Don't do it! Gasoline probably will not kill the entire colony much of the time, it is dangerous to handle, it kills any plant material it touches, and at least some of the residue remains in the soil and may leach or run off into ground and surface water. The gasoline is highly repellent to the ants, and is likely to cause the colony to relocate. There have been instances where burning a fire ant mound has led to burning a house. See also FAQ #1107, "Do any of the home remedies for imported fire ants work?"