Officials say a Coast Guard, BP and U.S. Environmental Protection Agency assessment team checking the area near the Whiting refinery on Sunday spotted no visible oil on the shore or in the water. Cleanup workers spent last week removing oil from about a half-mile section of shoreline.
The Coast Guard says BP is being allowed to remove most of the containment boom from the lake some 20 miles southeast of downtown Chicago where a refinery malfunction discharged oil on March 24.
BP estimates between 15 and 39 barrels of oil were discharged into the lake. That's between 630 and 1,638 gallons.