According to BDL, a defence PSU, the incident occurred when a small quantity of "waste explosives" went off while being disposed as a routine practice in a burning pit at the premises, resulting in injuring four persons there.
Four persons suffered burn injuries in the incident and condition of one of them is stated to be critical, Assistant Commissioner of Police (Santosh Nagar) Mohd Ashfaq, told PTI.
"Four persons were injured. All of them are being treated at Apollo DRDO Hospital. Best of treatment is being given," an official release issued by BDL said.
He said as per preliminary information, it was an accidental blast that occurred when the "waste explosives" were disposed, which is a regular process.
The BDL statement said that the burning pit is one km away from production facilities.