The blowout during pressurisation tests of a tunnel being constructed as part of the Docklands Light Railway (DLR) Lewisham Extension, on 23 February 1998, has left contractor Nishimatsu Construction Company facing a £1M (US$1.8M) bill. On 19 January this year, Nishimatsu was fined £700,000 (US$1.3M) and ordered to pay prosecution costs of £145,767 (US$272,363) in a court sentence following an investigation by the UK’s Health & Safety Executive (HSE). Combined with Nishimatsu’s own defence costs, the HSE estimated the total bill to be in the region of £1M.
This is understood to be the third highest fine for a construction industry safety incident in the UK. A spokesman for the HSE told T&TI: “The fine reflects the seriousness of the incident” and drew comparisons with the severity of the Heathrow Express collapse in 1994.
The blowout occurred at 4.45am on 23 February 1998 (T&TI March 1998) as trials were underway to pressurise a section of the southbound tunnel between two bulkheads, in order to construct a cross passage to an adjoining tunnel. Whereas one bulkhead was within 60m of the cross passage, where the tunnel passed beneath the River Thames, the other was only 60m from the launch chamber with approximately 8m of cover to the surface. It was here that the blowout occurred as the tunnel was pressurised to 2.2 bar. The HSE investigation determined that “no relevant calculations into the ability of the ground cover above the tunnel to be able to withstand the proposed compressed air pressures had been undertaken or commissioned.” The effect was to blow a 22m diameter crater out of the grounds of George Green School, with debris thrown up to 150m damaging the school buildings and adjacent properties.
Philip White, HSE’s head of operations, said: “Had the blow-out occurred just a few hours later, then a public disaster may have resulted. Almost undoubtedly there would have been significant numbers of seriously injured schoolchildren.”
Nishimatsu pleaded guilty to “failing to ensure the safety of persons not in their employment” a contravention of the Health and Safety at Work etc Act 1974. Peter Fisher, deputy general manager of Nishimatsu Construction stated the company accepts ultimate responsibility for the circumstances surrounding the uncontrolled release of compressed air and added that they have revised their procedures to ensure the possibility of a recurrence is avoided. Fisher said Nishimatsu were surprised at the scale of the fine and would be consulting its legal advisers. T&TI put some additional questions to a representative for Nishimatsu regarding why the bulkhead had been sited so near to the launch chamber, when it could have been closer to the cross passage under deeper cover, but was told that as elements of the case were subject to ongoing civil proceedings they would be unable to comment further at this stage. It was reported that Nishimatsu is mounting a civil case against WS Atkins, the tunnel designer, and that the case is due to be heard in April.
Related Files
Section of the DLR Lewisham Extension showing the approximate location of the bulkheads and blowout
