Investigators have blamed illegal production, as well as the use of the wrong chemical, for Saturday's explosion that killed six people and injured nine at a fireworks plant in southwest China's Guizhou Province.

The plant, in Zhenfeng County in Buyei and Miao Autonomous Prefecture of Qianxinan, had used potassium chlorate, a banned substance, in fireworks production, said Ju Rong, deputy chief of the provincial work safety administration.

The Chinese government banned the use of potassium chlorate in fireworks in 2006, and demanded all manufacturers use potassium perchlorate instead. Yet some profit-driven manufacturers still use potassium chlorate, which is more sensitive and explosive but cheaper by 50 percent, said Ju.

He said police are now looking for potassium chlorate suppliers in the county. "Many farmers cannot tell apart the two substances, both are white powders and are very much alike."

The official said Bi Zegang, owner of the illegal plant, was also killed in the accident.

Local police said Bi, a peasant of Zhenfeng County, had criminal records for illegal fireworks production and his wife was killed in one of the previous explosions.

Investigators said Bi employed only five people, but a group of villagers dropped by at his plant Saturday afternoon on their return trip from a marketplace in town.

Fireworks have a longstanding tradition in China's Spring Festival, which fell on Jan. 26 this year.

Explosions at nationwide fireworks plants have killed at least 30 people since production mounted in the run-up to the holiday, according to the State Council Work Safety Commission.

(Xinhua News Agency February 9, 2008)