Initial investigation revealed that the blast could have occurred while packing the explosives.
The death toll in the fire and subsequent explosion at the private explosives-manufacturing unit in the district has been roughly estimated at 19, police said.
The explosion was so intense that large blocks of concrete were strewn up to 50 metres from the site and it was difficult to identify and count the bodies.
The toll was "roughly estimated" at 19 from the missing list given by relatives of workers, Revenue and police officials said.
The muster roll of the company was being verified to ascertain how many workers were present at the time of explosion and to confirm the total number of deaths.
Local government hospital officials said that out of the total 19 bodies, some parts of bodies had been received for post-mortem.
Eight of the injured workers admitted in the hospital were in a serious condition and they were being treated at the intensive care unit of the government hospital.
District Collector Palanisamy said an investigation would be conducted by the Controller of Explosives and officials from the Labour Welfare Department.
Initial investigation revealed that the blast could have occurred while packing the explosives.
"Either the workers would have applied more pressure (while packing) or mixed the chemicals in wrong proportion," a Senior official of the Explosives Department said.
All the victims who succumbed to the blast were employees of the explosives factory at Murugampatti, about 50 kms from here.
Though local people wanted the factory to be closed permanently, the Collector said he had not received any request with this effect.
Explosives experts were camping in the factory to defuse unexploded gelatin sticks, if any, in the factory.
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