Teachers at a North Lanarkshire school campus where four current and former staff members were diagnosed with cancer could go on strike on the first day of the new term.
Significant concerns were raised regarding Buchanan and St Ambrose high schools in Coatbridge, which were built on a former landfill site, after incidents of blue water coming from taps.
Thirty-six NASUWT members have said they will not return to the schools unless they are satisfied the site poses no risks.
North Lanarkshire Council have insisted that there is no evidence of health risks ahead of the findings of a independent review being published later on Friday.
The school started using bottled water in March last year after tests revealed higher than recommended levels of copper in the pipes which supplied the taps.
The tests took place after blue-tinted water was discovered coming from the pipes.
Water, soil and air samples from the site were assessed as part of the Scottish Government-ordered review.
The site that the school buildings, which opened in 2012, were built on was used as a landfill site for industrial waste for 28 years between 1945 and 1972.
All of the union’s members have undergone or are seeking blood tests, with results already recieved by one member described as a “deep concern”.
Ms Chris Keates, acting general secretary of the NASUWT- teachers union, said: “Because of the failure of the council and the government to take seriously the concerns of teachers about the health risks of working on the campus, at the end of the last school term the NASUWT implemented strike action to withdraw its members from the site to protect their health and welfare.
“As a result of the action taken by the NASUWT and its members, the government finally conceded that, as the NASUWT had requested consistently, a full site survey was necessary to provide up to date test results, not only on the ‘blue water’ but also on all aspects of the campus environment.
“It is now anticipated that those results will be published on Friday.
“The NASUWT’s experts are on standby to analyse the report once it is published.
“However, the council and the government should be in no doubt that unless the NASUWT is satisfied that the site poses no risks to health our members will not be returning to work on the first day of term.”