Hazardous chemicals and Control of Major Accident Hazards (COMAH)

What to do in a chemical emergency, or if you hear the Severnside siren, and what companies use hazardous chemicals.

In a chemical emergency

If there's a chemical emergency:

  • go in, close doors and windows
  • stay in
  • tune in, information will be broadcast on local radio, TV, social media or internet news channels, see emergency information

If it's not safe to go inside, follow instructions from the emergency services.

Severnside sirens

The Severnside alert warning sirens (mp3, 460k) (opens new window) will sound if there’s been a hazardous chemical incident. The sirens are tested at 3pm on the third of the month. If you hear the sirens at any other time follow the emergency advice above and stay inside until you hear the all clear siren (mp3, 456k) (opens new window) .

The siren test includes:

  • three minutes of the alert warning
  • one minute of silence
  • one minute of the all clear siren

The sirens cover:

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

Control of Major Accident Hazards

Control of Major Accident Hazards (COMAH) regulations apply to businesses that make, store or use dangerous substances.

Operators of COMAH sites must have an emergency plan, which shows how they will:

  • minimise the effect of an incident
  • protect people and the environment
  • tell people if they’ve been affected
  • clean up the site

We also have an emergency plan, which details how we, emergency services and health agencies will deal with an emergency affecting the area surrounding a COMAH site.

For more information, email emergency.planning@bristol.gov.uk.

COMAH sites in Bristol

There are a number of sites around Bristol that have to follow COMAH regulations. Most are in the Severnside Industrial Complex. The Health and Safety Executive and Environment Agency monitor COMAH sites on Severnside.

Businesses are classed as upper-tier or lower-tier sites, depending on the amount of dangerous substances they use or hold in storage.

Upper tier COMAH sites on Severnside

Avara Avlon Pharma Services Ltd (formerly AstraZeneca)
Avlon Works, Severn Road, Hallen, South Glos, BS10 7ZE
Manufactures active pharmaceutical ingredients and stores flammable and toxic substances. Comes under South Gloucestershire Council.

Esso Petroleum Company Ltd
Avonmouth Terminal, St Andrew’s Road, Holesmouth, Avonmouth, Bristol, BS11 9BN
Stores petroleum based products.

Hallen PSD
Ison Hill, Hallen, South Glos, BS10 7SG
Stores aviation fuel. Comes under South Gloucestershire Council.

FloGas
Severn Road, Hallen, South Glos, BS10 7SQ
Stores Propane. Comes under South Gloucestershire Council.

Valero
Royal Edward Dock, Holesmouth Road, Avonmouth, Bristol, BS11 9BE
Stores petroleum based products.

Lower tier COMAH sites on Severnside

Augean Treatment
Smoke Lane, Avonmouth, Bristol, BS11 0YA
Stores and treats waste solvents, oils and water.

Berwick Wood PSD
Berwick Lane, Hallen, South Glos, BS10 7RS
Stores aviation fuel. Comes under South Gloucestershire Council.

Bristol Port Co.
W-Shed Holesmouth Road, Royal Edward Dock, Avonmouth, Bristol, BS11 9BT
Stores Ammonia Nitrate.

Yara UK Ltd
St Andrews Road, Avonmouth, Bristol, BS11 9HU
Stores fertiliser.

Lower tier COMAH sites, elsewhere in Bristol

BOC Ltd
Whitby Road, Brislington, Bristol, BS4 3QH
Stores and fills acetylene cylinders.

Wales and West Utilities Ltd
Glenfrome House Storage Site, Glenfrome House, Eastgate Road, Bristol, BS5 5NP
Stores natural gas.