Abstract: At 8:00 a.m. on October 22, 2001, an employee of West Coast Communications was installing cable communications systems in Paso Robles, CA. He was using a "ground rod slammer" to drive a copper grounding rod into the ground. The ground rod slammer consisted of a 20-lb. sledge hammer head with an approximately two-and-one-half-foot-long hollow handle or sleeve. The copper grounding rod was an eight-foot-long solid rod, 0.5 inches in diameter. The sleeve was placed over the rod and the force of the sledge hammer head was brought down to drive the rod into the ground. The employee had driven all but about 2.5 feet of the rod into the ground. Immediately prior to the final stroke, the sleeve came off the rod. The employee was in already in a downward motion and was unable to stop the inertia by the time he saw that the sleeve had come off. His right hand was caught between the rod and the 20-lb. sledge hammer head. The rod punctured his hand on the little finger side, entering about 0.5 inches above the wrist joint and exiting the back of the hand near the index finger and thumb. He was hospitalized with a puncture wound.