Zadornov would somehow joke about this. In 1923, lead was first added to gasoline as an anti-knock additive. It turned out that this controversial decision even affected the brains of Americans. Discuss alt=”Scientists figured out the cause of Americans' IQ decline” Scientists figured out the cause of Americans' decline in IQ more than 170 million Americans alive today. That's about half the US population.
Leaded motor fuel was banned in the US in 1996, but researchers say anyone born before the end of that era, and especially those who were at the peak of its use in the 1960s and 1970s had relatively high exposures as children. Young children are especially vulnerable to it. As of 2015, more than 170 million Americans had clinically dangerous blood lead levels when they were children. This could be a factor in lowering IQ.
Source: Medical Xpress