BP on Wednesday sued the maker of the device that failed to stop last year’s calamitous Gulf oil spill and the owner of the rig that exploded, alleging that negligence by both helped cause the disaster.

The British company said in papers filed in federal court in New Orleans that it is suing rig owner Transocean for at least $40 billion in damages, 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.