One can compare lead added to gasoline with carcinogens added to cigarettes. Both were introduced to make the use of the product smoother, and with it came massive health issues, and both industries funded fraudulent studies to create the false impression the product was safe. While carcinogens are still added to cigarettes, and will be forever since while the government's case against Big Tobacco revealed the practice, banning the practice was not included in the settlement for inexplicable reasons, and most of the massive fine was ultimately forgiven by the early naughts. Oddly, health issues are not the reason why leaded gasoline was phased out; it was phased out because leaded gas fowled catalytic converters, which were mandated to reduce emissions.