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Introduction to the Seveso III Directive

A new Directive on the control of major accident hazards involving dangerous substances known as Seveso III was published on 24 July 2012 by the European Commission.  It will amend and subsequently repeal the Seveso II Directive on 1 June 2015.

The Seveso II Directive is implemented in Great Britain through the Control of Major Accident Hazards (COMAH) Regulations and planning legislation which is the responsibility of the Department for Communities and Local Government (CLG) and the devolved administrations in Scotland and Wales.

The current Control of Major Accident Hazards (COMAH) Regulations 1999 will be repealed on 31 May 2015 to be replaced on 1 June 2015 with the Control of Major Accident Hazards (COMAH) Regulations 2015 that will implement the majority of the Seveso III Directive. The land use planning requirements of the Seveso III Directive will be implemented through amended planning legislation by the DCLG and the devolved administrations in Scotland and Wales and will come into force on the same date.

The Seveso III Directive addresses the consequences to the regulation of major accident hazard sites of the repeal of the Dangerous Substances Directive and Dangerous Preparations Directive (implemented in GB as the CHIP Regulations) and their replacement with European Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures implemented in GB as the CLP Regulation.

The Seveso III Directive does not fundamentally alter the regulatory regime laid out in Seveso II but does strengthen a number of areas such as public access information and standards of inspections.  The Directive’s alignment with the UNECE Convention on Access to Information, Public Participation in

These web pages, which will be updated as transposition of the Directive develops, include details of the main changes in the Seveso III Directive and how it will affect operators and other stakeholders.  There are links to other parts of HSE and external organisations where additional information is available and there is also a ‘question and answers’ section and a copy of a presentation about the new Directive which is designed to be used for familiarisation purposes and can be tailored to suit the users needs.

If you want to keep up to date with developments in the transposition of the Seveso III Directive, you can also sign up for our ebulletin .  You can also contact the team via email on, please note that although this inbox is monitored and all correspondence is read you may not receive a direct response.

Implementation timetable

24 Jul 2014 Seveso III Directive adopted by EU Commission
July 2012 - April 2014 Informal consultation with industry and stakeholders and drafting of COMAH 2015 Regulations
2 May - 27 June 2014 Formal consultation on COMAH 2015 (link)
Mid August 2014 Summary response published
Mid October 2014 Final Consultation response published
Summer 2014 - early 2015 COMAH 2015 Regs redrafted based on consultation response and final legal package put together
Early 2015 COMAH 2015 Regs to be laid before Parliament
March 2015 (approx) Online publication of legal guidance to support the COMAH 2015 Regulations (replacement for L111)
31 May 2015 Deadline for transposition of Seveso III
1 June 2015 COMAH 2015 Regs enter into force in GB
1 June 2015 onwards Additional guidance on specific topics will be available
Updated: 2014-08-01