There is no single evaporation rate for gasoline because the rate varies based on additives in the gasoline and the environmental conditions where it is stored. In an open container at room temperature, the volatile components of gasoline begin to evaporate immediately.
Avoid evaporated gasoline whenever possible. Gasoline irritates the lungs, skin and digestive tract, and it can damage the nervous system if it is inhaled in high amounts. Common side effects of low doses include dizziness and headache. Gasoline vapors cause liver and kidney tumors in laboratory animals, but no human trials have been conducted. Sufficiently high doses of inhaled gasoline cause coma and death.