In what order should monitoring be conducted?

Monitoring in hazardous environments follows a specific order to ensure the safety of responders. The correct sequence begins with oxygen levels because a sufficient concentration of oxygen is critical for survival. Before assessing other hazards, it's essential to confirm that the atmosphere is breathable; otherwise, workers may not be able to safely carry out monitoring for other hazardous substances.

After confirming adequate oxygen levels, the next step is to check for explosives. This allows responders to ensure that they are not working in an environment where there is a risk of explosive materials, which could lead to catastrophic consequences if disturbed.

Finally, monitoring for toxic substances comes last. While toxic exposure can be immediate and harmful, ensuring the environment is safe from explosive risks and has breathable air takes priority to protect responders from immediate dangers.

This systematic approach establishes a safe procedure for entering and assessing hazardous environments, prioritizing life-sustaining conditions and preventing immediately life-threatening situations.