The search for a definition

The phrase “contaminated land” is used with considerable frequency, but it is worth asking what the phrase actually means.  The irony is that many of the sources of advice on the subject notably omit to define the very topic which they then go on to discuss with considerable gravitas. 

The importance of brownfield developments

The starting point is that it is national policy prefers the use of brownfield and derelict land for development over greenfield sites and has done so for many years.  This is not only national policy but it accords with many public sentiments on the subject.  Indeed, it sometimes seems that hardly a month goes by lest there is a public protest about proposals to develop a greenfield site.  There is therefore a great incentive to press ahead with the regeneration of brownfield sites.  This is not an easy task because it often involves the assembly of development sites from parcels of land in separate ownerships and, possibly, the relevant authority finds it necessary to use compulsory purchase powers.  Also, this often requires that all or part of the site must be remediated so that it is suitable for the proposed use. 

This task inevitably involves many disciplines, from of the society is to the engineer to the planner and, sometimes, to the lawyer.  No particular discipline has priority and the person who is interested in the process must seek to gain some understanding of each aspect of it.  To that extent, he needs to be something of a polymath. 

Policies which hang in the air

National policy and many development plan policies a make reference to the development of contaminated land.  In many cases, the term “contaminated land” is used without particular definition or outwith any discernible interpretational context. 

For example, the National Planning Policy Framework states:

170. Planning policies and decisions should contribute to and enhance the natural and local environment by:
(f) remediating and mitigating despoiled, degraded, derelict, contaminated and unstable land, where appropriate.

178. Planning policies and decisions should ensure that:

a) a site is suitable for its proposed use taking account of ground conditions and any risks arising from land instability and contamination. This includes risks arising from natural hazards or former activities such as mining, and any proposals for mitigation including land remediation (as well as potential impacts on the natural environment arising from that remediation);

b) after remediation, as a minimum, land should not be capable of being determined as contaminated land under Part IIA of the Environmental Protection Act 1990; and

c) adequate site investigation information, prepared by a competent person, is available to inform these assessments.

The words “contaminated” and “contamination” are not defined in the NPPF.  Furthermore, interestingly, 178(a) speaks of taking account of any “risks arising from  . .  contamination”.  Whether by intent or otherwise, the author seems to have narrowed the field to what a scientist would, in this context, describe as ‘pollution’: for which see below.

The National Planning Practice Guidance is, frankly, unhelpful.  It uses the various phrases “land affected by contamination”, “land contamination”, “land being affected by contamination” and, simply, “contamination” without explanation and, if they are meant to mean different things, without differentiation.[1]

It is difficult to see how any under-graduate could get away with a thesis which fails to define the very terms which he then engages at length. He might say that “I cannot define it, but I know it when I see it”, but this brings with it the obvious rejoinder that other people might see things in different ways. [2]

Whether by design or default, it is left to the reader to seek to attribute meaning to the concepts which are not thus described in these policy statements.[3]  In the absence of guidance, this must, inevitably, be a matter for a jury of experts comprising scientists, engineers and planners. No doubt the lawyers will seek to join the fray; however, frankly, this is far from being a matter of law. To use the rhetoric of judicial review, it is a matter which goes to the merits and, therefore, the scope for judicial supervision should be limited.    

If one can, therefore, eschew the lawyers, then the answer to the question should be sought in the technical world.  However, before delving into the esoteric, it is necessary to begin with a jolt of the mundane. The use of the word “jolt” is calculated because it betokens the result of revisiting the familiar from a different, and sometimes, startling perspective.

For example, the owner of the house might be surprised to be told that his home is contaminated with “volatile organic compounds”.  He might be alarmed and worry about the health of himself and his family. He might demand that it be cleared of these ill sounding “compounds”. Therein lies the problem, because not only is it unlikely that this will happen but also it is usually completely unnecessary. The mere use of hair spray prior to going out for an evening will result in the emission of the volatile organic compounds which form part of it.  Certain types of paint and plastics emit volatile organic compounds and they are also emitted by many household products.  Arguably, his house could be said to be “contaminated” by these everyday things, but the real question is whether this actually matters.  In most cases the answer is that it does not.  That is to say, the levels of these emissions are normally well below any threshold which could infer potential harm.  Aside from anything else, they are lighter than air and will be expelled from the house in the course of normal ventilation.  The same could be said of radon gas. This is a naturally occurring contaminant and many houses are built in areas where radon gas emissions are detected.  However, there are well known techniques for mitigating the potential effects of the gas on health, such as passive ventilation systems.

It is, therefore, a fatal mistake to treat the word “contamination” as describing a singular and absolute condition which is harmful in all cases, because it is a variable.  Not only this, but the phrase relates to a wide spectrum ranging from contamination which is patently harmless to contamination which is patently harmful.  These extremes of condition share a common generic name, but they are very different when quantified and assessed against a measure of potential harm.  To put it another way, merely labeling land as “contaminated” tells one very little about the real condition of the land.  Qualification without quantification is not particularly productive.

Either those responsible for the drafting of national planning policy have been dilatory in not providing a definition or they have chosen to leave that exercise to local planning authorities as a matter of judgment.  If one takes the benevolent view, then deciding whether land is contaminated is best left to the local planning authority to be determined on a case by case basis having regard to the then prevailing scientific wisdom.  This makes more sense than a national body attempting a “one size fits all” definition when the sites in question vary to a considerable degree in matters such as topography, groundwater, geology, the nature of any potential contaminant and the existence or not of pathways by which any pollution might be transmitted to potential receptors.

