An explosion at a chemical plant in China has killed 19 people and injured 12, authorities said on Friday, the latest deadly industrial incident in the world's largest producer of chemicals.

It comes amid a drive to strengthen industrial safety, with China ramping up checks over the last year, in the wake of some high-profile incidents at coal mines and chemical plants.

The cause of Thursday evening's blast at Yibin Hengda Technology in an industrial park several hours southeast of Chengdu, the capital of the southwestern province of Sichuan, is not yet known, the local government in Jiang'an County said.