Alabama is suing BP Plc, Transocean and Halliburton for "catastrophic harm" caused by the Gulf of Mexico oil spill, the state's attorney general said on Friday.
Alabama is the first state to sue BP for damage from the world's worst offshore oil spill.
The decision stems from fear economic victims will be inadequately compensated and BP will shirk its financial responsibility, said Attorney General Troy King.
"We are making this claim because we believe that BP has inflicted catastrophic harm on the state ... We are suing them for the amount it will take to make Alabama whole," King told Reuters, declining to specify a figure for damages.
The suit also named Anadarko Petroleum Corp, among others.
Transocean owned the doomed Deepwater Horizon drilling rig that was hired by BP and exploded and sank in April, triggering the oil spill. Halliburton provided the cement work for the well while Anadarko was a minority owner.
"It is believed the explosion on the Deepwater Horizon was a blowout relating to the cementing work," the suit said.
Alabama Governor Bob Riley opposed the decision to sue BP, according to Mr. King, who argued the suit put the state in the strongest legal position.
The next step was discovery and gathering evidence, Mr. King said, adding that an out of court settlement was possible.
There was no immediate response to the suit from BP.
The suit accuses BP and the other defendants of "negligent or wanton failure to adhere to recognized industry standards of care."
"The defendants' conduct in operating the Deepwater Horizon and oil well illustrates their scheme to maximize profits and ignore dangerous risks posed to human health and property," it said.
Louisiana sustained the most damage to its coastline and waters from the oil spill that began in April and was plugged with cement on July 15. But oil also damaged the economies of Mississippi, Alabama and Florida.
The spill has hurt industries including fishing and tourism and has affected other sectors such as housing. People and businesses that have sustained losses can claim against a $20 billion BP compensation fund administered by Kenneth Feinberg, named by the White House as an independent overseer.
But Feinberg was undermining efforts by Gulf state attorneys general to make it possible for spill victims to claim damages from the fund while retaining the right to sue BP at a future date, Mr. King said.
At the same time, he said, BP was seeking to evade its responsibility despite a high-profile advertising campaign which states: "We will make this right" and promises to honor all legitimate claims.
Mississippi Governor Haley Barbour in July asked the state attorney general not to file a suit against BP to give the federal claims process a chance to work and to allow for a complete assessment of damage to natural resources.