Seven incidents of asbestos exposure have been recorded in Norfolk schools over the past five years.

The figures come as a coalition of local teachers' unions launched called for the government to pay for the removal of all asbestos, which can cause mesothelioma, an incurable cancer, from the county's schools.

Norfolk County Council lists 392 schools that contain the material, but refused to name the seven schools where exposure happened.

One incident came when 'screws fell out of skylight whilst being opened', and three were due to contractors working unsafely.

The full list was:

• 14/03/11 – Unsafe contractor working practices

• 21/08/12 – Contractor working unsafely

• 08/11/12 – Contractor working unsafely

• 31/10/12 – Works (planing of) a fire door – likelihood of exposure very low, precautionary report

• 19/04/13 – Screws fell out of skylight whilst being opened

• 13/12/13 – Items containing asbestos found in school grounds

• 30/08/13 – Discovered damaged AIB [asbestos insulating board] in store cupboard

The information followed a Freedom of Information request from Lucie Stephens, whose mother Sue, a teacher in Buckinghamshire, died of mesothelioma in June.

Bob Groome, Norfolk branch and district secretary of the Association of Teachers and Lecturers, said: 'This just goes to prove schools are not like other places. They say if asbestos is untouched or undisturbed, it's safe. But we are talking about schools and kids, and they are not the most health and safety conscious. They will kick a ball against a wall or the ceiling.'

A council spokesman said it could not be certain if anyone had been exposed, but 'the likelihood in the majority of cases is extremely low'.

Asked if the incidents showed there was a need to remove all asbestos from all schools, she said: 'No. The majority of these incidents were recorded as a precautionary measure, not because we believe a significant release occurred. Where asbestos is in good condition and managed appropriately there is no risk. We have robust processes for asbestos management and we monitor how well schools manage the process.'