The Ethyl Corporation began marketing gasoline with tetraethyl lead additive in 1924, and the use of lead as an anti-knock ingredient continued in the United States until it was completely banned for on-road use in 1996. In hindsight, perhaps making every motor vehicle an emitter of a vaporized neurotoxin wasn't such a great idea, but at least the Ethyl Corporation created this series of "Smart Bird" safety-themed advertisements during the middle 1950s.