News: Control of Major Accident Hazards (COMAH) exercise – “Exercise Koala 2016” – week beginning 7 March 2016. Read more


In order to regulate the use of dangerous substances in industry, the UK Government has enacted the Control of Major Accident Hazards Regulations 1999 and the Amendment Regulations 2005, commonly referred to as COMAH.

Within and around Bristol there are a number of major accident hazard establishments, mainly situated in the Severnside Industrial Complex, that are subject to COMAH legislation. The Severnside Complex, located to the northwest of Bristol, spans both Bristol City Council and South Gloucestershire Council areas. It occupies a strategic location next to the site of the Second Severn Crossing, the M49, M4 and M5 motorways, and the national rail freight network.

Severnside Sirens

For residents and businesses located in the Severnside area, a warning system exists especially to provide an audio warning to areas potentially at risk from hazardous chemical spillages or other related incidents.

The areas covered by the Severnside Sirens System include:

  • Portishead
  • Avonmouth
  • Shirehampton
  • Aust
  • Pilning
  • Severn Beach

Remember, if you hear the sirens: go in, stay in, tune in.

The system is tested on the third day of each month at 3pm, for example, on 3 November at 3pm. The audible tests consist of:

  • three minutes of the “Alert Warning”
  • one minute silence
  • followed by one minute of the “All Clear”.

The Severnside Siren System is maintained by an independent charitable organisation, the Severnside Sirens Trust.

To find out more information about COMAH in the Bristol area please click here.