Protecting workers from injuries during extreme heat
As climate change intensifies and heat rises, employees of all kinds face new levels of difficulty keeping cool and staying safe at work. A new study led by Barrak Alahmad, senior research scientist in the Department of Environmental Health at Harvard T.H. Chan School of Public Health, quantifies the problem. Below, he discusses the study and the potential paths forward, including the introduction of a national regulation on extreme heat in workplaces.
Q: How did you study heat’s impact on workplace safety, and what did you find?
A: In 2023, the Occupational Safety and Health Administration (OSHA) began requiring every employer with more than 100 workers to report every single injury that occurred in the workplace, even if the injury wasn’t severe or didn’t result in an insurance claim. OSHA compiled all of this data—which added up to around 850,000 injuries that year—and made it publicly available. We used this dataset to study the relationship between heat and workplace safety. We geocoded all of the injuries and linked them to the heat index—a metric that accounts for temperature and humidity—of the same day.
We found a clear dose-response relationship between heat and workplace injuries, meaning that the higher the heat index, the higher the risk of injury. Risk for injury started increasing for workers when the heat index reached 80 degrees Fahrenheit and really took off above 90 degrees. And this doesn’t only account for injuries that are explicitly related to heat, like heat strokes or heat exhaustion. We observed that heat is also driving falls, equipment mishaps, workplace violence—things that wouldn’t be recorded as heat injuries. We know people experience subtle physical and cognitive impairments on hot days. These impairments can increase the risk of workplace injury. By our conservative estimates, there are about 28,000 of these heat-related injuries each year that go undetected.
Q: What types of workers are most impacted?
A: When you think of heat in the workplace, you may think first of outdoor jobs—farms, construction sites, waste management, for example. But we also observed increased risk of injuries in indoor workplaces, like warehouses, kitchens, and schools. This is an issue that is pervasive across sectors. Across states, however, we did observe differences, depending on the regulations they had in place to protect workers from the effects of heat. Workers in states that require employers to provide some form of protection against heat—whether that be access to shade, water, and rest breaks, acclimatization policies that allow new workers to acclimate to heat, and/or emergency response protocols—had a lower risk of injury than their counterparts in states without these regulations, where protections are left up to the employer’s discretion.
Q: OSHA is currently considering introducing a national regulation on extreme heat in workplaces. What do you think of its proposal?
A: OSHA is proposing a rule that employers in all states must provide workers access to water, shade, and opportunities to cool themselves once the heat index reaches 80 degrees and must provide workers a 15-minute paid break every two hours once the heat index reaches 90 degrees. The proposal will be in the public comment phase until October 30, which is good timing for our study—we’re submitting it to the comments as evidence that even the slightest heat regulations in the workplace are helpful and can reduce the risk of injuries. Implementing regulations on a national scale will be a win-win for workers and employers alike. Employees will be safer and employers will be protecting their reputation, increasing productivity, and preventing absenteeism and turnover that can come with workplace injuries.
I’m super supportive of the regulation currently on the table. But I also think even more can be done beyond what OSHA is proposing. The proposal captures the most basic of worker rights, but doesn’t capture the full protections that workers need.
Q: What other protections would you suggest introducing?
A: We have the technology to make protections more sophisticated and effective. For example, one data-driven approach employers could take is establishing job-specific work-rest ratios based on physiological data collected through wearable devices on workers. Employers could measure employees’ heart rates and core temperatures and establish a baseline for how often a roofer, a welder, or someone working in a restaurant kitchen should be taking a break at certain temperatures. OSHA’s proposal represents the foundation of what employers need to be doing to address heat in the workplace. They all could elevate these required protections. In fact, it’s in their best interest to do so. If a business cares about its bottom line, doing the bare minimum is not an option. Because with climate change, the problem of extreme heat, and its attendant injuries, will only get worse. There must be action taken.
