Abstract: At approximately 7:00 or 7:13 p.m. on August 15, 2019, an employee was working for a firm that provided support activities for oil and gas operations. He was a truck driver. He was working alone outdoors in approximately 37 degree Celsius (99 degree Fahrenheit) weather. He was getting ready to clean residual oilfield mud out a tanker truck trailer. He was standing on the walkway of the trailer. He had opened the top hatches on the trailer along with the back valve. He was outside the trailer, using a hose to spray water into the trailer to remove residual oilfield mud. A coworker found him slumped over on the trailer walkway with the water hose running. Emergency services were contacted. Upon their arrival, the employee was pronounced deceased. He had sustained a cardiac arrest. He died. The employer notified the Division of the fatality on August 15, 2019, meeting reporting requirements. The Kern County, California, fire department also reported the fatality. An inspection resulted in no accident-related violations.