HL Deb 29 March 1979 vol 399 cc1691-2WA
Lord KENNET

asked Her Majesty's Government:

What is the evidence on which they base their statement (in particular relation to the hazardous substances stored at Canvey Island) that "experience shows that the worst effects of a flammable gas explosion would be unlikely to extend beyond a radius of one kilometre", (Commons Hansard; 22nd January 1979; col. 38) and whether this range is that which the Government use in their contingency planning concerning an incident at sea involving LNG/LPG carriers.

Lord WALLACE of COSLANY

I am advised by the chairman of the Health and Safety Commission that there have been relatively few unconfined flammable gas explosions world-wide, but such evidence as there is seems to support the view of the Health and Safety Executive that the worst effects of a flammable gas cloud explosion would be unlikely to extend beyond a radius of one kilometre. I am advised by my right honourable friend the Secretary of State for Trade that when dealing with an incident involving an LNG or LPG carrier at sea, the Government would take account of the down wind area potentially at risk for each year since the scheme's inception.

Baroness DAVID

The Answer is as follows:

should the gas not ignite at source and a flammable gas plume develop. This area will be greater at sea than in the case of an equivalent spillage on land because of the far greater evaporative rate caused by spillage in water. In the calculated "worst possible case" this area will extend beyond one kilometre.