The explosion took place in a village in Wenzhou city's Ouhai district in east China's Zhejiang province yesterday and fire raged in an area of 200 to 300 square metres after the explosion, rescuers said.
Fourteen persons were injured in the incident of which the condition of five was stated to be serious.
Local government of Ouhai District said that the workshop was illegal and was focused on polishing and processing hardware locks, state-run news agency Xinhua reported.
The explosion took place after the thick dust in the workshop was ignited by the sparks from the polishing machine, officials said.
