NEW ORLEANS — BP put profits ahead of safety and bears most of the blame for the disastrous 2010 spill in the Gulf of Mexico, a U.S. Justice Department attorney charged Monday at the opening of a trial that could result in the oil company and its partners being forced to pay tens of billions of dollars more in damages.

The London-based oil giant acknowledged it made "errors in judgment" before the deadly blowout, but it also cast blame on the owner of the drilling rig and the contractor involved in cementing the well. It denied it was grossly negligent, as the government contended.

The high-stakes civil case went to trial after attempts to reach an 11th-hour settlement failed.

Eleven workers were killed when the Deepwater Horizon rig leased by the BP exploded on April 20, 2010. An estimated 172 millions of gallons of crude gushed into the Gulf over the three months that followed in the worst offshore oil spill in U.S. history.

Justice Department attorney Mike Underhill said the catastrophe resulted from BP's "culture of corporate recklessness."

"The evidence will show that BP put profits before people, profits before safety and profits before the environment," Underhill said in opening statements. He added: "Despite BP's attempts to shift the blame to other parties, by far the primary fault for this disaster belongs to BP."

BP attorney Mike Brock acknowledged that the oil company made mistakes. But he accused rig owner Transocean Ltd. of failing to properly maintain the rig's blowout preventer, which had a dead battery, and he claimed cement contractor Halliburton used a "bad slurry" that failed to prevent oil and gas from traveling up the well.

BP has already pleaded guilty to manslaughter and other criminal charges and has racked up more than $24 billion in spill-related expenses, including cleanup costs, compensation for businesses and individuals, and $4 billion in criminal penalties.

But the federal government, Gulf Coast states and individuals and businesses hope to convince a federal judge that the company and its partners in the ill-fated drilling project are liable for much more in civil damages under the Clean Water Act and other environmental regulations.

One of the biggest questions facing U.S. District Judge Carl Barbier, who is hearing the case without a jury, is whether BP acted with gross negligence.

Under the Clean Water Act, a polluter can be forced to pay a minimum of $1,100 per barrel of spilled oil; the fines nearly quadruple to about $4,300 a barrel for companies found grossly negligent, meaning BP could be on the hook for nearly $18 billion.

The judge plans to hold the trial in at least two phases. The first phase, which could last three months, is designed to determine what caused the blowout and assign percentages of blame to the companies involved. The second phase will determine how much crude spilled into the Gulf.

During opening arguments, BP and its partners pointed the finger at each other in a tangle of accusations and counter-accusations. But BP got the worst of it, from its partners and the plaintiffs in the case.

Jim Roy, who represents individuals and businesses hurt by the spill, said BP executives applied "huge financial pressure" to "cut costs and rush the job." The project was more than $50 million over budget and behind schedule at the time of the blowout, Roy said.

"BP repeatedly chose speed over safety," Roy said, quoting from a report by an expert who may testify.

Roy said the spill also resulted from Transocean's "woeful" safety culture and failure to properly train its crew. And Roy said Halliburton provided BP with a product that was "poorly designed, not properly tested and was unstable."

Brad Brian, a lawyer for Transocean, said the company had an experienced, well-trained crew on the rig. He said the Transocean workers' worst mistake may have been placing too much trust in the BP supervisors on the rig.

"And they paid for that trust with their lives," Brian said. "They died not because they weren't trained properly. They died because critical information was withheld from them."

A lawyer for Halliburton defended the company's work and tried to pin the blame on BP and Transocean.

"If BP had shut in the well, we would not be here today," Halliburton's Donald Godwin said.

Underhill, the Justice Department attorney, heaped blame on BP for cost-cutting decisions made in the months and weeks leading up the disaster. He said two BP rig supervisors, Robert Kaluza and Donald Vidrine, disregarded abnormally high pressure readings that should have been glaring indications of trouble.

Kaluza and Vidrine have been indicted on federal manslaughter charges.

