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Contaminated land guide for developers

This guidance is primarily for property owners and developers who want to know what information they should submit to the council's Planning Department when they apply to redevelop or significantly change the use of land or buildings which could be contaminated.

Contamination, in most cases, is likely to arise from a previous use of the site or an adjacent site that had an industrial or waste disposal activity on it at one time or another.

The presence of contamination does not necessarily present an unacceptable risk. However, risk arises when a pathway is created between a contaminant and a vulnerable receptor. The contaminant may be chemical, biological, radioactive or physical. Development can create risk by introducing new pathways and also by introducing new receptors – for example where houses are built near the site of a former landfill site producing methane.

Where development introduces a particularly sensitive use, such as houses with gardens, schools or allotments, the possibility of land contamination should always be considered. For land to be contaminated there needs to be a pollutant linkage as shown below:

Sources --> Pathway --> Receptor

Planning applications

The presence or potential presence of contamination is a material consideration when the council considers planning applications. The council wishes to ensure that no development creates or allows the continuation of unacceptable risk. The standard of remediation to be achieved is the removal of unacceptable risk, making the site suitable for its new use and ensuring that it does not cause pollution of the wider environment.

An assessment of risk should always be carried out by the developer before the planning application is submitted.

The stages for assessing risk, proposing a remediation strategy and producing evidence that the work has been carried out satisfactorily are set out below.

Where land is known to be affected by contamination or where this is likely due to past uses, developers should submit with the planning application a Desk Study (Phase 1a) Study, which is the minimum requirement. This will include desk-based research, site reconnaissance and hazard identification.  The desk study should be undertaken by a competent person.

It is advisable for the developer to contact the council before submitting a planning application to discuss specific site details. Where significant contamination is known or suspected, additional research and risk assessment may be needed before an application can be determined. If applications cannot be approved due to a lack of information and if circumstances indicate possible unacceptable risk, planning permission may be refused. All aspects of investigations into possible land contamination should follow the guidelines within CLR11 Model Procedures for the Management of Land Contamination.

Examples of potentially contaminating uses:

  • metal processing and finishing
  • gasworks
  • oil and petroleum storage
  • manufacture of chemicals, including paints and fertilisers
  • timber treatment
  • landfill sites
  • scrap yards
  • abattoirs
  • railway or road haulage depots
  • allotment gardens
  • military land.

Use of planning conditions

There will be circumstances in which the past use of the land or buildings suggests the possibility of contamination.  However if the proposed end use of the development is not a sensitive one (i.e. not residential ora school etc), the council may impose a condition on any grant of planning permission.  Such a condition would ensure that the site is investigated and any necessary remediation is carried out before development takes place. 

Conditions may also be used where the council is satisfied that the risks are understood and that there is a remediation option but where not all the details have been resolved.

Other legislation

The aim of cleaning up land under the planning process is to achieve a minimum standard so that the site cannot be determined as 'contaminated land' under Part IIA of the Environment Protection Act 1990 . The guidance given here does not apply to the cleaning up of land under this legislation, although the information that the council would request is very similar. For details of Part 2A, please contact the Environmental Protection Team.

Building regulations approval may also be needed and the applicant must ensure that the South Thames Gateway Building Control Partnership is aware of contamination issues and that the appropriate requirements are met.

Further information

National Planning Policy Framework (NPPF) published by the Department of Communities and Local Government.

Stages in a contaminated land assessment

Stage 1 – Planning and desk study

All aspects of investigations should follow the guidelines within CLR11 Model Procedures of the management of Land Contamination.  The production of all of the reports and intrusive investigation should be undertaken by a competent person.

Desk Study (Phase 1a) – Desk-based research, site reconnaissance, hazard identification

  • Research site history to establish if previous uses could have led to contamination
  • Obtain as much information of the previous uses and potential contaminants as possible so as to highlight which areas of the site could be affected (including adjoining land where such risks exists). Ask the Environmental Protection Team for directions to any further land contamination guidance that the council may have
  • Identify who and what is a risk (e.g. future occupants, buildings and environment) and the potential pathways for those risks – this is known as the Conceptual Site Model.  All desk studies should include a Conceptual Site Model
  • Submit a report of the hazard identification to the council when submitting the application. If required, discuss the findings with the council and the Environment Agency
  • The council will then decide if the submitted report is to be accepted and whether there is a need to proceed to the next stage.

Phase 1b – Further desk based research, exploratory site investigation, hazard assessment

  • Using the information above, the applicant will need to undertake an initial intrusive investigation. Please note that monitoring for substances such as ground gas can take several months
  • If you believe your site may be affected by ground gas you should make reference to the guidance which has been produced by CIRIA 'Assessing risks proposed by hazardous gases to buildings' which makes recommendations regarding gas monitoring
  • Review the Conceptual Site Model
  • Decide which risk assessment modes are appropriate or need to be developed. Discuss and agree these with the council. Submit a report of the hazard assessment to the council's planning service. If required, discuss the findings with the council and the Environment Agency
  • The council will decide if the submitted report is to be approved and if there is a need to proceed to next stage.

Stage 2 – Risk estimation and assessment

Phase 2a – Intrusive investigations

  • The applicant will now need to determine what detailed intrusive work is required and what monitoring or sampling techniques need to be used
  • Identify how many samples will be needed for confidence and take guidance from a laboratory providing appropriate UKAS accredited analysis. Produce a methodology and timetable for carrying out the work. Carry out intrusive investigations
  • Use the estimation to inform a risk assessment and if required, discuss the findings with the council and the Environment Agency.

Phase 2b – Risk assessment

  • Assess the risks by applying appropriate human health, following the Contaminated Land Exposure Assessment (CLEA) methodology and non-human health assessment criteria, as agreed during Phase 1b. Refer to CLR Report 11: Model Procedures for the Management of Land Contamination
  • Identify remediation options and develop a Remediation Strategy, including a timetable
  • Submit a report of the risk estimation and assessment to the council. Agree the Remediation Strategy and inform all relevant interested parties (planning, environmental health, the Environment Agency, building control, the National House Building Council (NHBC) and identify a single point of contact at Medway Council for follow-up issues
  • The council, as the planning authority, will decide if the submitted report is to be approved
  • After approval, proceed to next stage if necessary.

Stage 3 – Remedial action

  • Implement the Remediation Strategy with regular updates to the single point of contact at the council, including unforeseen work
  • Where appropriate, seek site visits from Medway Council staff.

Stage 4 – Closure report

  • Upon completion, produce a concise, documented report of investigations, remedial action and validation undertaken to enable the council to discharge any planning conditions.

Please note: