COMAH Regs 1999

Control of major accident hazards Regulations 1999 (COMAH).

The COMAH Regulations implement the Seveso II Directive except for the land-use planning requirements which are implemented by changes to planning legislation. They replaced the Control of Industrial Major Accident Hazards Regulations 1984 (CIMAH) and came into force on 1st April 1999. The Regulations are amended from 30 June 2005 to reflect changes to Seveso II. This brief guide outlines the main duties and explains what you need to do if the Regulations apply to you.

What is the main aim of the Regulations?

The main aim is to prevent and mitigate the effects of those major accidents involving dangerous substances, such as chlorine, liquefied petroleum gas, explosives and arsenic pentoxide which can cause serious damage/harm to people and/or the environment. The COMAH Regulations treat risks to the environment as seriously as those to people.

Who is affected?

Mainly the chemical industry, but also some storage activities, explosives and nuclear sites and other industries, where threshold quantities of dangerous substances identified in the Regulations are kept or used.

The substances which cause the duties to apply are detailed in Schedule 1 of the Regulations as are the quantities which set the two thresholds for application.

Operators of sites that hold larger quantities of dangerous substances ('top tier' sites) are subject to more onerous requirements than those of 'lower tier' sites.

What do you need to do?

Firstly you need to determine if the Regulations apply to you. Regulation 3, together with Schedule 1, will provide the answer. If you have enough dangerous substances present to take you over the lower threshold then the lower-tier duties apply and if you have enough to exceed the higher threshold then the top-tier duties apply.

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