Caerphilly County Borough Council has confirmed it will no longer deal with the school’s advisors in getting rid of asbestos in the building.
The school has been closed since October last year with pupils having to travel to Ebbw Vale for lessons.
The local authority said on Thursday it had written to the Governors explaining the options that are now available to progress the works.
In a statement it said: “In April the council agreed to commit over £1million to Cwmcarn High School, but despite a period of committed negotiation with the firm to agree the detail of the scheme it is felt by the authority that an impasse has been reached.”
Cllr Rhianon Passmore, cabinet member for education said, “The council unanimously agreed to provide significant funding for emergency remediation and reinstatement works at the school to remove the asbestos danger. This money was not to be used on any other improvement or enhancement works outside the agreed remit.
“Unfortunately the advisors are insisting that a significant amount of additional improvement works are needed including painting, new flooring, new electrical wiring, a new alarm system and roofing improvements.
“This is not what was agreed by council as improvement/maintenance works fall outside the grant conditions and any such works would give the school preferred status and prejudice others. Therefore we have no other option than to deal with the school leadership direct to agree a new way forward.
“In order to ensure that the pupils can return to the school site as soon as possible, this will involve an option that the council has put forward to the Governing Body for the authority to take over the running of the asbestos removal project.”
Nigel Barnett, the council’s acting Chief Executive, added: “Unfortunately, if the Governing Body do not agree, the chances of the pupils returning to the site by the start of the Autumn term are significantly reduced and we would need to take decisive action to resolve the matter in the interests of the pupils and staff at the school.”