Under their joint operating agreement, Anadarko is responsible for 25 percent of the costs of any incident, including an oil spill. But their agreement also stipulates that if BP is responsible through gross negligence or willful misconduct, Anadarko -- and the other partner, Mitsui -- are off the hook.
The announcement that they won't pay comes as no surprise. Anadarko CEO Jim Hackett released a scathing statement last month that claimed the leak was "the direct result of BP's reckless decisions and actions."
"BP's behavior and actions likely represent gross negligence or willful misconduct and thus affect the obligations of the parties under the operating agreement," Hackett said.
Any legal action between the two companies will likely take place in private arbitration.
Mitsui, which owns a 10 percent stake in the well, has not said whether it will pay its share of about $111 million.
Late update: Anadarko spokesman John Christiansen tells TPMmuckraker his company is working in "good faith" with BP.
"Although we have notified BP that we are withholding reimbursement to BP at this time, we remain committed to working with BP in good faith to achieve a satisfactory resolution," he said.