Firefighters hampered

The sequence of explosions hampered efforts by firefighters to extinguish the blaze, which eventually spread over more than 10,000 square metres, Xinhua added, quoting firefighters at the scene.

"With explosions continuing and a fire raging, it is quite treacherous for rescuers, since there are huge hidden dangers amid the blasts, along with leaks of toxic gases such as ammonia and formaldehyde," Xinhua said.

The plant, owned by the Guangxi Guangwei Chemical Company, mainly produces polyvinyl acetate, calcium carbide and vinyl acetate monomer - chemicals used in making paints, adhesives and coatings, Xinhua said.

The cause of the blasts was still being investigated, and it was not immediately known how many people were in the plant when the initial explosion occurred, the report added.