An explosion at the Yibin Hengda Technology chemical plant in an industrial area southeast of Chengdu on Thursday afternoon.
The blast killed at least 19 people and injured 12 others.
The fire, which broke out as a result of the explosion, was extinguished at 23:30 local time.
Authorities in Jiangxi County said it had not yet been determined what caused the blast.
However, the causes are being investigated, while the injured are in stable condition in the hospital.