Preventing Heat Stress in the Workplace

It’s summertime, and that means hot temperatures. Employees who work outdoors or inside hot environments are at risk for heat stress illnesses. In fact, it’s not surprising to see many production environments that are not air conditioned, and temperatures can quickly reach dangerous levels. That’s why it is important to protect your employees from the “Hazards of the Heat”.       

Heat stress occurs when the body becomes unable to cool itself. There are many factors that may cause heat-related illnesses. High temperatures during summer months are the most obvious causes of heat stress, but there are other factors that contribute to this condition, including:

  • Low fluid intake by the worker (dehydration)     
  • Direct sun exposure (with no shade) for long periods (i.e. Landscaping/Facilities Maintenance, etc.)
  • Extreme heat from job task (i.e. No A/C in Service Departments, Paint Booths, etc.)
  • Limited air movement
  • Physical exertion
  • Use of bulky protective clothing and equipment
  • Poor physical condition or on-going health problems
  • Some medications 
  • Lack of previous exposure to hot workplaces
  • Excessive alcohol intake the day before
  • Previous heat-related illnesses

Types of Heat Disorders  

Heat-related illnesses often begin with minor symptoms. Heat fatigue is usually the first symptom. Conditions include a decline in performance (particularly physical activity), mental tasks, or tasks requiring concentration. Heat can also increase the risk of other injuries due to sweaty palms losing grip on tools, fogged-up safety glasses limiting visibility, dizziness and balance issues, as well as burns from hot surfaces.

More serious heat disorders include:  Heat Rash, Heat Cramps, Heat Exhaustion, and the deadliest risk is  Heat Stroke. Employees and Supervisors should be trained to recognize these symptoms and administer treatment plans. Here are the guidelines:

Heat Rash is the most common problem resulting from working in heated environments. A heat rash produces blister-like raised bumps on the skin that may itch or be painful to the touch. Treatment includes limiting time in the hot environment, keep the skin dry, and shower promptly after being in the heat.

Heat Cramps are painful muscle spasms that occur in the leg, arm, or abdomen. The cramps occur as a result of extended physical activity in a hot environment. Heat cramps are the first sign of dehydration. The worker should rest and drink water and electrolyte liquids like Gatorade. Eat salty crackers to increase salt in-take. DO NOT use salt tablets.

Heat Exhaustion is a result of the combination of excessive heat and dehydration. This is a serious condition, which left untreated, can lead to heat stroke. Symptoms include headache, nausea, dizziness &/or fainting, weakness, heavy sweating, thirst, moist-clammy skin, elevated body temperature. Employees in this condition should be moved to a cool, shaded area. Cool the worker with water or cold compresses to the head, neck and face. Drink water and electrolyte liquids like Gatorade. If the worker cannot drink or becomes lethargic, call 911. Make sure someone stays with the worker until help arrives.

Heat Stroke is the most serious illness associated with working in heated environments. If left untreated, heat strokes will result in death. Symptoms include hot dry skin (sweating may or may not still be present), red-bluish skin, rapid pulse, confusion, loss of consciousness, seizures/convulsions, very high body temperature. Call 911 immediately. Soak clothing and skin in cool water and use a fan to create air movement. Make sure someone stays with the worker until help arrives.

Preventing Heat Disorders

The best way to prevent heat illness is to make the work environment cooler. If the work environment is not air conditioned, then consider installing portable fans and air chillers. If cooling devices are not available and/or temperatures remain excessive, other measures should be taken to minimize the heat related effects.

Workers who are new to a job in a hot environment, or workers who have been away for more than a week should be acclimatized to the work environment. This means that the worker should start out slow and work up to the physical activities required in the hot environment. NIOSH recommends the following schedule:

  • Employees with no prior exposure to hot environments - start out at 20% exposure per day with a 20% increase in exposure each additional day until full day exposure is reached.
  • Employees with recent prior exposure to hot environments- start out at 50% exposure on day 1, 60% exposure on day 2, 80% exposure on day 3, and 100% exposure on day 4.

Employees should be provided plenty of water and electrolyte liquids when working in hot environments. On average, workers should be encouraged to drink 1 cup of water (or electrolyte liquid) every 15-20 minutes. The use of salt tablets is not recommended, but a small amount of salt with food is encouraged during hot days to replenish the minerals lost from sweating.

Frequent breaks are necessary. Breaks should be provided in areas that are cooler than the work environment. If possible, heavy work should be scheduled during the cooler parts of the day and appropriate protective clothing provided. Consider using shifts and assigning additional workers for work pacing during excessively hot work-shifts. The permissible heat exposure threshold recommended by OSHA will vary depending on the type of work completed and air temperature within the work environment. For more information on specific work/rest restrictions, see the OSHA website. OSHA also provides a mobile device app that can be used to calculate the heat index and includes reminders and protective measures to take based upon the heat index.