Damage type: Chemical.
Unlocked at: Rank 12.
Price: 2500 for 5 Gas Bombs.
Time needed to explode: 2 seconds.
Explosion radius: 7m.
Other stuff: The gas cloud stays for 6 seconds, and it does 8 damage per frame to zombies on the gas cloud. There's also 40% chance of the zombie getting poisoned, taking 5 damage per second; and 1% chance of the zombie's virus geting affected by the gas, thus making it attack other zombies (This can't happen to bosses or the Turrets from Power Out). Both status effect will last after never. The status can only be caused by the explosion.