By Ben Lefebvre Of DOW JONES NEWSWIRES HOUSTON -(Dow Jones)- The U.S. Environmental Protection Agency ordered Enbridge Energy Partners LP (EEP) to continue cleaning the oil its Line 6B spilled into a Michigan river until the end of 2012, the agency said Friday. The order came after more oil was found submerged in the Kalamazoo River than originally thought, causing Enbridge to miss its original cleanup deadline of Aug. 31. Enbridge's Line 6B spilled about 20,000 barrels of oil outside of Marshall, Mich., in July 2010, with a large part of the crude reaching the river. Although Enbridge has made "huge" progress in cleaning the waterway, the sheer size of the river and moving currents have complicated attempts to locate all of the oil, said Ralph Dollhopf, EPA on-scene coordinator. "Every time we go back to look, we find more," Dollhopf said. "The river is causing the oil we are targeting to always move." Enbridge in September raised its cleanup cost estimate to about $700 million, about 20% higher than its original estimate. Cleanup work will soon be suspended for winter but will restart in spring, Dollhopf added. An Enbridge spokeswoman was not immediately available for comment. Enbridge Energy Partners is a U.S. affiliate of Canada-based Enbridge Inc. (ENB, ENB.T). -By Ben Lefebvre, Dow Jones Newswires; 713-547-9201; ben.lefebvre@dowjones.com Order free Annual Report for Enbridge Inc Visit http://djnweurope.ar.wilink.com/?ticker=CA29250N1050 or call +44 (0)208 391 6028 Order free Annual Report for Enbridge Energy Management Visit http://djnweurope.ar.wilink.com/?ticker=US29250R1068 or call +44 (0)208 391 6028