Six people were killed and 10 injured after a fireworks plant exploded Wednesday afternoon in north China's Hebei Province, local authorities said Thursday.

The explosion occurred at about 2:40 p.m. in Fuguishan Fireworks Plant in Fengning County, Chengde City. The casualties were all local villagers, according to a spokesman with the county's publicity department.

The injured were taken to a local hospital, one of them?was in critical condition, he said.

Song Huanwen, who contracted the village-owned plant, was on a business trip when the explosion occurred, he added.

The plant is a legal enterprise with more than 80 employees. No residential buildings were damaged in the explosion as they are hundreds of meters away from the plant, the spokesman said.

Police were investigating the cause of the explosion. But initial investigations showed that it was caused by human error, the spokesman said.