Police are seeking the owner of a fireworks factory, where an explosion Wednesday killed nine workers and injured 21 others in central China's Henan Province.

Police in Luohe City said Thursday they were seeking Tian Baoshan, 54, a native of Laogongtian Village, where the factory was located.

From the outside, a corner of the factory wall at the Yutian Fireworks Plant could be seen to have collapsed after the blast at about 4:50 p.m..

The injured were taken to a public hospital in Luohe city.

Villagers said minor firework blasts occurred in the workshop throughout the night.

The privately-owned plant had valid production licenses and was surrounded by cornfields, and away from village homes.

Fireworks are a major product of the Liji township, which administers the village. The township has seen three fireworks factory explosions in the last 10 years, but the latest blast was the worst in terms of casualties.

China's Spring Festival, the Chinese lunar New Year, which falls on Feb.3, usually brings a seasonal boom in firework sales.