An explosion at a polyvinyl chloride plant in northern China killed four people and injured dozens of others, according to government reports. The accident took place at the Yushe Chemical Industry complex. In operation since the 1970s the plant has capacity to produce 400,000 tpa of PVC from coal-derived acetylene. The acetylene is generated by hydrolysis of calcium carbide, which is in turn produced from lime and coal-derived coke. China produces most of its PVC via the acetylene process because coal is abundant in the country.