Made Ground, Brownfield Sites & Hazardous Materials: Risk Assessment Requirements for Minor Earthworks

Table of Contents

• Made Ground Explained: What Contractors Are Dealing With
• Why Minor Earthworks on Made Ground Carry Major Risks
• Asbestos in Soil: Specific Requirements
• Managing Unexpected Finds During Earthworks
• Protective Measures for Minor Earthworks on Brownfield Sites
• What Your RAMS Must Include
• Frequently Asked Questions
• Next Steps

Made Ground Explained: What Contractors Are Dealing With

"Made ground" is a geotechnical term for ground that has been built up by human activity — typically the deposit of fill material to raise levels, infill voids, or remediate former land uses. Made ground is pervasive across UK brownfield sites. It may contain almost anything: demolition rubble, clinker, ash, domestic waste, industrial waste, or a combination of all of these deposited over decades.

Unlike natural soils, made ground is fundamentally unpredictable. Its composition can vary dramatically over short distances. Ground investigation may characterise the general contamination profile, but cannot guarantee what any individual section of a trial pit or trench will encounter. This unpredictability is central to why risk assessments for minor earthworks on made ground must be more cautious and comprehensive than those on greenfield sites.

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Why Minor Earthworks on Made Ground Carry Major Risks

The term "minor earthworks" can give contractors a false sense of security. A shallow service trench through made ground on a former industrial site can expose operatives to significant concentrations of hazardous substances. The key risks include:

• Dust generation — Excavating contaminated fill generates dusts containing whatever is in the fill. For heavy metal-contaminated sites (former smelters, scrapyards, battery works), this can produce respiratory exposures that exceed COSHH limits without adequate dust suppression and RPE.
• Vapour generation — VOC-contaminated soils (petrol station forecourts, solvent spills) release vapours rapidly when disturbed. Minor earthworks can create excavations with VOC concentrations above Immediately Dangerous to Life and Health (IDLH) levels in confined conditions.
• Unexpected materials — Made ground commonly contains unexpected materials including asbestos-containing materials (ACMs), industrial waste drums, chemical containers, or radioactive material (on former nuclear sites). Finding these mid-excavation is a common occurrence on brownfield sites.
• Ground instability — Made ground is often poorly compacted and can be cohesionless when disturbed. Trench collapses in made ground are a significant risk, particularly where the fill contains granular materials.

Asbestos in Soil: Specific Requirements

Asbestos in soil is one of the most commonly encountered unexpected finds on UK brownfield sites, particularly those with a history of demolition or industrial use. The management of asbestos in soil is governed by CIRIA C733 (Asbestos in Soil and Imported Materials: A Good Practice Guide) and the Control of Asbestos Regulations 2012.

Key requirements for earthworks where asbestos in soil is known or suspected:

• Prior assessment — If ground investigation has identified asbestos in soil, an asbestos in soil risk assessment should be carried out by a competent specialist before earthworks begin. This should classify the contamination and inform the control measures.
• Asbestos survey — For buildings on the site, a Type 3 Demolition Survey (now referred to as Refurbishment and Demolition Survey under R&D Survey guidance) must be carried out before demolition activities that could introduce ACMs into the soil.
• Control strategy — The control strategy depends on the form of asbestos in soil: bonded asbestos (floor tiles, cement sheets — lower risk) or friable asbestos (sprayed coatings, insulation — higher risk). Your RAMS should specify the control strategy appropriate to the form identified.
• RPE — Where friable asbestos is present or suspected, P3 RPE is required during soil disturbance. Disposable Type 5 coveralls and appropriate gloves are also required.
• Waste classification — Soil containing asbestos is classified as hazardous waste and must be managed in accordance with the Hazardous Waste Regulations. Consignment notes are required and a licensed hazardous waste disposal facility must be used.

Managing Unexpected Finds During Earthworks

Despite thorough ground investigation, unexpected materials are frequently encountered during earthworks on brownfield sites. Your RAMS must include a clear unexpected finds protocol:

• Recognition training — Operatives must be briefed to recognise potential unexpected finds: visual indicators of contamination (discoloration, odour, visible fibres, buried drums), archaeological remains, unexploded ordnance (UXO) indicators.
• Stop and report — If an unexpected find is encountered, work in that area must stop immediately. The supervisor must be notified before work proceeds.
• Assessment by a competent person — The unexpected material should be assessed by a geo-environmental specialist before work resumes. This may require laboratory testing.
• RAMS update — If the unexpected find changes the risk profile for the works, the RAMS must be updated and re-briefed to operatives before work continues.
• Regulatory notification — Depending on the nature of the material, regulatory notification to the Environment Agency or local authority may be required.

For more detail on contaminated land RAMS requirements, see our guide on Contaminated Land RAMS: What Contractors Need Before Breaking Ground.

Protective Measures for Minor Earthworks on Brownfield Sites

Your RAMS method statement should specify the full hierarchy of protective measures:

• Pre-start briefing — Operatives must be briefed on the specific contamination profile of the site and the controls in place before work begins. Briefing must be recorded.
• Dust suppression — Water sprays during mechanical excavation and loading. Particularly important in dry weather.
• Respiratory protection — Minimum FFP3 for general contaminated soil work. Higher protection where specific hazardous substances are identified.
• Skin protection — Chemical-resistant gloves (nitrile minimum), disposable coveralls, appropriate footwear.
• Personal hygiene — Dedicated welfare facilities with hot water and soap. No eating, drinking, or smoking in contaminated areas. Segregated clean areas for welfare.
• Vehicle decontamination — Plant and vehicles working in contaminated areas must be decontaminated before leaving the site boundary. Wheel wash facilities may be required.
• Waste management — Segregate contaminated soil from clean fill. Keep records of volumes and destinations. Consignment notes for hazardous waste.

What Your RAMS Must Include

For minor earthworks on made ground or brownfield sites, your RAMS should include:

• Reference to ground investigation reports and contamination assessment
• Summary of known contaminants and unexpected finds risk
• Unexpected finds protocol
• Dust suppression plan
• RPE specification based on identified contaminants
• Skin protection and personal hygiene arrangements
• Welfare facilities: hot water, soap, clean change area
• Waste classification and management plan
• Asbestos in soil controls if asbestos is known or suspected
• Air monitoring for VOC sites
• Ground stability controls: benching, shoring, no unprotected entry into excavations
• Environmental protection measures: surface water, groundwater
• Emergency procedures

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Frequently Asked Questions

Q: Do we need a Phase 2 investigation before minor earthworks on a brownfield site?
A: If a Phase 2 investigation has not been carried out and the site has a history of potentially contaminating uses, you should not proceed on the assumption that the ground is clean. At minimum, request a Phase 1 desk study from the client. If the Phase 1 identifies a risk of contamination, a Phase 2 investigation should be strongly recommended before work begins.

Q: Who is responsible for the unexpected finds protocol on a CDM 2015 project?
A: Under CDM 2015, the Principal Contractor is responsible for managing safety on the site, including managing unexpected finds. Your RAMS should align with the Principal Contractor's unexpected finds protocol. As a subcontractor carrying out earthworks, you must stop work and notify the Principal Contractor immediately if an unexpected find is encountered.

Q: Can we reuse contaminated soil on site?
A: Only with appropriate regulatory approvals. Some contaminated soils can be treated on site and re-used under an Environmental Permit exemption. Others must be removed as hazardous waste. Your environmental consultant and the Environment Agency should be consulted before assuming that contaminated soil can be retained on site.

Next Steps

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