Final answer:
Incident safety officers must deal with physical and emotional overexertion threats to firefighters.
Step-by-step explanation:
Incident safety officers must deal with physical and emotional overexertion threats to firefighters regardless of their proactive work hardening efforts. These threats include the dangers associated with the physical demands of firefighting and the emotional toll of the job. Firefighters often face uncertainty, physical danger, and life-and-death decision making, which can lead to overexertion. Therefore, incident safety officers must address both the physical and emotional aspects of overexertion to ensure firefighters' safety.