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Do Stanley cups contain lead or pose a risk of lead poisoning? Experts weigh in

Recently, multiple social media users have posted about concerns that drinking from a Stanley mug poses a lead exposure risk. But is that true? Here's what to know.
/ Source: TODAY

The maker of Stanley cups is being sued over the presence of lead in its products. The primary allegation is that the company did not publicly confirm until January 2024 that lead is used in its manufacturing process.

The suit against Pacific Market International was filed in February 2024 as a potential class-action case by a Seattle-based firm.

Back in January, Stanley responded to claims that its products contain lead in a statement to TODAY.com. A spokesperson clarified that yes, lead is used in the manufacturing process, but the product needs to become damaged in order to expose the lead.

A subsequent statement posted on the Stanley website explained that "no lead is present on the surface of any Stanley product that comes into contact with the consumer nor the contents of the product."

On the bottom of each quencher made by the beverage container powerhouse is a circular barrier made of stainless steel, which covers a pellet that contains lead, a spokesperson for Stanley told TODAY.com. The pellet seals the product's vacuum insulation, and it is not accessible unless the stainless steel barrier comes off — which is possible but “rare,” the Stanley spokesperson noted.

Stanley cup lead
The bottom of a Stanley tumbler, where cover for the pellet, which contains lead, is located.Tyler Essary / TODAY

The lawsuit alleges that Stanley and PMI misled customers because they did not warn consumers about the potential for exposure from damage to the vacuum seal and did not disclose how much lead is in each cup. PMI did not immediately respond to NBC News' request or comment.

The lawsuit comes after a flurry of social media posts where some Stanley customers said they used at-home tests to assess if there’s lead in any of their Stanley products, to mixed results (though it’s often not clear what part of the cup is being tested and the quality of lead test being used). Some users have posted videos of themselves throwing their Stanley cups in the trash.

A spokesperson for the U.S. Centers for Disease Control and Prevention responded to concerns about lead being used in manufacturing in a statement to TODAY.com: “When lead is used in manufacturing, there is a risk of lead exposure for consumers of those products, especially for products intended for use in food consumption, like drinkware. There is also a potential occupational safety risk for workers and, without proper safeguards, could be a risk for workers’ families through take-home lead exposures.”

Here's what you need to know about lead in Stanley cups, whether there's a risk of exposure and what to do if your Stanley becomes damaged.

Do Stanley cups contain lead?

Yes, Stanley uses lead in its manufacturing process for its cups, but they only pose a risk of lead exposure if the cover on the bottom of the tumbler comes off and exposes the pellet used to seal the cup's vacuum insulation, a Stanley spokesperson says. (If this happens, you can submit a claim through the company's lifetime warranty.)

“Our engineering and supply chain teams are making progress on innovative, alternative materials for use in the sealing process,” the spokesperson adds.

The liquid inside a Stanley mug does not come in contact with the pellet, so "there really is practically zero risk of you ingesting any of the lead that’s in this cup," said Jack Caravanos, doctor of public health and professor of environmental public health sciences at New York University's School of Global Public Health.

Lead poisoning activist Tamara Rubin, aka Lead Safe Mama, first brought attention to the presence of lead in Stanley tumblers in March 2023. (Rubin earns a commission on the products she recommends that are purchased through her website. Some of her recommendations include competitors to Stanley.)

She's been passionate about protecting other parents from the dangers of lead poisoning ever since her then-7-month-old son became exposed to lead paint dust during a home renovation and suffered severe permanent brain damage. Rubin now advocates against the use of lead in any products that enter the home. In February 2023, she sent Consumer Reports a tip based on her own lead testing that later led to a product recall. She has also submitted reports to the U.S. Consumer Product Safety Commission (CPSC) on similar products that she says led to four additional recalls.

Related: The right and wrong way to clean a Stanley cup, according to experts

Rubin says parents often send her items that they suspect could contain lead, and she uses XRF technology, the same $35,000 spectrometer instrument used by the CPSC, to test for the presence of lead and other heavy metals. She says she’s tested several Stanley tumblers that people have sent her after the protective cover at the bottom has come off, and she has found lead.

“Though some people say (the) protective disc doesn’t come off easily, I’ve heard from many people who say that for them it has,” Rubin says, estimating that the latter group is in the hundreds.

She adds that, based on her own experience and what other parents have told her, heavy use, children fidgeting with the area and repeated washings can increase the likelihood the cover will come off. She says some people have told her they don't know how the cover came off and weren't even aware the cup was damaged at first.

The risks of lead exposure and poisoning

Lead is a naturally occurring metal found abundantly throughout the earth, per the National Institute of Environmental Health Sciences. Soil usually contains lead concentrations of less than 50 parts per million, but many urban areas contain soil with up to 200 parts per million, according to the U.S. Centers for Disease Control and Prevention.

A relatively inexpensive, durable and stable metal that doesn’t rust, lead was once used en masse during the early-to-mid 1900s and could be found in toys, gasoline, food, jewelry, cooking utensils, ceramics, electronics, batteries, plumbing pipes, paint and even cosmetics.

Federal and state laws have since helped lower the amount of lead people are exposed to, but lead is still found in some products today. In fact, the CDC tracks lead-related product recalls, from children’s clothing to food to cosmetics to medicine.

