BP Polythene Plant, Wilton

DBS Environmental Phase 2 Ground Investigations

BP Polythene Plant, Wilton

DBS supported an industry client through the process of Environmental Due Diligence for site acquisition.
  • Client: Confidential Developer Client
  • Date: November 18, 2014


DBS supported an industry client through the process of Environmental Due Diligence for site acquisition.

Our client was considering the acquisition of several potential development sites within the Wilton Works Complex, Teesside, an industrial area established by ICI in the 1940s for the chemical process industry. The sites included a 25 hectare site formerly used for chemical processing, and a 5 hectare site used as a polythene plant.

Historically, all sites had been in use for chemical processing at some point in time, or, were located in close proximity to chemical processing operations, and/or heavy industry.

The sites therefore had the potential for significant liabilities to be present should acquisition proceed, or , they had the potential to be impacted by off-site receptors from other operations within Wilton.

The sites were to be acquired for continued industrial use, so our brief from the client was to undertake due diligence work that protected them against long term risk, but also to be commercial and pragmatic in our approach to risk assessment, as the client was keen to acquire the sites to support their operations and any assessment of risk needed to be balanced accordingly. The sites were to be purchased for continued industrial use, a less sensitive end use for any eventual development.

Our approach was therefore to undertake environmental due diligence with a balanced approach, taking into account our clients development needs, whilst also protecting them against long term liabilities.

Environmental due diligence compromised the following main elements of work:

  •  Detailed review of all existing information available for each site, such as Phase 2 site investigation reports, regulatory reports, environmental monitoring reports and site closure reports;
  • Site Walkover Survey;
  • Obtain and review all current regulatory records for the site and surrounding area;
  • Review historical plans for the site and surrounding area, from “greenfield” status;
  • Undertake an assessment of UXO potential due to the sites being of national importance to the war effort in WWII;
  • Review the chemical process industry undertaken on relevant areas of the site, and produce constraints mapping;
  • Establish a Preliminary Conceptual Model, and undertake risk assessment for human health, controlled waters and property receptors; and
  • Recommendations for Phase 2 intrusive investigation, and environmental monitoring.

The work was reported in a Phase 1 Environmental Liability Assessment report.

The reports were undertaken in accordance with the requirements of the National Planning Policy Framework (NPPF), therefore, as well as meeting our clients due diligence needs, if the sites were eventually purchased the reports could be used to support a planning application for a change of use, saving our client significant costs and time at the planning application stage.

Due to the sites industrial nature located on a chemical works complex, there was much historical information available from vendors to support site divestiture. We undertook a detailed appraisal of all information available for each site to identify potential acquisition constraints and liabilities to our client, should purchase proceed.

The data review included re-interpreting historical site chemistry data that was not to current UK statutory guidance.

This was an exhaustive process but it helped to meet our client’s aims of being pragmatic in our assessment. A lot of the available site chemistry data was compared against Dutch Intervention Values, a common practice pre 2002 and the introduction of CLEA 2002 in the UK. The Dutch government pursue a policy of “multifunctionality”, rather than the re- use of brownfield land based on end use, like we do now in the UK.

The raw data was therefore re- interpreted to give a meaningful assessment in accordance with the current UK statutory regime for assessing risks from contaminated land, and addressed our client’s needs.