An explosion tore through a chemical factory in northern China, killing five people and injuring another 18, the official Xinhua News Agency said Saturday. The blast occurred Friday afternoon at the Cangzhou Dahua TDI Co. Ltd. in Cangzhou, a city in Hebei province, Xinhua said. The cause was under investigation, it said. Some 2,000 residents of a nearby village were evacuated because officials feared a possible toxic leak, but they returned home by evening, Xinhua said. Most of the houses in Dazidian village, were damaged, it said.