THE US District Court for the Eastern District of Louisiana yesterday ruled on the issues raised in the Phase 2 trial of the Deepwater Horizon case pertaining to the quantity of oil spilled and BP's source control efforts following the accident.

The court also found, however, that BP was "not grossly negligent in its source control efforts".

No penalty has yet been determined, and BP said yesterday it believed that "considering all the statutory penalty factors together" the odds were in its favour for a penalty at the lower end of the statutory range.

In a reprieve for BP, US District Court Judge Carl Barbier rejected the US government's 4.2MMbbl estimate, decreasing the potential maximum fine from $18 billion.

The fine will be based on the law's provision for as much as $4300 per barrel released. BP has set aside $3.5 billion to cover the pollution fines and has already spent more than $28 billion in spill response, cleanup and claims.

BP had taken a $43 billion charge to cover all the costs, according to an October 28 earnings statement. The company said the ultimate cost was "subject to significant uncertainty".

BP said the decisions in the Phase 1 and Phase 2 trials represented steps in the process for assessing a CWA penalty. The third phase of the CWA trial, currently scheduled to begin in the Court on January 20, will address the penalty to be assessed.

During the penalty proceedings, the Court is required to consider the application of eight statutory factors, including the violator's efforts to minimise or mitigate the effects of the spill.

This includes the seriousness of the violation or violations; the nature, extent and degree of success of any efforts of the violator to minimise or mitigate the effects of the discharge; the economic impact of the penalty on the violator; the economic benefit to the violator, if any, resulting from the violation; the degree of culpability involved; any other penalty for the same incident; any history of certain types of prior violations; and any other matters as justice may require.

Judge Barbier had previously found that BP's exploration unit acted with gross negligence in causing the largest offshore oil spill in US history.