A blast near a chemical plant in Zhangjiakou city, in north China's Hebei province, has killed 22 and injured 22 others early Wednesday morning, local authorities said.The blast occurred near Hebei Shenghua Chemical Industry Co., Ltd. in Zhangjiakou at around 0:40 a.m. local time. Fire caused by the blast has engulfed 38 trucks and 12 vehicles, according to the sources from Zhangjiakou city government, Xinhua news agency reported.The injured have been rushed to hospitals. Further investigation is underway.