EE WAS ATTEMPTING TO REMOVE A ROCK THAT WAS LODGED BETWEEN THE DUAL WHEELS ON THE MACK WATER TRUCK. HE FIRST USED A PRY BAR TO TRY TO REMOVE THE ROCK AND WAS UNSUCCESSFUL. HE THEN TRIED TO BRE AK THE ROCK WITH A HAMMER. THE TIRE BLEW WHEN HE STRUCK THE ROCK WITH THE HAMMER AND IT THREW THE HAMMER OUT OF HIS HAND AND SENT HIM HURTLING APPROX 8'. BREAKING HIS THUMB, REQUIRING SURGERY