An official news release Wednesday said the explosion occurred just after midnight at a loading dock next to the plant operated by the Hebei Shenghua Chemical Industry Co. Ltd. The plant is in the city of Zhangjiakou, which is to play host to the 2022 Winter Olympic Games.
It injured 22 other people and destroyed 38 trucks and 12 passenger cars.
Industrial safety remains a major concern in China, where requirements for the storage and transport of chemicals and other dangerous products are often not strongly enforced.
An explosion in 2015 traced to improperly stored chemicals killed at least 173 people in Tianjin, about an hour east of Beijing.