Two people were killed and another person injured following an explosion at a firework plant in east China's Shandong Province, Xinhua quoted local police as saying. The explosion was so strong it knocked down the four-room facility in Tancheng County. Police recovered the bodies of two female workers, aged 57 and 59, on the scene. They were from different villages in the county. Another villager working in nearby cornfield was injured. The person is in stable condition and under medical treatment, said an official with the county's work safety bureau. Police said the firework plant was illegal. An investigation into the cause of the explosion is underway. Another illegal firework plant exploded on Sunday in a village in the southern Guangdong Province. Four people, including a 4-year-old boy, were killed and two others injured.