While solemn commemorations marked the first anniversary of the calamitous BP oil spill, legal claims filed by the oil giant and other companies involved in the disaster show that lengthy court battles lay ahead.

Around the Gulf Coast Wednesday, residents said prayers on the beach and lit candles in the heart of New Orleans, while relatives flew over the sea where 11 rig workers died a year ago. In New Orleans courts, BP filed lawsuits alleging negligence by the rig owner and the maker of the device that failed to stop the spill. The blowout preventer maker and rig owner filed their own claims.

BP said in its lawsuit filed in federal court in New Orleans that Cameron International provided a blowout preventer with a faulty design, alleging that negligence by the manufacturer helped cause the disaster. The lawsuit seeks damages to help BP pay for the tens of billions of dollars in liabilities it has incurred from the disaster.

It also was seeking $40 billion from rig owner Transocean, accusing it of causing last year's deadly blowout in the Gulf of Mexico that led to the worst offshore oil spill in U.S. history. BP says every single safety system and device and well control procedure on the Deepwater Horizon rig failed.

The lawsuit against Cameron said the blowout preventer "was unreasonably dangerous, and has caused and continues to cause harm, loss, injuries, and damages."

Houston-based Cameron noted in a statement emailed to AP that Wednesday was the deadline under the relevant statute for all parties to file claims against each other. It said it has filed claims of its own to protect itself.