Two police constables were injured when they went to investigate a cylinder blast site at Begumpur in Rohini.
The incident took place around 11.30 am on Saturday when the constables had gone to a local gas agency in the market to investigate a cylinder blast.
Eyewitnesses told police the when the two policemen were investigating the first blast, a fire broke out which caused another blast inside the shop.
Three fire tenders were rushed to the spot and took more than an hour to bring the fire under control. Police said the two constables, Jitender and Sandeep, were standing on the terrace of the shop when the second blast occurred.
The two were rushed to the nearby Sanjay Gandhi memorial hospital and were discharged after first-aid, police said.
Investigating officers said the owner of the agency had stocked around 30-40 cylinders in his shop. Police are unsure as to how the fire started.
An officer said several small LPG gas cylinders were also found in the shop. Locals have told police that the owner refilled LPG in small cylinders and sold it. Police are verifying this.
“We are probing to see if the fire was caused when the employees of the shop were refilling gas in the small cylinders, which is illegal. We are in the process of registering an FIR,” an officer said.