The six-year-old child who died in the blast at a factory in West Delhi's Moti Nagar on Thursday had come to meet his mother, who worked there, according to a survivor of the deadly mishap that claimed seven lives.

Hanshu and his father had arrived at the paint-coating unit half an hour before a cylinder explosion levelled the three-storey structure. "The child was crying at home, so his father brought him to his mother," said Ashok, one of the eight injured victims.

The boy and his father Rajesh died in the blast, while his mother Manju is among the injured. She is yet to be told about the death of her son and husband, said sources.

Recounting the horror from his hospital bed, Ashok said he was lucky to have survived the mishap. "I was going down the stairs to pick a cylinder from the ground floor. There was a thunderous boom and I was hit by a collapsing wall."

Eyewitnesses said many working or putting up at a scrapyard immediate next door were among those buried under the debris. "Machines were running on the ground floor and parts of ceiling fans were being painted on the first floor at the time," said Ashok.

Among the dead was Sanjay Pratap who was working on the first floor. His brother Gangesh who was on the ground floor sustained serious injuries, said their uncle Mahender. "Gangesh was working there for the past three years. He used to make fan blades. Sanjay had joined the factory two months ago," said Mahender.

Gangesh was unconscious after the incident. Mahender said, "When he regained consciousness, he first inquired about his brother Sanjay."