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Application of COMAH

Does COMAH Apply?

All surface engineering sites with significant quantities of very toxic and/or toxic substances and/or those dangerous for the environment, if they have not already done so, should now review their chemical inventories to check whether COMAH applies. Where COMAH does apply as a result of the revised classification for chromium (VI) trioxide, operators should:

Practical, sector specific guidance on COMAH has been prepared by the CA and is now available in ‘Surface Engineering, COMAH Application & Main Duties’ and ‘COMAH Guidance for the Surface Engineering Sector’.

Further guidance on CHIP classification (including chromic acid) and the main COMAH duties is available in A guide to the Control of Major Accident Hazards Regulations 1999 (as amended) (Llll).

Specific COMAH guidance - Surface engineering sector

Where COMAH does apply to surface engineering sites, the CA are taking a practical, proportionate approach, which means the amount of effort required by the sites affected to comply with COMAH should reflect the level of ‘major accident’ risk they represent. Some new industry specific, practical guidance (see download below) has been prepared by the CA to assist sites affected to achieve the right approach towards the COMAH risk assessment required. This guidance:

It should be noted that this guidance is not a generic COMAH safety report model for surface engineering sites. Guidance on writing a safety report can be found in HSG190 ‘Preparing Safety Reports’.

Additional information

Some surface engineering sites hold significant quantities of substances and preparations which are very toxic or toxic for humans and/or very toxic or toxic to aquatic organisms. These include cyanides, dichromates and chromium trioxide. They may be held as raw materials, in tank solutions or as waste. As a result, some surface engineering sites may have been brought within the scope of COMAH (the Control of Major Accident Hazards Regulations 1999, as amended 2005).

COMAH application is based on either a list of ‘Named Substances’ or certain generic hazard classification categories for ‘dangerous substances’, the latter of which includes (i) ‘very toxic’ or ‘toxic’ to humans, and (ii) ‘very toxic’ or ‘toxic’ to aquatic organisms. ‘Dangerous substances’ and the generic hazard categories are defined by CHIP3.1 (the Chemical [Hazard Information and Packaging Regulations] 2002, as amended 2005). Where the quantities of these substances held equals or exceeds the relevant COMAH threshold quantities, COMAH applies.

Chromium (VI) trioxide (CrO3) was reclassified ‘very toxic’ for human health by CHIP (31 October 2005). This may have brought certain sites into the scope of COMAH, particularly those already holding quantities of other toxic substances. To alert the industry to this issue and provide guidance, the COMAH CA (Competent Authority – HSE and the environment agencies EA/SEPA working jointly) held a Surface Engineering and COMAH Awareness Day (December 2005).

Updated: 2015-06-15