Construction Activity

What we know about the site

The site is known to be affected by historic contamination based on its former use as a gasworks. Extensive site investigation surveys, carried out by both National Grid and Berkeley, have identified hotspots of contamination in a few specific locations (rather than widespread significant contamination across the site).

The primary gas production site was located to the north west (now the Golden Business Park), with the Berkeley landholding historically used for gas storage only. The site has previously undergone remediation by National Grid to remove significant sources of shallow contaminated soils. However, based on the most recent site investigation completed by our specialist environmental consultant, there is still residual contamination at the development site, and this must be addressed as part of the site’s redevelopment for a residential end-use.

Our remediation strategy

There are two elements to our planned land remediation:

• Selectively removing localised areas (i.e. ‘hotspots’) of contaminated soils and taking it offsite for treatment/disposal. The soil will be taken directly from the site (via the new access road to Orient Way). As previously agreed, there will be no active soil treatment on site, but enabling works to facilitate the relevant development levels will be required, including the backfilling of gasholder voids.
• The site investigation identified localised residual impacts to groundwater at the site. Treatment of groundwater at these locations will be completed to encourage and stimulate natural processes, promoting environmental improvement longer-term.

Following remediation and construction of the foundations, the site will be capped and new imported soils laid in areas of public open space, to ensure that any residual contamination in the ground is unable to impact the future residents and visitors to the site. This is standard practice for all regeneration schemes on brownfield (previously developed) land.

We are actively considering ways to review and refine the strategy to make it more sustainable and reduce the impact on our neighbours.

The remediation strategy has been prepared by Ramboll UK Limited, an expert environmental consultancy which is highly experienced in working on gasworks sites.

Preventing odour and poor air quality

Air Quality usually refers to the concentrations of chemicals or of particulates present in air, and whether these are a risk to human health or the environment. VOCs (Volatile Organic Compounds) are chemicals released into the air as vapours – many of which are found in common household items and products (such as cleaning products, paint, aerosols etc.), and are sometimes present in the air at background concentrations. Particulates are solid particles and liquid droplets found in the air – common sources can include exhaust fumes, dust, smoke and tyre/brake wear from vehicles.

Odour is largely a potential ‘nuisance’ issue. Whilst the level of odour may be related to the concentration of a chemical in the air, odour impacts are subjective and are different from air quality impacts, and are therefore assessed differently.

During 2025 Isopleth carried out extensive testing to measure the ‘baseline’ air quality and odours on the site. This built upon Ramboll’s 2021 testing and means that we can track any changes that occur during the remediation works, so that any potential increases can be promptly investigated, and subsequently mitigated and controlled.

Trial pits were also dug to investigate shallow soils at the site. The trials data identified that proposed land remediation work has the potential to generate off-site odours and therefore appropriate control measures and monitoring will be implemented by our specialist contractor to mitigate any boundary odour nuisance.

An Air Quality (VOC) and Odour Management Plan has been developed for this . Measures to prevent odour and poor air quality include:

• Monitoring equipment to measure VOCs, which will provide an alert if there are notable increases against agreed thresholds. Our contractors will be immediately alerted to any exceedances*;
• Spot check monitoring “sniff testing” at specific locations (work areas);
• Continuous live monitoring at five* boundary sites. We have introduced an additional monitor to those that our expert contractor and the Council have agreed is necessary;
• Temporary cover systems for potentially odorous material over evenings and weekends;
• No out of hours excavation or disturbance of contaminated soils;
• Minimisation of stockpiling and disturbance/ manipulation of contaminated soil;
• Lorries avoiding schools and residential areas by using the new access from Orient Way unless in special circumstances. (Access requirements will be publicised in advance if required.);
• Water misting with with suppressant to capture odours at the source (mobile units) or site boundary (static nozzle system). The mist could be scented to help mask the odour.
• Odour suppressant foam for covering excavation faces or stockpiles in the short term;
• A selective and planned approach to the excavation of contaminated soils.

Contact information for Berkeley’s project team will be made available to assist with any complaints or incidents, the process for which is set out within the complaints procedure at the bottom of this page.

We have committed to providing weekly updates and will continue to this commitment for the remediation works. The reporting will be set to show where / if any exceedances occur and what measures are taken to rectify the situation*.

Preventing dust

An Air Quality Dust Management Plan has been developed to mitigate potential impacts from dust emissions during the construction. Measures to reduce dust include:

• 2.4 metre hoarding (solid fence) on the boundary;
• Sheeting/screening to prevent dust blowing from temporary stockpiles;
• Wheel washing of vehicles exiting the site;
• Coordination with other high risk construction sites within 500 metres;
• Water cannon / misting units to control dust at source of operation;
• Damping down of dusty areas and haul road with water;
• Workers will be required to change dirty boots before leaving site to reduce transport of dust
• Real time dust monitoring using continuous monitors at the site boundary
• Offsite visual checks for dust to inform use of control measures

How can we monitor what is happening?

Air Quality data will be summarised on a weekly basis in a transparent and plain-English Environmental Monitoring Report, compiled by Berkeley’s third-party environmental monitoring consultant. This report will be published on the project website each week and will set out:

• Air Quality (Dust) & Volatile Organic Compound levels gathered from live boundary monitoring equipment across five locations*.
• This will be presented weekly*, indicating if the pre-agreed Air Quality levels have been exceeded and note how any such incident was resolved by the contractor;
• The reporting will be set to show where / if any exceedances occur and what measures are taken to rectify the situation. The exact format is to be determined by the contractor appointed to carry out the remediation works;
• In the Air Quality and Odour Management Plan it is envisaged that the Monitoring Provider will produce a weekly ‘dashboard’ report including a summary of the previous week’s monitoring data from the VOC monitors and sniff tests, details of any threshold level exceedances recorded.

A newsletter will be produced each month. This newsletter will include an overview of upcoming works, completed works, programme, key dates and any community events.

There will be an opportunity for members of the public to sign up to an electronic mailing list to receive a copy of the newsletter via email.

Each newsletter will be sent via email to those on the mailing list

Who approves these plans?

In addition to the extensive investigations and reports completed to date, the development is subject to strict planning conditions that require all remediation and contamination issues to be fully assessed and approved by the Council and, where relevant, the Environment Agency before any works can commence on site. Berkeley are already working closely with these bodies to ensure that that all conditions will be satisfied and formally discharged before development proceeds. Alongside these there will be continuous monitoring of odour and dust and weekly air quality dashboard reports.

Complaints procedure

Berkeley will maintain a complaint register including the date and time of the complaint, as well as contact details for the complainant. The origin of the complaint will also be recorded (e.g. direct or via local or other regulatory authority). Details recorded will include a description of the nuisance, duration, if it is constant or intermittent and whether the source is identifiable.

• Berkeley will investigate complaints by undertaking site inspections and recording site activities, mitigation measures employed, implementing remedial measures and updating management plans where necessary.
• Berkeley will investigate potential alternative (e.g. off-site) sources of odours and record evidence of these (i.e. photos or “sniff” testing) if identified.
• Berkeley will respond to complainants with details of the findings of any investigations undertaken and also any mitigation/control measures implemented.
• Berkeley will report back to senior management and operatives on the investigation findings, including any mitigation / control measure applied. The complaints register will be made available for review by the local authority if requested.