Brock, the BP lawyer, said Transocean employees on the rig also played roles in misinterpreting the "negative pressure test."

"It was a mistake made by several men from two different companies," Brock said. "They were trying to get it right. They were trying to do the right thing."

Hundreds of attorneys have worked on the case, generating roughly 90 million pages of documents, logging nearly 9,000 docket entries and taking more than 300 depositions from witnesses who could testify at trial.

"In terms of sheer dollar amounts and public attention, this is one of the most complex and massive disputes ever faced by the courts," said Fordham University law professor Howard Erichson, an expert in complex litigation.

The spill fouled marshes, killed wildlife and closed fishing grounds. Scientists warn that the disaster's full effect may not be known for years. But they have reported dying coral reefs and fish afflicted with lesions and illnesses that might be oil-related.

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  • Gulf Coast Battles Continued Spread Of Oil In Its Waters And Coastline

    PORT FOURCHON, LA - JULY 03: Workers clear off some of the oil washing on to Fourchon Beach from the Deepwater Horizon oil spill in the Gulf of Mexico on July 3, 2010 in Port Fourchon, Louisiana. Millions of gallons of oil have spilled into the Gulf since the April 20 explosion on the drilling platform. (Photo by Joe Raedle/Getty Images)

  • In this June 5, 2010, file photo Plaquemines Parish coastal zone director P.J. Hahn lifts his boot out of thick beached oil at Queen Bess Island in Barataria Bay, just off the Gulf of Mexico in Plaquemines Parish, La. After three long months, the bleeding from the bottom of the Gulf of Mexico has been finally, mercifully stanched. But in so many ways, the prognosis remains uncertain. (Gerald Herbert, AP)

  • Mississippi River water (L) meets sea wa

    Mississippi River water (L) meets sea water and an oil slick that has passsed inside of the protective barrier formed by the Chandeleur Islands, as cleanup operations continue for the BP Deepwater Horizon platform disaster off Louisiana, on May 7, 2010. The Gulf of Mexico oil slick threatens disaster for the fragile US coast, causing clean-up efforts to focus on the best of a bad set of options: fight it there before it arrives here. An army of workers hired by British Petroleum, along with the US Coast Guard and local officials in Louisiana, have rushed to set out protective booms, spread dispersants and burn the oil when they can as it moves toward the shore. The strategy is to deal with the growing slick as much as possible before it laps into wetlands on Louisiana's coast, where its effects could be catastrophic and cleaning it is infinitely more difficult if not impossible. AFP PHOTO/Mark RALSTON (Photo credit should read MARK RALSTON/AFP/Getty Images)

  • An American flag lays in a slick of oil that washed ashore from the Deepwater Horizon oil spill in the Gulf of Mexico on July 4, 2010 in Gulf Shores, Alabama. The oil spill may have a huge negative economic impact on gulf coast businesses during what should be a busy 4th of July. Millions of gallons of oil have spilled into the Gulf since the April 20 explosion on the drilling platform. (Joe Raedle, Getty Images)

  • In this April 21, 2010 file photo taken in the Gulf of Mexico more than 50 miles southeast of Venice on Louisiana's tip, the Deepwater Horizon oil rig is seen burning. A BP scientist identified a previously unreported deposit of flammable gas that could have played a role in the Gulf of Mexico oil spill, but the oil giant failed to divulge the finding to government investigators for as long as a year, according to interviews and documents obtained by The Associated Press. (Gerald Herbert, AP)

  • In this May 5, 2010 file photo, shrimp boats are used to collect oil with booms in the waters of Chandeleur Sound, La. (Eric Gay, AP)

  • In this June 3, 2010 file photo, a bird is seen on the beach at East Grand Terre Island along the Louisiana coast after being drenched in oil from the BP Deepwater Horizon oil spill. Retired Coast Guard Adm. Thad Allen, the federal government's point man on the disaster, said Sunday, Sept. 19, 2010, BP's well "is effectively dead." A permanent cement plug sealed BP's well nearly 2.5 miles below the sea floor in the Gulf of Mexico, five agonizing months after an explosion sank a drilling rig and led to the worst offshore oil spill in U.S. history. (Charlie Riedel, AP)

