British Petroleum is more than doubling the amount of oil it estimates was spilled into Lake Michigan from its Whiting refinery in Northwest Indiana. BP initially said that 18 barrels of oil were leaking into the lake, but has revised this estimate to 39 barrels or 1,638 gallons of oil. BP revised its estimate after taking into account the amount of oil collected from vacuum trucks and absorbent booms, as well as balls of oil that have washed up ashore. Strong winds have pushed most of the oil towards a shallow cove between the refinery and a steel mill. According to BP spokesman Scott Dean, federal authorities requested an estimate which was based on a visual observation of the water's surface. The U.S. Environmental Protection Agency said that the spill poses no long-term risk to the lake, which is a source of drinking water for 7 million people in Chicago and its suburbs. The EPA has not commented on BP's estimates, stating that it is conducting its own investigation into violations of the federal Clean Water Act. U.S. Sens. Dick Durbin and Mark Kirk of Illinois and Chicago Mayor Rahm Emanuel have asked for more aggressive action against BP and the two senators have also requested a meeting with BP's American CEO John Minge. "This spill raises questions about the long-term safety and reliability of BP's new, expanded production at Whiting," Durbin and Kirk wrote in a letter asking for a meeting with Minge. "It is in all of our best interests … to ensure that this greater processing capacity will do no harm to Lake Michigan." The leak was reported around 4:30 p.m. Monday by refinery workers and according to he EPA the leak was plugged by 9 p.m. The refinery performs the initial steps in refining heavy Canadian oil from the tar sands region of Alberta. It is now back to being fully operational, said BP.