Dangerous Heat Threshold: Study Reveals 85-Degree Heat Index Triggers Sharp Rise In Workplace Injuries

When the heat index climbs to 85 degrees, worker safety takes a dangerous turn, according to a new study from George Washington University and Harvard's T.H. Chan School of Public Health.

The Heat-Injury Connection

Published in Environmental Health, the nationwide study analyzed workplace injury data across 48 states and discovered a concerning pattern: once daily heat index values reach approximately 85 degrees, workplace injuries begin to climb. And when temperatures rise past 90 degrees, injury rates spike dramatically.

"Even moderately hot conditions can subtly increase workplace injury risk," explained lead researcher Barrak Alahmad from Harvard's occupational health and climate change program. "This pattern held true across nearly every industry we examined."

The Numbers Tell The Story

The research reveals that extreme heat contributes to roughly 28,000 workplace injuries annually across the United States. This is likely a conservative estimate, since not all heat-related incidents are reported or recorded.

Silver Lining In State Standards

There's encouraging news from states that have implemented workplace heat exposure standards: Workers in these areas show lower injury rates during hot weather, suggesting protective policies actually work.

This research arrives as OSHA considers implementing nationwide heat protection standards for workers, a move that could prevent thousands of injuries each year while protecting America's workforce from our increasingly hot summers.

Senior writer Chris DeWeese edits Morning Brief, The Weather Channel’s newsletter.