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Questions and answers about contaminated land

What is contaminated land?

Contaminated land is land that contains harmful chemicals (pollutants) in sufficient quantities so as to present a risk or potential risk to human health or the environment.  The law dictates when land is legally defined as being 'contaminated' and tries to ensure that such land does not present a significant risk to health or the environment. 

The Government's long-term aim is to work towards a future where all the potentially contaminated land in England and Wales has been identified, assessed and when necessary, made safe.  The scale of the task means this is likely to take many years to achieve.

How does land become contaminated?

Land contamination can occur through a number of ways.  These can include previous industrial activities (e.g. former gas works), waste disposal (e.g. historical landfills) or accidental release of chemicals (e.g. leaking oil tanks).  In some cases there are naturally occurring high levels of chemicals, contaminating land.

What is the extent of land contamination in the UK?

As with many other industrialised nations, the UK has a legacy of contaminated sites, including former factories, mines, steelworks, refineries and landfills.  At these sites, there can be a variety of potentially harmful substances such as oils and tars, waste metals, organic compounds, gases and mining materials that are left over from or created by historical activities on site. 

It is estimated that there are approximately 325,000 potentially contaminated sites within the UK. 

Is there a risk to public health?

Many of the potentially contaminated sites do not pose any significant risk to human health or the environment because there is no link between the contamination and those potentially at risk from it. For a source of pollution (e.g. petrol that has leaked from an underground storage tank) to be a risk, there has to be a means by which people come into contact with the chemical by breathing, eating or by skin contact. 

If exposure does occur, a number of other factors are important including the amount to which you are exposed (dose), the way you are exposed and the length of time you are exposed.  Therefore, people have to be exposed to the pollutant either in large enough quantities, or long enough periods of time to potentially cause harm.

Who is responsible for dealing with contaminated land?

Local authorities are responsible by law for identifying and compiling a register of what they consider as potentially contaminated sites.  The public have a right to access this register.

Using historical information, each local authority will search for sites in their own areas which are most likely to be contaminated and prioritise them for inspection to establish the degree of contamination.  Where the local authority has identified a piece of land which may present a risk to health or the environment it will be investigated and they can 'determine' this contaminated land (a legal process which allows local authorities to take certain actions in making the land safe).  Following this, the authority will try to identify who was responsible for the contamination of the land and agree what works they should do to prevent the contamination posing further risk. 

If the local authority decides that the land meets the definition of contaminated land (specified by DEFRA), it will be regulated by the authority or, in some circumstances, the Environment Agency.  Local authorities are also responsible for making sure that any future developments that they may regulate through the planning regime (e.g. building new homes) will not result in harm to the occupiers resulting from its previous use.

How is contaminated land dealt with?

There are two approaches that a local authority can follow to deal with land contamination.

The Development Control Process

If a piece of land is to be re-developed or have its use changed, then any risk to future users due to contamination of the site should be assessed at the planning stage. It is the responsibility of the owners of a site to ensure that the site is fit for the purpose for which planning permission is being sought.

Local authorities can place planning conditions which would ensure any contamination of the site is properly dealt with as part of the redevelopment.  For example, if a developer builds housing on a former industrial site, the planning authority will require that the site is investigated and cleaned up, reducing any risk to future users, as a condition of the planning consent.  If existing housing is on a site that may be affected by pollution, local authorities may require small developments such as conservatories to be assessed prior to development.

Under Part 2A of the Environmental Protection Act 1990

If it is suspected that a piece of land may pose a risk to any site users or the environment then this is dealt with under legislation designed to protect current users.  Under this legislation local authorities are responsible for identifying sites which are most likely to be contaminated and prioritise them for inspection to establish their condition.  Following investigation they can determine this by law as contaminated land.

Identifying contaminated land is only the first part of the process.  After this the risk needs to be dealt with and a programme of appropriate action needs to be put in place to reduce the risk - this is called remediation. 

The purpose of remediation is to break the link between the contamination and those potentially at risk from it.  Sometimes this means that contaminated soil is removed, but not always.  In some situations the contamination will remain but steps will be taken to prevent anyone coming into contact with it.

What is the role of Public Health England (PHE) and contaminated land?

PHE has no specific statutory role in relation to contaminated land, but plays an important advisory role in the overall health risk assessment process.  We work alongside other governmental agencies (e.g. Environment Agency) on development of contaminated land policy including provision of expert advice such as the toxicology of chemicals.  We can also provide advice to local authorities on matters including risk assessment and risk communication.

PHE also plays an important role in communicating potential health risks from land contamination to members of the public. We are able to provide assistance to local authorities when directly contacted by those affected, provide expertise during public meetings and produce written communications: letters, leaflets or press releases.

What should I do if I think I live on land which is contaminated?

If you have a reason to believe that your land may be contaminated, you should contact your local authority.


Last reviewed: 1 July 2013