Gas can

Gas cans, also known as fuel or petrol cans; can be found throughout the game. They can be picked up with the Use key (default: "E" for PC; "X" for Xbox 360) and release flames similar to a Molotov cocktail when shot. A player can not shoot while holding a gas can, but can still melee. There is no inventory space for this weapon, so the only method of transporting it is to pick it up and carry it. These cans are usually found around crescendo events and the finale. They are used to set up traps and provide a strong defense during large Horde attacks. Strangely, the gas tank makes the same sound of glass shattering that the molotov does when ignited.

Tactics

 * The gas tank has a wider area of effect than the molotov cocktail, making it more effective for large choke points and wide open spaces.


 * If placed before a showdown or event, the gas tank can be significantly less dangerous than thrown weapons. Due to lag or confusion, a molotov cocktail and pipe bomb can land in close proximity to the survivors, making them a detriment and sometimes forcing the survivors to abandon their preferred choke point.  The gas can provides a safe weapon that can be set of from a distance with no risk of accidental targeting.


 * The gas tank can be carried from level to level if it is brought into the safe room. If you find a gas tank near the end of the level, it might be more valuable to save it for the next level than waste it (Campaign and single player only, not versus).


 * While it is often better to drop the gas can for hordes, small groups and single common infected can be killed with the melee attack of the gas tank. This means it can often be carried much further than most people think.


 * The fire from the gas can doesn't normally burn in water, but has been known to burn in a few bodies of water.


 * The gas tank cannot be damaged while being carried, so dont worry about friendly-fire killing everyone. But note, as soon as the tank is dropped, it is damageable again, leading to events just as bad as being shot while you're carrying it.


 * if a gas can catches on fire it may be possible that you can pick it up and drop it without it blowing up


 * You can use the gas can to get the "Burn the Witch" and "Towering Inferno" achievements, despite the fact both achievements say you need to use a molotov.

Survivor Tactics
In the finales of levels you will often find Propane tanks and Gas Cans. It's best to drop them in choke points where you know the zombies will come from, and then detonate it with a Hunting Rifle shot. Beware of its large area of effect - don't get caught in it. It is also very effective against tanks. Place the Gas Can, and then wait for the Tank to get near it and shoot the can, setting the Tank on fire for a sure kill. A well placed gas can can mean the difference between life and death on finales on Advanced/Expert. It should also be noted that when thrown, rather than dropped, it will bounce and won't roll in a straight line, meaning it may not reach its intended point. It is therefore usually best to drop it on the spot you want it. You can also use one of these to cover your back during a panic event.

Infected Tactics

 * Gas cans, in addition to propane tanks and oxygen tanks, give a clear signal of where the survivors expect infected to come from. you can use this to your advantage by spawning or moving to areas that are in opposite directions of these weapons.
 * Another strategy as the infected is to light yourself on fire as the hunter and pounce the survivor holding the gas can. The pounced survivor will drop the gas can, which will ignite on contact with your flaming body, dealing even more damage to the pounced survivor and making it extremely difficult for other survivors to melee you off or save the other survivor if they become incapped.
 * If you're playing as a smoker, one strategy is to position yourself on one side of the flames and drag a survivor through it.