Nearly 28,000 Work Injuries Every Year Are Linked to Hot Weather

WASHINGTON (Oct. 6, 2025) — New research shows the hidden toll of work injuries caused by workplace exposure to extreme heat in the U.S. The new research supports an Occupational Safety and Health Administration (OSHA) national standard protecting workers exposed to extreme heat.

The study, by a team of researchers at the George Washington University and Harvard T.H. Chan School of Public Health, was published in the journal Environmental Health. The team analyzed a dataset put together by OSHA that tracks workplace injuries in 48 states.

“These findings underscore the value of protecting workers from extreme heat, said David Michaels, senior author and professor of environmental and occupational health at the GW Milken Institute School of Public Health. “A strong OSHA standard will not only prevent heat illness and death but will also prevent thousands of work injuries every year.”

Key Findings

• Work injury risk starts to climb when the daily heat index hits about 85 degrees Fahrenheit and rises steeply past 90 degrees Fahrenheit.
• These work injuries tied to exposure to extreme heat were seen across almost all industry sectors, including jobs that are done indoors.
• Workers in states with OSHA workplace heat exposure standards appear to have a lower risk of injury on hot days.
• Nationally, about 28,000 injuries can be linked to work on hot days.

Why It Matters

Extreme heat can damage the body and the mind, and these injuries can leave workers with lost wages, permanent health problems and can even lead to premature death. OSHA has proposed a national standard requiring employers to protect workers from extreme heat and this analysis supports the need for such protections.

“Extreme heat can result in fatal heatstroke. But before we get to these levels, we found that even moderate hot conditions can subtly increase the risk of workplace injuries,” said Barrak Alahmad, first author and director of occupational health and climate change program at the Harvard T.H. Chan School of Public Health. “A finding that was remarkably consistent in almost all industries we examined.”

This is the first nationwide model on this subject, and it shows a previously unrecognized danger of heat in the workplace. Most heat-related injuries are not recorded as such, so the 28,000 workplace injuries every year is probably an underestimate, Michaels says.

The study, “A Nationwide Analysis of Heat and Workplace Injuries,” published Oct. 6 in the journal Environmental Health.