Something went wrong, please try again later. Invalid email Something went wrong, please try again later. Clouds of toxic chlorine gas were released into a public swimming pool in a "deliberate attack" that has left 25 people poisoned. Investigating officials believe, however, that the poisoning was due to pool workers miscalculating the amount of chlorine needed to sterilise the pool. (Image: Newsflash)Their miscalculations since led to a massive overdose that, according to local media, led to a toxic chlorine gas rising from the waters, effectively poisoning the swimmers.