The death toll from Thursday's firework plant explosion in the central province of Hunan rose from ten to 13, an official said today.

Four other workers were injured, including one in danger, said Wu Guanbao, an official with the provincial production safety supervision bureau.

"This is the most serious firework production accident so far this year in the province," Wu said.

Li Huashan, director of the Anhua work safety supervision bureau, told Xinhua News Agency that the blast occurred at about 5:00 PM in Yiyang City, one of the country's fireworks production centers.

One explosion in one workshop set off further blasts in another six at Jiangnan Fireworks Plant, leaving approximately 500 square meters of devastation.

Li said there are 17 firework plants in Anhua, eight of which have already been closed for safety reasons.

An investigation into the cause of the accident is underway.

(Xinhua News Agency September 16, 2005)