As the world grapples with rising temperatures due to climate change, a new wave of concern is sweeping through America’s workplaces. From bustling construction sites and steamy kitchens to the hushed halls of psychiatric hospitals, the dangers of extreme heat and chronic dehydration are coming into sharp focus. Recent research, legal battles, and expert commentary are converging to highlight just how complex and urgent the challenge of keeping workers safe under these sweltering conditions has become.
On October 7, 2025, a landmark study led by Barrak Alahmad, a senior research scientist at Harvard T.H. Chan School of Public Health, quantified the true scale of heat’s impact on workplace safety. Drawing on a massive trove of data—about 850,000 workplace injuries reported by employers with more than 100 workers in 2023, as required by the Occupational Safety and Health Administration (OSHA)—the study linked each incident to the local heat index on the day it occurred. According to Harvard’s public health experts, the findings revealed a striking pattern: 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,” Alahmad explained in an interview published by Harvard T.H. Chan School of Public Health. What’s more, the study found that heat didn’t just cause the obvious heat strokes or exhaustion. It also drove up incidents of falls, equipment mishaps, and even workplace violence—injuries not typically chalked up to heat exposure. The researchers estimate that some 28,000 heat-related injuries occur each year but go undetected because they’re masked as unrelated accidents.
This heat-related danger isn’t confined to outdoor laborers. While farms, construction sites, and waste management crews are clearly at risk, the study also documented increased injury rates in indoor settings like warehouses, kitchens, and even schools. The threat, it seems, is everywhere—and it’s growing.
But not all workers are equally vulnerable. The study found that states with regulations requiring employers to provide heat protections—such as access to shade, water, rest breaks, acclimatization policies, and emergency response protocols—had lower injury rates than those where protections were left up to the employer’s discretion. “Even the slightest heat regulations in the workplace are helpful and can reduce the risk of injuries,” Alahmad emphasized. “Implementing regulations on a national scale will be a win-win for workers and employers alike.”
That’s precisely what OSHA has in mind. The agency is currently proposing a national regulation that would require employers to provide water, shade, and cooling opportunities when the heat index hits 80 degrees, and a 15-minute paid break every two hours once it reaches 90 degrees. The public comment period for this proposal is open until October 30, 2025, and Alahmad’s team is submitting their findings as evidence in support of these new rules. Yet, as Alahmad points out, “the proposal captures the most basic of worker rights, but doesn’t capture the full protections that workers need.” He advocates for more advanced safeguards, like using wearable technology to monitor workers’ heart rates and core temperatures, allowing for job-specific work-rest ratios tailored to the demands of different roles.
While the science is clear on the risks, the legal landscape is anything but settled. The National Law Review reported on October 7, 2025, that two cases before the Tenth Circuit Court of Appeals could set crucial precedents for how OSHA enforces workplace safety. These cases involve psychiatric hospitals where staff reported assaults by patients, and OSHA issued citations under the Occupational Safety and Health (OSH) Act’s “General Duty Clause.” This clause requires employers to provide workplaces “free from recognized hazards … likely to cause death or serious physical harm.”
The Occupational Safety and Health Review Commission (OSHRC) has consistently upheld citations for workplace violence in settings like healthcare, arguing that such hazards are foreseeable and that feasible abatement measures—like written prevention programs and staff training—exist. But when it comes to heat stress, OSHA has had a tougher time. In 2023, for example, OSHRC vacated heat-related citations against the U.S. Postal Service, finding that the government failed to prove there were effective ways to reduce the hazard. As The National Law Review points out, defining heat as a workplace hazard is tricky because so many variables—humidity, wind, workload, personal protective equipment, acclimatization, and individual worker attributes—come into play. This makes it hard for OSHA to meet the General Duty Clause’s requirements for hazard recognition, employee exposure, likelihood of serious harm, and feasible abatement.
Employers and regulators alike are watching the Tenth Circuit’s upcoming decisions closely. The outcomes could either reinforce current enforcement practices or force OSHA to meet stricter standards of proof in both workplace violence and heat stress cases. The stakes are high: whatever the court decides will shape how future cases are handled and could influence the effectiveness of OSHA’s proposed heat regulations.
Amidst these regulatory debates, the day-to-day reality for workers remains fraught with risk—especially from chronic dehydration, a danger that often flies under the radar. In an article published on October 8, 2025, Dr. Robert Sallis, MD, underscored the pervasive threat of dehydration for those laboring in high-heat environments. “Chronic dehydration is a subtle and pervasive threat in the background,” Sallis wrote, noting that it not only impairs cognitive and physical performance but can also lead to life-threatening mistakes—particularly for first responders like police officers and firefighters.
Sallis highlighted a recent poll from Pocari Sweat’s State of Sweat Index, which found that a staggering 83% of high-heat workers experience at least one symptom of dehydration daily, and nearly half say it hurts their comfort and performance every week. The problem, he argues, is that simply providing water isn’t enough. “Water is a great thirst quencher but a less-than-ideal rehydrator,” Sallis explained, because it suppresses thirst and increases urination, leading to less effective hydration. Instead, he advocates for a science-backed approach to hydration—akin to what professional athletes receive—using carbohydrate-electrolyte beverages and proactive strategies to keep workers at their best.
For businesses and public agencies, these findings are more than academic. Chronic dehydration and heat-related injuries don’t just threaten worker health; they sap productivity, increase absenteeism, and can tarnish reputations. As Alahmad put it, “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.”
With scientific evidence mounting, legal standards evolving, and the climate growing ever hotter, the message is clear: protecting workers from the hazards of extreme heat and dehydration is no longer optional. It’s a matter of life, livelihood, and the future of safe, productive work in America.
