Bayer site FAQs

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Get answers to common questions about the work carried out to remediate the former Bayer CropScience Site at Hauxton.

Latest FAQ's (post-remediation)

1. What is the latest position as to decontamination verification condition 10 under S/2307/06 and condition 5 of S/2308/06?

These conditions have been discharged as of 27-May-2014 under applications S/2121/12/DC and S/2120/12/DC

2. Can i view the documents submitted to discharge the remediation conditions

Yes. You can view a comprehensive list of the conditions with links to the documents submitted and decisions on our website.

Historical FAQ's (Pre-remediation)

1. What is going on?

The site is being remediated or "cleaned up" as a statutory requirement under Part IIa of the Environmental Protection Act 1990 and to allow redevelopment of the site in accordance with a recently granted conditional planning consent.
(Information provided by: Environment Agency)

2. What was the site?

Until recently, the site was occupied by Bayer CropScience and has a long history of agrochemical production, such as pesticides and herbicides since the 1940s. The site is owned by Bridgemere UK PLC. The site has conditional planning permission for redevelopment.
(Information provided by: Environment Agency)

3. Who is working on site?

Harrow Estates plc, have employed a specialist remediation contractor, Vertase FLI, to undertake the remediation works. Vertase FLI are a nationally based specialist contractor with experience of remediating similar sites throughout the UK. Atkins Plc, an environmental and engineering consultancy, are also present on site to provide independent validation and monitoring of the works being undertaken by Vertase FLI.
(Information provided by: Environment Agency)

4. What is remediation?

Remediation is a process whereby the soil and groundwater is cleaned up to make it suitable for proposed future use. The predominant remediation technique being used on the site is called 'Bioremediation'.
(Information provided by: Environment Agency)

5. What is bioremediation?

Bioremediation is a natural process using microorganisms already present in the soil to degrade contaminants to harmless by-products.
(Information provided by: Environment Agency)

6. What are the nature of the works?

Briefly, the remediation works involve excavating contaminated soils before processing and treatment. The excavation activity is an essential part of the process allowing access to the soils so that contaminants can be effectively and efficiently treated. Soils are processed using screens (these are mechanical sieves/shredders breaking up the soil to enable treatment). Once screened, soils are transported within the site to a separate area of the site for covering and treatment. Contaminated groundwater is collected from the excavations and treated in the water treatment plant. Once treatment is complete and laboratory analysis confirms this, the soils will be returned to the ground.
(Information provided by: Environment Agency)

7. What happens to the soil once it is treated?

The soil is comprehensively sampled and tested at a laboratory and once it has met stringent levels required to make sure that there will be no further unacceptable risk to groundwater and human health, it is put back into the ground.
(Information provided by: South Cambridgeshire District Council)

8. When will work be complete?

The work will take approximately 80 weeks in total. They are due to be completed in September 2011.
(Information provided by: Vertase FLI)

9. Why not just leave the contamination in the ground?

Since the 1940s the site was involved in the production of agrochemicals including pesticides and herbicides. This has resulted in contamination of soil and groundwater beneath the site. Due to the risk posed to the groundwater and nearby watercourses, the site was determined as Contaminated Land in 2003 under Part IIA of the Environmental Protection Act 1990 and designated a Special Site for regulation by the Environment Agency. The site must therefore be remediated and cannot be left in its current form as it poses a potential threat to the Riddy Brook and River Cam. The site has also been granted outline permission for residential and mixed use development subject to it being remediated to a standard suitable for these uses.
(Information provided by: South Cambridgeshire District Council)

10. Why can the contamination not all be taken off site and out of our neighbourhood?

Taking soil off site would still generate smells as the material would need to be excavated and then transported. There would also be the impact of construction traffic on local roads with numerous vehicles coming and going from the site.

Government and European Policy in recent years has moved away from taking material away to landfill. The emphasis is now placed on remediation being carried out in a sustainable way, which involves treating contaminated material at source to an acceptable standard and re-using it where possible.
(Information provided by: South Cambridgeshire District Council)

11. What happens to material that can't be treated on site?

The overall remediation strategy is to treat material at its source and to reuse it where possible. Some of the material recovered from the site will be unsuitable for treatment such as asbestos containing materials, drums and other waste including some soils.

