The end of lead
How a single taxi ride saved millions of lives
This is an article from the new issue of Works in Progress, Issue 19. Read the full issue on our website.
Clare Donaldson, Lauren Gilbert, and James Hu explain how to eliminate lead everywhere.
Lead has been a part of human life for more than eight thousand years. Though relatively rare in the Earth’s crust, lead is easy to extract and it’s useful: easy to shape, bend, and melt.
Human use of lead began in the Neolithic, long before humans figured out how to mold iron or copper or bronze. Mining of the mineral had begun by 6500 BC, as humans began to forge coins and fishing weights and ornaments from this dull, soft metal. Usage scaled up over the next several millennia; by the height of the Roman empire humans were mining tens of thousands of tonnes of lead every year. Romans used lead for everything from writing slates and bullets to coffins and plumbing. It is from the last that we get the modern word for plumbing: the Latin word for lead is plumbum.
Nor were the Romans the last to find new uses for lead, even though production fell in the latter half of the first millennium. In the Middle Ages it found its way into stained glass and cosmetics. By the Renaissance lead’s easy-to-mold nature made it perfect for the moveable type of printing presses. By the Industrial Revolution, lead mining had once again reached Roman heights.
And humans just kept coming up with new uses for it. In the 1920s tetraethyl lead was added to gasoline to reduce engine knock (a loud, juddering effect caused by uncontrolled fuel combustion in high-compression engines).1 Leaded gasoline spread quickly; by the 1970s, global lead production hovered at around 2.5 million tonnes per year, some 30 times more than what the Romans mined annually.
Today, we no longer use leaded gasoline, but lead remains a key part of modern life. Lead is the world’s seventh-most mined metal. A majority of lead production goes into lead-acid batteries, which are familiar for their use in cars, where their high surge power makes them ideal for starting engines. They are also used widely as backup generators for rebooting systems like data center and hospital equipment.
If lead were benign this would be a story of technological success: ingenuity leading to more and better usages of a mineral that we’ve known about for thousands of years.
Unfortunately, it is not. Two thousand years ago, even the Romans noticed health problems among those who worked with lead: they became pale and sickly, and too much exposure could even lead to paralysis and delirium. But lead was useful and Roman medicine hardly an exact science; some illness might simply be the price society paid for such a versatile mineral.
With two thousand years more of medical knowledge, we can be more precise about lead’s impact on the body. If you ingest lead, it is absorbed through the gut; if you inhale it, it enters through the lungs. From there, it passes into the bloodstream, where it is deposited into the bones and organ tissues.
If it stayed there, perhaps lead exposure could be ignored. But, like all body systems, the bones are not static. Lead re-enters blood in the churn and change of resorption, the nonstop process that dissolves the bones’ contents into the bloodstream as part of the metabolic replacement of old bone tissue with new.
Once released into the bloodstream lead harms the endothelial cells that line the inner walls of blood vessels, while causing a different type of cell – known as vascular smooth muscle cells – to proliferate, simultaneously stiffening and clogging the arteries. At the same time, lead damages the kidneys by both hardening the organs’ blood vessels and poisoning the tubes responsible for filtering blood.
These processes, in combination, substantially raise the risk of conditions like high blood pressure, heart disease, stroke, and kidney disease. A national observational study showed that, after adjustment for various other risk factors, American adults with higher levels of blood lead had a 37 percent higher overall mortality risk, 70 percent higher cardiovascular disease mortality risk, and 108 percent higher coronary heart disease mortality risk.
From the blood, lead also slips into the brain. The blood-brain barrier, which protects the neural tissue from most toxins, lets lead through principally because lead ions chemically resemble calcium ions, vital to the proper functioning of brain cells. Once in the brain, lead degrades cell membranes, blunts neurotransmission, and deregulates intracellular signaling pathways that depend on calcium ions. It even directly kills off brain cells.
This can cause a laundry list of neurological and mental disorders: cognitive impairment, nerve damage, hearing loss, dementia, schizophrenia, and behavioral and attention problems. Many studies have found that lead exposure increases violent crime.
