Indoor heat exposure is a growing problem for service sector workers, according to a new report by the Harvard Kennedy School-based Shift Project. The report found widespread instances of indoor workers feeling overheated and regularly experiencing temperatures over 80 degrees.
With rising temperatures and more frequent heat waves, workers are increasingly at risk of uncomfortably high temperatures in the workplace, which impacts health as well as productivity, says the report, authored by the Shift Project, a joint initiative of Harvard Kennedy School’s Malcolm Wiener Center for Social Policy and the University of California, San Francisco. The report also notes that there is no federal regulation specifically addressing heat standards in the workplace, though OSHA is actively working toward establishing a federal heat standard.
In the report, based on data from 3,514 service sector employees across the United States, researchers found widespread reports of indoor workers feeling overheated and regularly experiencing temperatures over 80 degrees, often with little recourse.
Among workers employed in retail or food service who work indoors, 65% reported feeling uncomfortably hot or overheated at work, and 36% reported always or often experiencing uncomfortable heat at work.
Heat exposure by the numbers
“We expected to find some indoor heat exposure among retail workers, but not nearly the levels we did find,” said Hana Shepherd, associate professor of sociology at Rutgers University and one of the report’s authors. “These numbers suggest that millions of service sector workers across the country are regularly exposed to potentially unsafe levels of heat indoors each summer and they have very limited ability to mitigate their heat exposure. This creates various health risks for them”
Federal standards currently being proposed by the Occupational Safety and Health Administration (OSHA) would use a threshold of 80 degrees to define workplace heat exposure, which nearly half of workers surveyed report already experiencing.
Additionally, the researchers found that among retail and food service workers who work indoors:
- 37% had a heat-related headache
- 34% experienced heat-related fatigue
- 24% had heat-related nausea in the past year
The greatest exposure to heat among indoor retail workers was reported by warehouse workers (63%), fast food workers (58%), and restaurant workers (52%). However, the report also noted that nearly 40% of indoor workers in retail stores—a group historically omitted from heat standards and regulations—regularly experience at least 80-degree temperatures at work.
“We need to broaden our conception of who is affected by workplace heat exposure. It’s not just those working outdoors or in kitchens.”
“We need to broaden our conception of who is affected by workplace heat exposure. It’s not just those working outdoors or in kitchens,” shared Kristen Harknett, a professor of sociology at the University of California, San Francisco and co-director of the Shift Project.
Pointing to the patchwork of state and federal workplace protections and the inconsistent enforcement of existing indoor heat standards, the report’s authors argue that their findings illustrate a “clear need for updated federal and state regulations and enforcement regarding standards and procedures for evaluating and mitigating exposure to heat in indoor work.”
The report was authored by Shepherd, Harknett, and Henri Jackson, a pre-doctoral fellow at the Shift Project. The research was supported by grants from the National Institutes of Aging, the National Institute for Occupational Safety and Health, and the Annie E. Casey Foundation.
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Image caption/credit: Employees of Learning Resources, an educational toy company, work at a warehouse in Vernon Hills, Ill., Friday, April 11, 2025. AP Photo/Nam Y. Huh, File