Employee was prying on the tail gate of the Mack truck with a slate bar. Tail gate was frozen. He experienced pain in his abdominal muscle. On 3/9/07 he informed me he had a lump in his abdomen and was scheduled for an MRI on 3/13/07. A hernia was detected. He was scheduled for surgery on 4/9/07. His 1st day missed was 4/9/07.