Odour Response in Calne

What have we done so far?

We understand how unpleasant and frustrating odour can be, especially when it affects your home and day-to-day life. Addressing these concerns is a priority for us.

The Environment Agency regulates waste sites through strict permits, which set out how sites must operate. At the Lower Compton landfill site, our focus has been on making sure the operator Hills meets these requirements, particularly when it comes to reducing odour beyond the site boundary.

In response to the concerns raised by the community, we have had staff actively monitoring odour in the local area since March 2025. This work sits alongside our Ambient Air Monitoring Station, which is based locally and records odour levels around the clock, 24 hours a day.

We are also working closely with our partners:

• Wiltshire Council, which leads on statutory nuisance odour.
• UK Health Security Agency (UKHSA), which provides expert advice on any potential health impacts

Together, we are taking action to ensure that Hills improves its operations and reduces odour as quickly as possible.Environment Agency staff monitoring at the Lower Compton site

What we’ve required the site to do:

• After seeing an increase in odour reports, in March 2026 we required Hills to produce an action plan, this included bringing forward the permanent capping of the current operational area, after we established this was the main source of odour from the landfill site. This is the best long-term solution to minimise odour from a landfill.
• These works are due to be completed by the end of July. We are regularly visiting the site to check that the work is progressing properly and on time.
• We have also required Hills to produce a clear plan setting out how they will minimise odour going forward. This includes addressing changes to waste composition, management procedures on site, and sizing of future landfill cells to allow more frequent capping. We are currently reviewing this plan to make sure it is strong enough and will make a real difference.
• Once the capping works are complete, we will carry out extra odour monitoring to assess the change in odour levels.

Environment Agency staff inspecting the progress of permanent capping works at the Lower Compton Hills waste site, June 2026

What's happening with the data?

We know many residents want clear answers about odour levels and any potential impacts.

We have an air monitoring station in Calne that continuously measures levels of Hydrogen Sulphide, Methane and Particulates. Our specialist monitoring team is currently checking and validating an interim dataset collected between October 2025 and April 2026 to make sure it is accurate and reliable. This is an important step when dealing with detailed scientific information. Once complete, we will share this with the UKHSA who will make public health risk assessment.

Once this process is complete:

• UKHSA will carry out an independent public health risk assessment
• This will help explain whether the odour levels could impact health or be considered a nuisance

We appreciate that waiting for this information can be difficult. While we cannot share the data just yet, we want to reassure you that it will be made public once UKHSA have made their public risk assessment.

When the UKHSA public health risk assessment is complete, we, along with our partner organisations, will hold a community event. This will give you the opportunity to:

• Hear directly from the agencies involved
• Understand what the data shows
• Ask questions and raise concerns
• Learn what further actions are being taken

We are committed to keeping you informed and will share further updates as soon as more information becomes available. In the meantime, your reports remain vital in helping us understand when and where odour is being experienced, and we encourage you to continue reporting any issues.

Permanent capping works progressing at the Lower Compton Hills site, June 2026

Environment Agency staff monitoring at the Lower Compton site