This material will be segregated on site until it is removed under the appropriate waste transfer documentation to a suitable licensed facility. Any lorries taking untreatable materials off site will be covered, ensuring that the cover is weighted down to prevent it blowing up during transit. This ensures that waste material remains within the confines of the skip throughout its journey and prevents waste particles and odours becoming airborne. Prior to leaving the site all lorries are washed down and inspected (see FAQ 12).
(Information provided by: South Cambridgeshire District Council)

12. If it is not suitable to allow people to live on it now, how is it safe to clean up?

The site is being remediated by a specialist contractor who is controlling the process to make sure that it is carried out safely. The works are also being independently supervised by an environmental consultant who is permanently on site and they are visited regularly by the Environment Agency and South Cambridgeshire District Council as regulators.
(Information provided by: South Cambridgeshire District Council)

13. Can contaminated soil be accidently carried off site on vehicles?

No, the site is divided into a "clean" and "dirty" side which is segregated by fencing. Though there are daily vehicle movements on and off of the "clean" side of the site for site workers and deliveries etc, there are relatively few vehicles accessing the "dirty" side of the site such as for new vehicle/plant deliveries. Any such movements on and off the "dirty" side are wheel washed prior to leaving the site to prevent potentially contaminated mud being deposited on the road.
(Information provided by: South Cambridgeshire District Council)

14. What chemicals have been found on site?

A list of the chemicals found on the site was submitted with the planning application.

15. Why can't we see what is going on?

The activities being carried out involve heavy plant and machinery and it is essential that the perimeter is secure. Encouraging passers by to watch at viewing windows or platforms may put them at risk from nearby traffic and could distract staff on site, placing them at risk.
(Information provided by: Environment Agency)

16. What is happening on the opposite side of the A10

Located across the A10 from the main site, there is a waste water treatment plant designed to treat any contaminated water recovered from the main site. Site operatives are moving between these areas frequently undertaking maintenance and taking samples for testing.
(Information provided by: Vertase FLI)

17. What happens if the underground pipes that take water to the Waste Water Treatment Plant (WWTP) across the A10 are leaking?

The pipes taking water from the east side of the A10 to the wastewater treatment plant on the west side of the A10 are laid in a concrete box trench and surrounded in activated carbon which would absorb any contamination should any leakages occur. The concrete trench falls back toward a sump on the west side of the A10, which is checked periodically for any contamination ingress. If the pipes were to leak, the activated carbon would absorb the contamination and the sump would collect it. The sump would then be emptied and the water transferred to the WWTP to allow the cause to be investigated.
(Information provided by: Environment Agency)

18. Who is supervising and regulating the work?

The work is being monitored full-time on site by the international environmental and engineering consultancy, Atkins Plc. Atkins are present on site to independently monitor and validate that the work is being carried out in line with the appropriate permissions for the site.

The remediation work is being carried out under the conditions of an Environmental Permit, which is regulated by the Environment Agency. South Cambridgeshire District Council also have a planning enforcement role.
(Information provided by: Environment Agency)

19. What is the role of each organisation?

The Environment Agency (EA) has responsibility for regulating the conditions set out in the Environmental Permit for the site. The EA will also respond to environmental incidents related to the site including reports of excessive emissions or odour nuisance from the site.

South Cambridgeshire District Council have responsibility for regulating the planning conditions set out in the planning permission and are also working closely with the Environment Agency to respond to, and address the concerns of nearby residents.

The Health Protection Agency is an independent UK organisation that was set up to protect the public from threats to their health from infectious disease, chemical, radiation and environmental hazards. It does this by providing advice and information to the general public, to health professionals such as doctors and nurses and to national and local government. The Norfolk, Suffolk and Cambridgeshire Health Protection Unit (the HPU) provides this service locally with support from a national team of scientists and toxicologists who review the monitoring results and provide expert analysis.
(Information provided by: Each Agency)

20. Have risks to workers onsite been assessed?

Full Control of Substances Hazardous to Health (COSHH) assessments and risk assessments for workers on site have been carried out and all required precautions are being taken. A strict policy with regards to site health and safety is being enforced at the site. All workers within what is referred to as the 'dirty' zone of the site wear Personal Protective Equipment (PPE) without exception and this is strictly enforced.
(Information provided by: Vertase FLI)

