The ammonia gas leakage was spotted at the cold storage of the factory, located in densely populated Badami Bagh area. Soon after the spread of the gas the factory workers and residents of the adjacent houses started falling victim to it.
More than 150 people fainted due to gas leakage. The Rescue service was called in which shifted the affected people to Mayo Hospital where the condition of three children is stated to be critical, police said.
Three people have been arrested in this connection, police said.
Meanwhile, the residents blocked the road for several hours demanding action against the factory owners and city government officials. They also demanded shifting of the factory from the residential area.
Earlier this month, 46 workers were killed and over 100 injured when the four-storey building of the polyester factory was collapsed in Sundar Industrial Estate of Lahore.