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Prevention

Most heat-related health problems can be prevented, or the risk of developing them can be reduced. For indoor environments, refer to the information below.

Campaign to Prevent Heat Illness in Outdoor Workers
Engineering Controls

The best way to prevent heat-related illness is to make the work environment cooler. A variety of engineering controls can reduce workers' exposure to heat:

  • Air conditioning (such as air-conditioned crane or construction equipment cabs, air conditioning in break rooms).
  • Increased general ventilation.
  • Cooling fans.
  • Local exhaust ventilation at points of high heat production or moisture (such as exhaust hoods in laundry rooms).
  • Reflective shields to redirect radiant heat.
  • Insulation of hot surfaces (such as furnace walls).
  • Elimination of steam leaks.
Work Practices
  • Employers should have an emergency plan in place that specifies what to do if a worker has signs of heat-related illness, and ensures that medical services are available if needed.
  • Employers should take steps that help workers become acclimatized (gradually build up exposure to heat), especially workers who are new to working in the heat or have been away from work for a week or more. Gradually increase workloads and allow more frequent breaks during the first week of work.
  • Workers must have adequate potable (safe for drinking) water close to the work area, and should drink small amounts frequently.
  • Rather than being exposed to heat for extended periods of time, workers should, wherever possible, be permitted to distribute the workload evenly over the day and incorporate work/rest cycles. (See About Work/Rest Schedules.)
  • If possible, physical demands should be reduced during hot weather, or heavier work scheduled for cooler times of the day.
  • Rotating job functions among workers can help minimize overexertion and heat exposure.
  • Workers should watch out for each other for symptoms of heat-related illness and administer appropriate first aid to anyone who is developing a heat-related illness.
  • In some situations, employers may need to conduct physiological monitoring of workers - see Monitoring Workers at Risk of Heat-related Illness.
Personal Protective Equipment

Workers should be aware that use of certain personal protective equipment (e.g., certain types of respirators and impermeable clothing) can increase the risk of heat-related illness.

In some situations, special cooling devices can protect workers in hot environments:

  • In some workplaces, insulated gloves, insulated suits, reflective clothing, or infrared reflecting face shields may be needed.
  • Thermally conditioned clothing might be used for extremely hot conditions; for example:
    • A garment with a self-contained air conditioner in a backpack.
    • A garment with a compressed air source that feeds cool air through a vortex tube.
    • A plastic jacket whose pockets can be filled with dry ice or containers of ice.
Training

Workers and supervisors should be trained about the hazards of heat exposure and their prevention. Topics should include:

  • Risk factors for heat-related illness.
  • Different types of heat-related illness, including how to recognize common signs and symptoms.
  • Heat-related illness prevention procedures.
  • Importance of drinking small quantities of water often.
  • Importance of acclimatization, how it is developed, and how your worksite procedures address it.
  • Importance of immediately reporting signs or symptoms of heat-related illness to the supervisor.
  • Procedures for responding to possible heat-related illness.
  • Procedures to follow when contacting emergency medical services.
  • Procedures to ensure that clear and precise directions to the work site will be provided to emergency medical services.
clip art thermometer

Extreme Heat Alerts

OSHA has partnered with the National Oceanic and Atmospheric Administration (NOAA) on weather service alerts. NOAA's alerts are based on a "heat index" that indicates how hot it really feels when relative humidity is factored with the actual air temperature. This information can help workers and employers take precautions in a timely way to prevent heat-related illness.

**These resources were adapted from: California OSHA's heat campaign materials.

***California and Washington state have their own heat illness prevention standards; these materials reflect the requirements in those standards.


*Accessibility Assistance: Contact OSHA's Directorate of Technical Support and Emergency Management at (202) 639-2300 for assistance accessing PDF materials.

All other documents, that are not PDF materials or formatted for the web, are available as Microsoft Office® formats and videos and are noted accordingly. If additional assistance is needed with reading, reviewing or accessing these documents or any figures and illustrations, please also contact OSHA's Directorate of Technical Support and Emergency Management at (202) 639-2300.

**eBooks - EPUB is the most common format for e-Books. If you use a Sony Reader, a Nook, or an iPad you can download the EPUB file format. If you use a Kindle, you can download the MOBI file format.

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