At least 18 people have died in a coal mine in Chongqing, south-west China, following a carbon monoxide leak, state media reported on Saturday.
One survivor was successfully recovered and rescue operations remained ongoing, official broadcaster CCTV said.
Twenty-four miners were trapped underground in the Diaoshuidong colliery in Yongchuan District at about 5 pm (0900 GMT) on Friday.
Work was underway to dismantle and remove equipment from the mine, which was suspended and shut down two months ago, according to news site The Paper.
Authorities were investigating what caused the deadly leak.
China’s mines are known for being among the world’s most dangerous. Thousands died every year in accidents throughout the 2000s as rapid, unregulated expansion fuelled China’s economic boom.
In 2003, the death rate per million tons of coal mined in China was 130 times higher than in the United States and 250 times higher than in Australia, according to the World Investment Report.
The number of accidents and fatalities has fallen consistently since then, due largely to the closure of small mining operations and falling demand for coal, according to the China Labour Bulletin.
Sixteen people died of carbon monoxide poisoning at the Songzao coal mine, also in Chongqing, in September. The deaths occurred after a conveyor belt caught fire, releasing lethal levels of the gas. Only one miner was rescued.