After her husband nearly died from heatstroke, she took her fight to the highest levels

August 2016 was, at the time, the planet's hottest month on record. In Freehold, New Jersey, where Jim Klenk was driving his usual route for UPS, midday temperatures were hitting highs in the 80s and 90s. During one of those punishing late-summer days, Klenk, who was 58, started feeling sick. He was disoriented, his wife, Theresa Klenk, recalled. He hadn't been able to urinate all day. Like most of America's more than 1.5 million parcel delivery drivers, Jim drove a vehicle that lacked air conditioning. On a typical shift, he would be in and out of his truck every few minutes, spending the bulk of his time in the back cargo area, where temperatures can exceed 120 degrees, according to the Teamsters union, which represents UPS drivers. Theresa, a nurse, said Jim didn't want an ambulance or a trip to the ER. Eventually, though, she managed to get him to the hospital where she worked. He was already in kidney failure by the time they arrived. "They pulled me out and asked me what Jim's last wishes would be," she said. Heatstroke, one of the most common and most deadly heat-related illnesses, had put Jim in acute renal failure, Theresa said. But he got lucky, and he was able to go home after five days in the hospital. For Theresa, Jim's close call was a turning point. At the time, she said, no UPS drivers wanted to speak up about the increasingly brutal conditions for fear of being reprimanded. She felt uniquely positioned to begin advocating for change. The physics of staying cool While it may seem surprising in the 21st century that delivery trucks would lack air conditioning, the problem of keeping drivers cool is complicated. Unlike long-haul truckers, the people delivering packages door to door are behind the wheel for only a few minutes at a time. They're mostly on their feet, retrieving boxes from the back and hauling them to their destination. According to UPS, drivers stop on average every three minutes — barely enough time for air-conditioning to make a dent. But as record temperatures grip the planet — this summer was the hottest on record, by a significant margin — delivery drivers are clamoring for any relief they can get. This year's record heat caused dozens of deaths, filled some hospitals to pandemic levels and prompted government warnings about avoiding extended exposure to heat. Still, there are no laws in place compelling employers to protect workers from the heat. The Occupational Safety and Health Administration, or OSHA, began the process of drafting a heat standard for workplaces nearly two years ago, and it's not clear when, or if, those rules will be put in place. Business groups including the US Chamber of Commerce object to such rules, arguing that the question of heat safety is too complex to apply common guidance across industries. But labor advocates say the rules are long overdue. Officially, there were 436 workplace deaths between 2011 and 2021 due to exposure to high heat, or roughly 40 a year, according to the Bureau of Labor Statistics. Experts say those numbers grossly underestimate the number of actual deaths from heat exposure on the job. Because heat illness can impair cognitive function, people may make mistakes on the job that appear unrelated to the temperature. Excessive heat is a problem across the parcel-delivery industry. About a third of all US Postal Service vehicles currently have air conditioning, a spokesperson said. A FedEx representative told CNN that all vehicles owned by FedEx are air-conditioned, though the majority of its FedEx Ground fleet is operated by independent contractors. "Safety is always our priority, and we encourage our team members and service providers across FedEx to take precautions in the hot weather by staying hydrated, taking frequent breaks, and recognizing the signs of heat-related illnesses," FedEx said in a statement. An Amazon spokesperson said all company-branded vehicles are air-conditioned and always have been.