VIDEO: Crews have contained a large fire in Mercer County. The fire in Mercer County has caused U.S. 68 to shut down. The fire started near the intersection of U.S. 68 and Chinn Lane. Fire crews say a combine harvester and a soybean field caught fire. Crews believe the combine harvester exploded, which caused the fire. The smoke was so heavy, it was visible on the tower cameras in Lexington. Fire departments from other counties also responded to aid Mercer County firefighters. U.S. 68 was shut down for hours as the fire jumped the highway putting other homes in danger and visibility was extremely limited. A field across U.S. 66 sustained fire damage. The Kentucky Transportation Cabinet says the highway has since reopened. No injuries were reported. The fire didn't reach any structures.