  • This May 28, 2010 image taken from a BP live video feed shows fluid escaping from a fractured pipe which has been spouting oil for 36 days on the seabed off the Louisiana coast following the explosion of the Deepwater Horizon offshore drilling platform. The United States filed suit on December 15, 2010 against BP and eight other companies for damages stemming from this year's oil spill in the Gulf of Mexico, the worst in US history. The complaint was filed by the Justice Department with a federal court in New Orleans, where thousands of individuals and small businesses have already sued the oil giant. (AFP / Getty Images)

  • Massive Oil Slick Threatens U.S. Gulf Coast

    GULF OF MEXICO- MAY 5: Gathered concentrated oil burns during a controlled oil fire May 5, 2010 in the Gulf of Mexico. The U.S. Coast Guard oversaw the oil burn after the sinking and subsequent massive oil leak because of the sinking of the Deepwater Horizon oil platform off the coast of Louisiana. (Photo by Justin E. Stumberg/U.S. Navy via Getty Images)

  • In this aerial photo taken in the Gulf of Mexico, more than 50 miles southeast of Venice on Louisiana's tip, an oil slick is seen as the Deepwater Horizon oil rig burns. (Gerald Herbert, AP)

  • BP CEO Tony Hayward (C) answers questions from the media on an oil-stained beach on May 24, 2010 at Port Fourchon, Louisiana. Hayward said that BP is doing everything possible to clean up the massive oil spill still gushing into the Gulf of Mexico. Officials now say, however, that it may be impossible to clean the hundreds of miles of coastal wetlands and islands affected. (John Moore, Getty Images)

  • A brown pelican covered with oil from th

    A brown pelican covered with oil from the BP Deepwater Horizon oil spill, swims at Sandy Point in the Gulf of Mexico, near Venice, Louisiana, June 15, 2010, prior to being captured by team of biologists from the US Fish and Wildlife Service. Birds are caught and then cleaned at the Fort Jackson Oiled Wildlife Rehabilitation Center. AFP PHOTO / Saul LOEB (Photo credit should read SAUL LOEB/AFP/Getty Images)

  • Gulf Coast Battles Continued Spread Of Oil In Its Waters And Coastline

    GULFPORT, MS - JULY 1: An Oil cleanup worker uses a shovel to remove thick oil that washed ashore from the Deepwater Horizon oil spill in the Gulf of Mexico on July 1, 2010 in Gulfport, Mississippi. Millions of gallons of oil have spilled into the Gulf since the April 20 explosion on the drilling platform. (Photo by Joe Raedle/Getty Images)

  • In this June 3, 2010 file photo, a brown pelican is mired in heavy oil on the beach at East Grand Terre Island along the Louisiana coast. Retired Coast Guard Adm. Thad Allen, the federal government's point man on the disaster, said Sunday, Sept. 19, 2010, BP's well "is effectively dead." A permanent cement plug sealed BP's well nearly 2.5 miles below the sea floor in the Gulf of Mexico, five agonizing months after an explosion sank a drilling rig and led to the worst offshore oil spill in U.S. history. (Charlie Riedel, AP)

  • Massive Oil Slick Reaches Louisiana Gulf Coast

    VENICE, LA - MAY 02: Oil spill workers head out to their boats as they prepare to help with the cleanup of the massive oil spill created in the aftermath of the April 20 explosion of the Deepwater Horizon offshore oil rig May 2, 2010 in Venice, Louisiana. High winds and rough water have slowed the cleanup effort. (Photo by Scott Olson/Getty Images)

