Concentrations of more than 1, 000 asbestos bodies per gramme of dry lung tissue were found in 13%.

BBC: 'One in seven' damaged by asbestos

And Chris Keates, head of the NASUWT teaching union, said local authorities and governing bodies were not taking issues linked to asbestos seriously enough and were failing to comply with their statutory responsibilities.

BBC: Asbestos danger 'in many schools'

Decaying bodies probably pose less of a threat than other issues, such as asbestos, said Dr. Paul Dungen, head of the Oklahoma City Health Department.

CNN: CDC, EPA: Little risk to public from sites