rig.
Both companies have declined to comment on the ruling.
In September, Barbier found BP grossly negligent and guilty of willful misconduct in the spill, a ruling that could result in BP paying up to $18 billion in penalties.
Texas-based Halliburton and Switzerland-based Transocean were found negligent but not reckless.
The judge divided fault for the spill at 67 percent for BP, 30 percent for Transocean and 3 percent for Halliburton.
BP is currently appealing that decision.
The penalty phase of the BP trial is set to start on January 20.