Anadarko Petroleum Corporate Headquarters, Texas

Anadarko Petroleum is an independent oil exploration and production company, based in the Woodlands, north of Houston. Companies in this field seek out and develop new or existing oil and gas fields, generating revenue primarily by discovering, developing, and leasing these lands for oil and gas production. Many smaller companies work onshore, where expenses for exploration are less, others work offshore, competing with major oil companies. Anadarko works both on and offshore, in Alaska, Algeria, Brazil, Columbia, Ghana, Mozmbique, Wyoming, and elsewhere, with over 5,700 employees, generating a cash flow of $8.9 billion in 2013. It is one of the largest independent deepwater producers in the Gulf of Mexico. Anadarko was heavily involved with developing the Marcellus Shale natural gas deposit in Pennsylvania. In 2010, as a result of the Deepwater Horizon explosion and oil spill, BP invoiced Anadarko over $272 million, for its share of cleanup costs. Initially Anadarko refused to pay, but ultimately settled with BP for $4billion, in exchange for indemnification against all future claims. In 2014, Anadarko agreed to a $5.15 billion settlement with the federal government - the largest ever for environmental contamination - to settle claims related to the cleanup and remediation of thousands of heavily contaminated sites which it owns.