BEIJING—A gas explosion at a coal mine in southwest China has killed 19 miners and trapped dozens more, state media reported Thursday.

The Xiaojiawan coal mine in Sichuan province's coal-rich Panzhihua city exploded Wednesday evening with 152 miners inside, Central China Television said.

Rescuers recovered the bodies of 16 miners who died from carbon monoxide poisoning, CCTV said.

Three other miners died at a hospital after being pulled to the surface, CCTV said. It did not provide details on the cause of death of those miners.

CCTV said 28 miners remained trapped.

The mine is owned by Zhengjin Industry and Trade Co. Ltd. and the owners are in police custody for investigation, the Panzhihua city government said in a statement posted on its official microblogging site.

Coal mine accidents are common in China, where work safety rules are often ignored. Last year, 1,973 miners were killed in coal mine accidents in the country, but that was down 19 percent from the previous year as authorities continue to beef up safety measures.

The State Administration of Work Safety said last week that it planned to close more than 600 small coal mines—considered more dangerous than larger mines—this year to further reduce fatalities.