Coinciding with the MAC post on the status of the MAIIF study into confined space incidents, “Confined Space Casualities Worse Than Expected“, fellow blogger Robin Storm alerted us to an article in the Scandinavian Shipping Gazette regarding a joint Swedish-Canadian research project set up following the death of a seafarer and injuries to a stevedore while unloading a Hong Kong-registered vessel, the Saga Spray, vessel in Helsingborg, Sweden, in November 2006. The deadly cargo? Wood pellets.
In all, 12 people involved in the Saga Spray taken to hospital and fie required decompression chamber treatment. Seven people have died and several have been injured under similar circumstances in Sweden over a two year period.
An almost identical incident occured in Rotterdam on 10 May, 2002, on another ship of the same company.
The culprit is Carbon Monoxide, CO, which replaces oxygen in the bloodstream and causes unconsciousness and eventually death within minutes if overexposed. According to researcher Urban Svedberg, the highest level measured in his research is 13,000 parts per million,ppm. In Sweden the recommended maximum is 5,000ppm.
What is particularly worrying is that oxygen measurements can still show 20 per cent oxygen even though the atmosphere is poisonous. Carbon monoxide can be deadlier at even lower levels of oxygen.
Says the report “Today, there is no hand-held instrument that can measure over 1,000 ppm carbon monoxide and a potential fixed gas warning system would need to be both exact in the low range and still manage a high gas concentration of up to 15,000 ppm”
How does the Carbon Monoxide get there? Wood pellets are made of compressed sawdust, planer shaving and tree bark. the Code of Safe Practice for Bulk Cargoes rates them as a Category B cargo which can present a chemical hazard. The pellets can oxidise, sucking oxygen out of the atmosphere, so reducing the level of oxygen in the hold, and at the same time put out carbon monoxide.
Take no cargo for granted. Always ventilate well and test the atmosphere before entry – if in doubt, don’t.
Make sure you and your crew are aware and up to date on known hazards.