Emergency services were called to an incident at Woods Loke Primary School in Lowestoft after pupils sustained minor injuries when liquid leaked from a stress toy.
Eight children, a mix of boys and girls aged 10 and 11, suffered blistering and redness after the toy burst and fluid began irritating their skin. The toy had been brought into school by a pupil.
Staff members followed school procedure and evacuated the relevant classroom.
Headteacher Joel Crawley emphasised that the fire service had been called as a precaution.
'The emergency services were here within five minutes and I'd like to thank them for responding so fast,' he said.
'The fire service swept the building for harmful substances and informed us that it was safe to resume classes.'
Four children were treated by ambulance crews at the school, whilst another four were taken to James Paget University Hospital in Gorleston for treatment.
The chemical has since been sent off for testing.
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