Teachers have voted to strike and almost 10,000 people have signed a petition following a spate of cancers among staff at a school.

Concerns have been raised about "blue water" coming from pipes and possible chemical contamination at the Townhead Road complex, built on a toxic landfill site in Coatbridge.

The NASUWT union, which represents 12 staff at Buchanan High School, said staff will go on strike from June 20 until June 28.

The £44m campus opened seven years ago on a site used to dump waste from the metal industry and households.

Four teachers have been diagnosed with bladder cancer and many parents say their children have complained of headaches, tiredness and other medical problems.

A union spokeswoman said its members have no choice but to strike over the health concerns.

She said: "Whilst the NASUWT is in dispute over the situation at the school we have taken the unprecedented step of removing our members from the school site because of the serious health and safety concerns.

"The failure of the employer to act to address these concerns is unacceptable and our legal advisers are also taking appropriate action.

"No stone should be left unturned when the health of staff and pupils is at risk.

"The NASUWT should not be in a position where we have to take such action, but if an employer fails to act appropriately we will."

At least six parents have formally withdrawn their children from the schools. But officials are adamant that there is no cause for concern and no evidence that the site is the cause of any ill health.

Angry parents demanded action at a public meeting last week.

Mum Josie Morgan said her son Tommi, who has autism, joined Buchanan High as an S1 pupil last August. The school teaches children with additional support needs.

By October, Tommi was completely blind and tests revealed levels of arsenic in his system three times normal levels.

She said: ""I'm disgusted. I want to see the school shut. It's just talk, our confidence in them has gone and all the other children I've heard of who've got numerous things wrong with them, also the teachers as well."

Blue water can be caused when water sits inside copper pipes for prolonged periods - but officials say that it does not cause cancer.

Copper piping throughout the campus has been replaced with plastic and there have been no reports of blue water since.

A statement from North Lanarkshire Council said: "Specialist doctors from the public health department of NHS Lanarkshire have confirmed that no incidence of cancer is linked to the schools. They have also confirmed that no other serious illness is connected to the schools or the site on which they are built.

"The council will liaise directly with trade unions on matters of concern to staff. All the facts demonstrate that the schools and the site on which they are built is safe."