When the researchers analyzed lead gas use data from 1940 and combined that data with data on blood lead concentrations from the mid-1970s, they found that more than 54 percent of americans who were alive in 2015 were of people were exposed to dangerous levels of lead as children. That's more than 170 million adults. These individuals are now at greater risk of developing neurodegenerative, mental and cardiovascular disease due to the lead they inhaled, ingested or absorbed as children.
Exposure to lead in any concentration is unsafe at any stage in a person's life, but this highly toxic metal can be especially harmful to small children because logo design it can hinder brain development, cause permanent learning difficulties, and behavioral problems .
Overall, the researchers estimate that lead gas has lowered the nation's cumulative intelligence quotient (iq) score by 824 million points, or nearly 3 points per person. And that's just average. For those born in the 1960s and 1970s, when lead-containing gas use peaked, their iq scores may have been lost to 6 to 7 points. This group of people was exposed to lead concentrations eight times higher than today's health limits.