Agenda item

Health impacts of Walleys Quarry Landfill Site, Silverdale

To consider matters relating to Walley’s Quarry Landfill Site with a focus on health implications for residents.


Katie Spence - Regional Deputy Director Health Protection from the UK Health Security Agency(UKHSA), Alec Dobney - Regional Head, Environmental Hazards and Emergencies from the UKHSA, Will Proto – Consultant for Health Protection from the UKHSA, Steve Barlow – Public Health Registrar from the UKHSA, Nesta Barker – Service Director, Regulatory Services from Newcastle Under-Lyme Borough Council and Dr Richard Harling, Director of Health & Care from Staffordshire County Council attended the Committee to discuss the Health Risk Assessment of air quality monitoring results from March 2021 to August 2023 at Walleys Quarry Landfill Site and the health impacts.


The Committee were advised that on 5 October 2023 the Environment Agency (EA) announced that there were concerns around the accuracy of the historic hydrogen sulphide date collected around the Walleys Quarry Landfill site.


The Chairman informed Committee that the Environment Agency had been invited to attend the Committee however, the EA had declined the invitation. The Chairman, on behalf of the Committee, wrote to the Secretary of State for Environment, Food and Rural Affairs and the Minister for Environmental Quality and Resilience to request that the EA reconsider their position to not attend the Committee. The Minister for Environmental Quality and Resilience wrote back to the Chairman to advise that “the EA believe that Staffordshire County Council have all the information requested to inform their discussion at the Health Scrutiny Committee. Consequently, they have decided not to attend.”


The Committee expressed their disappointment that the EA had not attended the meeting to answer questions that the Committee may have had and requested that the correspondence be made publicly available. The Chairman agreed.


The UKHSA informed Committee that:


·         Due to the issues with the calibration of monitoring equipment raised by the EA, the historic hydrogen sulphide data that UKHSA had used to produce monthly risk assessments since March 2021 now had a greater degree of uncertainty.

·         No reference to the monitored hydrogen sulphide data had been included within August’s risk assessment.

·         Due to the historic hydrogen sulphide data having a greater degree of uncertainty which currently invalidates the previous human health risk assessments, UKHSA could at this stage only qualitatively assess the risk to human health on a theoretical basis assuming that the local population may have been exposed to levels of hydrogen sulphide above the long-term health-based guidance value prior to September 2023.

·         Pending further investigation, the new hydrogen sulphide data could not form a continuation of the old datasets.

·         To assess short-term peak exposures, UKHSA compare data to Acute Exposure Guideline Values (AEGLs)

·         Historic data reported in March 2021 showed that AEGL-1 had been exceeded. Without confidence in the current hydrogen sulphide dataset UKHSA could not say whether further breaches of the AEGL-1 had occurred. However, hydrogen sulphide concentrations would have been required to be a factor of 50 times higher to reach the AEGL-2 values, where there may have been concern for irreversible or other serious long-lasting effects of impaired ability to escape, which was extremely unlikely.


The UKHSA concluded that:


·         UKHSA could not currently rely on historic hydrogen sulphide data to assess the risk to people’s health. The risks of long-term health problems were likely to be small but could not be excluded at this stage. UKHSA were aware that some people continue to experience short-term health effects.

·         UKHSA recommended that all appropriate measures continue to be taken to reduce the off-sire odours from the landfill site, to reduce the health impacts experienced in the local community.


The Committee noted the following comments and responses to questions:


·         UKHSA were waiting for the Department for Environment, Food and Rural Affairs (DEFRA) and the EA to confirm if the data from March 2021 – August 2023 could be retrospectively recalculated and adjusted to provide that data if it was possible. It was reported that it may not be possible to adjust the data due to the complexity of the data.

·         It was reported that the monitoring equipment had now been calibrated correctly. There were ongoing risk assessments made by the UKHSA based on the current data since the monitors were recalibrated in September 2023. The Current data from September 2023 did not highlight cause for concern as emissions were within acceptable parameters and the long-term risk to health was low.

·         It was reported that there was a safety factor incorporated in the risk assessment for people at a higher risk of harm due to, for example, pre-existing respiratory issues or age.

·         It was important to recognise the impact on the community, the physical and mental impacts as a result of the issues at Walleys Quarry. The NHS had arranged a specific mental health support service and a health helpline for local residents to access support.

·         There was a meeting scheduled with the chief scientific officer at the EA in December 2023 to look at the data and determine if the data collected in between March 2021 and August 2023 could be adjusted and made usable. It was reported that the EA were investigating if the calibration issue had happened elsewhere. The UKHSA did not have scenarios depending on the outcome of this meeting, however a risk assessment could be completed quickly if data was made available.

·         There had been some analysis done in Autumn 2022 to look at current routine data such as deaths, hospitalisation, GP consultations and prescribing data to determine if there were any signals to indicate health impacts due to exposure to Walleys Quarry. It was reported that this analysis had not yet highlighted any impact at population level however this analysis could not exclude impact at individual level individual circumstances or long-term impacts. The Committee discussed and recommended that the analysis be updated where possible.

