Control of major accident hazards (COMAH)

If your business manufactures, stores or uses any dangerous substances over a certain amount, the Control of Major Accident Hazards (COMAH) Regulations apply to you.

Identify the category of your site

There are two thresholds for dangerous substances under COMAH. These thresholds vary for different substances.

If you store or use an amount meeting the lower threshold for a dangerous substance your site is classed as a lower tier site provided it does not exceed the upper tier threshold. If you store or use more than the upper threshold your site is an upper tier site.

Check rules for classifying dangerous substances

Dangerous substances covered by the COMAH Regulations include:

• ammonium nitrate
• oxygen
• hydrogen
• formaldehyde
• halogens
• petroleum products

Dangerous substances also include those that fall into classifications defined by the European Community Regulation on Classification, Labelling and Packaging of Substances and Mixtures (CLP Regulation). 

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 some dangerous substances under COMAH, when all the substances you store or use are added together you may need to comply.

Comply with Planning Regulations for dangerous substances

If the COMAH Regulations apply to you, you may also be regulated under planning legislation and need a hazardous substances consent from your council’s local planning office. For further information, you should contact the Northern Ireland Planning Service.

COMAH regulator

COMAH is regulated by the HSENI and the Northern Ireland Environment Agency (NIEA). These organisations are jointly referred to as the Competent Authority (CA).

You will have to pay for most of the work the CA does in connection with your site, for example:

• assessment of safety reports
• on site inspection of how major hazard risks are managed
• investigation of major accidents

If you are unsure whether COMAH applies to you, contact the HSENI or the NIEA.

If you operate a site covered by the Control of Major Accident Hazard (COMAH) Regulations, you must meet requirements for using and storing dangerous substances.

Notify the Competent Authority (CA)

If the COMAH Regulations apply to your site, you must notify the CA before you use or store dangerous substances. You must also tell the CA before starting any new operation and send them any additional information they need.

The notification must give details about the operator, the site, the processes carried out and an inventory of the dangerous substances present. 

If there are any significant changes to the information you provided in your notification you must tell the CA immediately. You must also tell them if your site closes, or if any part of the site closes where dangerous substances are handled, produced, used or stored.

Assess the risks and prepare a major accident prevention policy

You must take all necessary measures to prevent major accidents and have plans, systems and procedures in place at your site. You must be able to demonstrate this to the Competent Authority (the HSENI and the Northern Ireland Environment Agency (NIEA)).

You must carry out assessments to understand and predict how a major accident could happen on your site and the possible consequences of a major accident. Situations to consider include:

• leaks and spills due to vessel or pipework failures
• explosions, eg caused by mixing incompatible chemicals in reactors
• fires, eg in processing areas, warehouses or chemical or fuel storage areas

You must prepare a major accident prevention policy (MAPP) document. This should outline your approach to the control of major accident hazards on your site.

You must also prepare a safety management system document. This should cover the detailed steps you will take to control major hazards. It should also show the structure of your organisation and the responsibilities, procedures and resources for putting the MAPP into action.

For further details, you should contact the HSENI or the NIEA, or check schedule 2 of the COMAH Regulations. 

Comply with the COMAH containment policy

You must comply with the COMAH containment policy if you store liquid dangerous substances in bulk. You must:

• ensure your primary containment, eg storage tanks, are designed and constructed to relevant standards
• use suitable secondary containment, eg a bund, to contain any liquid which escapes from a primary container or its equipment
• develop plans to help reduce the off-site impacts of an incident

Deal with incidents correctly

If a major accident occurs, such as a significant leak, spill, fire or explosion, you must take all necessary steps to minimise its effects on people and the environment.

You should implement your emergency procedures. These will be part of your MAPP or, for top tier sites, must be a separate plan.

You should contact the HSENI immediately by calling the 24-hour HSENI Helpline on Tel 0800 032 0121.

You should also report the incident to the HSENI.

You should also report any pollution incident as soon as it happens to the NIEA Water Pollution Hotline on Tel 0800 80 70 60.

Make sure that your staff are aware of these phone numbers and know what to do if an incident happens.

If you operate a site covered by the Control of Major Accident Hazard (COMAH) Regulations, you must meet requirements for using and storing dangerous substances. See COMAH regulated site requirements.

If you operate a site where the quantities of dangerous substances you use or store meet or exceed the upper thresholds in the COMAH Regulations, you will be classed as a top tier site. For more information about the different tiers, see does COMAH apply to my business? Upper tier operators must meet some additional requirements.

Submit a safety report

You must submit a safety report to the competent authority (CA) - the Health and Safety Executive for Northern Ireland (HSENI) and the Northern Ireland Environment Agency (NIEA). Your safety report must demonstrate that you have put in place a major accident prevention policy (MAPP) and a safety management system to implement the policy.

You must review the safety report:

• at least every five years
• to account for new facts or new technical knowledge
• if you change your safety management system

You must tell the CA about these reviews, even if you don't make any changes to the safety report.

For new top tier installations you must submit a safety report prior to construction and before operating with dangerous substances.

You must tell the CA immediately if you make any changes to your safety report.

Prepare an internal emergency plan

You must prepare a separate internal emergency plan before your business starts operations. This must give details of what you will do in the event of an accident. It should include:

• names or positions of people who will put emergency procedures into action
• names or positions of people who liaise with the HSENI for the external emergency plan
• details of the procedures for contacting the CA and other local emergency services
• details of events that may cause a major accident and actions that will be taken to avoid them
• a description of the safety equipment and resources available to deal with an incident
• details of how the risk to people on-site is minimised
• details of how the risk to the environment is minimised
• actions to be taken if an incident warning is issued
• arrangements to inform the HSENI of an incident, so that the external emergency plan can be put into action
• details on how staff are trained to deal with emergency situations
• arrangements for helping to minimise off-site impacts of an incident

When preparing your emergency plan you should liaise with the CA and other relevant agencies, for example the local fire, ambulance and police services and local health and social services board. They can advise on possible effects to areas outside your site.

Test and review your internal emergency plan at least every three years and revise it as necessary.

Inform local people

You must provide information about your activities to local residents, workers at other premises and every school, hospital or other establishment serving the public, which may be affected by a major accident on your site. This should include:

• the name and address of your business
• the position of the person responsible for keeping local residents and businesses informed
• confirmation that your business needs to comply with the COMAH Regulations, and that you have notified and submitted a safety report to the HSENI
• a brief explanation of the activities undertaken at your site
• what dangerous substances are on your site, using common names where they exist, and their dangerous properties, eg explosive or flammable
• information on the hazard posed by these dangerous substances to people and the environment, and the safety measures in place to control the risk of an accident
• details of how people will be informed and the actions to take if a major accident occurs
• confirmation that your business is required by law to be prepared for major accidents, and to liaise in particular with the emergency services to deal with major accidents and minimise their effects
• making reference to your external emergency plan which should include advice to people to co-operate with instructions from the emergency services in the event of an incident