  • A man cleans a beach May 4, 2010 in Bilo

    A man cleans a beach May 4, 2010 in Biloxi, Mississippi, as the gulf coast is still being threatened by the oil spill from the BP Deepwater Horizon platform disaster. AFP PHOTO/Stan Honda (Photo credit should read STAN HONDA/AFP/Getty Images)

  • U.S. President Barack Obama picks up balls of tar while touring the beach May 28, 2010 in Port Fourchon, Louisiana. The oil spill resulting from the Deepwater Horizon disaster now officially ranks as the worst in U.S. history. (Win McNamee, Getty Images)

  • Hermit crabs struggle to cross a patch of oil from the the Deepwater Horizon spill on a barrier island near East Grand Terre Island, La, Sunday, June 6, 2010. (Charlie Riedel, AP)

  • Workers put the finishing touches on the

    Workers put the finishing touches on the Pollution Control Dome at the Martin Terminal worksite in Port Fourchon, as BP rushes to cap the source of the oil slick from the BP Deepwater Horizon platform disaster in Louisiana, on May 4, 2010. BP delayed until May 5 the deployment of a giant 'dome' to try to contain the main leak spewing crude oil into the Gulf of Mexico. The British energy giant now plans to load the 98-ton structure onto a boat at 'noon tomorrow' before shipping it out to the leak site. The dome, which is to be guided onto the largest of three oil leaks by remote-controlled submarines a mile down on the seabed, should be 'operational within six days,' Suttles said. Two weeks after the Deepwater Horizon rig exploded, the full impact of the disaster is being realized as a massive slick looms off the US Gulf coast, threatening to wipe out the livelihoods of shoreline communities. AFP PHOTO/Mark RALSTON (Photo credit should read MARK RALSTON/AFP/Getty Images)

  • A dead fish is seen on the beach May 5,

    A dead fish is seen on the beach May 5, 2010 in Pass Christian, Mississippi as the gulf coast is still threatened by the oil spill from the BP Deepwater Horizon platform disaster. Emergency crews rushed to protect fragile shorelines and islands as the Gulf of Mexico oil slick expanded, prompting a mobilization of more national guard troops and alerts as far as the Florida Keys. With oil still gushing Wednesday from the ruptured offshore well, volunteers and others descended on the region to help stave off a looming environmental crisis from the huge oil patch. AFP PHOTO/Stan Honda (Photo credit should read STAN HONDA/AFP/Getty Images)

  • Seagulls and other birds fly past oil booms that were placed in preparation of the looming oil spill from last week's collapse and spill of the Deepwater Horizon oil rig, Saturday, May 1, 2010, along the North Shore south of Venice, Louisiana. Wildlife in the region is vulnerable to the looming oil spill from last week's collapse and spill of the Deepwater Horizon oil rig. (Eric Gay, AP)

  • Bayou Candlelight Vigil Marks 100 Days Since BP Oil Spill

    GRAND ISLE, LA - JULY 29: Local residents gather near an oil processing area on the beach to commemorate 100 days of the BP oil spill on July 29, 2010 in Grand Isle, Louisiana. Eleven lives were lost and three to five million barrels of oil have spilled into the Gulf of Mexico since the BP Deepwater Horizon exploded on April 20, 2010. (Photo by Chris Graythen/Getty Images)

  • Eric Melerine sheds tears as he talks about possibly losing his fishing business, that has been in the family for genertions, if he can't continue to work because of the oil spill in the Gulf of Mexico on May 1, 2010 in Delacroix, Louisiana. As oil-polluted waters approach the Louisiana coast, fishermen don't want to take chances selling possibly contaminated crabs so they are pulling their traps and dumping their catches. Oil is still leaking out of the Deepwater Horizon wellhead at a estimated rate of 1,000-5,000 barrels a day. (Joe Raedle, Getty Images)

