DEADLY underground gases could suffocate future residents at Cinderford’s Nothern Quarter site, according to an official engineering report.

Engineers from Parsons and Brinckerhoff say there is a high risk of asphyxiation to future occupiers of buildings as a result volatile vapours arising from historic landfilling on the £100m regeneration site.

The preliminary risk assessment, conducted on behalf of the Homes and Communites Agency, also states there is a high risk that ground gases escaping from old mine shafts could kill.

District Councillor Andrew Gardiner, who has concerns over health risks at the site said: “The contaminants are lethal.

“The old Hawkwell tinplate works which was once active in the area deposited heavy metals coating liquids.

“Through the 60s and 70s, Rank Xerox used tankers to deposit various liquids; later lemon-based degreasers were pumped at discharge points.

“The tankers often discharged soluble oils in the morning and the used contaminated liquid degreaser in the afternoon.

“While Broadmoor Chemical Works has long been closed, the land is now used as a sawmill and retains a large underground lagoon where sugar of lead, acetate of lime and naphtha were once manufactured.

“There is evidence it was used more recently because the acid-resistant large bore vulcanised pipes extend north-west to old mine shafts.

“There are two landfill sites under the mining craters and in the underground vicinity of the proposed college and housing development site.”

The preliminary risk assessment also states areas of the Northern Quarter, such as the proposed Gloucestershire College site, could suddenly collapse due to untreated mine shafts beneath it.

Information from the Deputy Gaveller reveals that of the 37 mine shafts in the area only two are known to have been capped.

Fourteen shaft are located beneath the restored open cast area.

Cllr Gardiner added: “There is clear evidence that the college site retains its coal seam strata, eight major voids and 20 coal seams which were encountered during the 2014 drilling of eight boreholes.”

The report recommends conducting a geophysical survey and boreholes to identify the position of any underground voids and shafts.

All soil samples will be subject to in-situ testing and laboratory analysis.

This will be followed by rounds of groundwater, ground gas and vapour monitoring.

Forest of Dean District Council planners were this week expected to accept the risk assessment report.

A spokesperson for the district council said: “An application will be presented to planning committee for consideration of discharge of condition 43, part 1 (land contamination) for plot E1 at Cinderford Northern Quarter.

“The application is in relation to the planning permission for the Northern Quarter, P0663/14/OUT.”