21. Why weren't the site workers wearing protective clothing when I walked past the site?

All employees and site visitors take special precautions including Personal Protective Equipment (PPE) when on site. This should not be confused with people entering the site from the A10 or those walking around the neighbourhood who do not require any special equipment. The site is separated into two zones, the "clean" zone is the area where the site access and compound are situated. PPE is not required in these areas. On entering the site itself or the "dirty" zone as it is known, where remediation is being carried out, full PPE is required.
(Information provided by: Vertase FLI)

22. Why does the site smell?

The remediation process requires the soil to be excavated. There are odours associated with the contaminants in the soil. As these contaminated soils are dug they can release odours that had previously been trapped underground.
(Information provided by: Environment Agency)

23. Is the air being checked?

As part of the conditions imposed by the planning permission and Environmental Permit a comprehensive regime of environmental monitoring is in place. Part of this monitoring programme includes monitoring air quality. Air quality is monitored both on and off site. These include fixed locations, locations in response to complaints and at random locations. The results of this monitoring are forwarded to the Environment Agency and the Environmental Health department of South Cambridgeshire District Council (SCDC). The Health Protection Agency (HPA) has been providing assistance with interpreting the results.
(Information provided by: Environment Agency)

24. What is being sprayed around the boundary?

There is a deodoriser system being used at the site to help control the unpleasant smells being released from the soil during excavation works. There are nozzles mounted along the fence line around the site that spray a fine mist of water and a dilute deodoriser. These are non-toxic and pose no harm to passers-by or to local residents. They are very similar to air fresheners and odour neutralisers used in the home. The contractor has been using a variety of perfumes, which so far have included "Pine", "Bubble Gum" and "Summer Fruits".
(Information provided by: South Cambridgeshire District Council)

25. I noticed that smoke is being pumped out of the top of the barriers/railings during site working hours. What is it?

This is not smoke, it is the odour control system, which sprays a fine mist of water and a dilute deodoriser, explained above (see question 12). They work much in the same way as household "air fresheners" and "neutralisers".
(Information provided by: South Cambridgeshire District Council)

26. What precautions are being made to make sure that any emissions from the site are safe?

In order to treat the contamination it is necessary to excavate the soils from the ground, which inevitably releases odours. Best available techniques are being used on site to control air emissions and odours as far as reasonably practicable. In addition to mechanical and physical controls, environmental engineers from both Vertase FLI and Atkins are actively monitoring emissions arising from the site. This information is fed back immediately to the site to allow any required changes to works to be made. Constant air monitoring is also in place with analysis being carried out by an independent laboratory. Vertase FLI have been made aware of recent concerns from local residents regarding odours from the site and they are continuing to develop alternative methods to solve the problem.

If the terms of the documentation issued by the Environment Agency (i.e. the Licence and deployment form) are not being complied with then action may be taken by the Environment Agency namely. Alternatively, if there is evidence to establish that emissions from the site are causing a Statutory Nuisance then an Abatement Notice may be served by the District Council requiring the steps specified in such Notice to be adhered to. However, it should be noted that if the terms of the Abatement Notice are not complied with, the District Council will need the consent of the Secretary of State for the Environment before taking any enforcement action.
(Information provided by: Environment Agency)

27. Are odours being tested where they are most concentrated, rather than at random spots?

Both. A comprehensive monitoring regime is in place monitoring and analysing both on and off site, at fixed locations, locations in response to complaints as well as at random locations.
(Information provided by: Environment Agency)

28. Is any organisation looking at potential toxicology issues?

The Health Protection Agency (HPA) are providing public health advice. The HPA is given copies of all air monitoring data by SCDC for comment and have raised no toxicology concerns to date.
(Information provided by: Health Protection Agency)

29. Are the people involved with making public health decisions aware of the patchy nature of the distribution of odours?

The site team and regulators are aware of this and take this into account when investigating concerns. This is why it is important to telephone the Environment Agency hotline (0800 80 70 60) at the time the smell is affecting you/your activities in order to give a better understanding of how processes on site/wind direction/weather conditions are affecting the distribution of odours.
(Information provided by: South Cambridgeshire District Council)

30. Have risks to people offsite been assessed?

Yes, risks were assessed as part of the preparations before work began on site and as a requirement of the environmental permit and the planning permission. This is continually monitored and reviewed and is another reason why residents are encouraged to accurately report/record odour issues.
(Information provided by: Environment Agency and South Cambridgeshire District Council)

31. What chemicals are being released into the air and are they harmful?

The chemicals expected to be present include a range of chemicals broadly classed as volatile organic compounds (VOCs). Air quality monitoring has been carried out both onsite and at the boundary of the site for a number of these compounds.

