Fire
Fires can be started either by using a molotov cocktail or by leaving an oven on for too long. Fire will attract zombies to the location of the flames. The fire will burn down structures and will burn zombies/survivors to death. Generally, zombies take slightly longer to kill with fire than a survivor but is not immune to it. If the fire touches a wall or any other flammable structure, the structure will eventually burn down.
Once the fire is set, it is very likely that the fire will start spreading and will do so if there is something to spread on. The fire can spread on includes survivors, zombies, and structures, which in turn look for even more things to spread across. Once the fire has nothing to spread across for a few dozen in-game minutes, the fire will eventually die out.
As of the current version, there is no way to manage fire or to even prevent a character from burning up should he or she catch on fire. Therefore, it is especially important to take caution when utilizing fire since quite often, since fire is likely to engulf the starter as well as the target.