The COMAH Regulations cover industrial facilities which pose a potential major accident hazard to workers, the local area or the environment due to the quantity and nature of the material that they handle. The regulations apply to sectors including oil and gas, water treatment works, explosives manufacturing/storage and the production and storage of potentially hazardous chemicals.   Around 950 sites in Great Britain fall under the current COMAH regime.  The regulations require that risks are properly managed and controlled under a Safety Management System and that there are adequate emergency response plans to deal with major accidents and to minimize their effects.

The HSE have published a consultation on the proposed Control of Major Accident Hazards Regulations (COMAH) 2015.  The consultation opened on 2 May 2014 and will run until 27 June 2014.  The new regulations will come into force on 1 June 2015, the date imposed by the EU Seveso III Directive.  It is anticipated that the estimated cost to business to implement the proposed changes will be approximately £1.8m per year over ten years.

Scope and Applicability

The most significant changes reflect the move from the current Chemicals (Hazard Information and Packaging Supply) (CHIP) classification system to the new Classification, Labelling and Packaging (CLP) regime from 1 June 2015.  There are a number of changes to categories and types of hazardous materials including new categories and changes to qualifying limits.

These changes mean that some sites may become COMAH sites for the first time and other existing sites may move between lower and upper tier, where the level of duties on operators differ.   This may have far-reaching effects and all sites, including non-COMAH sites, need to consider these changes very carefully given the implications of the falling under the regulations, the variation in duties depending on which tier (upper or lower) of the COMAH regulations is relevant, regulator enforcement and the recovery of regulators' costs under the COMAH charging regime.

One significant complication arising as a result of the proposed changes is that when considering whether the COMAH regime applies to them, site operators will need to consider not only the changes in classification of their own inventories and processes but also whether it is reasonably foreseeable that dangerous substances which equal or exceed the specified quantities will be generated during loss of storage or a major incident.

A major factor to take into account will be whether the site is part of a "domino group" containing other installations which may be at risk from loss of control of chemical storage and contribute themselves to the generation of dangerous substances.   It is also not presently clear whether the intervention of emergency services will be relevant in this consideration – in other words whether emergency response could in itself contribute to the generation of dangerous substances  - for example through the application of fire-fighting materials so as to bring a site within the COMAH regulations.  It is clear however that the proposed changes outlined above will require operators to carefully consider major accident scenarios as a preliminary step in order to determine applicability of the COMAH regulations.

A further problem when determining the scope and the level of applicability of the COMAH regime is that the operator of a site not only has to consider the amount of dangerous substances in inventories on site,  but also the quantity within any pipeline going to the site.  Quite how this will work in practice is unclear given the variation in materials that may be in a pipeline at any given time.

Changes to scope mean that those businesses which have deliberately arranged their operations and inventories to avoid falling under COMAH will have to review whether those arrangements are still effective.  Existing COMAH sites will be required to review their Safety Reports, update them and re-notify the Competent Authority to reflect the changes in inventories.  In terms of new Safety Reports for new installations, the HSE has proposed that operators of upper-tier sites submit reports at pre-construction and pre-operation stage to allow for greater input by the Competent Authority.

Public information

The new rules substantially strengthen existing COMAH rules on the provision of information to the public.  The new rules indicate a presumption in favour of publication which will require a culture shift in some within the industry. 

The new regulations require all COMAH sites (both upper and for the first time lower tier) to make certain information about the site, its hazards and emergency plans electronically available to the public via the Competent Authority.   Additional requirements for upper tier sites will be to provide to the public general information about the nature of major-accident hazards scenarios,  their potential effects on human health and the environment, whether there are any cross-border effects on any other European Member State and the control measures adopted to address them.

For Upper Tier sites, the Secretary of State's restriction on disclosure of Safety Reports will be removed from 1 June 2015 and the regulations require its publication.  This has proved controversial.  Concerns have already been expressed within the chemicals industry about the tension between making information available to the public and commercial confidentiality/national security.

The consultation paper identifies that the onus will be on operators to identify information which is commercially confidential or may affect national security and this has to be taken into account by the regulator when dealing with information requests or publication.   However, it is not yet clear whether there is any mechanism for dealing with differences in approach between the regulator and industry on whether information should be published.

An HSE secure IT portal is being developed to deal with COMAH notifications (in the same manner as the Department for Energy and Climate Change deals with its notifications) and this will be piloted later this year.   Select information uploaded to this portal will then be made electronically available to the public.  Also available to the public will be details of the Competent Authority's last inspection and the inspection plan.


Whilst the primary focus of industry concern appears to be on the new public information requirements, scope and applicability is also likely to present significant challenges to industry, particularly to those who may be nearing Upper Tier limits or to non-COMAH sites who might find themselves newly caught by the regulations by a reasonably foreseeable major accident scenario.