Humans have long been aware of the dangers of lead exposure to their health. Even the ancient Romans did not stumble into lead exposure by accident. Writers such as Vitruvius and Pliny the Elder warned about harmful effects from lead pipes and fumes.1 Yet that awareness did not stop widespread use.
Many chose lead vessels for cooking, especially when they reduced grape must into sweet syrups known as sapa and defrutum. Agricultural writers such as Cato the Elder recommended boiling acidic grape juice in lead pots. When the acidic must contacted lead, it formed lead acetate, a compound with a distinctly sweet taste often called “sugar of lead.”2 Compared with copper or bronze, lead produced a smoother, more appealing flavor.
This sweetness enhanced wine and food, particularly among Roman elites who consumed wine daily and valued refined taste. Skeletal remains from Roman burial sites routinely show elevated lead levels, especially among aristocrats, which supports chronic dietary exposure.
In the 1920s, scientists at General Motors found that adding lead to gasoline improved engine performance and reduced knocking. The additive, known as tetraethyl lead, quickly became standard in fuel across the United States.3 For decades, drivers filled their tanks with leaded gasoline, unaware of the long-term consequences.
By the early 1970s, mounting evidence linked lead exposure to serious health problems, especially in children. In response, the U.S. Environmental Protection Agency (EPA) introduced strict limits on lead in gasoline in 1973. The phaseout moved forward over the next two decades, and leaded gasoline for on-road vehicles was fully banned in the U.S. by 1996.4
The banning of lead in gasoline is one of the rare times the EPA got something right because it has a history of questionable policies.5 Now, a newly published study shows just how significant that lead exposure was, though it cautions that there’s still a long way to go before the threat of lead is fully eliminated.6
Hair Records Show How Lead Exposure Shifted Over Time
The study, published in the Proceedings of the National Academy of Sciences (PNAS), examined how much lead Americans were exposed to during the peak years of leaded gasoline use and assessed how effective later policies have been in reducing that exposure and improving safety.7 For the analysis, the researchers used human hair samples collected along Utah’s Wasatch Front, dating back to 1916, and compared those samples to modern hair collected after 2020.8
The individuals represented in the hair archives lived in the same region, but in different time periods. The earliest samples reflect people who grew up before the EPA formed, during years when leaded gasoline released toxic particles into the air. In contrast, more recent samples represent children and adults who lived after leaded gasoline was phased out.
• Phasing out lead in gasoline had dramatic impact — The study found that hair lead levels in older samples often ranged between 28 and 100 parts per million (ppm), a level that reflects extremely high environmental contamination. Those numbers remained common throughout the 1960s, meaning anyone born in that era lived in a world where the air, dust, soil, and household environments were consistently enriched with lead.
Measurements fell sharply in the 1970s, dropping to around 50 ppm in that decade, then to about 10 ppm in the 1990s, and eventually falling below 1 ppm in samples collected after 2020.
While the U.S. Centers for Disease Control and Prevention (CDC) has set an upper blood lead level (BLL) limit of 3.5 micrograms per deciliter (mcg/dL) — above which immediate action should be taken to lower it — they also note that there is NO safe BLL.9
• Regulatory action drove a 100-fold drop in lead exposure — The study directly ties the decline in hair lead to regulatory action, noting that exposure “declined by about 2 orders of magnitude since the establishment of EPA.” In other words, it signified a 100-fold reduction. Before this shift, gasoline alone contained about 2.2 grams of lead per gallon (0.6 grams per liter).
• Lead still lingers in the environment — Although modern hair samples show far lower levels than in past decades, the study cautions that old lead has not vanished. Lead that settled into soil years ago does not break down. During dry weather, construction, yard work or shifting winds, that contaminated soil and dust can rise into the air again, which creates new exposure long after the original source disappeared.
• The protections in place could change any moment — The researchers noted that lead exposure could rise again if environmental regulations change. They pointed to a March 12, 2025, announcement from the EPA describing plans to reconsider or roll back certain regulatory provisions related to its environmental mission.
