Extreme heat events are the largest source of weather-related mortality in the United States, with documented impacts on both workers compensation claims, negative health outcomes, and increased emergency department visits. According to the Natural Resources Defense Council (NRDC), approximately 51 million U.S. workers are at high risk to extreme heat based on their occupation, yet only 9 million live in states with permanent workplace heat standards.

NRDC recently engaged Milliman to study the relationship between workers compensation costs, healthcare services utilization, and excessive heat in North Carolina, a state with no workplace heat standards, where an estimated 1.7 million workers (27% of the workforce) are at high risk to extreme heat.

This report summarizes the research methods and findings, which included a strong correlation between indemnity costs and the heat index of annual hours above static threshold (90°F) for the groups of workers that were studied.

This report was commissioned by NRDC.