What are the heat stress categories?

Heat stress categories are typically defined by the Wet Bulb Globe Temperature (WBGT) index, which considers temperature, humidity, wind speed, and solar radiation. The categories include: 1) Low Risk (WBGT < 80°F), where heat stress is unlikely; 2) Moderate Risk (80-84°F), where caution is advised; 3) High Risk (85-88°F), necessitating more stringent precautions; and 4) Extreme Risk (≥ 89°F), where strenuous activities are highly discouraged and immediate measures should be taken to prevent heat-related illnesses. These categories help guide safety protocols in hot environments.