The blast ignited other vehicles, leaving charred and smoking remains of trucks and cars scattered on a road as firefighters worked at the scene, according to images posted online by state media.
A sources told he heard a “very loud bang” after midnight and saw a field and trucks engulfed in flames outside the Hebei Shenghua Chemical Co. factory in Zhangjiakou, a city some 200 kilometres 124 miles northwest of Beijing.
The side of a building was covered in soot in front of a row of burnt out trucks across the road, footage broadcast by CCTV showed following the latest deadly incident to hit a factory in China.
The blast damaged 38 trucks and 12 cars, the local publicity department said .
The injured were taken to hospitals for treatment following the blast at 00:41 am.