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Protective Measures to Take at Each Risk Level

Drinking Water

Water should have a palatable (pleasant and odor-free) taste and water temperature should be 50°F to 60°F, if possible.

Other Drinks

Encourage workers to choose water over soda and other drinks containing caffeine and high sugar content. These drinks may lead to dehydration. Drinks with some flavoring added may be more palatable to workers and thereby improve hydration. Encourage workers to avoid drinking alcohol during hot weather events.

Actions for Moderate Risk Conditions:
Heat Index is 91 degrees F to 103 degrees F

At the moderate risk level some precautions in addition to those already mentioned are needed to prevent heat-related illness. Review heat-related illness signs and precautions with workers. Remind workers to drink water. Provide workers opportunities to rest in cool, shaded areas. Be aware of conditions that could increase risk.

  • Alert workers to the heat index anticipated for the day and identify each precaution in place at the work site to reduce the risk of heat-related illness.
  • Provide adequate amounts of cool water and disposable cups in convenient, visible locations close to the work area.
  • Remind workers to drink small amounts of water often (before they become thirsty). A good rule of thumb is to drink about 4 cups of water every hour when the heat index suggests a moderate risk level.
  • Ensure that adequate medical services are available. Where medical services (e.g., emergency medical services, clinic, hospital) are not available within 3-4 minutes, you must have appropriately trained personnel and adequate medical supplies on site. The trained personnel should have a valid certificate in first aid training from the American Red Cross or equivalent training. (A first aid certificate is required at maritime and construction worksites.))
  • Respond to heat-related illness and medical emergencies without delay.

    Workers who show symptoms of heat-related illness need immediate attention. Treating milder symptoms (headache, weakness) early by providing rest in a shaded area and cool water to drink can prevent a more serious medical emergency. Call 911 immediately if a worker loses consciousness or appears confused or uncoordinated. These are signs of possible heat stroke. Heat stroke is fatal if not treated immediately.

  • The resources under Educational Resources are useful training tools for daily meetings and toolbox talks.

    Review heat-related illness signs and symptoms and site-specific precautions during daily meetings or toolbox talks. Be sure everyone knows procedures for responding to possible heat-related illness.
    • What steps to follow if a worker exhibits signs and symptoms of heat-related illness
    • Who to call for medical help
    • Who will provide first aid until the ambulance arrives
  • Schedule frequent rest breaks in cool, shaded areas.
    • Provide air conditioned or shaded areas close to the work area.
    • Set up temporary shade when working in open fields or areas without easy access to shade or air conditioning.
  • Acclimatize new and returning workers. Gradually increase the workload or allow more frequent breaks to help new and returning workers build up a tolerance for hot conditions over time. If the heat index increases suddenly, allow all workers more frequent breaks for a few days while they become accustomed to the warmer conditions.
  • Implement actions for the High Risk Conditions (103°F - 115°F) if heat index approaches 103°F OR work is strenuous, in direct sunlight, or involves the use of heavy or non-breathable clothing or impermeable chemical protective clothing.
  • Set up a buddy system, if possible, to enable workers to look out for signs and symptoms of heat-related illness in each other. Often, a worker will not recognize his own signs and symptoms.
  • Instruct supervisors to watch workers for signs of heat-related illness.Check routinely to make sure workers are making use of water and shade and not experiencing heat-related symptoms.
  • Encourage workers to wear sunscreen and use other protections from direct sunlight. Provide shade, hats, and sunscreen, when possible. Sunburn reduces the skin's ability to release excess heat, making the body more susceptible to heat-related illness. Repeated overexposure to sunlight also leads to skin cancer.

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Heat Index Risk Level Protective Measures
Less than 91°F Lower (Caution) Basic heat safety and planning
91°F to 103°F Moderate Implement precautions and heighten awareness
103°F to 115°F High Additional precautions to protect workers
Greater than 115°F Very High to Extreme Triggers even more aggressive protective measures


OSHA is a Weather-Ready Nation Ambassador committed to working with NOAA and other Ambassadors to strengthen national preparedness for and resilience against extreme weather
OSHA is a Weather-Ready Nation Ambassador committed to working with NOAA and other Ambassadors to strengthen national preparedness for and resilience against extreme weather.


How can OSHA help? Workers have a right to a safe workplace. If you think your job is unsafe or have questions, visit OSHA's Worker's Page or call 1-800-321-6742 (OSHA). It's confidential. For other valuable worker protection information, such as Workers' Rights, Employer Responsibilities, and other services OSHA offers, visit OSHA's Workers' page.

OSHA also provides help to employers. OSHA's On-site Consultation Program offers free and confidential advice to small and medium-sized businesses in all states across the country, with priority given to high-hazard worksites. For more information or for additional compliance assistance contact OSHA at 1-800-321-6742 (OSHA).