Application of COMAH

COMAH application is based on either a list of named substances or certain generic hazard categories for 'dangerous substances', the latter of which includes toxic to humans, and hazardous to aquatic organisms. 'Dangerous substances' and the generic hazard categories are defined by the Classification, Labelling and Packaging Regulation 2008 (CLP). Where the quantities of these substances held equals or exceeds the relevant COMAH threshold quantities, COMAH applies.

All surface engineering sites with significant quantities of substances classified as toxic and/or those hazardous to the environment should review their chemical inventories to check whether the Control of Major Accident Hazards Regulations 2015 (COMAH) apply.

Where COMAH does apply, the CA take a practical, proportionate approach, which means the amount of effort required by the sites affected to comply with COMAH should reflect the level of 'major accident' risk they represent. Upper Tier sites will be required to submit a 'Safety Report'.

Guidance has been prepared by the CA to assist sites affected to achieve the right approach towards the COMAH risk assessment and the production of a Safety Report where required. This guidance is available on the COMAH pages of the HSE website.