The authors also referenced broader discussions about how revisions to long-standing environmental policies could affect public health, health care costs and the economy. While no direct deregulation of lead exposure has occurred, they highlighted proposals under consideration that could introduce greater flexibility in how the 2024 Lead and Copper Rule is enforced, which may influence future exposure levels.10
Lead Exposure Still Exists, and Continues to Affect Cognitive Development
While the PNAS study I discussed above acknowledged the reduction in lead exposure, another study11 (published in the same journal) noted that more than 170 million Americans were exposed to lead levels high enough to damage their brains during childhood, and we need to “plan for the health needs of these Americans.”
For the analysis, the researchers traced childhood BLLs from every U.S. birth cohort from 1940 to 2016 by combining federal biomonitoring data with historical records of leaded gasoline usage.12
• Generational divide in lead exposure and childhood BLLs — Younger cohorts, especially those born after 1990, lived in environments with drastically lower exposure. Meanwhile, older cohorts (those born between 1951 and 1980) experienced the peak period of contamination.
Overall, the researchers found that over 170 million people had childhood BLLs above 5 mcg/dL, with more than 54 million exceeding 15 mcg/dL during early childhood.
• A staggering number of children have been exposed to lead — BLLs above 5 mcg/dL were nearly universal — over 90% — among people born between 1951 and 1980. That means if you were born during that period, your brain development occurred under the influence of lead during your most vulnerable years.
The authors also found that more than 4.5 million Americans had childhood BLLs exceeding 30 mcg/dL, which represents extremely heavy exposure and aligns with levels documented to produce major cognitive and behavioral harm.
• The cumulative neurological cost of lead exposure — The researchers estimated that as of 2015, an average of 2.6 IQ points per person across the entire U.S. population had been lost, adding up to 824,097,690 IQ points across the population, due to early-life exposure.
Note that the loss is not spread evenly across age groups. People born during the peak era of leaded gasoline lost far more cognitive capacity compared to those born later, simply because their exposure was higher, more frequent, and began earlier in life.
• Effect of gasoline on total lead exposure levels — Similar to the previous study, this one also highlights the impact of leaded gasoline on public health, specifically children. When stricter regulations emerged in the 1970s and leaded gasoline was gradually phased out, BLLs in young children dropped nearly as fast as gasoline-related emissions declined.
• Lead exposure also affects behavior, heart health and brain aging — Aside from IQ, the researchers hinted at other ways exposure can eventually affect the human body. These include “criminal behavior, personality, psychopathology, social mobility, cardiovascular disease, kidney function, and pathological brain aging.” Having emphasized this, they noted that future studies can follow this path and paint a more complete picture of lead’s true impact on public health.
• Generations that saw the greatest impact — The researchers noted that those born during the 1950s, 1960s, and 1970s were exposed to the highest levels of lead in air, dust, and soil because leaded gasoline emissions were at their peak. Since cognitive development is rapid during early childhood, this exposure window produced the greatest harm.
The authors describe lead as a “developmental neurotoxicant,” meaning it directly harms the growing brain by interfering with fundamental neurological processes. As noted in a different study, lead exposure can also cause stunted growth, which not only affects cognitive development, but also physical, emotional, and social development.13
• The impact of leaded gasoline outweighed other known sources — Gasoline-derived lead was overwhelmingly the strongest predictor of population-wide exposure throughout the entire study period. While other sources existed, such as paint, plumbing, and industrial emissions, none matched the widespread distribution and daily inhalation risk created by combusting leaded gasoline.
Minimize Your Lead Exposure with These Strategies
While banned from gasoline, lead is still found everywhere. Common sources include contaminated tap water and lead-based paint from old houses. Even household products, such as certain toys, cosmetics, and glazed pottery can contain lead.
Reducing exposure requires a multifaceted, proactive approach to safeguard both your immediate and long-term health. The following steps can help lower your risk while supporting your body’s natural detox systems:
1. Inspect your home and address hazards promptly — Homes built before 1978 are more likely to contain lead-based paint or contaminated soil. If any of these criteria apply to your home, arrange for professional testing and, if lead is detected, work with contractors certified by the EPA to safely remediate the problem.
