Social distancing (the 6 foot rule) and wearing masks are two of the best ways to prevent person to person transmission of COVID-19 virus.
Remember that masks protect others if the wearer is infected. They are not meant to protect the wearer.
The issue of wearing masks and heat stress to workers has been a topic of discussion on several fronts.
The related issue is when do workers NOT have to wear a mask, especially when considering the potential for heat stress related illness.
The CDC has posted the following information on masks and heat stress: (emphasis added)
"CDC recognizes that wearing cloth face coverings may not be possible in every situation or for some people. In some situations, wearing a cloth face covering may exacerbate a physical or mental health condition, lead to a medical emergency, or introduce significant safety concerns. Adaptations and alternatives should be considered whenever possible to increase the feasibility of wearing a cloth face covering or to reduce the risk of COVID-19 spreading if it is not possible to wear one. For example…
People who work in a setting where cloth face coverings may increase the risk of heat-related illness or cause safety concerns due to introduction of a hazard (for instance, straps getting caught in machinery) may consult with an occupational safety and health professional to determine the appropriate face covering for their setting. Outdoor workers may prioritize use of cloth face coverings when in close contact with other people, like during group travel or shift meetings, and remove face coverings when social distancing is possible."
This CDC information, in combination with adhering to other Federal, state and local COVID-19 requirements / guidelines, may provide some heat stress relief to workers.
Note information on the use of face shields on this webpage as well.
Contractors should evaluate facial covering polices very carefully and include heat stress assessments on all jobsites including identifying tasks and processes that would require mask use (when social distancing is not possible).
This may identify opportunities for workers performing certain tasks and operations to not wear masks (when social distancing is part of the work). Training of workers on the mask policies is critical to success.
Keep in mind that OSHA (Federal or state plan) can provide citations for both heat stress and COVID-19 using the General Duty Clause (not providing a safe workplace).