Two workers were killed and three injured after a boiler blast in a food company in northwest China's Ningxia Hui Autonomous Region, Xinhua quoted hospital sources as saying. A boiler in Yishunzhai Food Co. Ltd in Yongning County exploded at around 9:40 a.m. Friday when workers were debugging it. Two were killed at the scene while three were injured. The three were rushed to a hospital in Yinchuan, the regional capital, for emergency treatment. One of them suffered serious burns but had no life dangers, a nurse said. The cause of the incident was still being investigated.