Photo taken on Jan 14, 2016 shows the explosion site in Tongxu county of Kaifeng city, central China's Henan province. The number of victims killed by an explosion in an illegal fireworks plant in Henan on Thursday rose to ten. Another seven are injured and under medical treatment in the hospital. [Photo/Xinhua]

ZHENGZHOU -- The death toll has risen to 10 in an explosion at a fireworks plant in Central China's Henan province on Thursday.

Another seven injured people, including five with critical injuries, are being treated in hospitals.

Authorities have placed the person responsible for the blast under control.

The blast occurred at 10:48 a.m. in Tongxu County, the local work safety authority said.

The cause of the blast is still being investigated.