COMAH Notification

COMAH Notification during 2015 – 2016 phase in period.

COMAH notification is more complicated than usual during the 2015 – 2016 transition period.

Firstly, you need to work out whether you are liable for COMAH under the 2015 Regulations (see our COMAH liability page).

  • If you are not within COMAH, and never have been, then you do not need to bother the HSE with this information, although it can be useful to keep any calculations and notes in case you are asked about your COMAH status in future.
  • If you are in COMAH, and going to drop out, you should contact the HSE to notify them. This may save you money in Inspectors’ fees.
  • If you are going to stay in COMAH, or go into COMAH, then you have to abide by the notification deadlines in the COMAH 2015 Regulations.

In order to work out when your notification deadline is, you also need to know what your COMAH status was before 1st June 2015, under the previous COMAH regulations.  (If you are unsure about this, you can contact us to discuss).

Once you know your COMAH liability before 1st June 2015, and after 1st June 2015, you can work out your notification deadline, which is based on whether you were in COMAH beforehand or not, and the specific reason(s) why you are going into COMAH.

As this is quite complicated, we have summarised the requirements in a factsheet, included as part of our COMAH Liability Toolkit (details below).

After 1st June 2016, it is understood that the COMAH notification deadlines will return to the previous requirements of notification before exceeding the inventory thresholds, then 3 months to compile a Major Accident Prevention Plan (Lower Tier sites) or 12 months to compile a Safety Study (Upper Tier sites).

If you need help with any aspect of COMAH liability or notification, contact Janet on 01422 24 22 22 or email Janet.

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COMAH liability

Read our COMAH liability webpage.
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COMAH Liability Toolkit toolkit

The COMAH liability toolkit contains 5 useful documents:
  • COMAH Factsheet
  • COMAH Calculation Factsheet
  • Top 16 COMAH calculation mistakes
  • When to notify under COMAH 2015-16
  • Should you control your inventory to avoid COMAH or stay in Lower Tier?
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SevaluateTM is an Excel based program which runs your COMAH (Seveso III) calculations for you, provides printable reports showing the main contributors to your COMAH liability, and allows you to predict the impact of changing your COMAH inventory on your COMAH liability.
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External Links

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COMAH Regulation 2015

This pdf is housed on It is 44 pages long and the pdfs size is 268 kb.
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