Andrew Bolton looks at some of the lessons of last month's Mont Blanc tunnel blaze.
Next month's French government report on the Mont Blanc tunnel fire should pinpoint the failings which led to one of the worst civil engineering disasters in recent history.
More than 40 people died while trapped half way through the 11.6km tunnel: the fire was so intense that the final death toll may never be known. It already seems clear that a series of cultural and technical factors combined to transform an incident into a disaster.
The blaze was triggered by a Belgian lorry carrying margarine and flour. This cargo ignited inside the tunnel after an engine fire got out of hand. The driver tried to put it out, but was caught out by the speed with which his vehicle became engulfed in flames.
In the last week tunnel operator Autoroutes et Tunnel du Mont Blanc has claimed that smoke from the truck set off a fire alarm at the tunnel entrance, triggering the closure of toll gates at the entrances. But motorists inside the tunnel quickly became trapped. Firemen at the site said many of the dead were killed by smoke inhalation while still in their vehicles or while trying to escape.
The fire immediately threw up questions about the 34 year old tunnel's design - a single bore carrying one lane of traffic in each direction.
There is no escape tunnel. Instead operator ATMB relied on sealed shelters fed with fresh air to protect motorists caught in fires. But air supply to some of these shelters appears to have been inadequate. Fire fighters trapped in the blaze found their way to one shelter but were forced to share oxygen from canisters they were carrying instead. One fire fighter died of a heart attack after being rescued from the shelter, most likely after inhaling noxious fumes.
The fire has also highlighted the difficulty of assessing the risk of a serious blaze happening in tunnels. 'One has to anticipate a fire, but do you design for a plausible or worst case scenario?' says fire consultant and visiting professor at City of London University Dr Gordon Cooke. '(Mont Blanc) appears to have been one of the worst possible scenarios.'
Many tunnels built after Mont Blanc have separate escape routes if only because they are high capacity twin bore structures with one tunnel for each direction. If there is a fire in one bore, motorists can quickly escape through cross passages to the other.
ATMB has invested in safety upgrades in recent years partly in response to earlier, less serious fires. The fire shelters, at 300m intervals along the tunnel, were built in 1997. The operator has also upgraded smoke evacuation systems. But as previous fires in the tunnel were dealt with successfully without casualties, envisaging a more serious event at Mont Blanc appears to have been difficult.
One problem can be traced to the fact that the chain of responsibility for fire safety in the tunnel is blurred - a factor highlighted by the rash of finger-pointing which broke out in the days after the fire.
Jean Guy Laurent, regional fire chief of the Haut Savoie regional authority, criticised ATMB for refusing to allow full scale fire practices in the tunnel. But ATMB president Remy Chardon was quick to rebut this claim, saying he 'neither refused nor authorised a fire drill'.
NCE asked Chardon whether he thought the ATMB should have taken a lead in initiating fire practices. He then claimed that fire practices were an issue for the central or regional governments, rather than the responsibility of his organisation.
The tunnel's complicated ownership structure may have contributed to this situation. At the French end, ATMB is 54% owned by the French government. The remainder is split between various private sector organisations. The other end of the tunnel is run by an Italian company and comes under Italian jurisdiction, further complicating matters. As such there appears to be much opportunity for safety issues to fall between owners and nations with none taking full responsibility.
In comparison, privately-owned Eurotunnel operates the whole of the Channel Tunnel and is under a strong obligation to the British and French governments to maintain safety standards. It holds an annual fire drill, as well as carrying out smaller, more frequent safety tests.
There is also a feeling within the roads lobby that political cronyism has created an air of complacency around the operation of the Mont Blanc tunnel. ATMB president Chardon is a former politician, not a businessman or engineer, and worked closely with French president Jacques Chirac before taking up his post. Chardon appeared unaware of some safety issues faced by the tunnel when questioned by journalists after the fire. For example, he was unable to say whether a sprinkler system had ever been considered.
International Roads Federation director general Wim Westerhuis is clear where fault lies - he blames the French government for failing to upgrade the tunnel.
The tunnel is financed through tolls and the revenues had paid-off construction costs by the early 1970's. Despite this, funds for reinvestment have been constrained by heavy taxes on the tunnel's profits. 'Profits from the tunnel are siphoned off to other government spending; the French government takes 30% of the tunnel's revenue in taxes,' says Westerhuis.
Plans to build a parallel bore to increase capacity and provide a fire escape foundered in the past because of the cost and environmental objections. A smaller, non-revenue generating service tunnel appears to have been ruled out.
As it is, the tunnel has been operating well above its original design capacity of 450,000 vehicles per year for some time. ATMB's last annual report shows that the tunnel handled 1.1M vehicles in 1997. This increase in traffic will have substantially increased the risks of a fire breaking out on a vehicle in the tunnel.
ATMB says there have been 15 fires in the tunnel since it opened in 1965.
'These fires were all brought under control by our in house fire fighting team, supported by the fire brigades at Chamonix and Courmayer,' it said in a statement. ATMB points out that the last fire involving a heavy goods vehicle was brought under control in seven minutes.
This track record appears to have strengthened arguments against greater investment in fire prevention. Now it seems that a more cautious, simpler tunnel safety culture will be needed if another catastrophe is to be avoided. It also seems inevitable that in future more of the tunnel's toll revenue will have to be harnessed to pay for safety enhancements if the tunnel is to remain in service next century.