While both adults and children can suffer severe consequences from lead exposure, it is generally young children who receive the most exposure and who suffer the gravest consequences.2
To begin with, normal play and hand-to-mouth behavior make young children much more likely than other groups to ingest lead from sources like dust and soil, which can contain lead from paint chips, mining activity, and legacy contamination from gasoline. As they grow and develop, they absorb four to five times as much lead per unit of exposure as adults do, in part because of how lead imitates the chemistry of calcium. Children use much more calcium than adults because they are still growing new bones; replacing their calcium ions with lead is therefore particularly dangerous.
Most things that sicken children leave evidence for parents and doctors. But children exposed to lead don’t have a giveaway fever, or rash, or cough. There is no way for parents to tell that their children have been exposed, only the silent accumulation of cellular damage that, down the line, can cause long-term disease and impaired brain functioning.
Perhaps unsurprisingly, as human lead use ramped up, so too did human exposure to lead. By the 1980s, it's estimated that people were exposed to 1,000 to 10,000 times as much lead as ancient humans.
One of the first people to highlight this as a problem was a geologist named Clair Patterson. His research required him to take precise measurements of how much of each element was in a given sample. But all of his experiments kept turning up too much lead because lead was in everything. His students would accidentally contaminate experiments because environmental lead lingered on their hands and clothing.3
In one interview, Patterson compared contemporary Americans to Pigpen from Peanuts: ‘That’s what people look like with respect to lead. Everyone.'
Patterson started a letter-writing campaign to urge officials around the country to regulate lead. His first was to the governor of California, Pat Brown, who politely declined. He also wrote to Edmund Muskie, the US senator from Maine who chaired the Senate’s Subcommittee on Air and Water Pollution. Muskie invited Patterson to a Senate hearing on air pollution the following year.
By then, Patterson’s article had angered the industry-sponsored groups researching lead’s health effects. In a December 1965 symposium, Robert Kehoe, one of the foremost toxicologists of the time, said, ‘There is not enough lead in our environment to be a health hazard to anybody. Those who say there is are ignoring the substance of the scientific work that has been done.'
Within a few years, though, the evidence started to build up that Patterson, not Kehoe, was right. In 1967, an epidemiological study found evidence that higher atmospheric lead predicts higher blood lead levels in those exposed. In 1969, a World Health Organization expert committee found evidence that lead concentrations in ambient air on rush-hour highways were reaching levels 50 times those in non-urban areas. In 1973, a Centers for Disease Control and Prevention study demonstrated a relationship between smelter emissions in a residential area and elevated blood lead levels in children.
And in 1979, a landmark study demonstrated a relationship between childhood lead exposure and cognitive deficits. Lead exposure was not benign; American children were suffering because of it.
As all of this evidence accumulated, Americans began to reconsider the harms of lead. By 1970, the US Congress had passed the Clean Air Act, empowering the newly created Environmental Protection Agency to regulate fuel additives.
In November 1973, the EPA announced stricter regulations on lead in fuel, reducing the amount permitted in all grades of gasoline by 60 to 65 percent. Instead of lead, companies found other additives to raise the octane level of fuel, such as ethanol. Beginning in 1975, in response to stricter exhaust emissions standards, new vehicles in the US market began to be fitted with catalytic converters. Since leaded gasoline damages catalytic converters, it was banned for all post-1975 models.
One by one, countries began to phase out leaded gasoline in road vehicles: Japan in 1986, Austria and Brazil in 1989, Canada in 1990. In 1996, a year after Patterson died at the age of 73, a full ban came into place in the US. By 2001, most of Europe and the Americas, as well as a number of Asian heavyweights, including China, India, Pakistan, and Bangladesh, had made the switch to lead-free gasoline.
Progress was slower elsewhere. In 2002, more than 100 countries – including almost all of Africa – were still using leaded fuel in road vehicles.
The problem was not that lead was extremely useful in fuel. Reformulating fuel to use a different anti-knocking agent is relatively simple. The inventor of leaded fuel had found other alternatives in the 1920s – he had settled on tetraethyl lead because it was patentable and his employer could easily produce it.
