(ABC 6 News) – They’re big, stylish and all the rage – those popular Stanley Quenchers mugs.

Social media made them famous, and that’s where recent posts about those tumblers containing lead are raising concerns.

In recent months the Stanley Quencher has become a must-have for millions of fans, enjoying a wave of endorsements from TikTok creators, to being spoofed on Saturday Night Live.

But the laughing ended for some people when reports of the tumblers containing lead made the rounds on social media.

So, Consumer Reports looked to its partner from Lead Safe Mama to help guide consumers through the hype.

“Using XRF technology, we discovered that the exposed sealing dot on the bottom of the Stanley Tumblers was positive for a very high level of lead,” says Tamara Rubin, who owns Lead Safe Mama, LLC, and for years has been a leading lead poisoning prevention activist.

“On the bottom of the Stanley Tumblers there is a little button, and underneath that is a primarily leaded material, and Stanley melts that bit of lead into the hole on the bottom of the tumbler to create the vacuum insulation. Countless consumers have contacted us, and let us know that their little button of stainless steel with the logo has fallen off and that they were not aware that there was basically a hunk of bioavailable lead,” says Rubin.

Lead exposure can cause developmental problems, affect brain development, and lead to lower IQ.

Stanley’s website discloses that its sealing material does include some lead.

And Stanley isn’t alone, many similarly designed flasks and tumblers are manufactured the same way using lead solder.

On its website Stanley tells its customers to “Rest assured 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.” If you own a Stanley Quencher, and the button on the bottom falls off, stop using it immediately and contact the company for a replacement.

The company does offer a lifetime warranty. If you’re worried that your child might have been exposed to the lead, talk to your doctor about a blood lead test.

If you own one of those Stanley Quenchers, make sure you’re keeping it clean. If they’re dishwasher safe, that might be the best and easiest option. Otherwise, separate all parts of the tumbler and hand wash with warm water and a mild detergent.