SADDLEWORTH School pupils have been taken ill after inhaling a dangerous substance.
Three ambulances were called to the Uppermill facility after reactions to something added to an e-cigarette.
Now teachers and staff are calling on people to help them track down its source.
Police are working with the school to track down the suppliers and a group of pupils was spoken to on Monday, May 20 and had the dangers pointed out to them.
A statement on behalf of executive head Matthew Milburn and headteacher Dave Watson said: “A number of pupils have been taken ill due to the inhaling of a dangerous substance that appears to be in circulation in our community.
“The substance in question has been added in an e-cigarette. The risks of taking such substances are obvious and potentially very serious.
“We have today met with the entire cohort concerned to re-iterate how dangerous, unacceptable and potentially life changing such behaviours are.
“By way of context, we have had to call three ambulances that could have otherwise been responding to genuine medical emergencies and accidents.
“We would call upon everyone in our community to be vigilant and work together to help us track down how this dangerous substance is being distributed to children.
“Parents and carers are asked to make it clear to their children that the consumption of such substances is harmful.
“We are working with the police to track down those responsible. If you have any information that might help us stop the distribution of such a dangerous substance, please contact Mr Casey at the school.”