Five persons, including the owner of the unit, died on the spot while two other succumbed to burns at a hospital, District Superintendent of Police Aswin Kotnis said.
Six persons who suffered serious injuries were undergoing treatment at different hospitals, he told PTI.
Five of the deceased, including the owner, were women.
The victims were involved in making fireworks when the mishap occurred at the unit at Parakallur, 42 km from here. The intensity of the explosion was so powerful that the entire godown was razed to the ground.
Range DIG Sanjay Kumar visited the spot, police said, adding that a probe has been ordered into the incident.
The unit used to make fireworks largely for their use in temple festivals in the region.
On September 5, 39 people were killed in a devastating blaze at a fireworks manufacturing unit near Sivakasi, the national hub for crackers in Virudhunagar district.