Rather, lead stayed in fuel due to a misconception. Many people believed that unleaded fuels were not backwards compatible and that using unleaded fuel required a car to have a catalytic converter. Since these were introduced relatively recently, cars in poorer countries often did not have one, and policymakers worried about this new fuel causing issues.
However, this wasn’t true. Leaded gasoline damages catalytic converters; it was a myth that unleaded gasoline isn’t backward compatible. Ethanol was a perfectly fine anti-knocking agent, and older cars would run well on the new unleaded fuel. An imaginary technical challenge was stalling the phase-out of leaded gasoline.
In the course of a single taxi ride in Cairo in 1995, this misconception fell apart. A project officer at USAID, Jim Goggin, happened to share a cab with an energy expert, who explained what lead in fuel actually did in engines. During the course of that single cab ride, Goggin started to come up with a plan to remove lead from gasoline in first Egypt and then the rest of Africa.
Following meetings with Egyptian ministers and the Egyptian General Petroleum Corporation where USAID offered scientific information and technical assistance to help shift existing oil refineries toward lead-free, the Egyptian government assessed the economic impact of a total transition and made implementing it a national priority. At the end of 1995, gasoline in the country’s second-largest city, Alexandria, was declared lead-free. By 1997, Cairo’s gasoline was lead-free. In 1999, all of Egypt phased out leaded fuels.
In 2002, the United Nations Environment Program established the Partnership for Clean Fuels and Vehicles at the World Summit on Sustainable Development in Johannesburg, and set as an objective the global phase-out of leaded gasoline. The partnership convened national governments, the private sector, and civil society to collaboratively address the remaining obstacles to the lead-free switch. Among these were still-prevalent myths around the backward compatibility of unleaded gasoline, hesitancy in the oil industry, and a lack of awareness of the health impacts of leaded fuel use among governments and the public.
It didn’t take much time – or money – to deliver results. In 2006, just four years after the launch of the partnership, leaded gasoline vanished from road vehicles across sub-Saharan Africa. At the ten-year mark, there were just four holdouts globally, and the program had spent only $6 million. In 2021, when Algeria used up the last of its leaded gasoline stockpile, it became the world’s last country to enact a ban on leaded gasoline.
Lead, then, may seem like a problem of the past. With leaded paint and leaded gasoline gone, to most people in rich countries, lead seems like one of those regrettable but resolved twentieth-century mistakes, like indoor smoking and high rates of industrial pollution.
Today, the average blood lead level in children in the US is just 0.83 micrograms per deciliter, a twenty-fold decline since the 1970s. Levels above 3.5 micrograms per deciliter are considered grounds for intervention, where public health officials will follow up with parents to provide information about how to reduce lead exposure, and likely visit a child’s home to determine where the lead exposure is happening.
Reducing lead exposure in the US has not been all sunshine and roses. It is expensive to replace lead pipes, and hundreds of thousands of lead pipes are still in service around the US. Children in Flint, Michigan, were once again exposed to high levels of lead in their water in 2014 and 2015.
Even at the height of that crisis, the exposure level was far less than historical levels. In 2015, the average child in Flint had a blood level of 1.3 micrograms per deciliter, one-seventh of what might have been expected a few decades before.
It is still likely to take decades to truly eliminate lead exposure among US children. But things have already improved drastically and they will likely continue to improve over time. Even in Flint, lead exposure is once again at a historical low.
Elsewhere the story is worse. Data is sketchy, but everything we have suggests that children in low and middle income countries are still exposed to staggering amounts of lead.
In 2019, a team of researchers attempted to put together estimates of lead exposure outside of Europe. They estimated that one in three children worldwide have lead levels high enough that, if they lived in the US, the health department would be at their home, testing everything they touch. The average child in a low- or middle-income country is exposed to five times as much lead as an American child.
Since lead damages the brain it limits potential in later life. In most cases, the harms are relatively minor when considered at the level of a single child. A child in a low- or middle-income country might earn 0.5 percent less than they would have if they had not been exposed to any lead in childhood. But when one considers how many children are exposed to lead, the total costs of lead exposure are very large. Estimates have put it near one trillion US dollars a year globally, around one percent of global GDP.
