A groundbreaking study published in Environmental Health by researchers from George Washington University and Harvard University has revealed a powerful connection between hot working conditions and an increased risk of workplace injuries.

Jon Wroten

The findings come as the Occupational Safety and Health Administration moves toward establishing a nationwide heat injury and illness prevention standard — a move long championed in California, the state that first led the nation in heat illness awareness and prevention.

California’s proven leadership in heat safety

For nearly two decades, California has set the benchmark for workplace heat safety. Under Cal/OSHA’s Heat Illness Prevention Standards for both outdoor and indoor workplaces, most California employers are required to implement comprehensive heat illness prevention plans (HIPP), providing employees with access to water, shade, rest, training and emergency procedures. These regulations have not only protected countless workers but have also served as the model for federal and state heat safety initiatives now under consideration nationwide.

Heat raises injury risk even before illness strikes

The new study, “A Nationwide Analysis of Heat and Workplace Injuries,” analyzed 2023 OSHA data across 48 states and attributed approximately 28,000 workplace injuries that year to heat exposure. The research showed that:

• The risk of injury begins to rise when the heat index exceeds 85 degrees, with a sharp increase beyond 90.
• Heat-related injury spikes were observed across all industries, including indoor workplaces.
• Workers in states with heat exposure guidelines, like California, showed lower injury rates in hot conditions.

Lead author Dr. Barrak Alahmad noted, “Extreme heat can result in fatal heatstroke. But even before we reach those levels, moderate heat can subtly increase the risk of workplace injuries.”

The hidden risks of heat exposure

While much attention has focused on the direct health impacts of extreme heat, such as heat exhaustion and heatstroke, this research highlights an equally critical concern: the indirect impact of heat on overall workplace safety. Elevated temperatures can impair concentration, coordination and decisionmaking, significantly increasing the risk of all types of accidents, from slips and falls to machinery incidents.

In other words, the danger of heat exposure extends beyond illness. It can quietly compromise vigilance and performance, creating a ripple effect that raises the likelihood of costly and preventable workplace accidents.

Protecting workers and reducing risk

The study underscores the need for comprehensive heat safety programs that address both illness and accident prevention. Employers are urged to strengthen their training, acclimatization protocols and emergency preparedness, and to ensure that workers have consistent access to shade, water and rest breaks.

California’s long-standing success with its Heat Illness Prevention Standard demonstrates that proactive regulation works. As more states and federal agencies move toward similar standards, employers nationwide have a clear roadmap to follow, one already proven to save lives and prevent injuries.

Key takeaway

The message is clear: Heat doesn’t just make workers uncomfortable, it makes them vulnerable. Whether through direct illness or secondary accidents, heat exposure poses a serious and growing threat to workplace safety. California’s leadership shows that prevention is both possible and practical, and it’s time for the rest of the nation to follow suit.

Jon Wroten is senior vice president at The PATH Alliance and managing director of California Risk Advisors LLC. He was previously chief of the Office of Self-Insurance Plans for the State of California.