Public Information on COMAH establishments

Legislative Background

The Chemicals Act (Control of Major Accident Hazards Involving Dangerous Substances) Regulations 2015 (the “COMAH Regulations”), implement the Seveso III Directive (2012/18/EU).

The Regulations lay down rules for the prevention of major accidents involving dangerous substances and seek to limit, to the greatest practicable extent, the consequences for human health and the environment of such accidents. The overall objective is to provide a high level of protection in a consistent and effective manner.

This is achieved through tiered controls on the operators of those establishments that are subject to the Regulations: the controls are more onerous where the quantities of dangerous substances present are greater.

Tiered Controls Under the COMAH Regulations

There are two tiers of establishment, which are related to the quantities of dangerous substances present. Depending on quantity, an establishment may be upper-tier or lower-tier. Upper-tier establishments have greater quantities of dangerous substances present and therefore are obliged to comply with additional requirements specified in the Regulations.

Measures Operators Are Required To Take

Operators are required to take all necessary measures to prevent major accidents and to limit their consequences for people and the environment.

The range of measures taken by an operator will vary and will depend on the hazards present at the establishment, but in all cases operators have to bring the risk down to an acceptably low level.

Most establishments have been in operation for many years and operate safely and without undue risk to the public.


All the establishments are subject to regular routine inspection by the Health and Safety Authority (which is the Central Competent Authority – CCA – for the Regulations). The frequency of inspection depends on the risk profile of the establishment and can be once every year or every other year or every third year; those with the higher risk profile are liable to more frequent inspection.

Public Information

The COMAH Regulations requires the CCA to make particular information on the establishments permanently available to the public. A greater level of information is provided for upper-tier establishments.