Phase 1 Preliminary Risk Assessments (Desk Study) For Planning Permission & Due Diligence
A Phase 1 Preliminary Risk Assessment, often referred to as a Desk Study or Stage 1 Risk Assessment, is a report that aims to analyse all potential sources of contamination and determine the contamination risk at a site, in addition to providing a scope for further investigations, if necessary.
Phase 1 Preliminary Risk Assessments are most commonly required to support planning applications or comply with planning conditions. Site conditions and potential contamination sources must be identified, to assess the risk to future residents, construction workers and the building itself. This process involves desk studies, including analysis of historical and geological map data, to identify previous uses of the site and collect environmental data on ground conditions, hydrology and relevant local features.
A Phase 1 Preliminary Risk Assessment identifies and assesses both on and off-site potential land contamination risks and the potential impact to the site and site users (e.g. people living or working at the site). This assessment is conducted by obtaining all available information on a site to develop what is known as a 'Conceptual Site Model'.
Where the Desktop Study identifies potential contamination a Detailed Site Investigation Report will also be required, including a site investigation documenting the characteristics of the ground, an evaluation of all potential sources of contamination and a risk assessment, together with an updated conceptual model.
– Example planning permission condition from Rushcliffe Borough Council
What Does A Phase 1 Preliminary Risk Assessment Include?
Environmental Data Collection - The process of collecting information on a site for a Phase 1 Preliminary Risk Assessment (Desk Study) generally involves analysing historical map data to identify past uses of the site and any past nearby contamination sources. It will also include analysing current maps to identify potential on and off-site sources of contamination. Ground conditions at and nearby the site are taken into account when assessing the potential impact of any identified contamination sources. This wide variety of data used to produce our Phase 1 Preliminary Risk Assessments, collated from research organisations, local authorities, regulatory agencies and government institutions and databases, allows us to develop an accurate Conceptual Site Model.
Conceptual Site Model - The Conceptual Site Model included in a Phase 1 Preliminary Risk Assessment is simply a written or diagrammatic explanation of the sources, pathways and receptors present at a particular site, which is then used to determine the level of contamination risk. Sources being where contamination comes from (e.g. past industrial activity), pathways being the ways contamination can travel through the environment (e.g. through soil or groundwater) and receptors are the things ultimately affected by the contamination (e.g. residents, rivers, groundwater, buildings etc).
Further Investigation - A Phase 1 Preliminary Risk Assessment is the first stage of the risk assessment process and aims to assess the level of risk present at a site and determine the need for further investigation. A Phase 1 Preliminary Risk Assessment may conclude that no further testing is necessary as the contamination risk present is minimal, however, it may identify unacceptable contamination risks, for which a Phase 2 Intrusive Site Investigation will be needed to quantify and assess the safety of the site.
Oakshire Environmental recently completed a phase1 and 2 contamination investigations for our residential planning application. The site itself had a complicated history as it was part of a decommissioned Waterworks. Over the many months Joe and Louis were very supportive and flexible in helping us answer all the contamination officers' questions. They helped us all the way until we received approval to build. For the phase 2, we were concerned about the intrusive nature of the site excavations. Joe was very helpful in explaining how it would be implemented so as not to impact the site. True to his word, on the day, the excavations and tests went smoothly and was finished within 4 hours.
- Chris Green
When Do I Need A Phase 1 Preliminary Risk Assessment?
Wherever historical or on-going contamination poses a potential risk to people, buildings and the environment, it is necessary to assess the nature and extent of this risk in a cost benefit analysis. Since it can be costly in terms of time and money and there will always be some element of contamination risk present on any site, it's important to assess whether the risks present are acceptable or whether they require further action. Planning legislation dictates that the land contamination risk assessment process be an integral part of any development project, this is why Phase 1 Preliminary Risk Assessments are commonly carried out to support planning applications, or to comply with conditions placed on planning approval.
Comply with planning conditions - While the wording of planning approval conditions, relating to potential land contamination, varies from council to council, the basic premise is the same and, therefore, so does the process followed to comply with them. For example, some conditions may simply request an assessment of the nature and extent of contamination at the site, whereas, others may look something like this:
No development shall commence until actual or potential land contamination at the site is investigated and a Phase 1 Preliminary Risk Assessment Report is submitted to and approved in writing by the Local Planning Authority. The Report shall be prepared in accordance with Land contamination risk management (LCRM)
Meet Our Risk Assessment Consultants
Louis Turner, Technical Director - Having graduated from the University of Nottingham with a degree in Environmental Science, Louis is recognised for his technical leadership and precision in environmental consultancy. Louis provides strategic oversight across all service areas, ensuring projects meet the highest standards of compliance, accuracy, and environmental responsibility. Louis directs contaminated land investigations, from desk-based risk assessments to intrusive site surveys. He ensures soil and ground gas analysis is conducted to UKAS-accredited standards, producing clear, evidence-based reports that support planning applications, regulatory approvals, and safe development decisions.
Joe Turner, Operations Director - Providing practical expertise and a client-focused approach, Joe ensures that every project is delivered quickly, efficiently, and without unnecessary hassle. He has successfully managed a wide variety of project types across the consultancy, bringing a wealth of operational knowledge and a reputation for keeping projects on track. Joe's leadership guarantees a smooth process for clients, from initial enquiry through to final reporting. Joe oversees contaminated land investigations, coordinating desk studies, site surveys, and remediation works. His operational management ensures that soil sampling, ground gas monitoring, and reporting are completed seamlessly, giving clients confidence in compliance and project delivery.
Richard Turner, Director - With over 30 years of experience in site development, he provides invaluable insight into pragmatic solutions that balance costs, practicalities, and client objectives. Richard has a detailed understanding of building regulations and a clear sense of what is and isn't possible on site, making him a trusted advisor for developments of all sizes. Richard applies his site development expertise to contaminated land investigations, ensuring that remediation strategies are practical, cost effective, and achievable on site. His focus on feasibility helps clients move forward with confidence.
Request A Phase 1 Preliminary Risk Assessment
Contact us for an informal discussion about your requirements or, if your requirements are more complex, a more formal consultation may be necessary. Following initial consultation we can provide an outline proposal detailing how we can help and the costs involved. If you're looking for more information about our services or our company then complete the below contact form and we will endeavour to respond to your enquiry in a timely manner, alternatively, give us a call on 0800 433 2906 and our experienced consultants can provide actionable advice and guidance.
If you need help or have a question, let us know and we will endeavour to respond same day. By sending this form you agreeing to our Privacy Policy and for the personal data entered above to be saved to allow us to properly respond to your enquiry. Data is not shared with third-parties.
References
British Geological Society. BGS GeoIndex
BSI Group. Code of practice for the design of protective measures for methane and carbon dioxide ground gases for new buildings
CL:AIRE. Category 4 Screening Levels (C4SLs)
Environment Agency. Land contamination risk management (LCRM)
Land Quality Management. The LQM/CIEH S4ULs for Human Health Risk Assessment
US EPA. Regional Screening Levels (RSLs)