Carbon Dioxide Hazard in Cargo Spaces
Why carbon dioxide kills before oxygen depletion does on organic cargoes, the MSC.581(110) 0.5 percent criterion, and the appendix 5 danger tables.
Carbon dioxide became an enclosed space entry criterion for the first time in 2025. MSC.581(110) paragraph 7.4.2 requires the level of carbon dioxide to be checked and to be less than 0.5 percent by volume, equal to 5,000 ppm, before entry. A.1050(27) carried no carbon dioxide criterion at all.
The reason is in section 10.5 of the same resolution. Paragraph 10.5.6 states that death caused by carbon dioxide can precede death resulting from oxygen deficiency in organic types of cargoes, and 10.5.4 records that oxygen may still read 17 to 14 percent when carbon dioxide has reached 4 percent or more. An oxygen meter alone is not a test of an organic cargo hold.
The full article will cover the biological and chemical sources of carbon dioxide in a loaded hold, the appendix 5 danger level tables from 250 ppm outdoor background through the 5,000 ppm eight-hour workplace exposure limit to the 80,000 ppm unconsciousness threshold, the gap left by SOLAS XI-1/7 not naming carbon dioxide among the four gases the instrument must measure, and the sensor technology needed to close it.