When re-entering an engine room that has been flooded with CO2, the investigating team should initially __________.

Correct Answer: Option D — enter from the highest level with breathing apparatus

CO2 is heavier than air and displaces oxygen, settling at the lowest points of a compartment. Entering from the highest level with an SCBA is critical to avoid oxygen-deficient atmospheres. This practice minimizes the risk of asphyxiation while allowing the team to assess the space safely from above.