ABSTRACT
Under major hazard regulations, those responsible for installations with the potential for generating major hazards must assess those hazards and formally report to the competent authority. The type of problem at issue is likely to involve the loss of containment and the resulting release of a hazardous substance to atmosphere. The nature of the hazards can be demonstrated perhaps explicitly by a couple of examples. Flammable gas clouds can cause devastating explosions if ignition sources are present. For example, the 30 tonnes of cyclohexane estimated to have been released in the Flixborough incident has been calculated as equivalent to that from the explosion of 16 tonnes of TNT. Even in the absence of an explosion, the thermal radiation from a burning cloud can cause severe damage at some distance. The fireball from 50 tonnes of LPG can injure humans at 500 m.
