A factory explosion in the Russian city of Dzerzhinsk has injured 79 people and damaged 180 homes nearby....Most of the people who were hurt were cut by flying glass from the explosion, which also caused a shockwave that smashed windows in homes and other factories in the city...Dzerzhinsk city officials have declared an emergency in the surrounding areas, while the Investigative Committee of Russia says it has launched a criminal investigation into potential safety violations at the plant.