Six people were killed and five injured from carbon monoxide poisoning while working in a coal mine in Guizhou province, local authorities said Friday.

The accident happened around 7 p.m. Thursday in Yanghe Coal Mine in Daguan township of Qianxi county, when 64 miners were working underground.

Fifty-eight miners, among whom five were injured, managed to escape the mine. The six trapped miners were found dead by rescuers early Friday morning, according to the safety supervision bureau with the local government of the province.

The five injured, who are not in serious condition, are being treated in hospital. The cause of the accident is under investigation, rescuers said.