SiteKiln gives you plain-English information, not legal advice. If you need advice specific to your situation, talk to the Environment Agency or a qualified environmental consultant.
If you dig up something that looks or smells wrong, the worst thing you can do is just bury it and carry on. That's how you end up in Part IIA territory, dealing with regulators instead of getting paid.
1. What "contaminated land" means in law
Under Part IIA of the Environmental Protection Act 1990, "contaminated land" is land where substances are present in, on or under the land and they cause or could cause:
- Significant harm to people, property, protected species etc.; or
- Pollution of controlled waters (groundwater, rivers, etc.),
and there is a significant pollutant linkage (source-pathway-receptor).
Who's liable
- Local authorities have a duty to identify contaminated land in their area and ensure it's remediated, either by the person who caused or knowingly permitted the contamination (Class A) or, failing that, by the current owner/occupier (Class B).
On a normal building job, your immediate concern is less "will the council formally determine this as contaminated land under Part IIA?" and more "will my actions spread contamination, pollute water, or leave me liable for clean-up and enforcement?".
2. If you hit something suspect during the job
If you find anything unexpected that could be contamination, stop work in that area until it's checked.
Red flag finds
- Buried drums, tanks, pipework or containers.
- Soil or water with strong chemical/oily smells, unusual colour, sheens (rainbow films) or obvious staining.
- Non-natural materials and wastes where they shouldn't be.
- Suspect asbestos, tarry wastes, or heavily stained ground.
What to do
- Stop work in the affected area -- make it safe, but no more digging or moving spoil.
- Tell the client and principal designer / principal contractor -- this might trigger planning or building-control conditions, and they may already have contamination info you haven't seen.
- Get competent environmental advice -- an environmental consultant or contaminated land specialist should assess the risk and advise on sampling, classification and remediation.
- If there's an immediate risk to controlled waters (e.g. free product in a trench, strong petroleum odour near a watercourse), contact the Environment Agency incident line and follow their advice.
Include a clear instruction in your method statements and inductions that if anyone sees suspect materials or smells, they must stop and report.
3. Dealing with excavated contaminated soil and waste
Once you know you've got contaminated material:
If it's reused on site
- That has to be under a proper remediation strategy and, where relevant, under the right waste exemptions/permits.
- You can't just spread it around or bury it elsewhere and hope for the best.
If it's taken off site
It becomes waste and must be:
- Correctly classified (using EWC codes and WM3 guidance to decide if it's hazardous or non-hazardous).
- Handled under the normal duty of care rules, with accurate descriptions and, if hazardous, consignment notes and 3-year record-keeping.
- Taken by a registered carrier to a facility permitted to accept that type of soil/waste.
If your actions cause contaminants to pollute water or create risks to health/the environment, you can be held liable, whether or not the client warned you in advance.
4. Planning angle -- why you don't want surprises later
- Before development, the planning system is meant to pick up land-contamination risks and deal with them through conditions and remediation so land is "suitable for use".
- Planning authorities often require a desk study, site investigation, risk assessment and remediation strategy as part of permission, especially on brownfield sites.
- If contamination is found after conditions are signed off and building is finished, councils can still use their Part IIA powers to force remediation if risks remain, and that may drag the developer/owner -- and sometimes their contractors -- back into the frame.
The safe route for a builder
- Assume brownfield or "previously used" sites may have issues until investigation proves otherwise.
- Don't ignore signs of contamination -- you will not be thanked later if the regulator sees your work has spread or worsened the problem.
Simple rule: if the soil looks or smells wrong, or you dig up mystery tanks or waste, stop, shout, and get proper environmental advice before moving another bucket. It's cheaper than being the one the council or EA decides "caused or knowingly permitted" the mess.
5. Common mistakes
- Burying it and carrying on -- the single worst thing you can do. If contamination is later traced to your actions, you're Class A liable.
- Moving suspect soil off-site without testing -- you might be illegally disposing of hazardous waste without knowing it.
- Not telling the client -- they may already have contamination reports from planning; you need to see them.
- Assuming "it's just old fuel" -- petroleum contamination can pollute groundwater for decades; the EA takes it very seriously.
- Ignoring smells and colours -- chemical odours, blue/green/black staining, oily sheens on water are all signs. Don't just dig through them.
- Not briefing the team -- your labourers and machine operators need to know what to look for and what to do (stop and report, not keep digging).
6. Who to contact
- Environment Agency -- incident hotline -- report pollution or contamination risks: 0800 807 060 (free, 24-hour)
- Environment Agency general enquiries -- 03708 506 506 (free from landlines)
- Your local council -- contaminated land team -- for Part IIA queries and planning conditions: gov.uk/find-local-council (free)
- Environmental consultant / contaminated land specialist -- for site investigation, sampling, risk assessment and remediation advice (paid)
- NetRegs -- environmental guidance for small businesses including contaminated land: netregs.org.uk (free)
- HSE -- if contamination poses a health risk to workers (e.g. asbestos, chemical exposure): hse.gov.uk (free)
7. Sources and legislation
- Environmental Protection Act 1990 -- Part IIA (contaminated land regime). legislation.gov.uk/ukpga/1990/43/part/IIA
- Contaminated Land (England) Regulations 2006 -- detailed rules for Part IIA. legislation.gov.uk/uksi/2006/1380
- DEFRA -- Contaminated land statutory guidance -- how local authorities should implement Part IIA. gov.uk/government/publications/contaminated-land-statutory-guidance
- Environmental Permitting (England and Wales) Regulations 2016 -- permits for waste treatment and water discharge. legislation.gov.uk/uksi/2016/1154
- Water Resources Act 1991 -- offences relating to water pollution. legislation.gov.uk/ukpga/1991/57
- WM3 guidance -- technical guidance on hazardous waste classification (Environment Agency).
8. Related guides on this site
- 11.4 Hazardous waste regulations -- what counts and how to dispose of it
- 11.6 Environmental permits for construction activities
- 11.8 Noise and dust complaints from neighbours -- your obligations
- 11.2 Duty of care for construction waste
- 4.4 Asbestos -- what to do if you find it or were exposed
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