Lawmakers and environmentalists today praised a plea agreement that levies historic criminal fines on BP PLC for the Deepwater Horizon disaster, while emphasizing that it should be only the beginning of the oil giant's payout for the unprecedented oil spill in the Gulf of Mexico.

The Justice Department announced today that BP will plead guilty to 11 felony counts of manslaughter for the workers killed in the Deepwater Horizon oil rig explosion on April 20, 2010. The company has also agreed to admit guilt to one misdemeanor count under the Clean Water Act, one misdemeanor count under the Migratory Bird Treaty Act and one felony count of obstruction of Congress.

Under the terms of the agreement, BP will pay $4 billion to resolve the criminal claims, plus $535 million to the Securities and Exchange Commission to compensate harmed investors from losses.

Reps. Ed Markey (D-Mass.) and Henry Waxman (D-Calif.), who led Congress' investigation into the oil spill, held a news conference today applauding the Justice Department for imposing what they characterized as a deserved record-setting penalty. They highlighted one guilty plea that directly involved them: the felony count of obstruction of Congress.

By pleading guilty to that, BP is acknowledging that it lied to Congress about how much oil was flowing into the Gulf, an issue Markey and Waxman investigated in the aftermath of the explosion.

"BP lied to me. They lied to the people of the Gulf. They lied to their shareholders. They lied to all Americans," said Markey, the ranking member of the House Natural Resources Committee.

Markey and Waxman also called for a speedy resolution to the civil charges the company still faces.

"We need to hold wrongdoers accountable," said Waxman, the top Democrat on the House Energy and Commerce Committee. "They have yet to be held civilly accountable."

Other lawmakers echoed that sentiment. The plea agreement is a "welcome step but closes only one chapter in this story," said Sen. Tom Carper (D-Del.), who sits on the Senate Environment and Public Works Committee and heads an oversight committee subpanel on federal financial management. Many federal, state and local claims remain unresolved, requiring "vigilance," he said.

"We will unfortunately be grappling with the human and environmental costs levied by this disaster for many years. For many, no amount of money can adequately repair the damage caused by this spill," Carper said. "But going forward, I will continue to focus my energy on ensuring that those responsible for this disaster are held accountable to the impacted citizens living on our Gulf Coast and to all Americans, as well as on ensuring that taxpayers are not left footing the bill for the effects of the spill."

Ongoing investigation

At a news conference today, Attorney General Eric Holder emphasized that the plea agreement pertained only to the criminal charges against BP, as well as SEC claims. The company still faces civil charges, with a trial set for February. DOJ plans to "vigorously enforce" its complaint, which alleges that BP is guilty of "gross negligence."

"I want to be really, absolutely clear that today's resolution does not -- does not -- mark the end of our efforts," Holder said. "In fact, our criminal investigation remains ongoing."

DOJ officials also highlighted the fact that the plea agreement stipulates that most of the fines will go to conservation efforts for the Gulf Coast states, calling such a deal "historic." BP has agreed to pay almost $2.4 billion to the National Fish and Wildlife Foundation, while $350 million will go to the National Academy of Sciences for an endowment that will fund research on improving drilling safety measures.

Environmental groups applauded that move, calling it a step forward that nonetheless is far less than what is needed to restore the Gulf Coast.

Sierra Club Executive Director Michael Brune was one of the harshest critics, criticizing the Justice Department for letting "BP off with a slap on the wrist after causing the largest oil disaster in American history."

"The Sierra Club is working to make sure that the remaining civil Clean Water Act and Oil Pollution Act lawsuits will result in penalties topping $60 billion, which better reflects the harm BP inflicted on the Gulf," he said. "We urge the Department of Justice to pursue the remaining legal charges vigorously, and bring BP to justice for their crimes against Gulf families and businesses."

But Bethany Kraft, director of the Ocean Conservancy's Gulf Restoration Program, expressed hope that the settlement would "set the stage" for record fines for the civil charges, which could add up to much more than $4 billion. National Wildlife President Larry Schweiger also called the settlement a "good down payment."

"There's still a lot of work to be done when it comes to penalizing the parties responsible for the Gulf oil disaster through the civil provisions of the Oil Pollution Act and the Clean Water Act, but this criminal settlement marks important progress and devotes much-needed resources toward restoration," he said.