(The Postal Service has more employees than UPS - 630,000.) Postal Service - which also doesn't currently air-condition the majority of its delivery trucks. employer with more heat incidents reported to federal regulators than UPS is the U.S. At least 107 UPS workers in 23 states have been hospitalized for heat illnesses since 2015, according to state and federal worker-safety data and hundreds of pages of documents obtained by NBC News through freedom-of-information requests. Jeenah Moon / for NBC NewsĪcross the country, some UPS workers caught between rising temperatures and the growing pressure of the delivery economy have found their bodies are breaking down. "I pray every year I don't get a heatstroke." Jim Klenk's UPS uniform. "Our workload is increasing and we're still expected to get done faster," a driver in Kentucky said.