Lead from gasoline blunted the IQ of about half the U.S. population, study says

Exposure to leaded gasoline lowered the IQ of about half the population of the United States, a new study estimates.

The peer-reviewed study, published Monday in the journal Proceedings of the National Academy of Sciences, focuses on people born before 1996 — the year the U.S. banned gas containing lead.

Overall, the researchers from Florida State University and Duke University found, childhood lead exposure cost America an estimated 824 million points, or 2.6 points per person on average.

Certain cohorts were more affected than others. For people born in the 1960s and the 1970s, when leaded gas consumption was skyrocketing, the IQ loss was estimated to be up to 6 points and for some, more than 7 points. Exposure to it came primarily from inhaling auto exhaust.