Heat Deaths Highest Among Military, Farm, Construction

Heat-related deaths among working-age US adults are concentrated in outdoor, physically demanding jobs, with rates in military, farming, and construction occupations more than triple the national average, according to a research letter published in JAMA.¹

The investigators, from the University of Pennsylvania Perelman School of Medicine and the Icahn School of Medicine at Mount Sinai, note that federal workplace surveillance may undercount this burden. The Census of Fatal Occupational Injuries reported 55 heat-related deaths in 2023, but it counts only deaths directly attributed to a traumatic workplace injury and excludes illness-related causes such as myocardial infarction. To capture a broader picture, the team used National Vital Statistics System data and the National Occupational Mortality Surveillance system, which records a decedent's usual, or longest held, occupation and industry.

Outdoor Sectors Carry the Highest Heat Mortality Rates

Among 2,492,948 deaths in adults aged 16 to 64 years from 2021 to 2023, 2035 were heat-related, defined by a primary or contributing International Classification of Diseases, Tenth Revision code of X30 or T67. The national age-adjusted mortality rate (AAMR) was 0.3 deaths per 100,000 working-age adults.

By occupation, AAMRs were highest in military-specific jobs (1.6 per 100,000; 95% CI, 0.8-2.9), farming, fishing, and forestry (1.1; 95% CI, 0.8-1.5), and construction and extraction (1.1; 95% CI, 0.9-1.2). By industry, the military (1.0; 95% CI, 0.6-1.8), construction (0.8; 95% CI, 0.7-0.9), and natural resources and mining (0.8; 95% CI, 0.6-1.0) ranked highest. Rates were lowest in management, business, and financial occupations and in education, legal, community service, arts, and media occupations (0.13 per 100,000 each).

The rankings held across alternative measures, including proportionate mortality ratios and summer deaths from acute kidney injury, hypovolemia, or electrolyte abnormalities (Kendall W, a measure of ranking agreement, was 0.93 for occupation and 0.91 for industry). Occupation or industry data were missing for 23.7% of heat decedents and were imputed, but a sensitivity analysis found none of the highest-rate groups became statistically indistinguishable from the national mean after reclassification. The authors noted that military occupations ranked near the top despite established military health services.

Cardiovascular Causes and Demographic Disparities

Heat decedents were more likely than other decedents to be male (77.6% vs 63.4%) and to live in metropolitan counties (84.8% vs 81.7%). Among the 456 deaths in which heat contributed but was not the primary cause, cardiovascular conditions were the primary cause in 68.4%.

Female sex was associated with lower odds of heat-related death across most sectors. Hispanic ethnicity was associated with higher odds across multiple occupations, including farming, fishing, and forestry (OR, 2.38; 95% CI, 1.18-4.83) and construction and extraction (OR, 2.04; 95% CI, 1.52-2.74), which the authors said may reflect regional and task-level segregation within occupations. Individuals who identified as Black were associated with higher odds in farming, fishing, and forestry occupations (OR, 2.77; 95% CI, 1.12-6.83) and the natural resources and mining industry (OR, 2.60; 95% CI, 1.37-4.90), but lower odds in production occupations (OR, 0.40; 95% CI, 0.16-0.99).

Surveillance Gaps and a Pending Federal Heat Standard

The authors cautioned that deaths cannot be attributed specifically to occupational exposure and may reflect heat risk outside of work. Heat-related diagnostic codes also have low sensitivity. Still, they wrote that deaths influenced by occupational heat exposure may exceed workplace-based surveillance estimates and that the findings point to sectors that may benefit from federal heat safety standards.

The Occupational Safety and Health Administration published a proposed heat injury and illness prevention rule covering general industry, construction, maritime, and agriculture in August 2024. Its public hearing concluded in July 2025, and the post-hearing comment period closed in October 2025, but a final standard has not been issued.²

References

1. Szeto JJ, Khan RF, Hennessy S, Khatana SAM. Heat-related mortality in working-age adults by occupation and industry. JAMA. Published online October 5, 2026. doi:10.1001/jama.2026.18171
2. Heat injury and illness prevention in outdoor and indoor work settings rulemaking. Occupational Safety and Health Administration. Accessed October 6, 2026. https://www.osha.gov/heat-exposure/rulemaking