·         UKHSA confirmed that they were receiving sufficient data in order to make a risk assessment. The Committee discussed that the monitoring equipment around Walleys Quarry should remain in place for the foreseeable future to ensure that the levels of hydrogen sulphide were consistently reducing.  The UKHSA supported this proposal.

·         There was limited data available to assess the impacts of prolonged exposure to hydrogen sulphide. There had been studies of communities exposed to higher levels of hydrogen sulphide, however these studies had a number of limitations and did not necessarily reflect the population living in proximity to Walleys Quarry. The Committee discussed that there was a need for further longitudinal studies of health impacts in the community, as a result of long-term exposure to hydrogen sulphide.

·         The Committee also discussed the wider impacts of Walleys Quarry on the local community. The Committee supported the proposal to have a study into these wider impacts of Walleys Quarry.

·         The Health and Safety of the staff working on the site as a result of the emissions from Walleys Quarry was raised and the Committee agreed to write to the Health and Safety Executive to highlight the issue.


The Committee agreed to ask the following questions to the Environment Agency:


Reliance on the data collected from the monitoring stations.

1.   Are we certain it is just the monitoring of H2S that is affected?  If so, how do we know that?


2.   Given the data on other pollutants and toxins, has an independent third party verified that this data is accurate, otherwise we might just be making assumptions based on another false picture?


Process Evaluation

3.   What is the Environment Agency’s internal auditing processes in respect of Environment Agency equipment?


4.   Were these routine audits just not completed during the intervening years?


5.   How did this issue go on for the past six years – since 2017 – and why was it not picked up sooner – i.e. what are the fail-safe measures to prevent these sorts of mistakes happening in the future?


6.   Has a full drains-up ‘lessons learned’ being completed on these failings and can that be shared with committee?


7.   When the general public, experiencing the smell coming from Walleys Quarry for so long, and started complaining did no one think of bringing in a separate independent third-party body to verify that the Environment Agency’s readings were accurate or to check the verification process?


8.   What happened between Friday 1st September 2023 and 5th October 2023, in detail, between the Environment Agency knowing that there was a problem with their data and the time that information was shared with the general public?


9.   Why do the 3 / 4 monitoring stations monitor different things?


Retrospective Recovery of the Data

10. The figures being under reported, the stats – will it be too difficult to infer the same pattern due to many environmental factors too… In the absence of which – where do we stand?


11.There are no timescales related to the retrospective recovery of the data – can you give some further details on the size and scale of the work to be completed – surprised no indication on the basis of how long to consider – resources team size, being given to it.


Wider Impact Across Staffordshire / the UK

12.How many other monitoring stations at landfill sites are there in Staffordshire – well in England?


And are they similarly affected.


Staffordshire’s Health & Care Overview and Scrutiny Committee

13.Given the understanding that some of the information regarding the monitoring equipment at Walleys Quarry could be incorrect, can you please explain in detail why the invitation to meet with Staffordshire Health and Care committee was not accepted?


14.Can you please explain the main nature of the complaints you received in October 2023… 115 to the EA and another 26 to Newcastle Borough Council. This would give the committee a better understanding of the main concerns that people living in the vicinity of the Quarry are still worried about.


Longer Term Impact

15.How is the Environment Agency going to try and build trust with partners and the general public, that its data in future is accurate and reflective of the situation?


16.Given the lack of longitudinal studies on the impact of Hydrogen Sulphide on groups of people, will the Environment Agency fund a health impact study to identify this, specifically based on the Walleys Quarry local population, so that it can fill this gap in knowledge and make sure that any impact of their regulation of this site is mitigated for fully?


Clarification on the Papers submitted.

17.What does “The calibration slopes between sulphur dioxide and hydrogen sulphide within the analysers, had not drifted relative to each other since the beginning of September. Therefore, we are confident that this data from the beginning of September is also reliable.” mean and what does a third-party expert advice?


Resolved – That (a) the report from the UK Health Security Agency and the Environment Agency be received.


(b) the correspondence between the Chairman and the Secretary of State for Environment, Food and Rural Affairs and Minister for Environmental Quality and Resilience be made publicly available.


(c)  the Committee recommend and support:


·         that the Director for Health and Care undertake analysis of health data, where possible, in order to determine if there were any signals to indicate health impacts due to exposure to Walleys Quarry.


·         that the Environment Agency maintain the monitoring equipment around Walleys Quarry for the foreseeable future to ensure that the levels of hydrogen sulphide was consistently reducing.


·         the Director for Health and Care continue to pursue the proposal to have a study into wider impacts as a result of Walleys Quarry.


(d) the Committee write to the Health and Safety Executive to highlight health and safety concerns of staff working at Walleys Quarry, in light of the announcement from the Environment Agency that there were concerns around the accuracy of the historic hydrogen sulphide date collected around the Walleys Quarry Landfill site.


(e) the Committee request a response to the questions detailed above from the Chief Executive of the Environment Agency.

Supporting documents: