Abstract: At approximately 9:45 a.m. on March 28, 2011, Employee #1 was mechanical altering a metal part on a service truck with a portable pneumatic grinder. The equipment and materials used were a compressor, compressor hose, air powered portable grinder, Kasco A36 4" grinding wheel, a vice and a piece of metal. As he worked, the grinding wheel exploded and ejected a piece of it. This debris struck him and caused a complex laceration on his left arm. A coworker heard the sound and traveled over to assist him. The coworker then went to the office and had another employee summon emergency medical personnel. They arrived and transported him to a medical center, where he underwent surgery and received post-operative care, and was hospitalized for two days.