Leaks in the fuel system are the most common cause of vehicle fires, so that's why they take the top spot on our list [source: Chandler Law Group]. As we've already seen, any number of complicating factors can cause a fuel leak, but they're tricky because fuel leaks can also arise on their own and with very little warning. A fuel system leak is really dangerous. We've already discussed that a lot of a car's fluids have corrosive, poisonous and flammable properties, but gasoline is among the worst. Gasoline at a temperature of just 45 degrees Fahrenheit (7.2 degrees Celsius) or above can quickly catch fire from a simple spark. It happens all the time in a running car, after all, but it's contained by the engine. And gasoline that reaches 495 degrees Fahrenheit (257.2 degrees Celsius) will ignite by itself. It's easy to see how fuel dripping onto hot metal and plastic parts can cause a fast-spreading fire. The best way to reduce chances of a fuel system fire is to make sure the car is properly maintained and to keep it out of the situations we've already described. And if you ever smell gas in or around your car, find and fix the leak immediately!