In court filings in Houston federal court Tuesday, the oil firm responded to a U.S. Justice Department lawsuit filed in December that estimates 4.1 million barrels spilled after the Deepwater Horizon explosion on April 20, 2010. The well was capped July 15 and permanently sealed Sept. 19.
The federal government says it will seek civil penalties of $1,000 to $4,300 per barrel based on whether willful negligence is found.
BP denies willful negligence and says fines should be set at $32,500 for each day the well flowed.
That system would yield fines from $2.8 million to $4.9 million, depending on whether the capping or sealing date is used. The per-barrel system would mean fines of $4.1 billion to more than $20 billion.
BP's partners in the well, Anadarko Petroleum Corp. and MOEX Offshore, a unit of Mitusi, also filed papers denying negligence or willful misconduct.