The ignition of chemicals caused a fire in the classroom
A 10-year-old girl was airlifted to hospital suffering from "significant" burns after a chemical explosion at her school.
Emergency crews were called to Swanage Middle School, Dorset, at about 1630 GMT on Wednesday.
The pupil, who was taking part in an experiment at an after-school science club, was transferred to the burns unit at Salisbury District Hospital.
The Health and Safety Executive (HSE) said it has begun an investigation.
The girl was treated at the scene by paramedics for burns to her hand and arm before being airlifted to Dorset County Hospital in Dorchester.
She was then transferred to the specialist burns unit at Salisbury District Hospital where she remained overnight.
A spokesman for Dorset Police said that the girl's injuries were "significant" but not believed to be life-threatening.
Crews from Dorset Fire and Rescue Service spent an hour making the classroom safe following a fire caused by the ignition of chemicals.
Head teacher Dave Pratten said an investigation was being carried out
A spokeswoman for Dorset Fire and Rescue confirmed they had received reports that an explosion had occurred in the science block.
Dave Pratten, head teacher of Swanage Middle School, said: "Our thoughts are with her and her family and we wish her a speedy recovery.
"I would also like to thank the school staff who administered appropriate first aid and those who helped ensure that other pupils were safely evacuated from the laboratory.
"The pupils who were in school at the time should be praised for their calm and sensible response to the accident.
"The safety of our pupils is paramount, and we will carry out a thorough investigation into the circumstances of the accident."