It has also sparked a series of lawsuits and federal investigations into the companies involved. Last month BP reached a $US250 million settlement with Cameron International, the designer and manufacturer of the rig's failed blowout preventer, ending all claims between the two relating to the spill. BP has also reached agreements with other companies involved in the rig including Anadarko and Weatherford. But agreements with Halliburton and Transocean, which operated the rig, have proved harder to achieve, with both parties launching lawsuits.