Abstract: On July 5, 1994, Employee #1 started work as a truck driver at Industrial Oil Unlimited (contractor). It was also his first day with the Maxwell Companies (personnel services). Employee #1 was helping a senior truck driver load 11 drums and 36 five-gallon pails of lubricants onto a delivery truck. The truck was equipped with air conditioning, power lift, and power steering. Employee #1 and the senior driver left the job site at 12:40 p.m. to start deliveries. They had made three stops by 2:15 p.m. After the third stop, Employee #1 slumped over the steering wheel of the delivery van. He died of pre-existing coronary occlusive disease. His rectal temperature, 102.2 degrees Fahrenheit, was the basis for determining that environmental heat stress was a contributor to the cardiac arrhythmia.