Imran (36), resident of Farukh Nagar was killed, while injured Umesh (18) has been admitted at GTB Hospital in New Delhi for treatment, DSP Anil Kumar Yadav said.
"The explosion that occured around 8 am was so powerful that the entire building collapsed," he said, adding it took two fire tenders to douse the fire.
"Investigation reveal that factory was licensed and only two persons were present during the incident. One of them lighted his cigarette and possibly threw the burning bud inadvertently somewhere inside the godown where explosives were kept," District Magistrate Nidhi Kesarwani said.
Police have lodged an FIR under section 304 of the IPC against the factory's owners Iqurar, Ishtekar and two managers Naeem and Abrar.
"They are absconding and will be nabbed soon," the DM said, adding several illegal factories have also been sealed in Farukh Nagar which is the main hub of firecrackers manufacturing.