Teachers who have been striking over health fears at a “blue water” school campus in Lanarkshire will return to work on Friday.

Trade union NASUWT said its 36 members will resume teaching at Buchanan and St Ambrose high schools in Coatbridge following guidance from its own advisors that it was safe to do so.

The campus, built on a former landfill site where domestic refuse, sewage, and industrial waste was dumped in the past, had been at the centre of claims that staff and pupils were becoming sick as a result of exposure to toxins.

Three teachers have developed bladder cancer since it opened in 2012 and another two teachers fell ill with two different types of cancer.

READ MORE: Cancer-causing chemicals found in grounds at 'blue water' school

In September 2018, NASUWT questioned whether blue water flowing from the taps - caused by copper contamination from pipes - could be linked to a case of bladder cancer in one its members.

Two children have since tested positive for elevated levels of arsenic in their urine, including one 13-year-old autistic boy who went blind.

However, an independent review concluded that there was no evidence from air, soil and water quality sampling that there was any link between the schools and the cancer cases, and that there was also an “alternative clinical explanation” for the boy’s vision loss.

It stressed that copper is not carcinogenic and that arsenic levels were well within safe thresholds.

The teachers began their industrial action on Monday, the first day of work for staff following the summer holidays.

READ MORE: Blue water school review should debunk the scare stories - but it probably won't

Most pupils at the schools returned for lessons yesterday, although North Lanarkshire Council confirmed that a “very small number” of children with additional support needs, who attend Buchanan High, had been unable to attend the start of term following individual risk assessments.

Although the review stressed that the school building and the site were safe, it recommended remedial action to eradicate a patch of polychlorinated biphenyls (PCBs) which had been detected on the outskirts of the campus during soil sampling.

PCBs are industrial chemicals known to cause cancer. Dr Margaret Hannah, the public health consultant who led the review, stressed that there was no danger to staff or pupils as the PCBs were underground and would only pose a cancer risk through long-term daily exposure.

However, she advised that the affected soil should be removed “as soon as possible” as a precaution. The council said it would do so.

Chris Keates, NASUWT acting general secretary, said: “It is reassuring that our experts believe that the remedial action that has been taken has now made it safe for our members to return to work.

“However, there are still a number of important issues which need to be addressed.

“The ongoing health issues being experienced by some of our members, including those diagnosed with bladder cancer, remain of deep concern.”

READ MORE: Warning over back-to-school spike in asthma attacks

The union claimed another of its members tested positive for elevated levels of arsenic this week.

Ms Keates said the union’s industrial action ballot will not be withdrawn until there is confidence that all of the review recommendations are implemented fully.

NASUWT also wants a series of air, water and gas membrane test results that confirm that there is no deterioration of the position.

Ms Keates will be meeting the council next week for further discussions.