After the Deepwater Horizon blowout that killed 11 workers and spilled large amounts of oil into the Gulf of Mexico, BP have been found guilty of gross negligence and could face up to $18 billion in further fines.
The firm had appeared confident to avoid this verdict, but US district judge, Carl Barbier, made his decision that they had been reckless as well as negligent.
BP has promised to launch an appeal but this has not helped their share price which has dropped by 5%, wiping more than £5 billion from its stock market value.
Along with this huge fine, the firm has already paid more than $43 billion out as a result of the accident.
The judge interestingly attributed 67% of the blame for the disaster to BP, 30% with its US rig operator and 3% for the Texan-based well expert Halliburton.
More is yet to follow as next year the judge will rule on how much oil was spilled. This could lead to additional penalties under the US Clean Water Act.
BP disagrees with the decision from Judge Barbier and "believes that the finding that it was grossly negligent with respect to the accident and that its activities at the Macondo well amounted to wilful misconduct is not supported by the evidence at trial. The law is clear that proving gross negligence is a very high bar that was not met in this case. BP believes that an impartial view of the record does not support the erroneous conclusion reached by the district court."
The accident has led to big changes at BP including the departure of previous chief executive, Tony Hayward.