  • Massive Oil Spill's Damage To Gulf Environment And Economy Increases

    WAVELAND, MS - JULY 09: An oil coated containment boom is seen close to the shore after it was moved out of place during the high winds and waves in the past days which brought oil ashore from the Deepwater Horizon oil spill in the Gulf of Mexico July 9, 2010 in Waveland, Mississippi. Millions of gallons of oil have spilled into the Gulf since the April 20 explosion on the drilling platform. (Photo by Joe Raedle/Getty Images)

  • Massive Oil Spill's Damage To Gulf Environment And Economy Increases

    WAVELAND, MS - JULY 09: A worker uses a shovel to pick up oily globs that washed ashore from the Deepwater Horizon oil spill in the Gulf of Mexico July 9, 2010 in Waveland, Mississippi. Millions of gallons of oil have spilled into the Gulf since the April 20 explosion on the drilling platform. (Photo by Joe Raedle/Getty Images)

  • One of the New harbor Islands is protected by two oil booms against the oil slick that has passsed inside of the protective barrier formed by the Chandeleur Islands, as cleanup operations continue for the BP Deepwater Horizon platform disaster off Louisiana, on May 10, 2010. Days after failing to contain the Gulf of Mexico oil spill with a giant dome, BP said it will make a second attempt this week using a smaller version dubbed the "top hat." A four-story, 100-ton box was lowered Friday to the seabed to try to capture most of the oil and allow it to be funneled up to a ship on the surface, but it was rendered useless on Sunday when ice crystals formed in its domed roof. BP experts believe the smaller "top hat" containment box would not suffer the same problem as it would not hold so much freezing cold seawater, and they are preparing to drop it into the inky depths to carry out a similar fix to what is unfolding as one the worst oil spills in US history. (Mark Ralston, AFP / Getty Images)

  • Gulf Coast Battles Continued Spread Of Oil In Its Waters And Coastline

    GULFPORT, MS - JULY 1: Thick oil is seen washed ashore from the Deepwater Horizon oil spill in the Gulf of Mexico on July 1, 2010 in Gulfport, Mississippi. Millions of gallons of oil have spilled into the Gulf since the April 20 explosion on the drilling platform. (Photo by Joe Raedle/Getty Images)

  • Gulf Coast Battles Continued Spread Of Oil In Its Waters And Coastline

    ORANGE BEACH, AL - JUNE 27: Workers place absorbent material on to the beach as oil residue washes ashore from the Deepwater Horizon oil spill in the Gulf of Mexico on June 27, 2010 in Orange Beach, Alabama. Millions of gallons of oil have spilled into the Gulf since the April 20 explosion on the drilling platform. (Photo by Joe Raedle/Getty Images)

  • Massive Oil Spill's Damage To Gulf Environment And Economy Increases

    WAVELAND, MS- JULY 09: Workers clean up oily globs that washed ashore from the Deepwater Horizon oil spill in the Gulf of Mexico July 9, 2010 in Waveland, Mississippi. Millions of gallons of oil have spilled into the Gulf since the April 20 explosion on the drilling platform. (Photo by Joe Raedle/Getty Images)

  • Gulf Coast Battles Continued Spread Of Oil In Its Waters And Coastline

    ORANGE BEACH, AL- JUNE 27: Pete Duchock holds his daughter, Maddie Duchock, as they stand near oil residue that has stained the beach after washing ashore from the Deepwater Horizon oil spill in the Gulf of Mexico on June 27, 2010 in Orange Beach, Alabama. Pete Duchock said his daughter cried after seeing the oil washing ashore when they arrived for their vacation. Millions of gallons of oil have spilled into the Gulf since the April 20 explosion on the drilling platform. (Photo by Joe Raedle/Getty Images)

  • Gulf Coast Battles Continued Spread Of Oil In Its Waters And Coastline

    ORANGE BEACH, AL - JUNE 26: A beach goer walks on the beach where oil is seen in the water as it washes ashore from the Deepwater Horizon oil spill in the Gulf of Mexico on June 26, 2010 in Orange Beach, Alabama. Millions of gallons of oil have spilled into the Gulf since the April 20 explosion on the drilling platform. (Photo by Joe Raedle/Getty Images)

