The injured included a one-and-a-half-year-old child who had come there with his mother.
All the injured have ben admitted to government hospital.
It was feared that more persons could have trapped in the debris and the blaze which was caused due to the explosion, police said.
In a similar explosion at a cracker manufacturing unit in Narayanapuram village in the district, the country's fireworks hub, last month, eight persons were killed and three sustained burns.