Dharmalinga Raja (70) succumbed to burns at the Government Rajaji hospital at Madurai today, police said.
The condition of three injured was stated be serious.
The fire broke out at the unit yesterday when the workers were stacking "dried fireworks sticks".
Friction while stacking these caused the blaze, police said, adding that the unit owner Azhagesan and foreman Muthiah, against whom police have registered a case, are absconding.
