Heat Illness Prevention
Overview: Working in Outdoor and Indoor Heat Environments
Millions of U.S. workers are exposed to heat in their workplaces. Although illness from exposure to heat is preventable, every year, thousands become sick from occupational heat exposure, and some cases are fatal. Most outdoor fatalities, 50% to 70%, occur in the first few days of working in warm or hot environments because the body needs to build a tolerance to the heat gradually over time. The process of building tolerance is called heat acclimatization. Lack of acclimatization represents a major risk factor for fatal outcomes.
Occupational risk factors for heat illness include heavy physical activity, warm or hot environmental conditions, lack of acclimatization, and wearing clothing that holds in body heat.
Hazardous heat exposure can occur indoors or outdoors and can occur during any season if the conditions are right, not only during heat waves. The following is a list of some industries where workers have suffered heat-related illnesses.
Outdoors
Agriculture
Construction – especially, road, roofing, and other outdoor work
Construction – roofing work
Landscaping
Mail and package delivery
Oil and gas well operations
Indoors
Bakeries, kitchens, and laundries (sources with indoor heat-generating appliances)
Electrical utilities (particularly boiler rooms)
Fire Service
Iron and steel mills and foundries
Manufacturing with hot local heat sources, like furnaces (e.g., paper products or concrete)
Warehousing
Heat-related illness is preventable, especially with management’s commitment to providing the most effective controls. An effective heat-related illness prevention program is incorporated into a broader safety and health program and aligns with OSHA’s Recommended Practices for Safety and Health Programs core elements.
Workers who have not spent time recently in warm or hot environments and/or being physically active will need time to build tolerance (acclimatize or, less frequently used, acclimate) to the heat. During their first few days in warm or hot environments, employers should encourage workers to:
- Consume adequate fluids (water and sports drinks)
- work shorter shifts,
- take frequent breaks, and
- quickly identify any heat illness symptoms.
Engineering controls such as air conditioning, with cooled air, and increased airflow, leading to increased evaporative cooling, can make the workplace safer. Other options for keeping body temperatures down in warm environments include making changes to workload and schedules. For example, empower supervisors and workers to slow down physical activity like reducing manual handling speeds or scheduling work for the morning or shorter shifts with frequent rest breaks in the shade or at least away from heat sources. Supervisors can encourage workers in warm environments to drink hydrating fluids. At a minimum, all supervisors and workers should receive training about heat-related symptoms and first aid.
Heat-related illnesses can have a substantial cost to workers and employers. Heat stress can cause fine motor performance (like rebar tying or keyboarding) to deteriorate even in acclimatized individuals. Heat illness can contribute to decreased performance, lost productivity due to illness and hospitalization, and possibly death. OSHA encourages water, rest, and shade as prevention as well as treatment for heat-related illnesses.
Learn more about Temperature Extremes in the Workplace.
St. Thomas
St. Croix
