Concerns about new Llanerch school above sewage tanks
Concerns have been raised about a school being built above sewage-holding underground tankers in Carmarthenshire.
Campaigners said they overflow during heavy rainfall, making the Llanerch fields site in Llanelli unsuitable for a new Welsh-medium primary.
It is the preferred location on a list of nine areas Carmarthenshire council is looking at for a replacement of Ysgol Dewi Sant.
The council said "no firm decisions" have been made.
Residents said the tanks - that hold both rain water and sewerage - make the site unsuitable and believe a legal document signed by the council and Welsh Water prohibits building above them.
Local AM Lee Waters said once the "green space" is lost "we'll never get it back".
"So I want the council to look at brownfield sites, the other options they were looking at, rather than digging up this precious space," he added.
Carmarthenshire council said the process was at a first stage and the Welsh Government would need to approve two more detailed business cases before the scheme could start.
"No firm decisions have been made as yet and the scheme will not proceed until all the appropriate consultations and approvals (planning, business case, etc.) are in place," a spokesman added.
A Welsh Water spokesman said it would "await the formal planning application for the site before submitting our response".
A consultation event will be held at the Diplomat Hotel, Felinfoel, Llanelli on 5 December.