BP has asked a US court to sack court-appointed settlement administrator Patrick Juneau for failing to disclose a conflict of interest before taking up the job of handling damage claims from the 2010 Gulf of Mexico oil spill.
The motion in the US District Court in New Orleans said Juneau lacked neutrality because he had advocated for claimants even before being appointed to manage the settlement programme, reports said.
Juneau told the Associated Press that he will respond in court.
The 2 September motion was the latest in a series of legal challenges filed by the British oil major, which has complained that Juneau has been too generous when approving claims.
As of 2 September, about $4.1bn (£2.5bn, €3.1bn) had been paid out to 49,868 claimants, according to Juneau's claims website.
Juneau has said he was just following the rules of the 2012 settlement accord that was approved by US District Judge Carl Barbier.
In March, BP warned that the cost of the 2010 Gulf of Mexico oil spill could pass the $18bn mark.
BP said it could face additional lawsuits, lose business in the wake of the damage to its reputation, and miss out on opportunities as its legal expenses were pressurising its cash flow.
BP initially estimated that its settlement with businesses and individuals harmed by the Gulf of Mexico oil spill would cost $7.8bn. As of 4 February, it had boosted that estimate to $9.2bn, and said this sum could grow "significantly higher."
The April 2010 disaster aboard the Deepwater Horizon drilling rig killed 11 workers and sent more than four million barrels of oil into the sea.
The case is Oil Spill by the Oil Rig "Deepwater Horizon" in the Gulf of Mexico, on April 20, 2010, US District Court, Eastern District of Louisiana, No. 10-md-02179.