Matthew: I'm self-employed pulmopres cost The U.S. government says 4.9 million barrels were spilled in the worst offshore disaster in U.S. history. BP says 3.26 million barrels leaked from the well during the nearly three months it took to cap the blowout at the Deepwater Horizon rig. Both those totals include 810,000 barrels that were collected during clean-up that the judge has agreed to exclude.