Eugene Symonds is looking up at a notice in one of his school’s temporary classrooms. “Warning: Encapsulated Asbestos. Do not cut or make fixings without proper authority and precautions,” it says.

Pupils at West Kidlington primary school in Oxfordshire use this area every day as a cloakroom. Symonds is trying to look on the bright side. “Our asset managers will tell us if there’s anything to worry about. I’m armed with the knowledge that if it’s enclosed and not causing problems, you should leave it alone,” he says. Then he stands back and looks at the notice again. “It is quite worrying, isn’t it? Now I’m not so sure.”

The 400-pupil school has had the four temporary classrooms since it opened in 1956. And while most of it was rebuilt after a fire in the 1990s, the prefabs survived – much to the chagrin of the staff.

‘The department recently carried out a survey of school property, but asbestos was specifically excluded from it'

It’s an issue that is exciting a growing chorus of complaint nationally. More than 75% of school buildings contain asbestos and many – mostly the huge number built in the three decades after the second world war – are now coming to the end of their useful lives.

According to the Local Government Association, disputes over asbestos removal from school buildings are holding up a significant number of projects.

Symonds, headteacher at Kidlington for 14 years, has been trying to fix the situation there. These antiquated classrooms are freezing in winter and too hot in summer, and when the school called contractors to replace its noisy, dated gas heaters with electric ones, one firm refused to do the work: it would mean moving ceiling panels that contain asbestos.

“I found myself teaching in that part of the school a lot last year, and the noise from the heating system was unbelievable,” Symonds says.

Last year the school applied under the government’s Priority Schools Building Programme (PSBP) to knock down and replace its 60-year-old classrooms. It was turned down for the £500,000 it would have needed to do the job. Even if it had succeeded, some contractors have told local authorities that the PSBP won’t pay for asbestos removal in cases like this one.

David Simmonds, chair of the Local Government Association’s Children and Young People Board, and also cabinet member for education in Hillingdon, recently told the House of Commons education committee that even where money was allocated under the PSBP for rebuilding projects, local authorities have still been expected to meet significant parts of the costs – including asbestos removal.

A headteacher told the same committee hearing that his school rebuilding project, in Stratford, east London, had been delayed because of a dispute between the contractors and the Education Funding Agency about who should pay for removing asbestos from a building that was to be demolished.

And Simmonds told Education Guardian that his own local authority had the same problem. The council was rebuilding three of its schools, he said. One of the projects – at Abbotsfield school in Uxbridge, west London – was a year behind schedule.

“We have ended up with fraught discussions … We said the old building needed to be demolished and that would involve asbestos removal. The answer was that they expected us to pay those costs. We have been saddled with a project where significant costs are essentially not funded.”

Approached by Education Guardian, the Department for Education said that, despite a number of ongoing disputes, the cost of asbestos removal for school building projects was funded under the PSBP. The local authorities said if that was the case, it needed to be made clear to contractors.

As asbestos removal is expensive, it can form a a large part of the cost of replacement. And with so many post-war buildings needing major works, the problem is not likely to go away.

According to a recent report from the all-party parliamentary group on occupational health and safety, the issue is a “time-bomb in our schools”. Almost all the 14,000 schools built between 1945 and 1975 contain the material, it says, along with most of those refurbished during that period.

And while some types of asbestos, if enclosed and well managed, do not pose a serious risk, the report says materials such as asbestos lagging, sprayed asbestos and asbestos insulating board, all of which can release dangerous fibres, are present in schools.

The all-party group quotes a report from the Medical Research Council, which estimates that even when a school building containing asbestos is in good condition, fibre levels are between five and 500 times those found outdoors. Children attending these schools are likely to inhale around three million of the fibres during their school lives, it says.

Despite this, a much delayed policy review published in March by the Department for Education quotes the Health and Safety Executive view that schools are a low-risk environment for asbestos.

The warning notice at West Kidlington primary school. Children use this area as a cloakroom every day. Photograph: Christian Sinibaldi/Guardian

“Requirements for managing asbestos in buildings are much more rigorous than in the past and the asbestos levels found in the ambient air of schools during normal occupation are likely to be lower than in the past. A recent study of the number of asbestos fibres found in lung samples suggests overall levels of asbestos exposure are decreasing in the general population,” it says.

But campaigners take a different view. Schools are very different places from offices, they say, because children can be careless and buildings can easily be damaged, allowing the asbestos fibres into the air. They also point out that cases of mesothelioma – which can take 30 years to develop and which is almost always fatal – have been growing.

Between 1980 and 1985 there were 15 mesothelioma deaths among school teachers – just three per year. In 2012 alone, there were 22. The legacy of the post-war school building boom has some way to go yet.

In 1972, Paul Crabtree began working as a religious education teacher at Bessemer boys’ secondary in Hitchin, Hertfordshire. Until shortly before the school closed in 1988 he occupied a post-war prefabricated classroom with asbestos in its fabric. “The wisdom was that if you left it alone it was all right,” he says. “But I have been affected by it.”

In September 2013 he had a pleural effusion – fluid on the lung – and in January last year he was diagnosed with mesothelioma. With the help of Irwin Mitchell solicitors, he is now bringing a case against Hertfordshire county council. As a result, he has seen reports dating from the 1980s which detail the extent of the asbestos in the building.

Despite this, he is philosophical: “I retired early from teaching when I was 57, because I had been diagnosed with multiple myeloma. I’ve had a melanoma removed from my arm. Nobody suggested those two other cancers were connected with asbestos – they don’t know. But now a third ‘M’ is going to get me,” he says.

And it is not only teachers who are affected – the DfE’s review accepts that because children have longer to live they are more at risk of developing mesothelioma. A growing number of legal cases now involve people who believe they – or their relatives – were exposed to asbestos as pupils.

One of those cases was brought by Sandra Naylor, who was diagnosed with mesothelioma in 2012 and who died last August, aged 52. Her husband, Iain, is now pursuing the action. Naylor attended Caldervale high school in Airdrie, North Lanarkshire, between 1974 and 1979.

“When Sandra put Caldervale and asbestos into Google, up it came – in 2011 during a renovation of the school, they discovered it was riddled with asbestos. She remembered workmen in the school while she was there, and lots of plastic sheeting. She must have come into contact with it then, like a lot of other kids.”

Neither Hertfordshire nor North Lanarkshire council wished to comment. But Michael Lees, whose own wife died of mesothelioma after working as a teacher, says it is an issue that needs to be kept high on the agenda. He runs a campaigning organisation called Asbestos in Schools, and regularly discusses the issue with officials.

And while the lack of funding for asbestos removal is an issue, he says, there is another: the DfE does not even know the full extent of the problem because it has not asked. The department recently carried out a survey of school property, but asbestos was specifically excluded from it.

“Most schools contain asbestos and its presence can be one of the major costs in maintaining, refurbishing or demolishing a school,” Lees says. “The audit of the condition of school buildings cost £20m, and yet the DfE specifically excluded one of the most expensive items to maintain, refurbish or demolish a school – asbestos.”