The Control of Major Accident Hazards (COMAH) Regulations 2015 came into effect on 1 June 2015. This guidance on the COMAH Regulations 2015 (L111, Third edition) applies from 1 June 2015. The COMAH Regulations 1999 have been revoked.

This guidance is for anyone who has duties under the COMAH Regulations 2015, particularly operators of establishments, and also others such as local authorities and emergency planners. The aim of the Regulations is to prevent and mitigate the effects on people and the environment of major accidents involving dangerous substances. This guidance on the COMAH Regulations 2015 gives advice on the scope of the Regulations and the duties imposed by them.

What has changed in the third edition?

Although many duties will be familiar from the 1999 Regulations, the 2015 Regulations contain some new or changed duties including:

• the list of substances covered by the Regulations has been updated and aligned to the CLP Regulation
• some definitions have been changed
• there are transition arrangements for safety reports
• for emergency planning, there is a new requirement for co-operation by designated authorities (Category 1 responders, as defined in the Civil Contingencies Act 2004) in tests of the external emergency plan
• there are stronger requirements for public information including a duty for lower-tier establishments to provide public information. There are provisions for electronic access to up-to-date public information.
• the domino effects duty is broader, including a duty for members of a domino group to co-operate with neighbouring sites to share relevant information.
• stronger requirements for the competent authority on inspection
• after a major accident local authorities must now inform people likely to be affected