Matthew Moczygemba knew something was wrong when he lost his thirst. It was midafternoon on a 103-degree day in Fort Worth, Texas, and the UPS driver had been delivering packages for several hours. Soon he felt dizzy, then he pulled his truck over and vomited onto the curb.

“I stopped sweating and was starting to get cold,” said Moczygemba, 35, who has worked for UPS for five years. “It was a bad feeling.”

Moczygemba wound up at a hospital emergency room, where doctors diagnosed him with dehydration and heat exhaustion, and gave him several bags of IV fluid, according to medical records.

He was released a few hours later, but he has not returned to work in the nearly three weeks since.

“I’m nervous about going back,” Moczygemba said.

With heat waves rolling across the country, and states like Texas and Oklahoma experiencing record hot summers, workers exposed to the elements are increasingly struggling under the heat.

More than a dozen UPS employees and union leaders say this year more workers seem to be getting sick and been hospitalized because of the heat than ever before. In response, they are demanding that the company put more safety measures in place.

“Left and right people are falling out,” said Jeff Schenfeld, a union steward in Dallas and UPS veteran of 25 years. “Something is different this year. It’s a lot more people.”

‘Sending drivers out to die’: UPS workers demand heat safety amid record temps (NBC News)