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The scope of the Seveso III Directive is based on the EU legislation on the classification, packaging and labelling of chemical substances and mixtures (known as the CLP Regulation). The CLP Regulation implements the UN’s Globally Harmonised System of classification (GHS).

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 case.

The alignment of the toxicity categories (shown in the table below) will lead to some sites changing tier or moving out of scope all together as the correlation isn’t a direct one.

Alignment of toxicity categories

In addition to the changes in toxicity there is 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’

Determining whether the Directive applies will be more complex for both industry and regulators, particularly in relation to mixtures and for sites close to the ‘upper tier’ threshold limits or just outside of scope of the current COMAH Regulations.  Further information on classification is available and the Health and Safety Laboratory are currently offering a training on Seveso III and the GHS.

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

Current indications are that this will lead to a predicted overall net decrease of COMAH sites by 13-18 but this is still to be fully determined.

The exclusion of some substances that initially come into scope because of the CLP classification could result in some sites, which do not have major accident potential, inadvertently coming into scope. There is no mechanism other than through the ordinary legislative procedure to take substances out of scope. However, Article 4 of the Directive, is an assessment process made by the Commission to decide whether it is impossible for a particular dangerous substance listed in Annex 1 of the Directive to have the potential to cause a major accident. Discussion is on-going with the European Commission about how the system will work in practice.

Updated: 2015-06-15