And because lead exposure is so common, minor harm ‘in most cases’ still makes it one of the world’s top killers. A 2023 paper attributes 5.5 million premature deaths every year to cardiovascular diseases caused by lead exposure. As the authors point out, that is more than three times the annual mortality estimated to come from unsafe water and poor sanitation (1.7 million deaths), and almost as many as that from all types of air pollution worldwide (6.5 million deaths).
Why are there still so many deaths from lead? The United Nations Environment Program and partners may have helped eliminate lead from gasoline around the world, but other sources of lead that have been eliminated in rich countries remain very common in low- and middle-income countries.
Let us consider lead in paint. The use of lead in paint was banned in the US in 1978, and in the UK in 1992. People who live in historic homes must test for lead paint, but for new homes, lead is no longer a danger.
All North American countries and 85 percent of European and Central Asian countries ban the sale of lead paint, but as of January 2024, only seven out of 39 countries in Africa for which there was data and one-third of countries in the Asia-Pacific region did (although in the latter case, most of the region’s largest countries by population had banned it).
The situation is worse than these statistics would suggest. In some countries that have banned lead paint on paper, it is still commonly available in the marketplace. Pakistan formally bans lead paint, but lead paints for home use, where they are prized for ease and durability, are still readily available. As a result, children in newly built homes are being poisoned every day.
Cosmetics, too, were once a common source of exposure to lead in rich countries. Queen Elizabeth I used a lead and vinegar cream to whiten her skin; Victorian socialites used white (leaded) paints to achieve the pale complexion they prized, and nineteenth century Americans used lead in lotions and creams. But by 1938, the US government had begun to take action to remove harmful substances from cosmetics. The US, the UK, Australia, and nearly every other rich country have enforced strict bans against lead cosmetics for decades. By contrast, a 2024 survey in developing countries suggests that some 12 percent of cosmetics purchased there are contaminated with substantial amounts of lead.
The lead-acid batteries that are used in many vehicles and nearly all backup power systems almost all use recycled lead. In rich countries, this recycling process is very safe and performed with protective equipment. In poor countries, where the dangers of lead are often completely unknown, people often hit the batteries with hammers and then melt down the lead in their homes, exposing everyone nearby to lead flakes and fumes.
In recent decades, these informal lead-acid battery recycling operations have proliferated in low and middle income countries. There are some 10,000 to 30,000 of them according to a 2020 estimate. Children near these sites have an average blood level of 31.5 micrograms per deciliter – some 30 times more than the average US child.
No one really knows how much of global lead exposure comes from any one source, and it’s quite possible high levels of lead exposure come from a combination of them. We do know, though, that it is possible to reduce lead exposure; after all, rich countries already have. There exist other dyes for eye makeup besides lead sulfide, and there are many modern paints that do not use lead. Leaded products are not even much cheaper than other alternatives on a direct cost basis, and when we additionally consider the social costs of using lead, they become far and away more expensive overall.
It is not clear exactly how much it would cost to remove lead from cosmetics, spices, and paint, and reform the battery recycling industry, but it is likely to be less than one percent of global GDP. Reducing lead exposure would pay for itself.
So if we know lead is bad, and removing it would likely pay for itself in the long term, why are any children still being exposed to lead?
Lead is a silent killer. When a child gets malaria, or is underweight, or is struggling in school, both parents and governments know that there is something wrong and that something needs to be done. But there are no immediate symptoms from lead exposure. Slowly, inexorably, lead exposure damages the health and prospects of young children around the world, and most of the time, neither their parents nor governments are aware of it.
In some countries we can only guess how many children are exposed to lead in their childhood; the data simply has not been collected. The best meta-analysis of lead exposure in low and middle income countries has data from only 30 countries, but what limited data we have suggests it is likely to be very common.
Consider Bhutan as an example. Before this year, there were some indications that Bhutanese children were likely exposed to lead, but the data was limited. This conclusion was based on a 2020 study in two cities in Bhutan which found that half of the children there had high levels of blood lead, and that Bhutanese children who have moved to the US often have high levels of blood lead. In 2024, the Bhutanese government conducted their first nationally representative survey of blood lead levels. It found that, in fact, 75 percent of children had elevated blood lead levels.
