Back to Basics, Heat illness

Back to Basics: Heat Stress and Illness Prevention and Protection

Back to Basics is a weekly feature that highlights important but possibly overlooked information that any EHS professional should know. This week, we examine heat stress and illness prevention and how to protect workers who work in high temperatures.

As summer begins and temperatures rise, EHS leaders and management must protect their workers from the dangers of heat stress and illness. According to OSHA, thousands of workers get sick and even die from occupational heat exposure, despite it being entirely preventable. Hazardous heat exposure can occur anytime, both indoors and outdoors, and the occupational risk factors for heat illness include heavy physical activity, high temperatures in the work environment, lack of heat acclimatization, and wearing insulating clothing.

Industries where workers have a higher risk of heat illness outdoors include agriculture, construction, landscaping, mail and package delivery, and oil and gas well operations. Indoors, workers are at a higher risk in bakeries, kitchens, laundries, electrical utilities, fire services, iron and steel mills, manufacturing, and warehousing. OSHA provides a full list of symptoms and first aid procedures for workers experiencing heat stress or illness.

New worker protection

OSHA says that 50%-70% of outdoor fatalities happen within the first few days of working in heat because new workers have not had time to gradually get used to the temperature. New workers can include temporary or existing employees who start new tasks in warm or hot environments while wearing additional clothing and doing more physical activity. Workers are also considered new if they have been absent for one week or more and are returning, workers who do their jobs through seasonal changes, and those who work on days when the weather is significantly warmer than on previous days.

Heat acclimatization is the process of the body gradually adapting and building up tolerance to higher levels of heat stress. Acclimatization results from:

  • The body producing more sweat, which means more evaporative cooling
  • Sweat containing less salt loss, which means a worker is less likely to develop electrolyte imbalances and heat cramps
  • The body becoming more efficient at getting rid of heat, which means a slower heart rate and body temperature increase
  • More blood flow to the skin, meaning more efficient cooling through the skin

Unacclimatized workers do not sweat efficiently, their sweat contains more salt, their body temperature and heart rate increase quickly, and their blood flow is not optimized for heat dissipation, says OSHA.

To protect new workers and establish a “culture of acclimatization,” employers should schedule new workers to work shorter amounts of time in the heat, give more frequent rest breaks, train new workers on heat stress and the importance of rest and water, monitor closely for heat illness symptoms, use a buddy system, and administer first aid as soon as a worker shows symptoms. After one to two weeks of following these precautions, new workers should be acclimatized and able to work a regular schedule.

Training and recognition

Employers, management, and workers must be trained on heat hazards, prevention, and first aid. They should learn the types of heat-related illness, the importance of immediate first aid, the procedures for contacting emergency medical services, the job-related heat risk factors, work and rest cycles, and fluid replacement guidelines. Supervisors in particular should know how to identify and control heat hazards, recognize early symptoms of heat stress, administer first aid, and when to activate emergency medical services.

Management should be able to recognize the risk factors that can lead to heat illness among employees, including environmental conditions, presence of heat sources, level of physical activity, use of clothing or gear that acts as insulation, and individual risk factors. Employers should assess both the environmental heat and a worker’s metabolic heat to determine total heat stress, and then they should compare the total heat stress to the published occupational heat guidance in order to decide if the work conditions are too hot. They should also use heat advisories from the National Weather Service and remember that heat stress can be experienced at lower temperatures.

Personal risk factors that put workers in more danger include:

  • Obesity
  • Diabetes
  • High blood pressure
  • Heart disease
  • Lower level of fitness
  • Use of certain medications (e.g., diuretics, psychiatric, blood pressure)
  • Alcohol use
  • Illicit drug use

Employers should remember that not everyone handles heat the same way, and that they need to monitor the physiological responses of their workers when possible, such as heart rate and body temperature, using thermometers and a clock to measure pulse. OSHA recommends developing a confidential occupational medical monitoring program to identify workers who are at a higher risk of heat illness.

Prevention plan and supervision

Employers should create a written heat illness prevention plan that outlines how to deal with new worker heat acclimatization, measure heat stress, respond to a heat advisory, determine if the total heat stress is hazardous, and what training will be provided to management and employees. Another key element of heat illness prevention is supervision, and OSHA says there should be an individual at the worksite who is responsible for monitoring conditions and implementing the heat plan throughout the day.

Preventing heat illness can also involve the use of engineering controls, specific work practices, and personal protective equipment (PPE), says OSHA. The most effective engineering controls will cool off the work environment, and they could consist of air conditioning, cooling fans, ventilation, reflective shields, and many other cooling methods. When engineering controls are not enough, employers should modify work activities by scheduling shorter shifts for new workers, requiring mandatory rest breaks in a cooler area, reducing physical demands, making sure employees are hydrated, and applying other administrative controls.

When engineering and administrative controls are still not adequate, employers should provide their employees with the proper PPE for heat stress, including insulated suits, reflective clothing, infrared reflecting face shields, and cooling neck wraps. OSHA says in extremely hot conditions, thermally conditioned clothing may be used.

For more information, click here for OSHA’s full recommendations for dealing with heat illness.