Heat exposure rules update as high temperatures continue

New emergency heat rules put in place last month require additional training for employees working outside in high temperatures. 

This is in addition to the training workers should have already received on the state’s permanent Outdoor Heat Exposure rule.


Washington’s Outdoor Heat Exposure rules still require employers to take steps to prevent heat-related illnesses when employees are exposed more than 15 minutes in a 60-minute period at any of the following Action Levels:

    • 52° F – Non-breathable clothing
    • 77° F – Double-layer woven clothing
    • 89° F – All other clothing

Employers are responsible for monitoring the actual temperature at the work site throughout the workday, except for employers who decide to fully implement all requirements in the rule. Temperature records are not required.


Provide enough drinking water for each worker to drink at least 1 quart (four 8-ounce glasses) per hour, and encourage them to do so.

Ensure drinking water is suitably cool to encourage drinking and readily accessible to workers at all times.

Note: There are other rules, like those for the construction industry or agriculture, that require access to drinking water, separate from this rule. Those rules may apply in addition to this one or when this one doesn’t apply.

Shade and Rest

Provide workers access to shade and encourage workers to take preventative cool-down rest periods when they feel the need to prevent overheating. Workers should not wait until they feel sick to cool down.

When the temperature is 89°F or higher, mandatory cool-down rest periods must also be provided (i.e., at least 10 minutes every two hours); and employers must ensure there is enough cooling shade at all times to fully cover all workers on a break or meal period while sitting in a normal posture.

In order to be cooling, shade must block direct sunlight and not be in areas where the heat defeats the purpose of the shade, such as in a car without running air conditioning or shade provided by crops where heat and moisture are trapped in the area. The location of shade must not deter or discourage use; for example, don’t situate shade next to a port-a-potty, dangerous wildlife like snakes, or wasp nests.

Both preventative and mandatory cool-down rest periods must be paid time unless taken during a meal period.

Alternative cooling methods may be used instead of shade, such as temperature-controlled environments like air-conditioned trailers or misting stations.

Acclimatization (getting used to the heat)

Employers are encouraged to ensure anyone new to working in the heat or who has been away from the heat for more than a week is closely observed for signs and symptoms of heat illness for 14 days using any of the following:

    • Phone or radio (for lone workers; if reception is reliable)
    • An arrangement where workers are teamed up and required to watch out for each other (i.e., mandatory buddy system).
    • Other effective methods.

There may be other times when acclimatization is recommended; for example, during a sudden temperature increase (e.g., a heat wave) compared to previous days.

For tips and examples of possible acclimatization schedules to follow, see NIOSH recommendations.

Identify and Respond to Heat Illness

Respond to workers showing signs and symptoms of heat-related illness by relieving them from duty, providing shade or other sufficient means to cool down, and monitoring to determine whether medical attention is necessary.

Ensure effective procedures for obtaining emergency medical services are established and known so they can be readily implemented when needed. Time is critical.

When the temperature is 89°F or higher, ensure:

Workers and supervisors have an effective way to communicate with each other, including workers working alone. Voice, visual communication, or use of electronic devices with reliable reception may be used.

Workers are observed for signs and symptoms of heat illness using:

    • Phone or radio (for lone workers; if reception is reliable)
    • An arrangement where workers are teamed up and required to watch out for each other (i.e., mandatory buddy system).
    • Other effective methods.

Plan and Train

Ensure the company’s written Accident Prevention Program (APP) includes outdoor heat exposure safety

information and procedures.

Workers and supervisors must be trained before working in the heat and annually after that. Training must be in a language the trainee understands and must cover the topics listed in the rule, including procedures included in the APP.

For further detail on requirements, see the Outdoor Heat Exposure rules.

An overview of the emergency heat rules is available in English and 13 additional languages.

Training resources on L&I’s Be Heat Smart webpage have been updated to the 2022 emergency rule requirements.

Employers who need to update their workers but have already provided heat safety training this year can opt to use the new Safety Orientation training resource available in English, Spanish, and Russian.