Avoid heat illness with water, rest and shade


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 be deadly, 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 can’t cool down and you may be at risk for a heat illness.

Take these precautions when working in hot environments:

Caution (at least 80°F at 60% humidity)

  • Drink water every 15 minutes.
  • Take breaks in the shade.
  • Take extra precautions if wearing non-breathable or impermeable clothing.
  • Wear sunscreen.
  • Learn to recognize symptoms of heat-related illness.

Extreme Caution (at least 86°F at 60% humidity)

  • Follow all of the precautions listed above.
  • Drink about 4 cups of water every hour.
  • Take frequent breaks in cool, shaded areas.
  • Protect yourself from direct sunlight.
  • Treat anyone with milder symptoms of heat illness (e.g., headache, weakness).
  • Call 9-1-1 immediately if anyone loses consciousness or appears confused or uncoordinated.

Danger (at least 92°F at 60% humidity)

  • Follow all of the precautions listed above.
  • Institute and enforce work/rest schedules.
  • Adjust job activities and work schedules to avoid physical exertion during the hottest periods of the day.

Learn how to recognize the symptoms of serious and potentially fatal heat illness.

Signs of heat exhaustion versus heat stroke

Dizziness Confusion
Headache High temperature
Sweaty skin Red, hot, dry skin
Weakness Fainting
Cramps Convulsions
Nausea or vomiting Lack of coordination
Fast heart beat  

Heat stress and face coverings

Can wearing a mask while I am working and it is hot out cause me to overheat?

No, a face covering alone will not cause a person to overheat. Studies have shown that filtering facepieces such as an N95 respirator do not cause additional physiological stress to most wearers and do not contribute to heat stress. Cloth face coverings and procedural masks are typically not as restrictive as wearing an N95 mask, and so are of even less concern regarding overheating of the wearer.

When can a face shield substitute for coverings/masks for outside heat exposed workers?

No. Face shields are not an equivalent replacement for face coverings when face coverings are required to be worn.

Can workers lower their mask below the chin occasionally throughout the day while working, and what steps should workers take to stay safe?

Yes, while working alone, and during cool down breaks, as long as appropriate distance from other people is maintained.

At what temperature above 80 degrees is it appropriate to remove facial coverings and masks when exposed to the hazard of heat stress?

It is not appropriate to remove facial coverings based on the temperature. Removing facial coverings is not an effective way of reducing body temperature. Regular protective measures to control heat stress must be implemented, such as drinking plenty of water, frequent breaks in a cool area, and scheduling work during cooler parts of the day.

For more information about heat stress and face coverings, visit the Washington State Department of Labor & Industries' (L&I) website.

For more information about heat illness, visit the U.S. Occupational Safety and Health Administration’s website.