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Let's Get Ready COMAH


Control of Major Accident Hazards Regulation

The Control of Major Accident Hazards regulations (COMAH) 2015 requires all site operators (including refineries, gas storage facilities and processing plants) who store or produce specific quantities of named hazardous substances to prepare a Major Accident Prevention Policy (MAPP) and an internal emergency plan.

The COMAH regulations were developed as a result of several serious industrial accidents in the UK and Europe. They are enforced by the Competent Authority (CA) comprising of the Health and Safety Executive, Environment Agency (EA) and the Scottish Environment Protection Agency (SEPA) and apply to both lower-tier and upper-tier establishments.  The aim of the regulations is to ‘prevent major accidents and limit their consequences to persons and the environment’ (Regulation 4) and imposes duties on various organisations. 

Let's get ready COMAH - Upper Tier

The site will be designated by the CA as upper-tier if it holds above the threshold quantities of named substances.  If designated upper-tier then they are also required to have a site-specific External Emergency plan in place and it is the duty of the Local Authority inside whose boundary the site is situated, to produce the External Emergency COMAH plan.

The External Emergency COMAH plan defines how responding organisations will work together in the event of a major accident at a upper-tier COMAH site and focuses on how the wider community will be supported in the event of a major accident on a COMAH site.

Humber Emergency Planning Service (HEPS) on behalf of the four local authorities (East Riding of Yorkshire, Hull City, North East Lincolnshire and North Lincolnshire) write and produce the external emergency plan for each upper-tier site in the Humber area in conjunction with our multi-agency partners (Humberside Police, Humberside Fire and Rescue Service, Yorkshire Ambulance Service, East Midlands Ambulance Service, HM Coastguard, Environment Agency, Public Health England and NHS Yorkshire and Humber).

We currently have 29 upper-tier sites across the Humber, all of which have External Emergency plans in place.  Each plan is tested and reviewed at least once every three years using a credible worst case scenario as identified in the site safety report.  The plan is tested using an activity based multi-agency table top exercise; this ensures that the plans are up to date and fit for purpose.

Let's get ready COMAH - Lower Tier 

Lower tier sites generally hold smaller quantities of named substances and are only expected to prepare a Major Accident Prevention Policy (MAPP) and Internal Emergency plan.  There are no requirements to work with local authorities or multi-agencies to prepare and produce an External Emergency COMAH plan or hold a multi-agency exercise.  Therefore it is up to the site to ensure they have adequate measures in place to deal with an emergency.

It may be useful to read through the universal plan and External Emergency plan template to understand how all of the multi-agency partners and site operators work together in the event of an emergency.

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