Transocean, Halliburton and BP are locked in legal battles over which company bears ultimate responsibility for last year's oil spill in the Gulf of Mexico.
An October report listed seven violations for BP and four each for Transocean and Halliburton and the U.S. Bureau of Safety and Environmental Enforcement in early December said it notified BP of five additional regulatory violations stemming from operations at the Macondo well.
The Wall Street Journal, citing unnamed and unidentified sources close to the matter, said federal prosecutors are in the drafting stage of filing charges against BP employees for the spill.
"The breadth of the investigation isn't known," the newspaper reported. "The prosecutors assert the employees may have provided false information to regulators about the risks associated with the Gulf of Mexico well while its drilling was in progress."
Charges of lying to federal regulators, a felony, could become public by next year, the Journal reported. If they materialize, they would be the first criminal charges tied to last year's oil spill.
The April 2010 incident touched off the worst spill in U.S. history. The U.S. Coast Guard said it considers 90 percent of the contaminated area clean.