Scientists have confirmed that the BP disaster is the worlds’ largest oil spill. U.S. federal scientists estimate that since the Horizon rig exploded on April 20, nearly five million barrels of oil have gushed from the rig. The 3.3 million barrel spill into the Bay of Campeche by the Mexican rig Ixtoc in 1979 was believed to be the largest spill. Though the BP spill was acknowledged to be the largest in American history, it was unclear whether it was bigger than Ixtoc. Since April, the estimates of the BP flow rate have steadily increased. Under the Clean Water Act, the U.S. government will penalize BP $1,100 a barrel. If the government finds that gross negligence led to the spill they could be charged $4,300 per barrel. Today, BP is undergoing tests to decide whether it’s safe to drill mud into the Macando well and seal it by the end of the week. That will curb the oil gush until the relief wells are operating. The relief wells are scheduled to work by Aug. 15, at which time engineers can pump cement into the well in the hopes of permanently sealing it.