The industrial use of tetramethyl/tetraethyl lead additives in gasoline was widespread throughout the U.S. from 1929 to 1996, when it was banned in use for on-road vehicles. Lead was used as a fuel additive due its ability to boost fuel octane ratings and thereby reduce “engine knock,” which can cause severe damage to an engine.
During the time period when lead was widely used in gasoline, over 13.2 billion pounds of extremely toxic, minute particles (particulate matter <10 µ) of lead were released into the environment. This highly soluble lead residue remains in the environment in very large quantities, especially in urban areas and around highways where the lead levels in soil range from 10-100 times greater than background levels.
Presently, leaded gasoline is still used in the automotive racing and the aviation industries, which continue to release highly soluble industrial lead into the atmosphere. Legacy leaded gasoline, though largely banned, continues to be a major source of lead exposure to humans and animals alike. Indeed, large urban centers such as New Orleans have reported over 3000 ppm lead in soils around residential areas. Further, contaminated soils along roadways are a significant source of lead exposure to wildlife that scavenge and ingest road-kill. Additionally, animals that take frequent dust baths are susceptible to dermal exposure to lead compounds.