As Planet Warms, Advocates Urge U.S. To Set Rules To Protect Workers From Heat - WLRN Two years ago, James Klenk of Freehold, N.J. suffered a heat stroke and went into renal failure after several days sorting and unloading heavy boxes in the back of a UPS truck. He had been a driver for UPS for 14 years and almost died that day. Klenk is one of countless workers across the country enduring symptoms of heat stress. High temperatures can pose health threats on a daily basis, including confusion, fatigue, and dehydration. More extreme heat can lead to heat stroke and organ failure, depending on a worker's environment and how quickly treatment is administered.