The blast occurred at around 8:38 p.m. at the synthetic ammonia production line in the Hubei Yihua Chemical Industry Co., Ltd. based in Yichang City, according to an official with the local government.

Initial investigation showed that the blast was caused by gas leak, the official said.

One person was seriously burnt, and 22 others were cut by broken glasses. All the injured have been hospitalized.

The powerful blast smashed all glasses of buildings within 50 meters.

The company, one of China's carbide providers, specializes in the production and sale of fertilizer and chemical products.

Operation of the blast-hit workshop has come to a stop. Investigation into the accident is underway.