From the available monitoring data assessed by the HPA, it is unlikely that emissions from the site are going to cause any short term health effects due to the direct effect of the chemicals themselves (such as runny nose, sore throat, breathing difficulties etc) or indeed any longer term health effects, however if you do have any concerns about your health, please see your family doctor or NHS Direct.
(Information provided by: Health Protection Agency)

32. How are the VOCs collected and measured in the air monitoring tubes?

Initially, an accredited laboratory are contacted to advise upon the analysis technique based upon available site information. The laboratory then prepares and sends out the diffusion tubes for placement. VOCs are collected on special adsorption tubes which contain a media to which contaminants adhere.

Two methods of diffusion tube analysis have been applied to the Hauxton monitoring regime:

  1. Active sampling - air is actively pumped into the diffusion tube. This monitoring is carried out over a 24-hour period.
  2. Passive sampling - air passes diffusively into the tube. This monitoring is carried out over a 28-day period.

The tubes are exposed to the air for the required period to allow the air to enter the tubes and the contaminants to adhere to the media.

At the end of the monitoring period, the diffusion tubes are sealed and sent to the laboratory for analysis by Gas Chromatography Mass Spectrometry (GC-MS). Once at the laboratory the contaminants are driven off the media by heating (desorbing) before passing through a GC-MS to identify and measure the contaminants that have been collected.
(Information provided by: South Cambridgeshire District Council)

33. Are the odours causing or going to cause health effects?

The human nose is very sensitive to odours, and many substances that are perceived as odorous are usually present at levels below which there is a direct harmful effect. Odours can however cause annoyance amongst the population possibly leading to stress and anxiety. Some people may experience symptoms such as nausea, headaches or dizziness, as a reaction to odours even when the substances that cause those smells are themselves not harmful to health.

It cannot be excluded that some resident's symptoms may be as a result of their reaction to particular odours and it remains our recommendation that all efforts are taken to reduce off-site odours to as low as is reasonably practical. Consult your family doctor or NHS Direct if you are concerned about any effects on your health.
(Information provided by Health Protection Agency)

34. What is causing the odours that we are smelling?

Odours are caused by compounds in the atmosphere which have the potential to trigger our sense of smell. These odorous compounds can originate from many sources including plants, animals and human activities. It is likely that some of the compounds present on the Hauxton site, during the remediation, are causing some of the smells that people are experiencing. However, because something smells does not automatically mean that it is harmful as our sense of smell is very sensitive and is often stimulated at very low levels which we would not expect to be harmful.
(Information provided by: Health Protection Agency)

35. Could the work take place more slowly to prevent odours?

At present, dependent on site conditions and environmental factors, the speed of the excavation and the amount of processing and turning is varied. However, by reducing the speed and progress of the work too much, it is likely that due to the nature of the contaminants (low odour threshold) a similar odour would still be generated, albeit over a much extended timescale. It is important therefore that the works are progressed as efficiently as possible; managing odours while allowing the works to be completed without causing extended odour issues.
(Information provided by: South Cambridgeshire District Council and Environment Agency)

36. Do working practices change during the remediation?

Working practices on site change constantly, reacting to site and environmental conditions and different contamination as well as in response to discussions with the regulators and observation by the site environmental engineers. The site constantly seeks to reduce emissions and odours and hold regular discussions to overcome problems. As an example, now a larger area of excavation is available, the reduced level area is being used to store and treat more odorous materials to reduce the potential for odours leaving the site.
(Information provided by: South Cambridgeshire District Council and Environment Agency)

37. Why can the remediation activity not be covered with a tent?

The site is very large and the remediation is required over the whole site to depths in excess of 6m in places. The foundations required for such a large structure (even if it only covered a fraction of the site) would be so significant in that the excavations for the foundations would likely cause significant odour impacts in themselves. In addition the available height and span in such a tent is unlikely to permit the safe excavation and handling of the material due to the scale of the equipment required for the remediation. Smaller tents have been suggested by some members of the public however the sheer scale of the excavation would prevent their safe use and may prevent the full remediation of the site as excavations would be restricted. At present all odorous materials remain covered to reduce odours during treatment and any gross contamination at the excavation faces is covered as necessary.
(Information provided by: South Cambridgeshire District Council and Environment Agency)

