Environmental guidance for your business in Northern Ireland & Scotland


The Control of Major Accident Hazards (COMAH) Regulations require you to take all measures necessary to prevent major accidents and limit the consequences for human health and the environment if you use or store quantities of dangerous substances on your site above certain thresholds.

A major accident could involve a release, fire or explosion from uncontrolled developments involving one or more dangerous substance. This could cause serious danger to human health or the environment, whether immediate or delayed, inside or outside the site.

The COMAH Regulations apply mainly to the chemical and petrochemical industries, fuel storage and distribution, and alcohol production and storage (maturation).  They may also affect businesses that store gas, manufacture and store explosives, or which have large warehouses or distribution facilities storing dangerous substances, eg agrochemicals, flammable liquids and propellants like aerosols.

This guide describes the types of business and the dangerous substances that the COMAH Regulations apply to. It explains the responsibilities of regulated sites, including assessing risks, how to deal with incidents, and how to notify the regulators with details of your site.

The Seveso III Directive is the European legislation that deals with the control of onshore accident hazards involving dangerous substances.  It replaced the Seveso II directive on 1 June 2015. 

The Control of Major Accident Hazards Regulations 2015 implement this directive in Great Britain.  In Northern Ireland the directive is implemented through the Control of Major Accident Hazards Regulations (Northern Ireland) 2015


Additional resources



Video Case Study: How to Prepare an Emergency Response for Your Business

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