Across the U.S. and Canada, the summer months bring widespread risk for heat illness to millions of workers who spend most of their days outdoors. According to the most recent data from the Bureau of Labor Statistics, 11 construction workers died from heat exposure in 2018, and another 370 required days away from work to recover from heat illness.

LIUNA General President Terry O’Sullivan
“LIUNA members working on road jobs to repair our aging highway system, on pipelines and other critical infrastructure projects and on other projects in the construction industry are at high risk for heat illness,” says LIUNA General President Terry O’Sullivan. “These jobs can require tough, physical labor, and when that physical exertion is combined with high temperatures, heat exhaustion and heat stroke can happen quickly.”
Increased Heat Illness Risk from Cloth Face Coverings
Construction employers and other businesses have implemented social distancing policies, stepped up cleaning and disinfecting protocols and taken other measures to prevent the spread of COVID-19 on jobsites.
Part of the safety measures that many construction employers have implemented is the mandatory use of cloth face coverings on the job. Face coverings are especially important when workers are working close together in enclosed spaces and when it’s not feasible to practice physical distancing during a task. However, a policy that mandates cloth face coverings (or N95 respirators) to help prevent the spread of COVID-19 should be reexamined during high-heat conditions.
Using face coverings makes it more difficult to breathe because the body has to work harder with each breath to pull the same amount of air into the lungs. Breathing may become more difficult as the cloth becomes soaked with sweat. When the body has to work harder than normal, our heart rate increases. The combination of strenuous physical activity, high-heat conditions and difficulty breathing has the potential to put workers at serious risk for heat illness, heat exhaustion and heat stroke.

Photo courtesy of the LIUNA Mid-Atlantic Region
Federal OSHA’s Position
OSHA briefly addresses this issue in their COVID-19 FAQ on cloth face coverings, a portion of which is included below:
Where cloth face coverings are not appropriate … during certain job tasks (e.g., because they could become contaminated or exacerbate heat illness), employers can provide PPE, such as face shields and/or surgical masks, instead of encouraging workers to wear cloth face coverings. Like cloth face coverings, surgical masks and face shields can help contain the wearer’s potentially infectious respiratory droplets and can help limit spread of COVID-19 to others.
Surgical masks are easier to breathe through than cloth face coverings, which are usually made using at least one layer of cotton. Face shields provide a barrier without requiring a worker to inhale air through any type of material.
Reducing Risk for Heat Illnesses
In addition to these options, employers can also reduce risk for heat illness by providing additional rest breaks, changing shift times to cooler parts of the day and/or rotating work crews more frequently during strenuous tasks. Employers should perform a risk assessment of each job task to determine conditions when using a mask may be hazardous or not required because of other controls. Depending on the task, possible controls may include increasing ventilation, installing physical barriers, staggering shifts, working alone, increasing physical distancing and increasing hand hygiene protocols.

Photo courtesy of the LIUNA Mid-Atlantic Region
Providing water, rest and shade, and allowing workers time to acclimate to high-heat conditions, are the most effective methods to reduce and prevent heat illness. Workers should be trained to recognize the signs of heat illness, including the signs of heat exhaustion and heat stroke. Employers should encourage workers who experience trouble breathing, feel dizzy or feel their heart racing to do the following:
- Move at least six feet away from their fellow workers, then remove their mask
- Find shade if it’s available to let the body cool down, then rest while drinking some cool water
- Seek medical attention if symptoms don’t improve within a few minutes
Facial Coverings Not a Replacement for Respirators
It’s important for both employers and workers to remember that cloth face coverings, surgical masks and face shields used to limit the spread of COVID-19 cannot be used in place of respirators when a respirator would otherwise be required. For example, if a worker is required to wear at least an N95 respirator due to exposure to respirable crystalline silica, a face covering does not meet that requirement. Remember: surgical masks and cloth face coverings are not respirators.
For more information on how to protect workers from exposure to COVID-19, see the Fund’s COVID-19 Worksite Safety & Health Program and our Guidance for Conducting Workplace COVID-19 Screenings and Assessments on our Coronavirus and COVID-19 resource page.
[Nick Fox]