Did BP crew members know that an explosion was imminent? Democrats on the House energy committee have released results from their investigation of the ongoing oil spill in the Gulf of Mexico, and their report finds "several new warning signs" occurring shortly before the blast. Flow indicators, meant to alert workers that pressure was building inside the drill pipe, went off several times in the hour before the drill pipe exploded, one just 18 minutes beforehand, the memo reports; also, BP recognized a "very large abnormality" two hours before the explosion but continued working, a move it calls a "fundamental mistake." The committee says they will continue to make further inquiries. Meanwhile, BP is readying its "top kill" contraption, which will be the company's first attempt to stop rather than contain the oil flow. A five-story blowout preventer is covering the wellhead of the rig, and mud will be pumped in to clog the flow of the oil.