What additional risk does a fire involving a vessel's fixed CO2 or other gas-based extinguishing system introduce, and what must be confirmed before the system is released?

A. Fixed gas systems only affect fire, with no displacement effect on breathable oxygen in the protected space

B. Fixed gas extinguishing systems pose no risk to personnel and can be released without any prior headcount or search

C. CO2 and similar gas systems work by displacing oxygen in the protected space, meaning anyone left inside would suffocate — a confirmed, accurate headcount and search to ensure the space is completely clear of personnel is an absolute, non-negotiable requirement before release, with the decision and timing controlled by the master or designated senior officer

D. A headcount is a useful but optional precaution before releasing a fixed gas system, not a strict requirement

A. AFF and basic fire fighting cover identical content, simply repeated at greater length

B. AFF is required for every single seafarer regardless of muster list role, with no distinction from basic training

C. Basic training covers initial detection, raising the alarm, and using a portable extinguisher on a small incipient fire, while AFF covers organising and leading a coordinated fire-fighting response — including breathing apparatus (BA) entry, ventilation control, boundary cooling, and command of a fire party — required for designated officers and fire team members

D. AFF only applies to passenger vessels and has no relevance to cargo ships

A. Air supply checks are only relevant after the team has already entered the affected space

B. BA entry teams should enter without informing the bridge or control point, to avoid causing alarm

C. No formal entry control or time logging is necessary as long as BA wearers feel confident about their own air supply

D. Each BA wearer's cylinder pressure/air supply duration, the team's entry time, an agreed maximum duration before mandatory withdrawal regardless of air remaining (to allow safety margin for the exit), and a clear communication and tally system so the bridge/control point always knows who is inside and for how long