UP's Hapur witnessed a massive blast out on Sunday where a boiler blasted in a chemical factory. This horrifying incident took 12 lives. Gunpowder used in manufacturing toy guns could be the reason behind the blast at a chemical factory in UP's Hapur, in which twelve people were killed and 20 injured after a boiler exploded on Saturday, June 4, said sources. The explosion was so strong that its sound was heard 10 km away. Watch this video to know national news.