The ‘scientific’ approach
Scientists often distinguish between ‘contamination’ and ‘pollution’.  This approach does not involve ascribing any notion of actual harm to the condition of ‘contamination’.  By this approach, ‘contamination’ can be described as the introduction or presence in, on or under land of foreign substances, whether harmful or not.  A site can be described as ‘polluted’ when it is not only contaminated but also that the contamination has the potential to cause harm to human health or ecological systems.  ‘Contamination’ is, therefore, a necessary but not a sufficient precondition for ‘pollution’.

It follows that the mere characterisation of a site as ‘contaminated’ does not necessarily mean that it is hazardous.  It is not possible to go on and provide any meaningful commentary on the state of the site without investigation and risk assessment.

For example, the notion that a site is contaminated by arsenic might set hearts racing; however, the reality is that short term-exposure to this substance is harmless. Arsenic is a common component in pesticides[4].  One could, rightly, characterise some arable fields as contaminated.  Furthermore, arsenic is a naturally occurring element that is widely distributed in soils and minerals. However, this characterisation is of no import in determining whether a site is suitable for its proposed use unless the arsenic is likely to be taken up by those who will occupy it in quantities which are actually harmful.[5] Thus, the considered approach to a development proposal involves ascertaining whether it is contaminated and, if so, whether it is polluted.  If polluted, then whether the presence of the contaminant represents a hazard to the health of the potential occupiers and, if so, whether the risk of injury is acceptable or not. 

Thus, it is precipitate to stigmatise a site simply because it is said to be ‘contaminated’.

The ‘statutory’ approach

The Environment Act 1995 provided a statutory definition of ‘contamination’ for the purposes of the regime now set out in Part IIA of the Environment Act 1990.  Some commentators[6] greeted this with dismay because, instead of providing consistency of meaning, it conflated the three stages mentioned above.  Section 78A(2) provides . .

“Contaminated land” is any land which appears to the local authority in whose area it is situated to be in such a condition, by reason of substances in, on or under the land, that—

(a) significant harm is being caused or there is a significant possibility of such harm being caused; or

(b)significant pollution of controlled waters is being caused or there is a significant possibility of such pollution being caused;

and, in determining whether any land appears to be such land, a local authority shall, subject to subsection (5) below, act in accordance with guidance issued by the Secretary of State in accordance with section 78YA below with respect to the manner in which that determination is to be made.

Section 78A(4) adds:

(4)“Harm” means harm to the health of living organisms or other interference with the ecological systems of which they form part and, in the case of man, includes harm to his property.

Thus, the statutory condition is engaged only after site investigations and risk assessments have been carried out.  This is appropriate to a regime which is limited to the detection and control of sites which pose a risk to human health or the environment in their current conditions, but it was never designed to be applied outside its statutory context.  Unfortunately, as is often the case, the phrase is often taken in isolation and accorded the status of a generally applicable ‘magic word’.

To give an example, a contaminated land policy in a local plan might be triggered if the local planning authority ‘suspect’ that land is ‘contaminated’.  If they take the scientific approach, then the application of the policy is initiated if there is a reasonable suspicion that the site is affected by a contaminating material and it is not necessary to venture any opinion about any potential hazards at this stage.  If the statutory definition of contamination is applied, then it is difficult to see how the local planning authority can have any reasonable suspicion of a condition which can only be identified after an involved technical process.

If this statutory definition were applied out of context then it would cause a considerable problem for local planning authorities because it would set the bar at a high level which excludes most sites from consideration.  Arguably, the local planning authority’s interest in the condition of the site should arise long before such findings can be reported.

The NPPG makes it clear that the statutory test is not one for the local planning authority:

"To ensure a site is suitable for its new use and to prevent unacceptable risk from pollution, the implications of contamination for development should be considered through the planning process to the extent that it is not addressed by other regimes. The latter include:

The system for identifying and remediating statutorily defined contaminated land under Part 2A of the Environmental Protection Act 1990, . . . ."

[1] https://www.gov.uk/guidance/land-affected-by-contamination

[2] The phrase was used in 1964 by United States Supreme Court Justice Potter Stewart to describe his threshold test for obscenity in Jacobellis v. Ohio.:

“I shall not today attempt further to define the kinds of material I understand to be embraced within that shorthand description ["hard-core pornography"], and perhaps I could never succeed in intelligibly doing so. But I know it when I see it, and the motion picture involved in this case is not that.”

[3] Abeit, the jury is out as to whether the NPPG carries the status of policy: see Judson v Amber Valley Borough Council [2020]

[4] I once read a long discourse on the difference between ‘herbicides’ and ‘pesticides’ and why it was a cardinal sin to mix the words up. I feel bound to say that I could not care less !

[5] In passing, I am not sure that I follow those murder mysteries where the victim of arsenic poisoning keels over within 30 seconds of imbibing a fatal dose. I gather that, if arsenic poisoning occurs over a brief period of time then the symptoms may include vomiting, abdominal pain, encephalopathy, and watery diarrhoea that contains blood.

[6] Including me !


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