Abstract: At approximately 9:15 a.m. on August 20, 2012, Employee #1 was working for an oil and gas well drilling and maintenance company in Tupman, CA. Employee #1 was a full-time permanent employee of the employer. At the time of the incident, Employee #1 was on a drill rig floor. Employee #1 was not a bystander. Rather, he was unscrewing a mud pump hose from a mud pump. His supervisor was at the operator controls of the drilling rig. The mud hose was a 4-inch diameter by six-foot long hose that weighed approximately 200 to 300 pounds (100-millimeter diameter by 1.8-meter long hose weighing some 91 to 136 kilograms). Employee #1 was struck in the back of the head by the mud hose. Before he sustained his head injury, Employee #1 was exhibiting symptoms of heat-exhaustion, due to his not being acclimated to the high heat of his surroundings. No equipment was involved in his heat exhaustion. Instead, Employee #1 was not adequately acclimated to the high heat that was present on the days prior to the incident. The employer reported the incident to the Division at approximately 9:23 p.m. on August 21, 2012.