Final answer:
The determination of whether an explosives emergency response is Level 1 or Level 2 is made by the incident commander or the senior officer in charge. Level 1 indicates a higher level of risk and requires immediate and more extensive response, while Level 2 represents a lower level of risk and may involve a more controlled and cautious approach to the situation.
Step-by-step explanation:
In an explosives emergency on an installation, the determination of whether the response is Level 1 or Level 2 is made by the incident commander or the senior officer in charge. This decision is typically based on the severity of the situation, the potential for extreme physical danger, and the uncertainty over whether a serious fire or hazard awaits after an alarm. Level 1 indicates a higher level of risk and requires immediate and more extensive response, while Level 2 represents a lower level of risk and may involve a more controlled and cautious approach to the situation.