What a classy way to mark the anniversary of the nation’s worst oil spill. BP filed suit Wednesday against Transocean, the owner of the rig that exploded a year ago in the Gulf of Mexico, for $40 billion, claiming Transocean is at fault for the disaster. The massive figure is meant to help BP defray the associated costs of the debacle’s cleanup. The disgraced British oil giant is also suing Cameron International, claiming its blowout preventer had a faulty design. "The blowout preventer failed to work and perform the function it was designed and manufactured to perform—i.e., to secure the well," BP said in the complaint.