Enclosed spaces causing lethal accidents

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In only a couple of days, a normal stairwell can become a deadly place to be in. Enclosed spaces are one of the most common causes of fatal accidents at sea, and a 20-year-old stevedore died in the hold of a coal ship in Oxelösund as recently as March this year.
Every year reports are written on people who have died or been seriously injured after going into storerooms, stairwells, holds or other enclosed spaces on board. The latest fatal accident in Sweden took place in March this year when a 20-year-old temporary stevedore died on a Panama-flagged coal ship in Oxelösund. According to information from the local TV channel, SVT Sörmland, the man went on board to help unload in a space that was filled with carbon monoxide.
“These accidents usually occur in roughly the same way,” says Urban Svedberg at Karolinska Institutet, who has carried out a lot of research into ships’ loads and enclosed spaces. “Loads may vary to some degree, but the sequence of events is about the same.”
A couple of breaths can be enough
Exactly what happened in Oxelösund is still unclear, but investigations from previous events illustrate how it can happen. The accident on Saga Spray in the port of Helsingborg in 2006 is just one example. The ship was docked and wood pellets had been unloaded. An ordinary seaman and a stevedore went down to guide a wheel loader being lowered into the hold to gather up the last pellets. The men never reached the hold; they both collapsed on the way down. Other crewmembers and stevedores rushed to their aid, but were also injured. Even the ambulance staff were harmed by the toxic atmosphere. The seaman died, while the unconscious stevedore was seriously injured but survived. Another six people were injured.
“It’s almost always the case that more than one person is harmed in these situations,” says Urban Svedberg. “If you see someone lying at the bottom of a shaft, it’s natural to assume that the person has fallen and you instinctively climb down to help. Once you notice that there is something strange about the air, it’s often too late. Two or three breaths and you pass out.”
The toxic atmosphere comes from biological and chemical processes that take place in loads with organic products or metals. One example of a high-risk load is timber – the bark of the trunks are full of micro-organisms that consume oxygen. Carbon monoxide can be formed in other types of loads, such as wood pellets, wheat and coal. The change from normal to deadly atmosphere can happen surprisingly quickly.
“A few months after the accident on Saga Spray we made measurements on her sister ship, Saga Horizon. Only a couple of days after loading in Vancouver, we noted high concentrations of carbon monoxide,” says Urban Svedberg.
Hazardous atmospheres can also be created in places with large quantities of metal, and many accidents have taken place in empty tanks and chain boxes. When steel rusts it absorbs oxygen from the air and if the levels become low enough, it is no longer possible to breathe. Neither low oxygen levels nor high concentrations of carbon monoxide give any warning signals; they are odourless and there are no changes in temperature or colour. Once you realize that something is wrong it may be difficult to get out of
narrow passages and up steep ladders.
“Rescuing injured people from these spaces is not always easy. You have to go down with tubes and equipment, and access can be difficult,” says Urban Svedberg.
Another problem is that the hazardous atmosphere in holds can easily spread to nearby areas such as stairwells and storerooms. Leaking doors and gaskets allow gases to seep out and spread over large areas.
“I think that many people who work at sea are aware that some loads can be dangerous and that you shouldn’t go down into holds without some precautions. On the other hand, awareness of problems in spaces next to holds is probably less, and accidents that happen these days are often in stairwells or storerooms,” says Urban Svedberg.
Linda Sundgren

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