Critics of the agreement noted that nearly four years after the spill, the cleanup has not been completed. Oil still washes up in places, particularly during storms, as happened in October with Tropical Storm Karen.

“They still haven’t really made it right when it comes to the gulf,” Mr. Hoke said.

Public Citizen, a consumer activist group, also expressed outrage, saying in a statement that the settlement “lets a corporate felon and repeat offender off the hook for its crimes against people and the environment.”

The accident continues to mire the company in lawsuits and court hearings. BP settled criminal charges with the Justice Department two years ago for $4.5 billion in penalties, but the oil company faces billions of dollars more in costs from a federal civil trial in New Orleans to determine how much it will be required to pay in Clean Water Act fines.

The company is also arguing that a separate settlement it made with businesses and individuals who suffered losses because of the accident has been misinterpreted. But a federal appeals court ruled this month that the company would have to abide by its agreement and pay some businesses for economic damages without their having to prove the damages were caused directly by the spill.

BP initially estimated that the costs of the settlement would run to $7.8 billion, but it now says the cost could rise well above that.

BP, which employs 2,300 people in the Gulf of Mexico, continues to explore on leases in the gulf from before the 2010 accident. At the end of 2013, the company had 10 drilling rigs in the deep waters of the gulf, and it reported a significant new discovery 300 miles southwest of New Orleans. BP said last year that it intended to invest at least $4 billion on average in the gulf each year for the next decade.

Oil production in the gulf remains below records set in 2009, and the industry continues to recover from a yearlong drilling moratorium that the federal government set after the spill. But several large oil companies, including Chevron and Royal Dutch Shell, are flocking back to the gulf. There were only about a dozen rigs working in the gulf three months after the disaster, and that increased to more than 60 by the end of last year.