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 and has been implemented in the Irish legislature by the Chemicals Act (Control of Major Accident Hazards Involving Dangerous Substances) Regulations 2015. It amended and subsequently repealed the Seveso II Directive on 1 June 2015.

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.

 Scope of Seveso III

As with Seveso II, Seveso III applies to an establishment that has dangerous substances as set out in Annex 1 at or above the qualifying quantities. Annex 1 contains two tables which are; Part 1 ‘categories of dangerous substances’ and Part 2 ‘named dangerous substances’. There are some changes in both named categories of dangerous substances and named dangerous substances between the current Annex I and the Seveso III Annex 1.

The toxicity categories have moved from Very Toxic and Toxic to Acute Toxic Categories 1-3 with exposure routes (dermal, oral and inhalation) specified in some cases. There is also a new category of ‘flammable aerosols’. In the named dangerous substances, heavy fuel oil and ‘alternative fuels serving the same purpose and with similar properties’ have been moved to the named substance entry for Petroleum Products and biofuels have been included in the entry of ‘Liquefied flammable gases’.

These changes mean that from 1 June 2015 a number of sites may:

  • enter the regime at the lower or upper tier threshold
  • move from the lower tier, or vice versa
  • leave the regime completely.

Public information

The Directive is aligned with the UNECE Convention on public information, public participation in decision-making and access to justice on environmental matters (known as the Aarhus Convention).

In line with the Aarhus Convention the changes will mean that:

  • All sites will have to provide basic information about their sites, Upper Tier sites will be required to provide more information than Lower Tier sites. This information must be permanently and electronically available and kept up to date;
  • Further information including Safety Reports and Inspection Reports will have to be made available on request.


The current requirement under Seveso II for a flexible risk/hazard based system for inspection will continue under Seveso III which means the frequency of site visits will continue to be based on the risk/hazard profile of the site. Relevant findings of inspections under other EU legislation will need to be taken into account in the hazard/risk assessment of sites and where possible inspections will need to be co-ordinated with other EU legislation.


Notifications from operators will have to include information about neighbouring establishments and other nearby sites where they are relevant to the major accident hazard scenarios. Sites will also be required to provide information about their inventories under CLP which means that under the COMAH Regulations 2015, establishments will be required to re-notify to demonstrate that they fall into scope and under which tier.

Safety reports

Upper Tier sites will still be required to produce Safety Reports. All Upper Tier sites will need to reclassify their inventories from CHIP to CLP to be attached to their Safety Reports.

Emergency planning

The fundamental requirements of emergency planning from COMAH 1999 will remain under Seveso III / COMAH 2015. The Directive has made the requirement for lower tier sites to have appropriate on-site emergency planning arrangements in place more explicit.

 What are the implications for me?

The Seveso III Directive, and by extension the COMAH Regulations 2015, apply to any business where dangerous substances, as set out in Annex 1 of the Directive, are either present on site at or above the threshold quantities or could be generated in the event of an accident. All types of businesses with dangerous substances are covered, not just those in the chemical sector.

If you already operate a COMAH site you will need to:

  • check the scope of the Seveso III Directive i.e. changes to Annex 1;
  • check other parts of the Directive which may apply e.g. more information may be required for the safety report which will then need to be revised, or public information requirements may have changed for your site.

For an operator currently out of scope under COMAH 1999 you will need to check the changes to Annex 1 of the Seveso III Directive which could affect whether your site remains out of scope or becomes an upper or lower tier site. If you are in scope of Seveso III you will need to check which requirements you will be obliged to comply with and meet the appropriate timescales.

Local authorities must prepare adequate emergency plans to deal with the off-site consequences of possible major accidents at upper tier sites, and should review and where necessary revise them. They must also test them at specified intervals.

Local authorities will need to prepare emergency plans for any sites in their area that become upper tier sites as a result of the changes in the Seveso III Directive.

Land use planning is one of the measures in the Seveso III Directive intended to mitigate the effects of a major accident in the unlikely event that one occurs. The changes to the land use planning requirements of the Seveso III Directive will be implemented through planning legislation.

If you need to find out more about SEVESO and train your staff call us on 087 9678 372 or enquire about our in-house SEVESO Awareness course that we can customise to your organisation’s requirements.


Chemicals Act

Aarhus Convention