Simon Tolson - Contamination doesn't just apply to toxic chemicals. It can apply to hazardous plants and weeds that have to be removed. Worse, the contractor can end up paying
contaminatION and the construction process are not the happiest of partners, particularly if the employer has passed the contract risk of site and ground conditions to the contractor – a common occurrence in design and build.

In a nutshell, the contractor wants to limit its responsibilities when building on contaminated land – including the burden of removing contaminated waste from that land – and the employer is eager to extend the contractor's obligations as widely as possible. This is where conflict lies. To show you what I mean, let us take a real-life example – and here I must thank Guy Hanscomb of solicitor Benson for telling me about it.

The JCT With Contractors' Design form used in this little episode contained in the employer's requirements a passage that read as follows: "The contractor shall be deemed to have visited the site prior to submitting his tender … to have acquainted himself with the means of access, the nature of the work, the nature of the site and all other circumstances affecting the execution of the works … no claim will be allowed on account of any omission or error arising from the lack of knowledge of such matters." And it went on: "The contractor is to obtain a soil contamination report with a copy to be submitted to the employer's agent. The contractor shall include within the contract sum, allowance for dealing with any contamination including disposal to a licensed pit … the contractor must carry out any investigations he considers necessary to establish for himself the true nature of the ground and shall design the works accordingly." So, to cut to the chase, the contractor is assumed to have checked the site and priced in any remediation work. If it failed to do this properly, then that's hard cheese.

The contractor had started operations, when one day a local walking past the site notified the contractor that there was a problem on the land with Japanese knotweed, a particularly aggressive imported weed. This was a bolt from the blue: neither the contractor, employer or consultant had been aware of this.

Did it matter? Japanese knotweed grows quickly and extremely densely, providing a poor habitat for insects, birds and mammals. It can also increase the risk of riverbank erosion and, in the case of giant hogweed, pose a health hazard.

It was certainly a health hazard for the contractor. It was instructed to stockpile all topsoil and grub its root structure down to 2 m – with the spectre of disposal off site and costly remediation looming. The employer's agent passed the buck back to the contractor saying it would have to foot the bill for eradicating it because it could be deemed contamination under the JCT contract. The contractor should have spotted the weed sooner and priced it in. Now it had missed the boat.

The contractor feigned surprise: surely the employer wasn't suggesting that a weed could be characterised as a form of soil contamination? Got it in one, said the employer. In came the experts: the Environment Agency, the DETR and the Royal Botanical Gardens at Kew.

In came the experts: the Environment Agency, the DETR and the Royal Botanical Gardens at Kew. They said Japanese knotweed was one of two land plants controlled by law under the 1981 Wildlife and Countryside Act

The men in white coats said this species was one of only two land plants controlled by law under the 1981 Wildlife and Countryside Act.

Under section 14 of the Wildlife and Countryside Act, it was an offence to plant the weed or cause it to grow in the wild. One-nil to the employer. However, although some local authorities have by-laws controlling the planting or spreading of weeds, in this particular instance the local authority did not. One-all, perhaps.

It is not an offence under criminal law to have Japanese knotweed growing on your land if you did not plant it, or to allow it to remain once it has established itself. But, boy, have you got a problem under the 1981 act if you move it by construction operations: as soon as you do, it becomes subject to waste regulations, and is defined as special waste. Two-one to the client.

However, at the base date (when the contract was deemed to have been enforced), nobody had tried to move it, so it could be deemed to fall outside the catch-all clause in the JCT contract. A score-draw then? At this point, time intervened to save the contractor's bacon. If the base date had been after 1 April 2000, when the Environmental Protection Act 1990 part IIa came into force, things would have been very different, as this legislation for the first time defined contaminated land to include the likes of knotweed, hogweed and possibly even a triffid or two. Contaminated land is defined in this act as land that appears to the local authority to be in such a condition, by reason of substances in, on, or under, the land, that:

  • Significant harm is being caused or there is significant possibility of such harm being caused
  • Pollution of controlled waters is being or is likely to be caused.

The statutory definition of contaminated land therefore required evidence of the presence of a "contaminant", a "receptor" that could be harmed by the contaminant and a "pathway" linking the two. If those elements could be deemed to exist, the land was contaminated. They did: the contaminant was the weed, the receptor the site and the pathway was the two together. The land was, therefore, designated contaminated. So if the base date had been after 1 April 2000, the contractor would have had to meet all the cost and implications. Fortunately for the contractor, time was on its side: it was therefore off the hook and saved by the bell.