Mandatory monitoring needed to address landfill stench – report

Alec Doyle, Local Democracy Reporter

A report to address a 20-year local campaign against rotten egg smells from a landfill site has called for mandatory odour monitoring to ensure public confidence.

The Senedd Petitions Committee made a series of recommendations to address the campaign led by residents of Johnstown, Rhos and Ruabon against smells coming from the Hafod Landfill site, but stopped short of revoking Enovert’s permit to operate the site.

While the report accepted a number of breaches in late 2024 and early 2025 which impacted residents, it did not find evidence to suggest that a closure was necessary.

One key finding urged Natural Resources Wales (NRW) to review its Hydrogen Sulphide thresholds – the gas that causes an unpleasant rotten egg smell for nearby residents – and to consider adding the smell to its environmental permit conditions.

The recommendations also include a drive for independently calibrated monitoring, transparent data reporting in real-time, as well as a call for clear advice from Welsh Government to local authorities on how to protect communities from statutory nuisance.

It comes in response to claims that the smells caused by hydrogen sulphide exceed safe exposure levels for humans, a claim that Enovert has refuted.

The committee says that it is a vital part of a need to restore public trust: “There is clearly a breakdown of trust between the local authority and some local residents on how the breaches at Hafod have been investigated,”

“The fact that monitoring work has been co-funded by Enovert, and analysed by consultants it had appointed, is likely to be a factor in residents’ lack of trust in the data.

“The Welsh Government should introduce mandatory automated odour monitoring at landfill sites. This is not something currently required by NRW and Welsh Government should ensure that regulators are sufficiently funded to facilitate this.”

It added that a thorough investigation was necessary into claims that periods of rainfall are amplifying the odours from the Hafod site, and that Wrexham Council should clarify for residents in simple terms how it intervenes in the operation of the site alongside online updates.

The last recommendations involved the Hafod Liaison group – which is made up of councillors and residents – which is urged to clarify the criteria for residents to participate, and ensure minutes are published punctually.

It also recommended that three residents should be part of a stakeholder group featuring representatives from Enovert, NRW and local councils.

‘Complaint fatigue is real’

A key defence of the measures taken at the Hafod site was falling resident complaints, though the committee found this was likely due to the lack of belief among residents that complaints were being listened to.

“Complaint fatigue is real,” it stated. “Members admire the commitment of campaigners to keep raising their concerns and calling for action.

“The committee’s scrutiny has put the voice of residents on the record. It has underscored the importance of trust and effective community relations – people need to not only feel their voices have been heard, but that they have been listened to and their concerns taken seriously.”

It also expressed shock at the continued reliance on subjective ‘sniff tests’ by NRW as part of its regulation activity.

“If it were not for consistent community complaints and the cooperation of Enovert, there would be no technical monitoring regime at Hafod.”

Resident and lead petitioner Steve Gittins welcomed the report, calling it a “massive day” for his community: “We have successfully shifted the narrative from a ‘local nuisance’ to a ‘national regulatory failure’.

“The report explicitly states that the ‘current permit will continue to fail communities and residents, unless it changes, not just locally, but nationally’.

“We aren’t stopping here. We will take these findings to the Seventh Senedd to lobby the new Welsh Government and ensure national landfill laws are rewritten.

“A massive thank you to the Senedd Committee for their diligence and to every member of the community around Hafod for your unwavering support.”

Next steps

A statement from Wrexham council said it continues to work with the involved parties to the community’s benefit: “We have already seen progress on a number of points raised in the report including the full calibration and re-scaling of data from all six monitoring pod’s, odour acuity testing for staff deployed for sniff tests and new terms of reference and a commitment to turn around minutes quicker from Hafod Liaison Group.

“Other recommendations are in progress as we continue to engage on ways to mitigate, monitor and reduce impacts of odour emitted from the site.

“Wrexham Council has installed two community air quality monitoring units and carries out in person officer odour checks throughout the affected communities five days a week. This is to help NRW assess the level of odour nuisance and inform the public via detailed reports posted on the NRW Citizens Space.

“Hafod Landfill Stakeholder and Liaison Groups will continue their ongoing commitment to maintain collaboration and keep the public informed as we progress.

“While NRW are the key regulator, Wrexham Council will remain fully engaged to support all partners to reach a satisfactory conclusion as outlined in the council motion (to seek a review of waste management at the site, explore possible alternatives, determine the impact on local people and demand ongoing, robust reporting of emissions).”

Enovert said it was aware of the report’s recommendations and will work to take action where required.

A spokesperson for NRW welcomed the report and said it would “carefully consider” its recommendations, while continuing to regulate the site and minimise odours in the meantime.

The Senedd committee has pledged that the report will form a larger review of Welsh landfill regulations carried out after the Senedd election in May this year.