Study ties high heat to nearly 28,000 workplace injuries a year

October 10, 2025

Washington — Tens of thousands of workplace injuries a year are linked to hotter temperatures, according to a recent study out of Harvard University and George Washington University.

Researchers from the universities examined 2023 data from OSHA’s Injury Tracking Application for establishments with 100 or more employees, primarily in high-hazard industries. “Each injury was geocoded and matched with high-resolution weather data for the specific injury date,” the study states. 

In addition to discovering that around 28,000 injuries were associated with hot weather, the researchers found that:

• The risk of injury increased when the heat index was around 85° F. That risk rises even more when the heat index is 90° F or higher.

• Injuries connected to extreme heat exposure were seen across almost all industry sectors, including jobs that are performed indoors.

• Employees in states with workplace heat exposure regulations appeared to have a lower risk of injury on hot days.

  
  

“Most heat-related injuries are not recorded as such, so the 28,000 workplace injuries every year is probably an underestimate,” senior study author David Michaels, an environmental and occupational health professor at GW and former OSHA administrator, said in a press release.

“These findings underscore the value of protecting workers from extreme heat. A strong OSHA standard will not only prevent heat illness and death but will also prevent thousands of work injuries every year.”

The study was published in the journal Environmental Health.