Washington State University
Environmental Health & Safety Outdoor Heat Stress Prevention Program

Departments are responsible to protect employees from outdoor heat stress hazards by:

  • Establishing a written outdoor heat stress program as part of their Accident Prevention Program when employees work in temperatures exceeding the following action levels:
    Outdoor Temperature & Clothing Action Levels

    • All other clothing: 89° F
    • Double-layer woven clothes including coveralls, jackets and sweatshirts: 77° F
    • Non-breathing clothes including vapor barrier clothing or PPE such as chemical resistant suits: 52° F
  • Providing sufficient amounts of drinking water
  • Establishing procedures for responding to outdoor heat related illnesses
  • Providing supervisor and employee training


Environmental Health and Safety has developed training materials that departments can use to meet the rule.


Outdoor Heat Stress Prevention written program template.

Fact Sheet: Heat-Related Illness – Don’t Lose Your Cool
Safety Policies and Procedures Manual: Outdoor Heat Stress