Heat stress surveys are performed under which trigger?

• A. CO orders
• B. Only during high-temperature days
• C. Any ETT drills greater than 3 hours
• D. After a heat stress casualty

Answer: (C)

Heat stress risk grows with the duration of work in protective gear, so these surveys are used as a preventive check during long drills. When training sessions extend beyond three hours, it’s important to monitor heat exposure, hydration, rest breaks, and signs of heat strain to prevent illness before it starts. This focus on duration captures the period of greatest cumulative heat stress, not just hot weather. While heat monitoring could be relevant after a casualty, the surveys are designed to be proactive during the drill. The other options don’t fit because carbon monoxide events aren’t about heat stress monitoring, heat surveys aren’t limited to hot days, and waiting for a casualty ignores prevention during lengthy exertion.