Final answer:
When firefighters do not wear their masks, they are at a higher risk of inhaling toxic smoke and gases, experiencing health issues like respiratory symptoms, and developing heart or lung disease. Wearing masks is crucial for their health and safety.
Step-by-step explanation:
When firefighters do not wear their masks, there are several predictable outcomes that can occur. First, they are at a higher risk of inhaling toxic smoke and gases, which can lead to respiratory symptoms, increased medication use, hospital admissions, and even premature mortality. Second, they may experience short-term aggravation of heart or lung diseases, which can further impact their health. Lastly, long-term exposure without masks can contribute to the development of heart or lung disease and premature mortality. It is crucial for firefighters to wear their masks to protect their health and safety.