Police are investigating the circumstances surrounding an incident which has left a teenager critically injured at Seven Hills.
Police and other emergency services were called to a residence in Aleta Way following reports the 15-year-old male had been injured in an explosion about 6.30pm yesterday, Saturday, June 30.
The teenager suffered a major wound to his hand and arm and was taken to Westmead Children’s Hospital.
"There was one major explosion and the bomb squad did attend and they removed a number of other items which they took to a local reserve where they were detonated safely," Inspector Maureen Deagan said yesterday.
"If these are devices from the railway, then we would be worried that there are others out there."
A NSW Police spokeswoman could not confirm media reports the boy had used a hammer to hit a train detonator.
The detonators are laid on rail lines to warn track workers of approaching trains.
However, the police spokeswoman said several detonators had been stolen recently.
"We are investigating whether these thefts involved young people."
A spokeswoman for the Children's Hospital at Westmead said the boy was in a stable condition last night.
Police are investigating the incident.
Nobody else was injured.
Anyone with information is asked to contact Crime Stoppers, 1800 333 000.