An official news release said the blast 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.

Another 22 people were injured and 38 trucks and 12 passenger cars were destroyed by fire, the statement from the Zhangjiakou city government said.

“We request that citizens do not go to the site to watch in order to avoid disrupting recovery efforts,” the statement said.

Industrial safety is a major concern in China, where requirements for the storage and transport of chemicals and other dangerous products are often weakly enforced.

A massive explosion in 2015 traced to improperly stored chemicals killed at least 173 people in Tianjin, about an hour east of Beijing.

More recently, 52 people were sickened when around 7 tons of the common chemical additive C9 leaked while workers were loading barrels onto a ship in Fujian province on Nov. 4.

While the Communist Party authorities emphasize improvements in industrial safety, they remain extremely sensitive about the potential for social unrest. Over recent years, grassroots movements have brought thousands onto the streets in cities across the country to protest plans for chemical plants, garbage incinerators and other projects deemed harmful to the environment.

In the C9 leak case, police staged a late night raid on the hotel room of a reporter writing about the accident for one of China’s most respected business media groups. The officers, who said they were conducting a routine inspection, departed after conducting a search, but footage of the raid was leaked online, prompting the local police department to issue a rare apology.