Summer is Here and So is the Heat. Work Safely.

May 20, 2021

Bernie Mizula
IUPAT Health and Safety Director

This is the first in a series of articles offered by the Finishing Trades Institute International on working safely on the job site. Questions, tips to share or comments for IUPAT Director of Health and Safety Bernie Mizula? Email him at 

Summer is here and with it, IUPAT members will be at increased risk of heat stress.   Heat Stress is a term used for factors that can cause a person’s body to “heat up” beyond its normal core body temperature of 98.6oF.  Heat stress factors include exposure to certain environmental conditions (e.g. hot temperatures, humidity, still air, etc.), type of work clothing worn (clothing that may prevent sweat from evaporating and heat to build up such as coveralls or Tyvek suits), and the metabolic heat created by our bodies burning calories to conduct work (harder, more intense work means the body produces more heat!).  

These heat stressors contribute to the bodies net heat load or heat gain.  Luckily, our bodies can tolerate slight core temperature changes and have a great ability to dissipate heat, however, if the heat gain increase is greater than 1.8oF, it puts us in harm’s way.  When the body is subjected to heat stress, it undergoes “heat strain”, a physiological process used to get rid of the excessive heat to keep our body’s core at its ideal temperature; in other words, our body tries to maintain heat balance.   When the net heat gain that a worker experiences starts to out-pace their body’s heat balancing ability, they may suffer a heat related illness (HRI).  These HRIs include heat fatigue, heat rash, heat cramps, heat exhaustion, syncope (fainting) and the most serious, heat stroke.  

While some HRIs may have minimal impact on workers’ health and can quickly subside if properly treated (such as heat fatigue or heat rash), others can be deadly such as syncope and heat stroke.   Once a person experiences an HRI, they can become more susceptible to heat stress and be at increased risk of developing future HRIs.  Other factors that may contribute to the onset of an HRI include: underlying health and/or physiological conditions, not being acclimated (a process of gradually getting someone used to heat stressors), pregnancy, diet (food and drink affecting hydration), and use of some over the counter/prescription medications.

Many work environments could have heat stress risk; construction work however, especially on sites with high heat stress environments (e.g. summer work, direct sunlight, humid air, high workloads, restrictive clothing, etc.) puts construction workers at an elevated risk for suffering HRIs (including death from heat stress).  

A 2019 Center to Protect Workers’ Rights (CPWR) study showed that construction workers accounted for over a third of the 285 on-the-job heat stress related fatalities between 1992 and 2016 (75% of these fatalities occurred in the summer months).  According to National Institute of Occupational Health (NIOSH), heat stress also puts workers at elevated risk to other health and safety job-related issues including accidents, ailments of the heart, lungs, kidney, and circulatory and reproductive systems.  

And if all of this was not enough, studies from National Aeronautics and Space Administration (NASA) have shown that heat stress can reduce work productivity and accuracy.   This is a good place to consider the heat stress factors IUPAT trades may face, and other factors (in addition to hot environments), which may put us at increased risk including; working in confined or enclosed spaces which may not be air conditioned, working near materials that can radiate heat such as concrete walls, glass or metal structures, use of protective clothing ensembles while blasting or applying coatings and the often repetitive, intense work.

Now the good news!  There are some simple heat stress controls that employers and health and safety professionals can implement to reduce your risk of suffering an HRI.  These include assessing a work environment for heat stress factors, using engineering controls (such as fans or air conditioning where possible), administrative controls (such as implementing a work/rest schedule based on adjusted Wet Bulb Globe Temperature (WBGT) and metabolic work load, acclimating new workers, working in shade or during cooler parts of the day, etc.), selecting clothing that allows for heat to dissipate (when possible), and training and providing workers the opportunity to drink plenty of water.  Ideally, an employer should have a written Heat Stress Program outlining how they will assess, control and communicate heat stress on their worksite(s).  

While there currently is no Occupational Health and Safety Administration (OSHA) heat stress regulation, OSHA does state that employers can be cited under the general duty clause, related standards, and some state specific standards for heat stress issues.  NIOSH has created criteria for a recommended standard for occupational heat stress which was revised in 2016 and provides excellent guidance for employers to reduce the impact of heat stress on their worksites.

The iFTI has a train-the-trainer and 4-hour worker course on heat stress covering what heat stress and HRIs are, how to assess heat stress and how to implement controls to reduce workers’ risk to HRIs.

If you have questions or concerns about heat stress, you may contact the iFTI at

You can also find more information on heat stress and how to reduce your risk at:

OSHA heat stress webpage: also has a heat stress web page and heat stress app: can also find information on the CPWR website. Search CPWR and “working in hot weather.”