Building or Developing on Contaminated Land

There is a (reasonably) well known quote by Mark Twain that goes:

“Buy land! They’re not making it anymore”

Personally, I quite like this, as it is a very succinct way of reminding people of the relative scarcity and finite nature of land.

What this means to the novice property developer and investor is that theoretically, at some point all land could be bought and developed upon. Of course, this is never likely to happen but what is foreseeable is a point where all available land has become so sought after that the asking price has been driven up to a level where it renders a project financially unviable.

In this situation, brownfield sites (sites that have developed previously and are currently available for a new use; possibly subject to a grant of planning permission) might have to be considered. Sometimes, these plots will have been used for activities that would render them contaminated (for example, a filling station). When novice developers think about a contaminated site, they might visualise being ankle-deep in oil or waste fuel while the building work is carried out. The reality is that this could never be the case.

The control of contaminated areas of land is governed by either the planning process as a whole, or Part IIA of The Environmental Protection Act 1990 (EPA 1990). Under Planning Policy Statement 23, a property developer is responsible for making sure the development is safe for its intended use. So if the site is suspected or there is proof of it being contaminated, the planning authority will require assessments to be carried out before any planning consent is granted.

Under EPA 1990 Pt IIA, if the site is not dealt with through the planning process, then a local authority has an obligation to investigate any potentially contaminated land within its boundaries. If any contamination is found, then the developer must carry out a clean-up if the contamination is considered a risk to people, property or the environment. Clean up of an area will include some or all of the following:

1. ‘Desktop study’, site visit and initial risk assessment. This will entail an appreciation of the site history; original, current and future/proposed use; information on expected contaminants and their sources; information on potential ‘receptors’ such as people and flora/fauna. When Phase 1 has been completed, a report containing a preliminary risk assessment and recommendations for further investigative work will be submitted to the local authority and the Environmental Agency prior to moving on to Phase 2.

2. Site investigation and risk assessment. This phase involves the investigation into the scale of the contamination. This could be heavy metals, oil and fuels or gas. A ‘Sampling Strategy’ will be drawn up to specify the depth, scope, pattern and frequency of sampling. An assessment of risk to human health, waterways and other receptors will also be carried out at this stage. Upon completion, a report will have to be submitted to the local authority and The Environmental Agency detailing the recommendation as to whether remedial action is required to make the ground fit for use.

3. Remediation approach and works. The approach to be adopted for remediation will include the intended standard to be achieved. The works is when the physical work is actually carried out to make the site fit for development. It might include the removal of contaminated soil from the site and/or the introduction of a layer of impermeable material to prevent contamination seeping through. Any potential source of contamination will also be remedied to prevent further contamination.

4. Validation of remedial works. This is when the ground will be re-sampled to establish how effective the works have been. A Remedial Works and Supporting Validation Report must be submitted to the local authority and the Environment Agency. If it has been successful, then a written decision will be issued and the usual application for planning consent can be submitted.
Clearly, this is not a particularly speedy process. And it is also unlikely to be particularly cheap. However, there are specialist companies who will look after the process for you. Assessing the cost involved is a difficult thing to do because it depends entirely upon the scope and nature of the contamination, the size and location of the site and the intended eventual use of the site.
A very approximate indication of prices however is:
Removal of contaminated material – £50-£170 per cubic metre.
On-site encapsulation – £40-£100 per cubic metre.
Soil washing £60-£120 per tonne.

Items that might have to be included in the above are:

Haulage costs.
Landfill tax
Accommodation of personnel (if required)
Traffic management

The best recommendation I can provide if you are considering developing on a site you suspect to be contaminated, is to speak to one of the specialist companies (links provided below). They are fairly unlikely to be able to give you a very accurate quote for clean-up, but should be able to give you some idea of approximate costs. An appraisal could then be carried out to see if the project is financially viable.

Building on a contaminated site might financially benefit you, as many other developers might be unwilling to use the land, even post clear-up. Subsequently, if you considered this a worthwhile idea, the land cost might prove to be substantially cheaper than the alternatives even after inclusion of the cost of clean-up.

Environmental Agency page on Contaminated Land

Land Remediation Specialists:


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