A vinyl chloride leakage caused the explosion that happened early on Wednesday near a chemical factory in Qiaodong District, Shijiazhuang City in north China's Hebei Province, authorities confirmed at a press conference on Friday.

The explosion occurred at 0:41 a.m. local time on Wednesday when a leak in a vinyl chloride gasometer got ignited, causing an explosion near the factory, according to the local government.

The incident killed at least 23 and injured 22 others. The injured have been treated and are in a stable condition. Four of them have been discharged, authorities said. 

The investigation into the cause of the leakage and other details is still ongoing.