Control of Major Accidents Hazards (COMAH) applies mainly to the chemical industry, but also to some storage activities, explosives and nuclear sites, and other industries where threshold quantities of dangerous substances identified in the Regulations are kept or used.
These regulations aim to prevent and limit the consequences of major accidents, at over 1,000 establishments which use or store significant quantities of dangerous substances, such as oil products, natural gas, chemicals or explosives.
A 'major accident' could involve an uncontrolled release, fire or explosion, which results in serious danger to human health or the environment. A major accident to the environment would cause severe and/or long-term damage.
In England and Wales, responsibility for enforcing COMAH is shared between the Environment Agency and the Health & Safety Executive, working together as a Competent Authority.
Further information can be found from the HSE.