Threat by teachers in class safety bust-up.
Children face being turned away today on the first day of term as staff refuse to work in certain classrooms.
They claim parts of the school have been left looking like a building site after work to build an extension and demolish huts over the holidays.
The 56 teachers at Lenzie Academy, near Glasgow, took a ballot for industrial action yesterday fearing the school is in breach of health and safety rules.
Danny Kane, of the Educational Institute of Scotland union, said yesterday: "The safety of our members and the children at Lenzie is paramount.
"When we took a look at the school, wires were trailing across halls, the PE department had no floors and the modern studies department no chairs.
"The playground has been turned into something which resembles a building site with bits of old rusty nails and rubble.
"We don't believe it's right to teach children under these conditions.
"Children would usually be accommodated in the hall if classrooms were unavailable but even that's being used as a storage area.
"The education authority is gambling with kids' safety by allowing them to return to school."
Teachers and council staff were last night trying to clear rubble from the school themselves in a bid to make it safer.
Ian Mills, director of East Dunbartonshire education, said: "We are aware of the EIS ballot and its comments.
"Work was progressing last night to clear the school of all debris lying in the corridors and we are hoping it meets with stated health and safety standards."
He was due to inspect the school this morning to make sure it was safe to open.