In 1924, lead compounds were added to gasoline so as to increase the efficiency of cars. In that "Kingdom of the Automobile," the United States, within 40 years the amount of lead used in this way increased from 400 tons a year to 280,000 tons.
一九二四年，鉛化合物「四乙基鉛」被引入汽油內，以改進汽車性能，在「汽車王國」美國，四十年內，鉛的用量就由每年四百公噸，增加為廿八萬公噸。