38. Is locally-grown food safe?

The Food Standards Agency have confirmed that the emissions identified from site are unlikely to have any effect on locally grown foods. They always recommend that fruit and vegetables are washed and peeled prior to use regardless of where they are grown.
The Food Standards Agency gives specific advice about foraging for fruit in any hedgerow. Their advice is:

  • Wash your harvest well, wherever you have collected it
  • Don't eat an unhealthy looking plant or fruit - if it appears burnt, bruised or has any sign of mould, for example
  • Don't eat plants and berries growing on old industrial sites, busy roadside verges or where the ground is visibly contaminated with oil or ash
(Information provided by: South Cambridgeshire District Council)

39. The chemical cocktail effect: 'Could the combination of the chemicals interacting have an effect on people?'

The current scientific view is that the probability of any health risk from exposure to mixtures of chemicals present at low levels is likely to be small. Furthermore, when there is exposure to multiple chemicals that cause toxicity in the same way, the combined effects are likely to be no greater than additive. Only two chemicals, toluene and tetrachloroethylene have consistently been detected by the monthly monitoring at the site boundary. Even if these two chemicals were to cause toxicity in the same way, there would be no reason to expect adverse health effects, since the levels detected are many times below the levels required to cause ill health.
(Information provided by: Health Protection Agency)

40. Can the chemicals released into air at the site cause cancer or birth defects?

We do not expect any appreciable increase in the risk of cancers or birth defects to be caused by emissions from the remediation activities at this site, based on the air monitoring data at the site boundary.
(Information provided by: Health Protection Agency)

41. What is the potential for clusters of disease developing in the future?

The toxicological properties of the substances detected at the highest concentrations around the site boundary have been considered and no adverse health effects would be expected from exposure at the levels found. Therefore we would not expect there to be any clusters of disease related to this site.
(Information provided by: Health Protection Agency)

42. Can emissions from the site cause or trigger asthma?

There is no reason to suspect emissions from the remediation works at Hauxton are sufficient to cause asthma. In individuals with pre-existing asthma, episodes can be triggered by contaminants in the air. Such contaminants might include volatile organic substances or odours but any effect would depend upon their chemical composition, the levels and duration of exposure and an individual's sensitivity to odour. The main substances of concern for asthma triggers are allergens and irritant gases, which are present in the air from a variety of sources including natural and human activities. It is unlikely that emissions from the remedial works at Hauxton would trigger asthma. It is likely that other potential sources of asthma triggers (e.g. plant pollen, traffic) are more important factors.
(Information provided by: Health Protection Agency)

43. Why are the United States Environmental Protection Agency (EPA) air quality standards not used?

For those chemicals where International, European and UK air quality standards were not available standards from other countries including the United States (Centre for Diseases Control and the Agency for Toxic Substances and Disease Registry) were used. Data from the US EPA was considered as part of this review; however relevant International, European or UK air quality standards were available for the substances covered by the EPA.
(Information provided by: Health Protection Agency)

44. Air quality monitoring: 'If you record the level of chemicals as an average how do you pick up the peaks in concentrations and couldn't this be more damaging to health?'

In order to identify peak concentrations of chemicals a hand held instrument, a photo-ionisation detector, is being used to measure total volatile organic compounds (TVOCs) in the air, at the excavation face and around the site. Using this method significant TVOCs peaks have not been detected beyond the site boundary.
(Information provided by: Health Protection Agency)

45. What do I do if the odour is affecting me?

If odours or vapours from the activities on site are causing a significant nuisance please contact the environment agency incident hotline, immediately on 0800 80 70 60.

For general enquiries or concerns please contact either the environment agency on 08708 506 506, ( or South Cambridgeshire District Council on 03450 450 063. (
(Information provided by: South Cambridgeshire District Council)

46. Where can I get more information?

The agencies have a joint web page hosted by South Cambridgeshire District Council for updating information on the remediation work. This will include a list of frequently asked questions and answers as well as an e-mail address for interested parties to raise concerns and ask further questions.

For general enquiries or concerns please contact either the Environment Agency on 08708 506 506 ( or South Cambridgeshire District Council on 03450 450 063 (

Vertase FLI are creating a new area on their website about the work being carried out on the site. The page will be regularly updated with general information about the remediation process and examples of other sites that have been remediated by Vertase FLI.

Last update: 11th November 2010

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