Faced a grim future on Tuesday as its failure to stop a Gulf of Mexico oil spill prompted a plunge in the energy giant's shares and the Obama administration opened a criminal investigation.
President Barack Obama, struggling to get on top of the worst oil spill in US history, vowed an overhaul of US laws and regulations needed to prevent a repeat of the April 20 rig explosion that killed 11 people and triggered the spill.
And after meeting co-chairs of a commission that will investigate the accident, Obama raised the prospect of criminal prosecutions and BP began a new strategy to end the six-week-old drama.
"If our laws were broken leading to this death and destruction, my solemn pledge is that we will bring those responsible to justice on behalf of the victims of this catastrophe and the people of the Gulf region," Obama said.
US Attorney General Eric Holder, on a visit to the region, said in New Orleans that the US government has launched a criminal probe and that federal agencies, including the FBI, are participating.
"If we find evidence of illegal behavior, we will be forceful in our response," Holder told reporters.
The oil giant's shares fell by as much as 17 percent in London on Tuesday before ending down 13 percent, at 430 pence. Later in New York, the American Depositary Receipts lost nearly 15 percent to close at 36.52.
The shares were hit hard by weekend news that its latest attempt to plug its blown-out seabed well had not worked, sparking fears oil could leak into the Gulf until August.
The shares have lost more than a third of their value, or about 46 billion pounds ($67 billion), since the leak started. The cost of dealing with the crisis now totals $990 million, and is rising.
Shares of other companies with stakes in the well were also down between 10 and 17 percent, including Anadarko, Transocean, Cameron and Halliburton.
In its next attempt to stop the mile-deep gusher, BP's next plan will use a dome to funnel oil to a tanker on the surface. Robotic equipment will use giant shears and a diamond saw to cut a pipe 35 feet (11 meters) above the wellhead that will allow BP to sit the dome on top of it.
