Sixteen people were killed in a coal mine due to excessive levels of carbon monoxide after being trapped underground in southwest China, according to local authorities.
The incident happened when a conveyor belt at the mine caught fire, producing excessive levels of carbon monoxide and trapping 17 miners underground.
Sixteen deaths have been confirmed following the conclusion of rescue operations on Sunday afternoon. The 17th person is in critical condition, and medics are fighting to rescue the individual, a municipal Government statement said.
According to Chinese regulation, the concentration of carbon monoxide underground must not exceed 0.0024%.
Exposure to high concentrations of carbon monoxide would kill a person in minutes.
Symptoms of carbon monoxide poisoning include dizziness, weakness, shortness of breath and difficulty breathing.
The cause of the accident is still under investigation.
In December 2018, seven miners were killed in Chongqing after the connecting segment of a skip broke and fell down a shaft.
The Songzao Coal Mine is owned by state energy firm Chongqing Energy and is the largest coal mine in the city.