Dozens of workers die and thousands more become ill every year due to heat exposure in the workplace. Heat exposure may result in serious illness or even death, but both are preventable.
Learn how to understand the risk factors, recognize and respond to symptoms, and implement methods to mitigate heat hazards in the workplace.
Understand Heat Hazards
Hazardous heat exposure can happen indoors, outdoors, and during any season, including during heat waves and hot summer months.
When temperatures rise, so can a worker's core body temperature. Increases in heart rate and sweat are the body's natural response to regulate temperature. However, if these mechanisms aren't enough to keep the core body temperature from rising, heat illness can occur.
Heat illnesses can range from mild to severe and even become fatal.
Types of heat illness include:
- Heat stroke: the most serious heat-related illness, where the body can no longer control its temperature. It can cause permanent disability or death.
- Rhabdomyolysis: a condition associated with heat stress. The rapid breakdown, rupture, and death of muscle can lead to irregular heart rhythms, seizures, and kidney damage.
- Heat exhaustion: the body's response to excessive loss of water and sweat from excessive sweating.
- Heat syncope: fainting or dizziness associated with dehydration or lack of acclimatization to heat.
- Heat cramps: associated with excessive sweating, which depletes water and sodium, and leads to painful cramps.
- Heat rash: a skin irritation caused by excessive sweating in hot, humid environments.
Heat Illness Risk Factors
Occupational risk factors for heat illness can include:
- Work environment: temperature, humidity, length of time near a heat source, and exposure to direct sunlight can factor into heat risk.
- Type of work: physical exertion, acclimation to working in heat, protective clothing, and equipment can affect heat risk.
Personal risk factors can also increase a worker's risk for heat illness. Factors such as health conditions like diabetes or high blood pressure, medications such as blood pressure medications or antihistamines, physical characteristics such as older age or pregnancy, and behavioral characteristics such as low water intake or substance use can also contribute to heat illness.
Plan Ahead to Protect Workers
If you have workers with occupational heat illness risks, a prevention plan can help ensure safety. OSHA recommends including the following elements in your heat illness prevention program:
- Have a heat plan. Your plan should include identifying heat hazards and heat monitoring, acclimatization, work/rest schedules, buddy systems, and protocols for emergencies and first aid.
- Designate someone to oversee the program. Train someone in heat hazards, illness symptoms, emergency response, and heat controls. If possible, train multiple Heat Safety Representatives, and always have someone on-site.
- Provide training for all workers. Everyone should understand heat risks, symptoms, prevention, and emergency protocols. Retrain annually and provide training to new hires.
- Acclimatize workers. Acclimatization can allow one's body to build tolerance to working in heat. Acclimatize new and returning workers by gradually increasing their exposure and workload. OSHA recommends no more than a 20% increase in exposure each day.
- Modify work schedules to reduce heat exposure. Rotate workers, add extra workers, shift physically demanding tasks to cooler times of day, and reschedule non-essential work for cooler days. Stop work if needed due to heat risk.
- Allow frequent breaks. Provide enough time to recover from heat and humidity.
Remember: Water, Rest, Shade
Providing water, rest, and shade opportunities for workers can help reduce the risk of heat illness.
Water
Employers should provide cool water for workers to drink. For short work periods, workers should be encouraged to drink one cup (8 ounces) of water every 20 minutes. For longer work periods, employers should provide electrolyte-containing beverages to help restore lost salt and other electrolytes. This can help prevent muscle cramps and potentially dangerous heat illnesses.
Provide cool beverages in a location that is near the work location, easy for workers to access, and in sufficient quantities for the number of workers and duration of work.
Rest
When heat risks are high, employers should require workers to take breaks, increasing the length and frequency of breaks as heat stress rises.
Breaks should last long enough for workers to recover from the heat. If workers rest in a cooler location, they will be ready to resume work more quickly. Breaks should last longer if there is no cool location for workers to rest.
Shade
Workers should be given a cool location where they can take their breaks and recover from the heat. Outdoors, this might mean a shady area, an air-conditioned vehicle, a nearby building or tent, or an area with fans and misting devices. Indoors, workers should be allowed to rest in a cool or air-conditioned area away from heat sources such as ovens and furnaces.