Lead Exposure Destroyed 824,000,000 American IQ Points
In the last century, nearly half the American population has been exposed to toxic levels of lead, collectively reducing our IQ by 824 million points.
Way back in 1921, famous General Motors inventor Charles Kettering was searching for a solution to his ‘knocking’ problem. The inventor of the starter motor a decade before, Kettering needed to find a new fuel mixture to reduce engine knocking, a destructive phenomenon in which fuel ignition happens at suboptimal times. He tasked Thomas Midgley Jr., another GM engineer, with helping to find a fuel mixture that was cheap, effective, and could be patented, and a few years later they stumbled upon adding Tetraethyllead, commonly shortened to TEL or just ‘lead,’ revolutionizing the industry. In the following decades, it became commonplace, and its use continued globally until August 30th, 2021, when the UN Environment Programme declared an official end to its use.
The world decided to stop using TEL because it’s a nasty neurotoxin. We’ve known since 1854 that when ingested by humans lead can have an array of negative effects particularly on the brains of children. Even in the 19th century we knew that when children ingested lead, usually from lead-based paint chips, they became ill, had development issues, went into comas, or died. Despite knowing this, we continued to use lead not just in paint but in water pipes. When TEL was added to gasoline, lead hung in the air of cities, as it was part of car exhaust. However, we didn’t take earnest steps to ban it until the EPA partially limited its use in gasoline in 1985 and totally in 1996. Those born before 1996 were likely exposed, with those born during peak use in the 60s and 70s being the most affected.
Researchers from Duke and Florida State Universities ran the numbers. Since TEL was added in the 1920s, Americans have collectively lost over 824,000,000 IQ points thanks to the reckless use of lead.
Running the Numbers
The researchers relied on 2 data sources: the National Health and Nutrition Examination Survey (NHANES) and the now discontinued Bureau of Mines Minerals Yearbook (BMMY). The NHANES is a part of the CDC and among many other tasks has measured and cataloged blood lead levels (BLL) in children since 1976, and the BMMY was responsible for monitoring the amount of lead-based gasoline used in the US.
NHANES data since 1976 showed that 131 million Americans had a BLL below 5 µg/dL, the medical limit for concern, monitoring, and intervention. 54% had BLLs of Americans were above this limit. 100 million people had BLLs above 10 µg/dL, and 10 million people had BLLs above 25 ug/dL. BMMY data from 1932-1993 showed that leaded-gas use rose sharply in 1940, peaked in the 1960s, and began its decline in 1970 with the passage of the EPA’s Clean Air Act. For the data that the researchers had, it was clear that BLL levels mirrored leaded-gas use. For the data that they didn’t have, the researchers were able to extrapolate based on the connection, creating a consistent trend extending decades in the past.
They found that “The average lead-linked loss in cognitive ability was 2.6 IQ points per person as of 2015. This amounted to a total loss of 824,097,690 IQ points, disproportionately endured by those born between 1951 and 1980.”
The Past Isn’t Dead
Although the use of lead has been banned, the world still suffers from its effects. UNICEF estimates that “Around 1 in 3 children – up to 800 million globally – has blood lead levels at or above 5 micrograms per decilitre (µg/dL), a level that the World Health Organization and the United States Centers for Disease Control and Prevention have stated it requires global and regional interventions.” The main sources are water pipes, paints, canned food, spices, cosmetics, toys, car batteries, and of course leaded gasoline. Although many of these are banned or at least heavily regulated, they still continue to expose people to lead as local governments lack the capabilities and/or willingness to enforce these laws. For example, UNICEF highlighted the recycled car battery industry, which is often located in lesser developed nations and done in “informal, unlicensed, and frequently illegal open-air operations close to homes and schools.”
The US population is at risk as well. Although we now have much better regulations, lead products and their persistent contamination can still be found. The CDC has identified 6 major sources of lead contamination.
- Pre-1978 homes. Lead-based paints were banned for residential use in 1978, although it is found in roughly 29 million housing units.
- Aging water pipes. Pipes installed before the EPA’s 1986 regulations have a much higher chance of containing lead. It’s estimated that 7% of US households have lead pipes, and some 400,000 schools and childcare facilities are putting children at risk.
- Some toys and jewelry. Old toys and jewelry may contain lead, as well those banned in the US but still sold in other countries.
- Some food products. Candy, spices, natural medicines, etc. from some countries, such as China, India, and Vietnam, have been found to contain lead.
- Certain jobs. People who have jobs that involve welding, working with stain glass, demolishing or renovating old buildings, shooting firearms, etc. have a higher likelihood of lead exposure.
- Living near airports and major highways. Because airplanes, cars, trucks, etc. used to burn leaded gasoline at an alarming rate, the soil in heavily trafficked areas are often still toxic.
Not only has lead reduced the US and global IQ, there’s convincing evidence that this drop has directly caused a loss of productivity, loss of GDP, and increased crime rates. In particular, the Lead-Crime Hypothesis has been the subject of a lot of debate in academic and policy-making circles.
For example, researchers Feigenbaum and Muller looked at the correlation between the installation of lead water pipes in the 20s and 30s and homicide rates roughly 20 years later. They hypothesized that children exposed to lead would be more likely to have a lower IQ as an adult and therefore more likely to be violent. They found that “Lead water pipes exposed entire city populations to much higher doses of lead than have previously been studied in relation to crime. Our estimates suggest that cities’ use of lead service pipes considerably increased city-level homicide rates.”
In a similar study, Aizer and Currie looked at 120,000 children from Rhode Island born from 1990 to 2004. They believed that the children who grew up closer to busy roads would be exposed to more lead, have lower IQs, and have greater chances of developing behavioral issues. By comparing proximity to busy roads and their rates of deviant behavior while in school, they concluded that “A one-unit increase in lead increased the probability of suspension from school by 6.4-9.3 percent and the probability of detention by 27-74 percent.”
Numerous other studies support the same conclusion: lead exposure has severely damaged not just the brains of children but has contributed to an array of societal challenges.
What Can We Do About It?
The obvious first step is understand if you or your children are at risk and avoid exposure. If you live in an old house or work in an old building, get an EPA inspection and continue with their abatement programs if necessary. Contact your local water authority to see how/if they are testing for lead in your water supply. Avoid jobs/hobbies that might expose you to lead if feasible. Get old jewelry or suspected products for lead or simply avoid using them if it’s not possible. Understand which areas used to be highly trafficked and don’t let your children play in or near them. Lastly, get yourself and your children tested. Any local healthcare provider should be able to do a simple blood test to determine any lead exposure.
Another answer is to demand better from the government. US regulations are getting better, as most sources of lead are banned or are getting replaced. For example, the Biden administration has committed $15 billion for replacing lead water service lines, $11.7 billion in replacing lead water pipes, $9 billion in lead remediation grants to disadvantaged communities, $1 billion to remove the USDA’s lead water pipes, $5 billion to remove lead-based paint and fixtures from homes, and $65 billion for public housing agencies to help assist communities affected by lead exposure. Investments such as these are expected to pay dividends. University researchers Billings and Schnepel estimate that every dollar spent on lead intervention would return a $1.80 in societal benefits.
Help support independent journalism by clicking the links below:
