Ma Mintang, survivor of the gas outburst, receives treatment in Renmin Hospital of Anshun City, southwest China's Guizhou Province, May 14, 2010. A total of 31 miners were working in a shaft of Yuanyang Colliery in Puding County of Anshun City when a gas outburst occurred at about 9:40 p.m. on Thursday. Rescuers on Friday confirmed that 10 people survived and 21 bodies recovered from the coal mine. Photo: Xinhua

A toxic gas burst during an illegal coal mining operation has killed 21 people and injured five others in southwest China's Guizhou Province Thursday, officials said Friday.

A total of 31 miners were working in a shaft of Yuanyang Colliery when the accident occurred at about 9:40 p.m. in Puding County, Anshun City. Rescuers on Friday confirmed that 10 people had escaped.

The gas burst was triggered by the detonation of explosives for illegal mining, the rescue headquarters said after an initial investigation.

The private mine, a combination of three minor collieries, began to improve its infrastructure facilities in 2008 when it received the first of the six necessary mining licenses from the local authorities.

Mining was prohibited until the mine passed inspections by authorities and gets the other five business licenses, but the company secretly started mining last year under the guise of shaft maintenance, said Hu Yingze, director of the county coal mining administration.

It had illegally produced more than 3,000 tonnes of coal so far, which was, in fact, theft of national resources, he said.

Sun Guoqiang, vice governor of Guizhou, blamed county-level authorities for failing to examine the mine.

"Did anyone of you visit the mine after approving the shaft maintenance project?" Sun asked officials of the county's coal mining administration and work safety watchdog.

Rising coal prices had driven the owners to start illegal production as the drought season cut short water supplies for power plants, which had to turn to coal. The market price for coal had risen to about 370 yuan ($54) per tonne from the normal price of about 300 yuan, said Sun.

Ma Shilong, survivor of the gas outburst, receives treatment in Renmin Hospital of Anshun City, southwest China's Guizhou Province, May 14, 2010. Photo: Xinhua

Local authorities did not fully perform their duties, and occasionally even abetted or sheltered illegal activities, said Wang Shuhe, deputy director of the State Administration of Coal Mine Safety, who arrived at the site in the evening to investigate the accident.

Five county-level and township officials, including Wu Guohong, vice head of Puding, Xu Dongfeng, director of Puding's work safety supervision administration, and Hu Yingze, were sacked or were suspended Friday pending an investigation.

Li Renjie, the mine owner, had disappeared after the accident and the police were searching him.

Puding has ordered operations suspended at all collieries and Guizhou will launch a safety survey of coal mines on Saturday.

Five of the 10 survivors are in hospital being treated for carbon monoxide poisoning.