Lead keeps showing up where it’s not supposed to be.

In 2024, one of the most potent neurotoxins known to humanity persists all over the world as a public health threat. For the second time in six months, lead contamination in food products has put public health authorities on high alert in the wealthiest nation in the world. Last fall, contaminated cinnamon-applesauce pouches caused dozens of lead poisoning cases across the US, eventually prompting recalls in November. And in March, the federal government announced that some ground cinnamon products also contained slightly elevated levels of lead and advised customers not to buy them.

Lead might seem like something we left behind in a past era. By the 1990s, nearly every country had eliminated leaded gasoline, once easily the most ubiquitous source of lead pollution when we spewed it into the open air. The US and Europe also instituted more stringent rules for another common source of exposure, lead paint, by greatly restricting or outright banning its use. You can see the improvements in the numbers: From 1978 to 1991, the average level of lead in the blood for Americans younger than 75 dropped by 78 percent.

But lead usage has actually been on the rise worldwide, even in the US. The proliferation of lead-acid batteries globally and less stringent rules in the developing world for everything from cookware to spices has allowed lead consumption to grow despite its known health risks.

Lead is linked to a wide range of neurological and development problems, and exposure is especially dangerous for children. Research has found kids with elevated levels of lead in their blood experience a range of effects, from speech and hearing problems to learning and behavioral issues. They develop more slowly, physically and mentally.

And it remains an especially serious plight for poorer countries: A 2021 review of studies involving children in 34 low- and middle-income countries found that 48.5 percent had elevated levels of lead in their blood. But in a globalized economy, some of the same lead pollution endangering kids in those countries can find its way into consumer products that travel around the world and contaminate the food that children in the US eat.

In the case of the applesauce, the cinnamon was originally harvested in Sri Lanka and then shipped to Ecuador, where it was ground into powder to be mixed into the products. Both countries are dealing with lead exposure crises: One 2021 study found that almost all mothers and children living in Quito, Ecuador, had levels of lead and other metals in their blood that exceeded public health guidelines. The pollution stemming from Sri Lanka’s active lead-acid battery manufacturing and recycling sector, too, has created health problems for the workers and people who live near the plants.

When the applesauce ingredients passed through Ecuador, they were contaminated there with lead before they moved for sale to the US, where there have been more than 500 confirmed or suspected cases of acute lead poisoning related to the recalled products. The FDA believes the lead may have been added intentionally for economic reasons. The Ecuadorian government has named one individual as a suspect in its own investigation.

The entire episode encapsulates the difficult truth about lead: Even though the US has cracked down within its borders, pollution elsewhere persists — and, in some cases, American efforts to reduce its own pollution merely moved the contamination to other parts of the world.

Read the full article about lead in American by Dylan Scott at Vox.