A complaint about petrol odours led investigators to discover an oil leak from an underground pipe near a Chicago area township in Illinois, US.
The U.S. Environmental Protection Agency (EPA) is monitoring the cleanup of an oil leak discovered on 14 December.
The EPA says the pipeline, owned by West Shore Pipe Line Co., was shut down. Federal officials say early estimates show 21,000 gallons of oil may have been released.
Reports suggest the leak comes from an underground pipeline that feeds into storage tanks in Lockport, which is about 35 miles southwest of Chicago.