The initial report by Santia Asbestos Management Limited had said airborne fibres at the 900-pupil school were 10 times higher than the accepted levels.
The structural report by Santia Asbestos Management Limited in October said the asbestos posed a potential health risk, and the union Unison said demolition was the safest option for staff and pupils.
Santia Consulting Ltd issued a statement on Friday saying the source of the asbestos contamination in the school "still remains in place consisting of substantially damaged asbestos insulating boards (AIBs) in the ceiling voids, damaged AIB in the room heaters and repeated damage of AIB window panels within classrooms".
However, on Monday it was revealed that a new report carried out on behalf of HSE by the Health and Safety Laboratory (HSL) - which carries out scientific research - that the method of testing carried out by Santia could "overestimate the levels of asbestos fibres as it does not distinguish between asbestos fibres and other fibres such as paper, clothing and skin cells".