Arsonist - Bronze Trophy
Kill 3 enemies in a single propane tank explosion.
Ok this is pretty self explanatory. Where I got the trophy was in The Shallows, in between the 2 spawn points of the area tucked away in the corner under a makeshift garage/shed area, there is usually a propane tank that spawns there but not always, though it seems to be the most common place I've seen them. Once in hand the best way would be to gather 3 walkers and kite them around. Attempting this later in the game makes it slightly easier since more walkers will start to spawn unless the radio states otherwise. Once you have 3 or more enemies, just drop it on the ground and shoot it with any firearm. I did it standing directly over it to make sure I got it. Yeah I died as well but death has no real consequence in this game as you can just go get your stuff back or reload last save, you won't lose anything.