(Updates with comment from Coast Guard)
By Elizabeth Dilts
NEW YORK, March 26 (Reuters) - Between nine and 18 barrels (378-756 gallons) of oil spilled into Lake Michigan from BP Plc's Whiting refinery in Indiana after a malfunction on Monday, the U.S. Coast Guard confirmed on Wednesday.
The amount of oil spilled is based on an initial visual estimate and may change, a U.S. Coast Guard spokesman said.
The spill occurred Monday afternoon at a recently upgraded water treatment plant in a cove that leads into the lake, the company and the U.S. Environmental Protection Agency said. About 5,000 square yards of water was coated in an oily sheen and oil slicks could be seen on the shore and rocks, BP said in an initial report to the EPA.
The cleanup continued Wednesday as crews vacuumed up 5,200 gallons of oily water from the area, a U.S. Coast Guard spokesman said. Barriers at the mouth of the cove to block the oil from flowing to the lake were replaced after strong winds and waves blew them out of place on Tuesday. The winds blew the oil further into the cove up onto the shoreline, the Coast guard spokesman said.
There is no evidence that oil leaked outside of the containment boom, the EPA said. (Reporting By Elizabeth Dilts; Editing by Nick Zieminski and Chizu Nomiyama)