Outdoor Heat Exposure

Updated June 28, 2022

Excessive exposure to heat can cause a range of heat-related illnesses, from less serious heat rash and heat cramps to more serious heat exhaustion and heat stroke. Heat stroke requires immediate medical attention because it can result in serious health effects or death, so take precautions while working in the summer heat.

For people working in hot environments, both air temperature and humidity affect how hot you feel. The higher the heat and humidity, the hotter the weather feels, because sweat is unable to readily evaporate. If the sweat your body produces cannot evaporate, your body cannot easily cool down, and you may be at risk for a heat illness. Certain factors, including personal health conditions, activities being conducted, and weather can increase the risk of a heat-related illness.

Heat exhaustion can also make workers more susceptible to falls, equipment-related injuries, and other on-the-job safety hazards.

University units with personnel who work outdoors must plan, prepare, and train for heat-related illness.

Applicability

Washington state outdoor heat exposure rules in WAC 296-62-095 apply to UW departments with personnel performing work in an outdoor environment from May 1 through September 30, annually, only when personnel are exposed to outdoor heat at or above an applicable temperature listed in Table 1 below.

In addition to requirements in the permanent rule, as of June 15, 2022 through September 29, 2022, additional temporary requirements go into effect for cool water, shade, cool-down rest periods, and observing and communicating with workers about signs and symptoms of heat illness.

Table 1: Outdoor temperature action levels

TYPE OF CLOTHING WORN ACTION REQUIRED AT OR ABOVE THIS TEMPERATURE
Non-breathable clothes, including vapor barrier clothing or PPE such as chemical resistant suits 52 degrees F
Double-layer woven clothes including coveralls, jackets, and sweatshirts 77 degrees F
All other clothing 89 degrees F

Exception: The rules do not apply if incidental exposure occurs when personnel are not required to perform a work activity outdoors for more than 15 minutes in any 60-minute period. The exception may be applied every hour during the work shift.

Responsibilities

Heat-related illness and first aid

Heat stroke

WHAT TO LOOK FOR WHAT TO DO
  • High body temperature (103°F or higher)
  • Hot, red, dry, or damp skin
  • Fast, strong pulse
  • Headache
  • Dizziness
  • Nausea
  • Confusion
  • Losing consciousness (passing out)
  • Call 9-1-1 right away-heat stroke is a medical emergency
  • Move the person to a cooler place
  • Help lower the person’s temperature with cool cloths or a cool bath
  • Do not give the person anything to drink

Heat exhaustion

WHAT TO LOOK FOR WHAT TO DO
  • Heavy sweating
  • Cold, pale, and clammy skin
  • Fast, weak pulse
  • Nausea or vomiting
  • Muscle cramps
  • Tiredness or weakness
  • Dizziness
  • Headache
  • Fainting (passing out)
  • Move to a cool place
  • Loosen your clothes
  • Put cool, wet cloths on your body or take a cool bath
  • Sip water

Get medical help right away if:

  • You are throwing up
  • Your symptoms get worse
  • Your symptoms last longer than 1 hour

Heat cramps

WHAT TO LOOK FOR WHAT TO DO
  • Heavy sweating during intense exercise
  • Muscle pain or spasms
  • Stop physical activity and move to a cool place
  • Drink water or a sports drink
  • Wait for cramps to go away before you do any more physical activity

Get medical help right away if:

  • Cramps last longer than 1 hour
  • You’re on a low-sodium diet
  • You have heart problems

Sunburn

WHAT TO LOOK FOR WHAT TO DO
  • Painful, red, and warm skin
  • Blisters on the skin
  • Stay out of the sun until your sunburn heals
  • Put cool cloths on sunburned areas or take a cool bath
  • Put moisturizing lotion on sunburned areas
  • Do not break blisters

Heat rash

WHAT TO LOOK FOR WHAT TO DO

Red clusters of small blisters that look like pimples on the skin

(usually on the neck, chest, groin, or in elbow creases)

  • Stay in a cool, dry place
  • Keep the rash dry
  • Use powder (like baby powder) to soothe the rash

 

Training

Prior to outdoor work in temperatures exceeding those listed in Table 1, personnel and supervisors must complete the Outdoor Heat Exposure and Heat-Related Illness training course located on the EH&S Training webpage.

Services available

If you need assistance related to preventing heat related illness, contact EH&S at ehsdept@uw.edu or (206) 543-7388. 

Frequently asked questions

Visit the Washington State L&I website to read frequently asked questions.

Glossary

A system where individuals are paired or teamed up into work groups so each employee can be observed by at least one other member of the group to monitor and report signs and symptoms of heat-related illness.

The use of devices to reduce exposure and aid cooling (i.e., air conditioning)