UPS, the world’s largest delivery company, is being cited by federal regulators for exposing its drivers to “excessive heat” for the first time in years, the Occupational Safety and Health Administration announced Tuesday.

UPS faces $13,260 in penalties, "the maximum penalty allowed by law for a serious violation,” according to an OSHA press release. The federal agency has the authority to issue citations for violation of workplace safety standards.

In July, an NBC News investigation revealed that more than 100 UPS employees were hospitalized for serious heat-related injuries between 2015 and 2018, more than any other company in the country except the U.S. Postal Service. UPS, which has almost 400,000 employees — 74,000 of them delivery drivers — does not air condition most of its warehouses or its brown delivery trucks, whose cargo areas can reach 150 degrees, drivers said.

NBC News spoke with more than two dozen UPS employees around the country who said this summer has brought heavy loads, long days and mounting pressure to deliver in record heat.

June and July were the hottest months on record, according to the National Oceanic and Atmospheric Administration.

"I think it’s probably time they got cited,” said Stephen Nowlin, a Texas UPS driver who suffered a heat illness in late June. “Not that I ever want my company to get cited, but if it’s going to change things and help people, then I’m all for it.”

OSHA cited UPS for exposing employees on delivery routes in Palm Beach County, Florida, to high temperatures on two days in June when the heat index hit as high as 104.7 and 108.68 degrees. The Aug. 23 citation notes that "such exposures may lead to the development of serious heat-related illnesses such as, but not limited to, heat cramps, heat exhaustion, heatstroke, and death."

UPS said in a statement that it intends to contest the citation, adding that it “takes OSHA citations seriously and has carefully reviewed the allegations."

UPS has vigorously disputed accusations from employees previously reported by NBC News that managers try to avoid calling for medical help or sending employees to the hospital. They said the over 100 heat-related hospitalizations uncovered by NBC News' investigation affected less than one-tenth of 1 percent of the company’s driver workforce.

“The overwhelming majority of UPS drivers are well trained and effectively manage their health and well-being while working outdoors,” Steve Gaut, UPS vice president of public relations, said.

Advocates applauded the citation, but said as temperatures rise, federal regulators need to do more to protect workers from heat.

"This citation was important in sending a message to UPS that it will be held accountable for heat violations, but it was also all too rare," said Shanna Devine, worker and consumer advocate at Public Citizen, a nonprofit advocacy group that has been leading a campaign for stronger heat protections of workers. "Thirteen thousand dollars is just a slap on the wrist for UPS."

Public Citizen is part of a large coalition of workers, advocates and labor groups that are backing legislation to better protect workers from heat, which was introduced by Rep. Judy Chu, D-Calif., in July.

“I think that OSHA made the right choice,” said Maurice Nelson, a longtime driver and union steward in Arizona. “It’s the duty of all employers to protect their employees. That didn’t happen here.”

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