Bhutan is not the only country like this. Most developing nations still need to accurately measure how common lead exposure is and where the exposure is coming from. Without this country-specific knowledge of the problem, governments can be reluctant to act.
But with it, they might. In early 2021, Malawi’s Bureau of Standards had its own Bhutan moment when top officials met with a team from the Lead Exposure Elimination Project (LEEP), which one of us jointly leads. LEEP had been working with the University of Malawi to test some of the country’s most common paint brands and had found that 67 percent of the samples contained lead.
This startled Malawi’s regulators, who had assumed that lead in paint was an outdated technology (understandable, given how many countries have banned it). Without that awareness, and with a tight budget and many other priorities to address, they hadn't recognized the importance of testing for lead in paint. Further, the equipment they had to test for lead was broken, and the cash-strapped Bureau had not been prioritizing its repair.
After LEEP shared its results, the Bureau moved quickly to implement a lead paint ban, and began sending warning letters to paint manufacturers within the year. By March 2022, they were running new tests, both with their own, now-repaired, equipment (LEEP helped them source a replacement part) and through an American lab for calibration.
In theory, a lead paint ban should be simple: we know how to find it and there is no serious pro-lead constituency to hold back regulation. Even manufacturers usually aren’t aware of the damage they’ve caused and often happily adopt lead-free solutions when required to.
But, even when political will is abundant, logistics can still be a challenge. Testing is expensive whether it entails buying specialized instruments or shipping samples to foreign labs; personnel across the country need hands-on training; procedures for testing must be established and ratified. When LEEP ordered the replacement part it helped the Bureau bypass a procurement process that could have delayed local testing by months.
Manufacturers also struggle with supply chains. Two companies in Malawi struggled to find a lead-free red pigment they could actually import; LEEP helped them find an Indian supplier who could ship to them via South Africa, but it took multiple days and dozens of phone calls (and two months for the shipment to arrive).
These weren’t the only obstacles in Malawi’s way, but in the end, all proved surmountable. As testing began, the Bureau worked with LEEP to issue a public statement pressing manufacturers to commit to a lead-free timeline; by the next day, one manufacturer was already fielding phone calls from furious customers. Growing consumer awareness also provoked a virtuous circle as manufacturers raced each other to go lead-free, knowing they could outsell competitors by offering safer paint. By 2023, the market share of lead paint had dropped by more than half, and it was hard to imagine that number going anywhere but down.4
Many global health problems are thorny and difficult. Lead, unusually, is not one of those. We already know how to reduce lead exposure. Rich countries have already done it.
There is already a cost-effective playbook for how to get the lead out. We simply need to apply it to more of the world. Screen people, especially children, for lead levels in their blood. Find the major sources of lead exposure. Get the lead out of those sources, by partnering with governments to bolster regulations and helping manufacturers switch to lead-free alternatives. A lead-free future is possible for all children, and might be surprisingly easy to achieve.
Clare Donaldson is the co-executive director of the Lead Exposure Elimination Project.
Lauren Gilbert works on horizon scanning for Renaissance Philanthropy.
James Hu is a program associate at Open Philanthropy.
All opinions are the authors’ own.
The inventor of tetraethyl lead, Thomas Midgley, also invented chlorofluorocarbon aerosols. These almost destroyed the ozone layer.
Very high doses of lead (over 60 micrograms per deciliter) can result in acute lead poisoning, which does cause symptoms. However, this is rare.
It took Patterson decades of work, and building the cleanest laboratory in the world, to rid himself of this incidental environmental lead. Anyone entering the lab had to strip down to underwear and wear a new plastic suit, uncontaminated by the lead-filled world outside the lab.
UNICEF and Pure Earth were involved in a similar effort in Georgia. In 2019, the Georgian government found that 41 percent of children had blood lead levels above 5 µg/dL. In Georgia, one of the most common routes of exposure was through spices – vendors would add lead chromate to make spices more yellow. By 2021, lead had been virtually eliminated from spices in Georgia.
WOW, the Romans used bullets! Who knew?
Fantastic, fantastic article - and hugely important. Thank you.
Kevin Drum (who died earlier this year) did some really important work on lead and crime. https://bit.ly/4lkhZPm