WORK halted on the new Lidl site in Prestatyn for nearly a week after contamination was uncovered during digging.
The site for the new store is a former gas works and diggers uncovered black sludge in pipes late last Tuesday.
A Denbighshire County Council (DCC) spokesman said: “Officers immediately responded and made contact with those persons working on the site.
“Having inspected the site thoroughly, staff confirmed that there was some very low-level residual land contamination.
“This was not considered to be a health risk. The site is contained within an enclosed and secure site with no access to the public.
“Work ceased around the exposed pipe area on site and officers from the council are working with the developers and contractors on further survey and remediation work.”
Local resident Jackie Rowe said she feared the sludge uncovered was the highly toxic ‘blue billy’, which is associated with the production of coal gas and contains high levels of cyanide.
Mrs Rowe said she has had an issue with the toxic waste in the past, with specialist teams coming in after she had found it coming out of the plug in her bath.
And upon smelling the same odour after the digging began last week she was concerned the workers had reopened the pipe and once again.
Lidl UK's regional head of property, Stuart Jardine, said, however: “I would like to reassure residents that the deposit is not toxic or harmful.”
He added: “As local residents will be aware, the site was formerly a gas works and is therefore being remediated as part of the planning permission for our new Lidl store.
“As with any site that has been previously used for heavy industry, there is always the possibility that we will find unexpected deposits.
“The area of redundant gas pipes was uncovered whilst removing relic foundations on another area of the site that wasn’t part of our remediation works.
“We have agreed a removal strategy with the council and our specialist contractor will now complete this work.
“We’d like to take this opportunity to thank local residents and the general public for their patience and the council’s support in this matter and we look forward to recommencing development of our new store very shortly.”
Work on the site has now restarted and the DCC spokesman added that the contractor was working with a contaminated land consultant to ensure the excavation of the remnants of the buildings of the former gas works in a safe fashion and in the shortest time possible to minimise the disruption to local residents.