KEY POINTS:
A person is in Christchurch Hospital with burns to 50 per cent of their body after an explosion at a suspected clandestine "P" laboratory last night.
Emergency services were called to the Hei Hei Rd house in Hornby about 11.30pm, southern fire communications shift supervisor Jan Wills said.
Two people in the house when the explosion and fire happened had taken themselves to hospital, Ms Wills said.
Detective Sergeant Greg Murton, of the Christchurch police drug squad, said it was believed a P lab was operating and the explosion happened during a "cook".
"A person was hospitalised with 50 per cent burns over their body, with full thickness burns over 30 per cent," he said.
Other people in the house at the time may also have suffered burns, but not contacted medical services or police, Mr Murton said.
The house had been cordoned with a police guard on duty overnight but there was no danger to neighbours.
Ms Wills said a decontamination unit was called in once it was suspected that a P lab had been operating and three people were decontaminated.
Firefighters extinguished the blaze about 2am.
- NZPA
