Fuel tanks leak. Cars leak. Waste fluids (fuel, oil, brake fluid, transmission fluid, coolant, refrigerant) leak and are improperly disposed of. Fuel spills when being pumped in or out of tanks.
Until 1996, leaded gasoline was generally legal in the United States (California phased it out in 1992). It remains legal as avgas and possibly for some specialised uses. Tetraeythyl lead is a toxic heavy metal compound thought to be a factor in the rise in urban crime, a phenomenon which traces its use and phase-out closely, though lagged about 20 years.
Among the compounds used as an alternative to lead was MTBE (Methyl tert-butyl ether), an oxygenate and ground-water contaminant, itself banned as a fuel additive in 2004 (2002 in California), though again it remains legal for other uses.
Petrol (gasoline) itself is often formulated with numerous other additives, and "is a mixture of a large number of different hydrocarbons", averaging hydrocarbon length of about 5-6. ("Naptha", shorter chains make more volatile fuels, longer chains heavier, e.g., kerosene, diesel fuel, fuel oil, bunker oil. "Octane" is an 8-chain compound with lower volatility, increasing the ignition point and reducing engine knocking due to premature ignition.) Various of the naturally-occuring, added, and refining-induced compounds themselves may be harmful or toxic, and include VOCs.
Until 1996, leaded gasoline was generally legal in the United States (California phased it out in 1992). It remains legal as avgas and possibly for some specialised uses. Tetraeythyl lead is a toxic heavy metal compound thought to be a factor in the rise in urban crime, a phenomenon which traces its use and phase-out closely, though lagged about 20 years.
Among the compounds used as an alternative to lead was MTBE (Methyl tert-butyl ether), an oxygenate and ground-water contaminant, itself banned as a fuel additive in 2004 (2002 in California), though again it remains legal for other uses.
Petrol (gasoline) itself is often formulated with numerous other additives, and "is a mixture of a large number of different hydrocarbons", averaging hydrocarbon length of about 5-6. ("Naptha", shorter chains make more volatile fuels, longer chains heavier, e.g., kerosene, diesel fuel, fuel oil, bunker oil. "Octane" is an 8-chain compound with lower volatility, increasing the ignition point and reducing engine knocking due to premature ignition.) Various of the naturally-occuring, added, and refining-induced compounds themselves may be harmful or toxic, and include VOCs.
https://en.wikipedia.org/wiki/MTBE_controversy
https://en.wikipedia.org/wiki/Tetraethyllead
https://en.wikipedia.org/wiki/List_of_gasoline_additives
https://en.wikipedia.org/wiki/Gasoline#Chemical_analysis_and...
https://en.wikipedia.org/wiki/Naphtha