Extreme heat is the leading cause of weather-related mortality worldwide and has been projected to intensify as climate change increases both mean temperature and humidity while amplifying the frequency and severity of heat waves across the United States. 

Assessing heat risk requires a metric that reflects the full physiological burden of heat stress. Wet Bulb Globe Temperature (WBGT) integrates air temperature, humidity, wind speed, and solar radiation into a single index. WBGT has established flag categories for risk quantification and has been adopted by numerous state high school athletic associations, the Occupational Safety and Health Administration (OSHA), the American Industrial Hygiene Association (AIHA), the American Academy of Pediatrics, and many athletic event organizers. WBGT better predicts heat-illness risk in athletes and laborers than air temperature or heat index alone.

I strongly urge the state of Virginia to adopt WBGT as the key metric to evaluate heat stress on workers and provide guidelines for work/rest periods for indoor and outdoor laborers. Adopting evidence-based WBGT guidelines will ultimately lead to better public health outcomes and allow for proper heat stress mitigation techniques to be used. This will ultimately increase worker productivity and lead to fewer lost labor hours and event cancelations due to taking an evidence-based and structured approach to preventing heat-related illness.