LOS ANGELES (MarketWatch) -- As part of its second-quarter earnings report, oil giant BP PLC said Tuesday that it will reduce its contributions to U.S. tax coffers by $9.9 billion, due in large part to the Gulf of Mexico oil spill. BP indicated in its report that it is taking a $32.2 billion charge against earnings for the Gulf response efforts, which allows them to take the tax credit. "We have followed the IRS regulations as they're currently written," outgoing BP Chief Executive Tony Hayward said in a conference call.