The 25-year-old explosives factory manufactured gelignite sticks used in water wells. A fire engulfed the building, triggering the explosion.
An blast at an explosives factory in India killed up to 15 people and injured three more on Thursday morning, local emergency department officials said.
Rescue workers recovered two bodies from the building and were searching for 13 missing people in Tiruchirappalli, a city in the southern state of Tamil Nadu. The team used bulldozers and drills to search for survivors in the burnt-out building.
"The building has been completely destroyed by the blast," local police officer Manoharan, who uses only one name, said by phone from the scene.
The fire of unknown cause engulfed the gelignite factory, triggering an explosion.
"We fear 15 have died. There were 18 workers inside the factory, but we are hearing that three had left before the blast," local official G Sathyanarayanan told AFP.
"Up to 18 people were inside the building at the time of the blast."
Authorities were investigating the cause of the fire in the 25-year old factory, which manufactured explosives for deepening and widening water wells in the rocky region, according to the Press Trust of India.
Tiruchirappalli is 325 kilometers (200 miles) south of state capital Chennai.
Fatal accidents are common in India's factories, which are often unregistered and unregulated. Last month a fire in a garment factory killed 13 workers in New Delhi.
aw/kl (AP, AFP, dpa)