Working in excessive heat can cause illness, whether outdoors (this summer again brought record-breaking heat to parts of North America), or indoors where equipment, combustion or other factors raise ambient working temperatures. Occupational safety and health agencies have slowly been expanding explicit requirements that employers protect their workers against heat stress. Most recently, the Maryland Department of Occupational Safety and Health (MOSH) adopted Heat Stress Standards effective September 30, 2024 (COMAR 09.12.32).