Some items, for example, were preserved behind glass and could not be disturbed without damaging them.
The spokesperson added: "All schools must comply with the strict legal duties on asbestos and any disturbed or damaged asbestos has been safely removed from the Michaela school site".
However, the Department of Education said at the time: "If asbestos is not disturbed or damaged, then it is safer to leave it in situ, with strong systems in place to contain and monitor it".
Cunliffe voiced alarm that wrecks are disturbed and damaged in the hunt for cannon and potentially lucrative cargoes: "They are disturbing them in a way that no respectable archaeologist would do". He adds that many shipwrecks are at great depths, and the techniques are "rather crude and can be very destructive".
The government says the Health and Safety Executive advice is that if asbestos is not disturbed or damaged, then it is safer to leave it in place and monitor it carefully.
It becomes dangerous when disturbed or damaged because fibres can break off and get in to the air, where they can be breathed in.
What's worse, the failed plantings sometimes pack a double ecological whammy, as restoration activities disturbed or damaged otherwise healthy habitats.
Responding to the figures obtained by the Local Democracy Reporting Service, councillor Ken Wood, said: "Whilst it is understandable that parents may be concerned by these statistics, the Health and Safety Executive (HSE) are clear that as long as asbestos is in good condition and is not disturbed or damaged there is negligible risk.
Until then, such an operation meant disturbing and damaging muscles, which made it almost impossible for a pitcher to come back.
Microbial solution was added to growth media ensuring that roots were not disturbed or damaged.
