Abstract: Employee #1, a 22-year-old, was changing spent batteries on seismographic lines. He was driving a six-wheeled ATV to each battery location along the line. The work site was remote with rocky terrain and had washed out ravines that had to be negotiated with the ATV. The employee had to drive the ATV across a ravine approximately 6 ft deep and 20 ft wide en route to the next battery. He descended the ravine at about a 45 degree angle. The ATV began to overturn and the employee apparently attempted to jump away from the vehicle. The ATV continued to roll down the ravine, landing on him and causing mechanical respiratory failure. Employee #1 was discovered dead approximately 1 1/2 hours later. Routine forensic urine drug testing was performed. The results were positive for exposure to marijuana and amphetamines. This could have been a contributing factor in the employee's inability to negotiate the ATV down the ravine.