At least 22 people were killed and another 22 wounded after an explosion in Zhangjiakou city in China’s northern Hebei province on Wednesday morning, AFP reported. The province, along with capital Beijing, will host the 2022 Winter Olympics.

The injured were taken to a hospital for treatment, said the local propaganda department on its Weibo social media account.

The incident took place at 12.41 am local time, 10.11 pm Indian time on Tuesday. The blast near the Hebei Shenghua Chemical in Zhangjiakou, located around 200 km from Beijing, caused a fire that burned 50 trucks of different sizes.

The department’s statement did not clarify whether the explosion occurred in the factory or outside. “On-site search and rescue work and investigation of the cause of the accident are still under way,” it said.

But a spokesman at ChemChina, the firm that owns Hebei Shenghua, said that the blast did not take place at the factory, Reuters reported.

An unidentified local safety production supervision official said the accident was caused by a hazardous chemical transport vehicle that exploded while waiting to enter the factory and ignited surrounding cars, the People’s Daily reported.

According to state media, all fires at the blast site were extinguished and an investigation is underway.

Industrial accidents are common in China. An explosion at a chemical plant in southwest Sichuan province killed 19 and injured 12 in July. In November last year, two people died and 30 were injured after a powerful explosion at a factory in Ningbo city in Zheijiang province.

In 2015, chemical blasts in a container storage facility killed at least 165 people in Tianjin city in the north.