Just days before the third anniversary of the Gulf oil spill, the first phase of a trial to determine if BP or its partners are guilty of gross negligence in the disaster came to a close on Wednesday.

U.S. District Judge Carl Barbier ordered an 80-day period in which to determine findings before moving on to the second phase of the trial, which will determine damages in the spill that killed 11 people and dumped 4 million barrels of oil into the Gulf of Mexico.

The U.S. government, along with people and businesses affected by the spill, brought the suit. If Barbier determines, following the trial’s first phase, that BP or its co-defendants acted with reckless indifference or wanton misconduct, the three companies could see a four-fold increase in the Clean Water Act penalties for which they are liable.

BP on Wednesday pointed the finger at its drilling partners—Halliburton Co., which cemented the Macondo well and Transocean Ltd., which operated the exploded Deepwater Horizon oil rig. On Wednesday, expert witnesses for BP argued that the cement Halliburton used to plug the well was unstable and needed remixing before use. Another witness testified that Transocean’s rig captain failed to activate the well’s blowout preventer, even though he had between four and eight minutes after the start of the disaster in which to do so, Thomson Reuters reports.

BP is already on the hook for significant damages connected to the spill. A settlement with individuals and businesses that suffered economic or medical damages in the wake of the spill will cost the company at least $8.5 billion. That amount could grow, the oil company said last month, because the claims that are being paid out are higher and more numerous than expected.

For ongoing InsideCounsel coverage of the BP oil spill, see:

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Transocean GC resigns, effective immediately