A number of pupils and a member of staff are being treated after being sprayed with an "unknown substance" at a school in Lancashire.
Emergency crews were called to Fulwood Academy in Preston at 14:45 GMT following reports that a girl sprayed "some sort of irritant" in a classroom.
Paramedics are treating those affected but their injuries are not serious, said police.
Two girls have been detained in connection with the incident.
There was a large emergency response with police, two ambulances, a rapid response vehicle and a fire engine sent to the school.