“Most people think of lead poisoning as a thing of the past, but lead is still all around us, often at dangerous enough levels to cause significant harm,” Jenna Forsyth, Ph.D., research scientist specializing in epidemiology and environmental science at Stanford University School of Medicine, tells TODAY.com.

Lead poisoning is most commonly caused by breathing in lead dust or particles, but it can also occur by touching a surface where lead is present, then touching one’s nose or mouth, thereby ingesting trace amounts of the toxic metal, according to the CDC.

“One family I worked with had a young child who got lead poisoning from ingesting oatmeal that he had playfully smashed with the bottom of a water bottle where lead was exposed,” says Rubin. (This bottle was not made by Stanley.)

Once lead enters the bloodstream, it can accumulate and cause severe health consequences, including cardiovascular disease and brain damage. Ronnie Levin, a 40-year veteran scientist of the U.S. Environmental Protection Agency (EPA) who now teaches at Harvard T. H. Chan School of Public Health, tells TODAY.com that lead is an “all-systems toxin. ... There isn’t a system in your body — from your nervous system to your immune system to your reproductive system — that isn’t harmed by it.”

One study published in The Lancet estimates that in 2019, more than 5 million adults worldwide died from cardiovascular disease related to lead exposure. Children are especially vulnerable because they absorb lead more easily than adults.

“Even low levels of lead that were once considered safe have been linked to harmful changes in intelligence, behavior and health,” Paul Allwood, the lead poisoning prevention and surveillance branch chief at the CDC’s National Center for Environmental Health, tells TODAY.com in an email. 

Symptoms of lead poisoning

According to Mayo Clinic, these are the most common symptoms of lead poisoning in adults:

  • High blood pressure
  • Joint and muscle pain
  • Memory and concentration trouble
  • Headache
  • Stomach pain
  • Mood disorders
  • Reproductive difficulties

Symptoms of lead poisoning in children include:

  • Developmental delays and learning difficulties
  • Irritability
  • Weight loss and loss of appetite
  • Fatigue and general low energy
  • Gastrointestinal symptoms, like stomach pain, vomiting and constipation
  • Hearing loss
  • Seizures
  • Eating things that aren't food (a disorder known as pica)

Does this mean I should get rid of my Stanley cup?

As long as that cover at the bottom of your Stanley cup stays in place, Levin says there is no risk in owning the product. “If that barrier remains intact, you won’t be exposed to any lead and won’t suffer any negative outcomes,” she explains.

What's more, health issues rarely arise from a single instance of lead exposure. “Repeated exposure to lead is what’s most worrisome,” Dr. Vicki Iannotti, a pediatrician at ColumbiaDoctors in Tarrytown, New York, and an assistant professor of pediatrics at Columbia University, tells TODAY.com.

It’s that kind of repeated exposure that concerns Rubin the most. “Children, and especially babies, like to fidget with things that have dimples they can rub,” she says. “If a parent lets their child fidget with an item like a Stanley mug after the bottom cap has come off, there is a very possible and likely transference of microparticulate lead via normal hand-to-mouth behavior in young children.”

Levin echoes similar concerns: “Though lead poisoning is unlikely to happen from a single instance, if a child puts the bottom of one of these cups against their mouth or rubs the surface with their fingers and then puts them in their mouth, contamination can occur.” 

Forsyth agrees that risk of exposure from a single instance of touching lead “is pretty low,” but says there are scenarios that could increase the risk, such as scraping the exposed led against a hard surface. For example, if a cup with exposed lead is slid across a counter or moved in and out of a cupholder with hard edges, then “tiny pieces of lead could flake off," she says.

And when lead comes in contact with anything acidic, it can become more absorbable, Forsyth explains. This could occur if you're drinking out of a cup with exposed lead and peeling an orange, then touch the exposed lead with fingers that have touched the orange, and then touch your nose or mouth. “Ingesting lead is what you need to avoid the most,” Forsyth says.

The World Health Organization notes that "there is no level of exposure to lead that is known to be without harmful effects."

So, keep an eye on the bottom of your Stanley cup to make sure that cover stays where it’s supposed to be. And if the cover does come off and exposes the seal containing lead, customers can submit a claim under the product’s lifetime warranty.

Do other insulated tumblers contain lead?

Stanley is not alone in using lead-containing pellets to seal its insulated cups. The Stanley spokesperson says in the statement that the pellet the company uses is “industry standard.” And Rubin says that she’s tested bottles from other companies that make insulated cups with similar pellets covered in a similar fashion to Stanley.

However, Stanley competitor Hydro Flask does not use lead in its manufacturing, according to a recent Instagram post.

"More than a decade ago we pioneered a new process that sealed our bottles without the use of lead," the company said. "Even though this process was more complex — and more expensive — we chose this path because we aimed for a higher standard, knowing lead could be harmful to our consumers, manufacturing partners and the environment."

Water bottle companies Owala and Klean Kanteen also do not use lead in their manufacturing.

It’s important to note that the CPSC monitors products, including insulated tumblers, for violating lead regulations and has recently recalled several children’s products for having accessible pellets that contain levels that exceed the federal lead content ban, CPSC press secretary Patty Davis tells TODAY.com. Examples include products sold by PandaEar, Cupkin, Tiblue, Klickpick, and Laoion.

Davis encourages consumers to report any lead-related concerns they have for any product currently on the market to the CPSC at SaferProducts.Gov.

“Each report is reviewed and could potentially lead to a recall,” she says.