A Gorleston high school was shut down for the day and all its 1000-plus pupils sent home after a specimen jar containing a fish was smashed during a morning biology lesson.

A Gorleston high school was shut down for the day and all its 1000-plus pupils sent home after a specimen jar containing a fish was smashed during a morning biology lesson.

Fireman and paramedics were called to Cliff Park High School at around 11am on Tuesday amid concerns about fumes and vapours from the chemical contents following the spillage.

Ten year 11 students were seen by paramedics but were not found to be suffering the effects of inhaling any of the toxic substance which later turned out to be formaldehyde.

Headteacher Mark Bailie took the precautionary measure of closing the school at around 1pm yesterday following what he called the “relatively minor” incident.

He said: “We have to take all the precautions because health and safety is paramount. It is not a very nice chemical. The emergency services advised us what to do. We cordoned off the area but because that area has such a lot of pedestrian traffic after talking to the chief fire officer it seemed prudent to send the students home until waste services could come in. The school will conduct its own investigation.

“Clearly I do not feel it is an over reaction. This stuff can cause problems by inhalation and we do not know what is in the air in these corridors. I did not do it lightly.”

Staff had been able to contact all but three of the 1040 students families via a text-based group call, he said.

A spokesman for Norfolk County Council said the science lab, although sealed was close to a stairwell used by hundreds of children.

He added: “They did everything they should do. They did not know what the chemicals were in the jar. They followed the protocol. Because they did not get a time of arrival from the waste contractors they thought it safest to close the school. The headteacher has assessed the risk and he is happy with the decision. It was in one science lab and it was locked up and contained. It was the issue of the stairwell and the waste contractors.”

An anonymous parent however, tagged the move to shut the school “a pathetic over-reaction.”