This website uses non-intrusive cookies to improve your user experience. You can visit our cookie privacy page for more information.

COMAH Facts Sheet

The Control of Major Accident Hazards (COMAH) Regulations 1999 bring the European Commission's Seveso II Directive into UK law. The Seveso Directive was as a result of the major accident at Seveso, Italy and modified following a major warehouse fire in Basle, Switzerland.

The COMAH Regulations apply mainly to the chemical and petrochemical industries. They may also apply to businesses that store fuels (including petroleum and gas), have large warehouses or distribution facilities, or manufacture and store explosives. The application of COMAH is determined by the presence of substantial quantities of specified dangerous substances.

The COMAH Regulations are enforced by a Competent Authority (CA) consisting of:

The CA's role is to oversee and coordinate the regulation of major hazards in Great Britain and ensure that the regime operates effectively.

The COMAH Regulations have at their heart the principle that those who create risk are best placed to manage it. COMAH requires the operators of all sites to which the regulations apply to take all measures necessary to:

COMAH sites are separated into two categories, depending on the quantity of dangerous substances present - top and lower tiers. Operators of top tier sites are subject to more detailed requirements under the regulations than those of lower tier sites.

Operators of all COMAH sites are required to have a written Major Accident Prevention Policy (MAPP), designed to ensure a high level of protection for people and the environment by appropriate means, structures and management systems.

The COMAH regulations also place a duty on the operators of top tier sites to provide comprehensive safety reports to the CA. They also have a duty to provide safety advice to people who are likely to be in an area that could be affected by a major accident, as well as schools, hospitals and other establishments serving the public.

The competent authority works to ensure that major hazard risks are properly identified, managed and controlled by those who create them. The cornerstone of this is an assessment of the hazards and risks arising from the design, commissioning, operation, testing, maintenance and emergency procedures present at major hazard sites. This work also ensures that the firms responsible for safety actively assess and manage the effects of potential equipment failure and human error on the overall safety of their processes.

The regulator adopts a risk-based approach in the control of major hazards. This ensures that the resources are primarily directed towards those activities and sites that give rise to the greatest risk.

Updated 2012-09-11