The government has named several companies in addition to BP as potentially liable for paying environmental damages. They include Transocean Ltd., which owned the drilling rig, and two owners of minority stakes in the well—Anadarko Petroleum Corp. and an arm of Japan's Mitsui & Co., MOEX Offshore 2007 LLC.
Federal law requires the U.S. government to document a spill's environmental damage—a process called a Natural Resource Damage Assessment—and requires companies found responsible to pay to fix the damage. If the government and the companies can't agree on a settlement, the fight can end up in court.
The long-term human toll is perhaps the hardest to gauge. The U.S. has launched a study to monitor 55,000 former cleanup workers for up to a decade, looking at everything from skin rashes to increased cancer risk. (WSJ, 4/13/2011)