  • BP CEO Tony Hayward Testifies Before House Hearing On Oil Spill

    WASHINGTON - JUNE 17: BP Chief Executive Tony Hayward is sworn in before the Oversight and Investigations Subcommittee for a hearing on the Deepwater Horizon explosion and oil spill June 17, 2010 in Washington, DC. BP agreed yesterday to place $20 billion into an escrow account managed by a third party to pay out claims resulting from the oil spill and also said it will not pay out additional dividends to shareholders for the remainder of the year. (Photo by Win McNamee/Getty Images)

  • Congress Holds Hearings On BP Oil Spill

    WASHINGTON - JUNE 17: A protester is escorted from the hearing room after disrupting the hearing of BP Chief Executive Tony Hayward (R) on the Gulf Coast oil spill on Capitol Hill June 17, 2010 in Washington, DC. (Photo by Alex Wong/Getty Images)

  • Members of AnimaNaturalis with their bod

    Members of AnimaNaturalis with their bodies covered with black paint protest against the oil spill of BP's drilling well in the Gulf of Mexico, on July 22, 2010 in Mexico city. Demostrators aim to alert people about the animals dying because of the oil spill and call to use less petrol. AFP PHOTO/ Omar TORRES (Photo credit should read OMAR TORRES/AFP/Getty Images)

  • Bayou Candlelight Vigil Marks 100 Days Since BP Oil Spill

    GRAND ISLE, LA - JULY 29: Cacinda Voisin (C) holds a balloon to comemorate the eleven lives lost and 100 days of the BP oil spill on July 29, 2010 in Grand Isle, Louisiana. Three to five million barrels of oil have spilled into the Gulf of Mexico since the BP Deepwater Horizon exploded on April 20, 2010. (Photo by Chris Graythen/Getty Images)

  • Crosses with descriptions of fish, wildl

    Crosses with descriptions of fish, wildlife and summer pastimes are displayed in a front yard of a home in Grand Isle, Louisiana, June 14, 2010, of things potentially lost to the BP Deepwater Horizon oil spill. AFP PHOTO / Saul LOEB (Photo credit should read SAUL LOEB/AFP/Getty Images)

  • A support ship related to the collection

    A support ship related to the collection of oil from over the site of the BP Deepwater Horizon oil well transitions through a sheen of oil as workers try to stem the flow of the oil spill in the Gulf of Mexico off the coast of Louisiana, June 12, 2010. AFP PHOTO / Saul LOEB (Photo credit should read SAUL LOEB/AFP/Getty Images)

  • Thick oil from the BP Deepwater Horizon

    Thick oil from the BP Deepwater Horizon oil spill floats on the surface of the water and coats the marsh wetlands in Bay Jimmy near Port Sulphur, Louisiana, June 11, 2010. AFP PHOTO / Saul LOEB (Photo credit should read SAUL LOEB/AFP/Getty Images)

  • Oil covered brown pelicans found off the

    Oil covered brown pelicans found off the Louisiana coast and affected by the BP Deepwater Horizon oil spill in the Gulf of Mexico wait in a holding pen for cleaning at the Fort Jackson Oiled Wildlife Rehabilitation Center in Buras, Louisiana, June 11, 2010. AFP PHOTO / Saul LOEB (Photo credit should read SAUL LOEB/AFP/Getty Images)

  • The glove-covered hands of Dan Howells,

    The glove-covered hands of Dan Howells, deputy campaign director with Greenpeace, are coated with a layer of oil after he dipped them in oil floating on the surface in the Gulf of Mexico following the BP Deepwater Horizon oil spill near Grand Isle, Louisiana, June 10, 2010. AFP PHOTO / Saul LOEB (Photo credit should read SAUL LOEB/AFP/Getty Images)

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