Containment of polluting materials

This control measure should be read in conjunction with Foundation for environmental protection – Pollution control hierarchy and equipment

If practical and safe to do, and unless there is a threat to life, containment is the preferred approach to manage incidents if polluting materials may harm the environment.

The following hierarchy of pollution control should be used in most instances when containing polluting materials, which can include contaminated fire water or firefighting foam run-off. The five stages of the hierarchy require a dynamic risk assessment to be undertaken within the parameters of an appropriate safe system of work, and appropriate personal protective equipment (PPE) to be worn.

• Hierarchy Stage 1 – Contain at source: The most effective intervention is to stop a pollutant at source, such as the point where a pollutant is escaping from a container, tanker, pipework or other vessel
• Hierarchy Stage 2 – Contain close to source: Where it is not possible or practicable to contain the product at source, or there has already been a significant loss of product, the next point of intervention is to contain the spillage as close to the source as possible, using items in the grab pack or other available materials, such as soil or sand
• Hierarchy Stage 3 – Containment on the surface: One of the most common ways for a spillage to enter the ecosystem is via open drain gullies connected to the surface water drainage system. As the drainage system provides a very efficient pollution pathway, steps should be taken to prevent polluting materials from entering it.
• Hierarchy Stage 4 – Contain in the drainage system: Pollutants often enter drainage systems before pollution control equipment can be deployed. If this happens, the drainage system itself can be used for containment. At other incidents, containment in the drainage system may be the preferred option, even if interventions can be made earlier, if it is the easiest and most effective way of containing pollutants. Being able to identify the drainage systems surrounding the incident is an important aspect of preventing environmental harm.
• Hierarchy Stage 5 – Contain on or in the watercourse: Fire and rescue service activity for the emergency containment of pollutants on or in a watercourse will be limited by the equipment carried, the size of the body of water and the practical skills and knowledge of personnel.

Advice or assistance for containment should be requested from environmental agencies, hazardous materials advisers or other organisations if required. In some areas the environmental agencies have large volume pumps that can be used to support or replace fire and rescue service pumps.

It may be necessary to divert polluting materials, including fire water or firefighting foam run-off, to holding or sacrificial areas, for off-site containment. Foul sewerage systems can be used to contain polluting material, if approved by the sewerage undertaker and environmental agency. When doing so, care should be taken that pollutants and sewage do not escape from any storm overflows into the sewerage system. The contained pollutants and sewage may then be removed.

It may be possible to divert polluting materials to a local sewage treatment works, where they can be treated or contained before their disposal. Sewage treatment works have storm tanks that are used to store the large volumes of diluted sewage produced during high rainfall. Approval from the sewerage undertaker must be sought before diverting pollutants to a sewage treatment works; the treatment process can be affected if levels of pollution are too high and could result in the release of pollutants and untreated or partially treated sewage. For more information refer to Foundation for environmental protection – Protecting sewerage and drainage.

Pollution control devices, such as drain closure valves, storage lagoons or balancing ponds are installed in some surface water drainage systems. These devices can be used to help contain polluting materials if permission is given by the appropriate authority; this could be a sewerage undertaker, responsible person, local authority or highways agency.