(Reuters) - Excessive carbon monoxide levels at a mine in Chongqing have trapped 23 people underground, China's official Xinhua news agency reported on Friday, in the second such accident in the southwestern municipaly in little over two months.
The incident occurred at the Diaoshuidong coal mine at around 5 p.m. local time (0900 GMT) on Friday, Xinhua said, adding that the local police and fire departments immediately lodged rescue efforts, while the cause is under investigation.
Mines in top coal producer China are among the deadliest in the world. In late September, 16 people were killed when high carbon monoxide levels trapped miners at Chongqing's Songzao coal mine.
Diaoshuidong is a high-gas mine with annual production capacity of 120,000 tonnes of coal, according to Xinhua, which added that the mine was built in 1975 and has been run as a private enterprise since 1998.
In 2013, three people were killed and two people were injured at the mine in a hydrogen sulphide poisoning incident, the news agency said.
(Reporting by Tom Daly, editing by Louise Heavens)