Respondent is an offshore oil and gas operator in the Gulf of Mexico. On May 21, 2003, Respondent was pulling drill pipe out of a hole and the drilling riser parted approximately 3000 feet below sea level. About 2450 Barrels of Accolade synthetic based drilling mud was discharged and sunk to the ocean floor. The water depth is 6015 feet at this location. This incident happened in the Dept. of Interior's Mississippi Canyon (MC) lease area and in block 778 (OSC-G-14658).