EE REMOVED HOSE & FITTING FROM AIR STARTER ON HAUL TRUCK USING PIPE WRENCH. HE SAID ARM STARTED HURTING LIKE HE MAY HAVE PULLED A MUSCLE. ON 4/1ARM KEPT HURTING SO HE WENT TO EMERGENCY ROOM. 4/2 INFO ONLY REPORT FILED BY LOCATION TO INVESTIGATE. 4/3 WORKER COMP CONFIRMED INJURY TORN BICEP TENDON NEEDING SURGERY.