CDC: Be Careful of Heat Stress

Heat stress can affect many outdoor and indoor workers. To prevent heat-related illnesses (HRI) and injuries, employers should develop and use a comprehensive heat-related illness prevention program at the workplace.

In occupational settings, heat stress is the combination of the heat your body produces (metabolic heat), environmental factors (for example, temperature and humidity), and clothing and personal protective equipment (PPE). While many workers need to wear PPE for protection from workplace chemical, physical, and biological hazards, PPE can increase the risk for HRIs. PPE can often alter the rate and amount of heat exchange between the skin and air. For example, impermeable materials used for protection against chemical hazards can be very hot to wear, as they trap heat close to the skin and prevent sweat evaporation.

Below are some elements for addressing heat stress that need to be included in workplace HRI prevention programs.

Control of Heat Stress
Employers should reduce workplace heat stress by implementing engineering and work practice controls.

Engineering controls might include those that:
Increase air velocity (if air temperature is below 95°F).
Use reflective or heat-absorbing shielding or barriers.
Reduce steam leaks, wet floors, or humidity.
Work practice controls include the following:

Implement a buddy system and routinely check workers to ensure they make use of available water and shade, and they do not have symptoms of an HRI.
Monitor the weather.
Limit time in heat and/or increase rest time in a cool environment.
Increase the number of workers per task.
Require workers to conduct self-monitoring.
Implement a heat alert program when a heat wave is likely.

Training
Employers need to provide training before hot work begins, and tailor the training to cover worksite-specific conditions.

Acclimatization
Workers become acclimatized to heat when they gradually work for longer periods in a hot environment. Benefits of acclimatization include less strain to the heart and vital organs, improved sweating (higher volume, earlier onset), and increased ability to perform physical tasks in the heat.

Hydration
Employers should provide appropriate hydration.

Rest Breaks
Employers should ensure and encourage rest and hydration breaks.