Sixteen people have died of carbon monoxide poisoning following an accident at a coal mine in the southwestern city of Chongqing, Sixth Tone’s sister publication The Paper reported.

The deaths occured Sunday after a conveyor belt at the Songzao coal mine caught fire, giving off lethal levels of carbon monoxide gas, according to the report. A total of 17 workers were trapped in the mine, and only one was rescued.

The survivor, whose health status is unknown, is currently being treated at a local hospital, according to The Paper. An investigation is underway to determine the cause of fire.

A miner working around 40 meters from the accident site told domestic outlet Haibao News that the incident occurred around 1 a.m. Sunday. He said workers were told to evacuate immediately, and a rescue team arrived 20 minutes later.

The Songzao coal mine is located in the city’s Qijiang District and operated by Chongqing Energy Investment Group, a state-run power company. Built in 1958, the mine had hosted a conference on preventing excessive gas limits during drilling around two weeks ago.

During an inspection in June, the coal mine was found to have nine potential safety hazards, according to the Chongqing Coal Mine Safety Administration. As a result, one of its operation sites was suspended.

Mining accidents kill hundreds of people in China each year, but authorities say casualty figures are declining. Last year, 316 people died in 170 mining accidents, marking decreases of 5% and 24%, respectively, compared with the previous year — although there was also a rebound of “large-scale” accidents in 2019.

Editor: Bibek Bhandari.

(Header image: Ambulances are parked near the mine where over a dozen workers died of carbon monoxide poisoning in Qijiang District, Chongqing, September 2020. From @央视新闻 on Weibo)