Abstract: On June 30, 2009, Employee #1, vacuum truck operator, was connecting and disconnecting hoses, opening and closing valves, driving to and from the well and brine water reservoir, during hot weather. He worked a fifteen minute rest/work regime and was relieved from climbing on to the trailer to open valves and allowed to doff the Tyvek suit to his waist and remove the respirator and gloves. A shade canopy was provided at the end of the trailer, a sufficient quantity of water was provided, and Employee #1 was encouraged to drink small quantities frequently. The truck's air conditioning was in continuous operation. Unloading time was 30 minutes, loading took 45 minutes and drive time between well and reservoir was five minutes. The supervisor stopped work early in consideration for the heat. Employee #1 returned to his hotel and experienced severe muscle cramps, causing him to contact the hotel's management, who summoned emergency medical services. He was transported to a local hospital and was treated for severe dehydration and renal failure. It was found that Employee #1 was not acclimated to the heat, but was also diabetic, hypertensive, obese and was not taking his medications or managing his blood sugar.