Question 1

Which class of compartment is most associated with oxygen depletion from cargo, rather than from welding, rust, or chemical off-gassing?

Accepted Answer

Holds carrying organic/biodegradable cargoes such as wood pellets, grain, or other vegetable products, which consume oxygen and release CO2 during respiration/oxidation Organic cargoes such as wood pellets, wood chips, grain, and similar biodegradable products consume oxygen and emit CO2 (and in some cases other toxic gases) through respiration and oxidation, even with no chemical reaction occurring — IMO MSC.1/Circ.1477 and the enclosed-space MSC.581(110) provisions specifically address this hazard, which has caused multiple fatalities.

Question 2

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

Accepted Answer

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.

Question 3

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

Accepted Answer

No — the company must ensure single-person entry into an enclosed space is not permitted Para. 3.11 explicitly prohibits single-person entry into an enclosed space under any circumstances covered by the recommendation.