Source of toxic gases could be underground

I DID the first quantitative risk assessment (QRA) for the Environmental Impact Assessment (EIA) of a proposed large chemical plant in the Pasir Gudang industrial area in the late 1980s.

QRA is an engineering assessment of the risk of death to the workers within the plant and the public outside the plant due to large liquid fires, gas explosions and fires, and toxic poisoning as a result of accidental releases of flammable and toxic liquids and gases from the chemical process during operation and storage of chemicals.