The US is suing BP and eight other firms for allegedly violating federal safety regulations in connection with the Gulf of Mexico oil spill: The lawsuit asks that they be held liable without limitation for all clean-up and damage costs. The Deepwater Horizon drilling rig explosion in April killed 11 workers and spilled millions of barrels of oil over several months. The oil leak became the worst environmental disaster in US history. The lawsuit charges the companies under the US Clean Water Act and Oil Pollution Act. US Attorney General Eric Holder said the complaint alleged that “violations of safety and operational regulations” caused the 20 April explosion.