A 37-page memo submitted to the U.S. District Court in New Orleans alleges a "culture of corporate recklessness" at BP led to the 2010 sea-floor oil gusher that released 4.9 million barrels and may still be seeping in the largest accidental oil spill in history.
"The behavior, words and actions of these BP executives would not be tolerated in a middling-size company manufacturing dry goods for sale in a suburban mall," the memo filed Friday said.
"Yet they were condoned in a corporation engaged in an activity that no less a witness than [BP Chief Executive Officer] Tony Hayward himself described as comparable to exploring outer space," the memo said.
Gross negligence could raise BP's penalties under the 1972 Clean Water Act to as much as $21 billion, the Financial Times said. Compensatory and punitive damages could be added to that sum.
The Wall Street Journal reported in May the department was also investigating whether BP executives lied to Congress about how much oil leaked.
The three-month gusher resulted from an April 20, 2010, Deepwater Horizon drilling-rig explosion that killed 11 men working on the platform and injured 17 others. The rig was connected to a BP oil and gas prospect well.
An e-mail the department cited was from a BP executive to his boss three days before the explosion expressing concern Macondo well workers were "flying by the seat of our pants" in an atmosphere of "paranoia" and "chaos." The executive asked what he could do, adding some employees said they might leave the company.
The e-mail he got from his boss said: "John, I've got to go to dance practice in a few minutes. Let's talk this afternoon."
BP responded to the Justice Department's latest filing Tuesday, saying it "believes it was not grossly negligent and looks forward to presenting evidence on this issue at trial in January."
A trial over civil penalties and damages is set for Jan. 14, 2013.
The department memo was in response to a BP request last month for Judge Carl Barbier to approve a $7.8 billion settlement with fishermen and other spill victims at a Nov. 8 hearing.
The department said it was concerned BP was trying to use the settlement to limit its future liability when the gulf's true environmental damage is known.
"BP's cherry-picked assertions of robust recovery are at best premature judgments on the health of the overall gulf ecosystem," the memo said.
The U.S. Coast Guard said Tuesday oil-covered pelicans and other wildlife were found in Louisiana marshes after Hurricane Isaac, which struck last week. Greenpeace found hundreds of tar balls on the beach at Bon Secour National Wildlife Refuge, Ala.
"This is another disaster on top of the hurricane that we're going to have to deal with," Louisiana Coastal Protection and Restoration Authority Chairman Garret Graves told The Huffington Post.
The Justice Department memo, unrelated to Isaac, cited dolphins in the gulf's Barataria Bay in southeastern Louisiana as "showing signs of severe ill health," dead and dying deep-sea coral along with a significant decrease in plankton-eating fish that normally live around those reefs, and heavy marsh oiling that "could cause negative impacts to marsh vegetation for decades to come."