TOXIC substances have been found below a site earmarked for a controversial new school development in a former industrial town.

Mercury, asbestos and carbon monoxide have been identified as posing a potential risk to human health at the Belle Vue site in Consett.

A contaminated land risk assessment has been carried out and submitted to Durham County Council, which wants to build the £44m Consett Academy and an adjoining sports centre on the former mine workings.

The report was done by geotechnical engineer Daniel Freeland, on behalf of Carillion Building North, which has been commissioned by the authority to build the school and leisure centre.

He said the substances were potentially harmful to the health of construction workers and ‘site end users’ or school children and leisure centre customers.

Mr Freeland said: “The contaminated land risk assessment has identified that siteworkers are most at risk from the contamination.

“The assessment has identified that the risk to end site users is low, provided that localised areas of contamination are excavated in areas to be defined as a residential land use i.e. the school buildings and associated soft landscaping.”

The dangers are said to come come from the ingestion or inhalation of materials such as subsurface soil, dust or vapour.

Mr Freeland said: “If asbestos containing material is encountered or anticipated then it is recommended to keep the material wet by damping it down so as to prevent loose fibres from becoming airborne.

“If potential asbestos is identified during siteworks then work should cease in the area and the advice of an asbestos specialist should be sought regarding further actions.

“The risk from carbon dioxide is considered low but gas protection measures are required.”

The report is part of an application the council has submitted to its own planning department for permission to knock down the existing leisure centre, swimming pool and football club, following the demolition of the former Civic Centre.

Following a judicial review, the council’s Highways Committee is expected to reconsider an application from Consett Green Spaces Group (CGSG), which opposes the development, to have the land registered as a village green.

The highways committee is expected to consider the application on January 17.

If appropriate, the planning application would then be considered by the council's county planning committee on February 5.