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Preventing Pollution from Fire Fighting Run Off [Hardfacts]


The Problem

Many industries routinely store and use large quantities of potentially polluting substances within their sites. In case of a spillage and particularly in the case of a fire, these substances could rapidly be transmitted to the nearest water course where they may give rise to a severe pollution problem.

It is therefore very important to develop a site emergency plan, which, among other things, considers the actions to be taken to control run-off of water used to fight any fire on site.

Sites, which are subject to the Control of Major Accident Hazards Regulations 1999 are required by the regulations to make arrangements for water used to fight fires on their sites. They are required to make plans for dealing with emergencies (including fire) as a condition of the grant of the permit.

Water is the most commonly used medium for fire fighting. However, several major pollution incidents have occurred when water used for fighting fires has been allowed to reach nearby rivers or water courses.

Fire fighting run-off may be polluting due to the actual materials on site, their combustion products and/or the use of fire-fighting foam.

Legal Implications

Polluting a water course is an offence under the Water Resources Act.

Polluting a sewer by discharging material without the prior consent of the water undertaking is an offence under the Water Industry Act. Additionally, operators of COMAH and certain permitted sites under the Environmental Permitting Regulations are required to make adequate plans and may find themselves in breach of regulations if these plans are not adequate.

In addition to prosecution, the Environment Agency can serve a works notice requiring environmental clean up, or require repayment of clean up costs the Agency incur. The Environmental Damage (Prevention and Remediation) Regulations  adopt a "polluter pays" principle and extend this legal duty further including "strict" as opposed to "fault based" liability in certain circumstances. Under these Regulations the financial penalties can also extend beyond traditional clean up (or primary) costs to include complimentary and compensatory remediation. Costs of such incidents can run into many millions of pounds and  are not covered as part of normal insurance policies.

Mitigating the Effect of Fire Water Run-Off

The first step is to assess the likely route of any run off from the site, then to calculate the likely volumes of fire water, which might result from any incident. The Environment Agency will be able to advise on the likely routes to surface and groundwaters, in conjunction with the Water Company who will be able to advise on sewerage routes. The Fire Services should be involved in the volume estimation and will advise on the quantities and the volume of containment required, based on fire-fighting best practice.

Containment Systems

Fire fighting water containment should be considered and may be required to protect both surface and foul water drainage systems. 

Containment Lagoons and Sacrificial Areas

Lagoons should be constructed which are of a capacity for retention of the area concerned.  Areas such as car parks, ornamental gardens or sports fields may be appropriate, providing that they are isolated from the drainage system, can be made secure, and are designed to avoid contamination of groundwater.


Permanent or portable tanks are another option for fire water retention. They must be constructed of a material resistant to the substances retained and tanks should be vented.

Penstocks and Shut-off Valves

Shut off valves or penstocks that can isolate parts of the site in an emergency are another alternative to prevent contaminated water reaching a drain or surface water.

Once the method has been chosen, the authorities should be informed in case there are any fundamental problems arising from this decision. Keep adequate plans of your emergency arrangements and ensure that site personnel are aware of them.


Potentially environmentally damaging materials should always be stored in adequately bunded areas. Bunds are normally arranged to hold the total of the tank volume, plus 10%, this being the volume of the initial fire- fighting or fire protection water or foam. However, much more than this volume would be required to fight a fire. Therefore bunds cannot normally be relied on as fire water protection, but they may be able to provide temporary containment to gain time.

Fire fighting strategies and Run-off Management

The emergency plan may consider fire fighting strategies and possible ways to reduce the amount of fire water run-off generated.

Letting the Authorities Know

As in all emergencies, the first step is to carry out appropriate evacuation systems and call in the Fire Brigade. Then call in the Environment Agency. The Environment Agency is committed to the prevention of catastrophic pollution as a result of fire and will usually attend an incident in order to ensure, as far as is practicable, the protection of the aquatic environment from the results of the incident. The Environment Agency also keeps stocks of appropriate equipment and materials to minimise the effects of an incident. 

Key Action Steps

  • Examine, and where neccessary develop, your emegency plan to take account of the potential polluting effects of any water used in fighting a fire at your premises
  • Involve the Emergency Services and Environment Agency in the development of your plans
  • Hold regular practices of these emergency plans
  • Make sure that the plans are reviewed and revised regularly
  • Ensure that the Environment Agency Emergency telephone number is readily available and that they are contacted in an incident. 


· The Environment Agency - Pollution Prevention Guidelines

- PPG 18, Pollution Prevention Guidelines

- PPG 21 Pollution Incident Response Planning

- PPG 28 Controlled Burn 

· HSE Guidance Note EH 70, the control of fire water run-off from CIMAH sites to prevent environmental damage, HSE, 1995

· Guidance on fire water run off can also be found in HSE COMAH safety report assessment guides.

Next Steps

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Please Note
This document contains general information and guidance and is not and should not be relied on as specific advice. The document may not cover every risk, exposure or hazard that may arise and Aviva recommend that you obtain specific advice relevant to the circumstances. AVIVA accepts no responsibility or liability towards any person who may rely upon this document.

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