What can ignite gasoline vapor?

Gasoline vapor can ignite when exposed to sources of ignition, with lighters and open flames being two primary examples. The reason that lighters or open flames are particularly dangerous is that they produce a significant amount of heat and a direct flame that can easily ignite gasoline vapor, which is highly flammable. Gasoline's flashpoint is low, meaning that it can produce vapors that are capable of igniting even at relatively low temperatures when exposed to such ignition sources.

Open air alone does not ignite gasoline vapor; it can help disperse vapors but does not provide an ignition source. Similarly, while electrical devices have the potential to ignite flammable vapors, not all electrical devices do so. Cold temperatures do not ignite gasoline vapor; in fact, they can reduce the volatility of the gasoline. Thus, the presence of a source capable of producing heat or an open flame, such as a lighter, is what directly leads to ignition.