One man died and several workers were injured when 66 gas cylinders discharged and flew through the air at speeds of up to 170 miles per hour.
The incident took place at a construction project in Mundells, Garden City on 5 November 2008. Crown House Technologies Ltd was the principal contractor for the project, which involved the construction of an industrial unit, in which a bank planned to house its data servers.
Kidde Fire Protection Services Ltd was sub-contracted to supply and install fire-suppression equipment at the new facility. Kidde Products Ltd subsequently carried out the installation work.
On the day of the incident several workers were carrying out duties in a storeroom at the site, which contained 80 argonite gas cylinders. Adam Johnston, 38, was walking through the room with a colleague when one of the cylinders discharged and caused a chain reaction, resulting in the discharge of 65 other cylinders.
Mr Johnston, who was struck by one of the cylinders as it flew through the air, died at the scene from multiple injuries. Several other workers tried to dive for cover from the cylinders, which each weighed 142kg and were shooting across the room at speeds of up to 170 miles per hour.
Some of the cylinders had sufficient energy to penetrate walls and ceiling voids, and consequentlym entered some of the more remote parts of the building. Six other workers were injured and the building was badly damaged.
The HSE investigated the incident and it’s thought one or more of the cylinders were destabilised and fell over during the work, causing its unprotected valve to shear off near the cylinder neck.
This released an uncontrolled jet of liquefied argonite gas under high pressure [equivalent to 300 bar], the force of which caused the cylinder to move, colliding with others and thereby creating a chain reaction.
HSE inspector Norman Macritchie explained the three companies had failed to carry out an adequate risk assessment for the work and didn’t coordinate the work activities at the site. There was also insufficient training and supervision of workers.
Said the inspector: “Mr Johnston had no control over the chain of events that led to his tragic death. He died while going about his business as a result of the shortcomings of others. It is only by chance that this incident did not cause further fatalities.
“Employees of other companies were allowed to enter the argonite store while it was potentially unsafe to do so, and there is no evidence that anyone explained the risks to them, or acted effectively to control these risks.”
€ᄄInspector Macritchie concluded: “This incident was devastating for [Mr Johnston’s] family and yet it could have been avoided had there been effective planning, management, monitoring and coordination of the relevant activities.”
Crown House Technologies appeared at St Albans Crown Court on 5 July and pleaded guilty to breaching s2(1) and s3(1) of the HSWA 1974. It was fined a total of £117,000 and ordered to pay £119,394 in costs.
Kidde Fire Protection Services pleaded guilty to breaching reg.6 and reg.13(2) of the Construction (Design and Management) Regulations 2007. It was fined £165,000 and ordered to pay £59,697 towards costs.
Kidde Products pleaded guilty to breaching s2(1) and s3(1) of the HSWA 1974 and was also fined £165,000, plus £59,697 in costs.
In mitigation, all three firms said they had no previous convictions and had entered early guilty pleas. They also said they subsequently worked closely with the HSE to ensure the work was completed safely.
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