What factor can increase the probability of ignition in a fuel spill?

The presence of sparks from friction or electrical components significantly increases the probability of ignition in a fuel spill because these sparks can provide the necessary energy to ignite flammable vapors. When fuel spills onto a surface, it releases volatile organic compounds that produce flammable vapors. If there are any sources of ignition nearby—such as electrical sparks from malfunctioning equipment or friction created by moving parts—these can ignite the vapors and lead to fire or explosion.

While factors like temperature of the spill, wind speed, and the presence of water do play a role in fire dynamics, they do not directly provide a means of ignition like sparks do. Higher temperatures can indeed increase the volatility of fuel, and wind can disperse vapors or supply oxygen, but without an ignition source like sparks, a spill may not ignite even under favorable conditions. Water's presence can sometimes inhibit ignition or suppress fires, especially if used as an extinguishing agent, but it does not inherently increase the risk of ignition.