Maritime Questions › Enclosed Space Entry

Following a near-miss where an entrant became dizzy but was recovered safely with no lasting harm, what should the company/vessel do?

Q: Under MSC.581(110), what is the maximum acceptable CO2 reading (by volume) before an enclosed space can be considered safe for entry?

Less than 0.5% by volume (5,000 ppm) Para. 7.4 sets the CO2 exposure limit at below 0.5% by volume (5,000 ppm) before entry; if this is not achieved, the space remains unsafe. CO2 is now explicitly addressed as a major asphyxiation hazard alongside oxygen depletion.

A. Only verbally remind the individual involved to be more careful next time

B. Quietly note it in a personal logbook without raising it through the SMS

C. Investigate and report the near-miss through the SMS, treating it as seriously as an actual injury, to identify and fix the root cause before it results in a fatality

D. No action is needed since no one was actually hurt

Under MSC.581(110), what is the maximum acceptable CO2 reading (by volume) before an enclosed space can be considered safe for entry?

A. Less than 0.5% by volume (5,000 ppm)

B. Less than 2% by volume

C. Less than 21% by volume

D. There is no specific CO2 limit, only an oxygen limit

Under the revised recommendations, is single-person entry into an enclosed space ever permitted?

A. Yes, provided the person carries a personal gas detector

B. No — the company must ensure single-person entry into an enclosed space is not permitted

C. Yes, for spaces that have previously tested safe within the last 24 hours

D. Yes, but only for spaces below 5 metres in depth

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