Environmental guidance for your business in Northern Ireland & Scotland
If your business manufactures, stores or uses any dangerous substances in amounts that exceed certain thresholds, the Control of Major Accident Hazards (COMAH) Regulations apply to you.
There are two thresholds for dangerous substances under COMAH. These threshold quantities vary for different categories of substances.
If you store or use more than the lower threshold for a dangerous substance your site is classed as a lower tier establishment. If you store or use more than the higher threshold your site is an upper tier establishment.
The COMAH Regulations 2015 change the classification of certain substances and change the threshold values for some dangerous substances. This means that some sites may change their classification, or may have become a COMAH regulated establishment for the first time after 1 June 2015.
Dangerous substances covered by the COMAH Regulations include named substances (eg hydrogen, ammonium nitrate), and those with:
Find a full list of dangerous substances and relevant threshold quantities:
These are separated into Part 1 (generic categories) and Part 2 (named dangerous substances).
Dangerous substances are categorised in accordance with the Classification, Labelling and Packaging (CLP) Regulations. If a substance, including waste, does not already have a standard CLP classification you must provisionally assign it to the most similar category or named substance until you can make a full assessment.
When classifying a chemical, you must consider:
Classification of a mixture is generally based on what is known of the constituent substances or similar products.
You must check your responsibility if you store more than one type of dangerous substance. Even if you don't exceed the threshold amount for any of the dangerous substances under COMAH alone, when all the substances you store or use are added together you may need to comply.
COMAH is regulated by a joint competent authority (CA), comprising:
You will have to pay for most of the work the CA does in connection with your site, for example:
Who COMAH applies to
If you are unsure whether COMAH applies to you:
If the COMAH Regulations apply to you, you may also be regulated under planning legislation and need a hazardous substances consent from your local council planning office or your local Planning Authority in Scotland.
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