As global temperatures rise, the U.S. federal government and some states are taking renewed interest in protecting vulnerable workers against the dangers of prolonged heat exposure on the job. Most recently, Maryland joined a handful of other states, implementing their own standards that require all workers to have access to water, shade and rest breaks when temperatures go above 80 degrees F.
In 2022, 43 United States workers died due to extreme heat, while others suffer from heat exhaustion, impaired cognition and other health problems. Many factors up an individual’s risk for heat-related illness including, but are not limited to, advanced or very young age, pregnancy, fever and mental illness.
Despite this risk, no federal heat safety standards are enforced nationally in the United States. The extent of U.S. Occupational Safety and Health Administration (OSHA) enforcement comes from the Occupational Safety and Health Act of 1970, which requires employers to generally operate hazard-free workplaces regarding heat safety. The National Institute for Occupational Safety and Health (NIOSH) also provides safety recommendations, such as heat safety training and limiting duration of heat exposure, but employers are not required to comply.
A recently published study in the Journal of Occupational and Environmental Medicine from researchers at the Dornsife School of Public Health adds support for one method of saving workers from heat: rest breaks. The group found an association between breaks and fewer on-the-job injuries and illnesses among construction workers in Dallas.
“In the study, we argue that rather than doing away with the 10-minute rest break mandates, as the Texas state legislature recently did, Texas should expand the policy to be more comprehensive,” said senior author Alina Schnake-Mahl, ScD, an assistant professor in the Dornsife School of Public Health. “A number of other states and cities have passed more comprehensive policies, so future research should examine how these policies impact workplace injuries and illnesses to help policymakers design the most effective policies.”
A push for worker heat protections has picked up steam the past few years. In September 2021, the U.S. Department of Labor and the Biden administration announced OSHA’s creation of a heat-related hazard alert enforcement initiative, and efforts to lay the groundwork for a federal workplace heat standard. In August 2024, OSHA published a proposed standard that requires employers to establish a plan to assess and control workplace heat hazards, including laying out the responsibilities of employers and the steps they will take to protect workers from heat hazards on the job.
Lead author Leah Schinasi, PhD, an assistant professor in the Dornsife School of Public Health, shared information with the Drexel News Blog about why rest breaks are critical, particularly for those doing intensive work in extreme heat in agriculture, construction and other industries; and how global climate change and the COVID-19 pandemic are making lawmakers and advocacy groups re-think protections for workers.
After OSHA’s proposed heat standard in July and Maryland recently instituting one, it seems like there’s a growing push for worker protections from extreme heat. What do you think is causing this recent push?
These workplace laws for heat illness prevention are certainly a long time coming. Advocacy workers, like the National Council for Occupational Safety and Health or the Natural Resources Defense Council, have supported or promoted the idea of workplace heat safety standards for years. But climate change and occupational health protections are both highly politicized topics.
At long last, some of that advocacy work seems to be gaining traction. Policy makers are waking up to the reality of our world’s changed (and changing) climate, and to the idea that extreme heat is a hazard that warrants protections and precautions.
There have been some well-publicized, tragic heat-related deaths of workers that have brought the issue of heat within the workplace to the forefront. The COVID-19 pandemic, also, brought new attention to the idea and importance of protecting members of our workforce who have historically, and continue to be, overlooked in thinking about safety and health promotion.
How did you design this study to capture the effects of the new work safety policies?
A very important strength of the study is that we used a type of study design that is called “quasi-experimental,” which means we were able to evaluate the impacts of the heat mandate policy in the real world, even though we couldn’t actually conduct a scientific experiment in a laboratory setting.
In our analysis, we compared rates of injuries and illnesses that construction workers in Dallas experienced, before versus after the rest break mandate was enacted. We compared these changes to changes in rates of injuries/illnesses in construction workers–in a similar county in Texas where a rest break mandate was not enacted.
From a statistical perspective, this is a very strong design because the before and after comparison allowed us to reduce concerns that our results are biased. Because of this, we can feel pretty confident about our results and may be able to draw important conclusions about whether the rest break mandate actually had an effect on injuries or illnesses in Dallas construction workers.
What do these findings indicate about Dallas’ rest break mandate for workers?
Although we didn’t observe much of an effect of the rest break mandate on rates of injuries or illnesses in construction workers in Dallas, null results are very meaningful; they tell us something really important about the exposure or policy that we evaluated. We believe that the null result suggests that 10-minute rest breaks do not provide adequate protection.
To interpret the null result, it’s important to consider the requirements of the policy that we evaluated, and to compare these with recommendations for worker heat safety protection that OSHA or NIOSH put forth.
NIOSH and OSHA recommend a variety of precautions to prevent heat illness or injury in workers. These include allowing workers, and especially ones who are new on the job or returning from time away, with acclimatization periods (incrementally increasing amount of time worked, in order to allow their bodies to adjust to high temperatures); provision of adequate hydration and hydration breaks (about 1 cup for every 15 to 20 minutes); provision of frequent rest breaks, ideally in shaded or cool areas and with length or frequency of the breaks varying depending upon things like workload and worksite conditions; heat safety training; medical monitoring; and opportunities for modified work schedules to reduce times working in the extreme heat.
By contrast, Dallas’ mandate only required that employers allow construction workers to take 10-minute rest breaks for every four hours worked. Now, when we compare this to the recommendations offered by NIOSH or OSHA, these 10-minute rest breaks for every four hours worked are far from comprehensive. And so, it is quite possible that our null results suggest that a 10-minute rest break for every four hours worked is simply not sufficient for providing protection.
Why do you think there’s been so little research on this topic before your study?
First, historically, heat has been overlooked as a workplace hazard, especially when compared to other exposures that laborers encounter, such as chemical exposures or fall risks. Increasingly, however, tragic, heat-related events — both inside and outside the workplace — have shown that ambient heat represents a critical threat to population health, and one that is worthy of research and attention.
There are also several structural reasons for the lack of research. There are far fewer research funding opportunities available to support occupational health work. There are also inadequate data resources available to answer important empirical research questions using quantitative methods.
Finally, many of the workers who labor in high heat exposure industries — agriculture, construction, municipal work and food service, to name a few — are transient, undocumented and low-income workers. They are hard to follow up with over time, for longitudinal research studies, or even to capture in short-term studies. Some workers may be wary of participating in research, some employers may not be supportive of research that identifies workplace hazards and there may sometimes be time or language barriers.
In my view, when considered together, the lack of resources to support occupational health studies is a tremendous injustice. Those who work in some of our most important, but also dangerous, jobs deserve the opportunity to have their stories and experiences represented in research. I very much stand behind the idea that strong empirical work paves the way for strong and effective policies that support health. I am hopeful that, moving forward, the lack of data and support for occupational health research will be overcome, so that we can inform policies that better support vulnerable workers and reduce health inequities.
Media interested in speaking with Schinasi should contact Greg Richter, assistant director of News & Media Relations, at gdr33@drexel.edu or 215.895.2614.
