Three workers were killed in an explosion in a fireworks factory at Konampatti in Tamil Nadu, police said.
The blast occurred on Thursday when the semi-trained workers were stuffing a chemical mixture into the fireworks. The impact flattened the shed, they said.
While two of them died on the spot, crushed by falling debris, another worker was seriously injured and died at the government hospital at Sivakasi on Thursday without responding to any treatment.
The factory manager and two foremen have been arrested, while the owner is absconding, police said.
Officials said the handling of chemical mixture required skill and training, which the workers probably did not receive leading to the accident.
This is the third accident in fireworks units in April.
Two workers died of injuries sustained in an explosion at a unit at Kundalapatti near Sivakasi on April 20, while a third died in a blast at a unit at Sundararajapuram on April 16.