At least three people were killed when an explosion went off at a chemical plant in north China\'s Hebei Province Tuesday morning, police said. The incident took place at Kaer Chemical Plant in Zhaoxian County, vice chief of Shijiazhuang public security bureau Cheng Weiqing said. The blast flattened one of the factory\'s workshops and broke window panes within a radius of 2,000 meters, Cheng quoted witnesses as saying. Tremors were felt in at least three villages near the plant, China\'s News Agency (Xinhua) reported.