Areas with flaking or deteriorating paint deserve special attention, as the dust created from chipping paint is particularly dangerous. Keep children away from these spaces until they are properly treated.
2. Check your water quality — Many older municipal water systems still rely on lead service lines, which can leach lead into household tap water. Installing a high-quality filtration system certified for lead removal is one of the most reliable and cost-effective protective measures. Use filtered water for drinking and food preparation and avoid using hot tap water — especially unfiltered — for cooking or mixing infant formula.
3. Strengthen your defenses with proper nutrition — Adequate calcium intake from sources such as grass fed dairy and bone broth can help limit lead absorption because calcium competes with lead in the body. A diet rich in iron, vitamin C, and B vitamins also supports healthy blood production and helps reduce the risk of lead-related anemia.
As for pregnant women, ensure sufficient folate intake to help protect developing babies from lead’s harmful effects on the nervous system.
4. Monitor BLLs regularly — Testing is the only way to know how much lead exposure you’ve accumulated. So, it would be wise for families living in older homes or high-risk areas to undertake routine screening.
Children under age 5 are especially vulnerable and need to be tested at regular intervals, while adults should ideally strive to keep blood lead concentrations below 3.5 mcg/dL. Early detection allows for timely intervention before serious health consequences develop.
5. Explore safe detoxification methods — Lowering elevated lead levels is a gradual process that takes time. To help you with this, consider chelation therapy with edetate disodium (EDTA). It has been shown to reduce certain cardiovascular risks, but it also carries side effects.
A more accessible option is N-acetylcysteine (NAC), which helps replenish glutathione — one of the body’s primary detoxifying compounds — and supports the safe removal of heavy metals.
Another strategy I recommend is sweating regularly, either through sauna or exercise. As I explained in a previous article, both of these activities induce sweating that helps remove toxic heavy metals from your system. Exercise was shown to be superior at detoxing compared to a sauna, but combining both methods produced synergistic effects.
Frequently Asked Questions (FAQs) About Lead Exposure Through Gasoline
Q: How has lead exposure changed over time in the United States?
A: Lead exposure has dropped dramatically thanks to EPA regulations. Hair sample studies show levels fell from as much as 100 ppm during the 1960s to below 1 ppm after 2020. The phase-out of leaded gasoline, which contained about 2.2 grams of lead per gallon, was the single most impactful policy change driving this decline.
Q: How many Americans were affected by lead exposure, and what were the health consequences?
A: More than 170 million Americans alive in 2015 had elevated blood lead levels in early childhood; several million were exposed to levels at least five times higher than today’s reference level. Those born between 1951 and 1980 had the highest exposure. Cumulatively, the childhood lead exposure among Americans born between 1940 and 2016 resulted in an average loss of 2.6 IQ points per person, totaling approximately 824 million IQ points across the living population as of 2015.
Q: Which age groups were most affected by lead exposure?
A: People born between 1951 and 1980 suffered the greatest harm, as over 90% had blood lead levels above 5 mcg/dL during childhood. This period coincided with peak leaded gasoline use, meaning their brains developed during the most contaminated era in U.S. history.
Q: Is lead exposure still a concern today?
A: Yes. Although airborne lead from gasoline is largely gone, lead persists in contaminated soil, old plumbing, pre-1978 paint, certain toys, cosmetics, and glazed pottery. Resuspended dust from decades-old contamination also continues to expose people, and researchers warn that recent regulatory rollbacks could weaken existing protections further.
Q: What steps can individuals take to reduce their lead exposure?
A: Key strategies include testing homes built before 1978 for lead paint, installing certified water filtration systems, maintaining a diet rich in calcium, iron, and vitamin C to limit lead absorption, monitoring blood lead levels regularly (especially for children under 5), and exploring detoxification options such as sauna, chelation therapy, or N-acetylcysteine (NAC) supplementation.
