As those who’ve worked in the construction industry for years can attest, the often excessive exposure to heat during the summer months in many parts of the United States can cause a wide variety of illnesses associated with heat stress, ranging from heat rashes and heat exhaustion to heat cramps and heat stroke. Thousands of workers report suffering occupational heat-related illnesses each year, dozens of which result in fatalities. Of those fatalities, 40 percent occur in the construction industry.

While heat stress illnesses are not exclusive to the summer months or even outdoor projects (any environment that exposes a worker to excessive temperatures can lead to a heat-related illness), construction workers are particularly vulnerable to occupational heat stress in July and August. The heat can be particularly dangerous for workers in areas that are experiencing unusually high summertime temperatures, as workers are less likely to be accustomed to working in hot environments with a general lack of shaded or air-conditioned spaces.

Another factor that plays into heat stress illness is humidity. High humidity prevents the body from evaporating sweat off the skin, which greatly slows the body’s natural process of releasing heat and can cause workers’ bodies to overheat quicker. Utilizing the heat index chart, which calculates the real-feel temperature using both the relative humidity and the actual temperature, is an excellent tool to help determine the potential dangers of working in those conditions.

OSHA doesn’t currently have any specific standards related to occupational heat exposure. However, companies still have a responsibility to protect workers from excessive heat exposure under the General Duty Clause of the Occupational Safety and Health Act of 1970, which requires employers to provide a working environment that is free from recognizable hazards that are likely to cause harm to employees.

There are many things employers can do to help mitigate occupational heat-related illnesses.
  • Stay informed about the temperature and heat index in areas where the company has jobsites. 
  • Adjust schedules so that the heaviest work takes place in the coolest parts of the day (morning or evening). Employers also should be cognizant that the use of non-breathable or bulky personal protective equipment (PPE) in extreme heat can cause workers to experience heat stress. If possible, jobs or tasks requiring workers to wear this kind of PPE should be scheduled during the coolest parts of the day as well. The time spent wearing such equipment also should be limited. 
  • Help workers acclimatize (e.g., physiologically respond and adapt to changes in environmental factors) to the heat by gradually increasing the time spent working in hot conditions during the course of a few days, repeating as necessary as temperatures continue to rise.
  • Schedule frequent rest and water breaks to allow workers to recover in air-conditioned or shaded areas. 
  • If applicable, adjust uniforms or dress codes to be more appropriate for the summertime heat (e.g., allowing workers to wear light-colored, loose-fitting items in breathable fabrics). 
  • Ensure plenty of water is available onsite for workers, and instruct foremen and supervisors to remind workers to drink water regularly.
The most important and impactful thing employers can do to help mitigate the effects of heat stress in the workplace is to provide training and educational resources about heat stress and heat-related illnesses. OSHA and the National Institute for Occupational Safety and Health provide many training resources for employers on topics related to heat stress. Training should be conducted on an annual basis, at least, and should cover risk factors, symptoms and preventative measures employees can take to mitigate their exposure to heat stress.

Kimberly A. Blanchard is a safety consultant for HR outsourcing firm G&A Partners. For more information, visit gnapartners.com.