Following a rise in popularity due in part to social media, one mother in the U.S. is speaking out about finding traces of lead in dozens of Stanley cups after conducting her own at-home tests.

For years, Tamara Rubin from Portland, Ore., a self-proclaimed "Lead-Safe Mama" and activist, has been pushing companies that use lead in the U.S. to recall thousands of its products.

She says various 40 oz. Stanley cups and tumblers have unsafe levels of lead between the stainless steel and the outer frame of the cup, and the lead can be exposed over time.

"I probably got about several hundred reports of the bottom caps coming off," Rubin told Â鶹ӰÊÓ at the end of January. She says she receives multiple emails and messages daily from people who have reached out to her. 

She says with increased dishwasher use and excessive moisture around the steel disc, the glue that keeps the cap in place can wear down.

"This is not an intermittent problem; the bottom cap regularly fails on this product," added Rubin.

Once the cap is off, she says the lead is then exposed in a small hole, which people, including small children, can come into contact with, Rubin worries.

"A small child that might be using it will fidget with the bottom of a product like that while they're drinking, that’s just kind of human nature," she said.

Â鶹ӰÊÓ contacted Stanley for comment but did not receive a response.

In a statement on its website however, the company does confirm lead is used in the manufacturing of its drinkware.

"Our manufacturing process currently employs the use of an industry standard pellet to seal the vacuum insulation at the base of our products; the sealing material includes some lead. Once sealed, this area is covered with a durable stainless steel layer, making it inaccessible to consumers."

The company added that no lead is present on the surface of any of its products and that it meets all U.S. regulatory requirements. Stanley also highlighted any concerns related to the bottom of the cup.

"In the rare occurrence the base cap of a product comes off due to ordinary use and exposes this seal," the company said, adding that any cups that have this specific issue has a lifetime warranty guarantee.

Is it safe?

Kevin Wilkinson, an environmental chemistry professor at the University of Montreal, says human exposure to lead should be avoided.

"Lead is a very toxic element, we have to be careful and we should take as much precautions as we can," Wilkinson said.

"If it was my cup and the lead is exposed, I wouldn't be using it. You want to be more safe than sorry with these kinds of things. The lead is a very toxic metal so you don’t want to take any chances."

Wilkinson says companies use lead in its products because it is an inexpensive metal that is easily mined and accessible. He warns that the longer people are exposed to lead, there can be a higher possibility of it leading to life-changing issues.

"Lead is recognized as a carcinogen, many of the earlier problems with respect to neuro-developmental effects, (researchers) saw that lead in the diet, especially in children lead to lower IQs," said Wilkinson.

On its website, the (CPA) says exposure was more common with lead previously used in gasoline up to the 1990s, and indoor household paints up to the 1950s. Lead exposure is not as common today due a decrease in its usage and tighter health restrictions.

"In Canada, we still have a lot of municipalities that have too much lead in drinking water," says Wilkinson, adding that many municipalities are making the necessary changes to its water lines, but says there is still a lot of work that needs to be done.

CPA says lead exposure can lead to headaches, abdominal pain, anemia, constipation, vomiting and sometimes even death. It adds that children are most vulnerable to lead exposure due to rapid growth and development, and can absorb 40 per cent more lead than adults.

The CPA also reported that, in 2003, the World Health Organization estimated about 3.5 per cent of mild intellectual disabilities worldwide are caused by lead exposure.

What’s next for Lead-Safe Mama?

Rubin says she will keep pushing to make sure Stanley and other companies stop using lead in its products.

Later this spring, she plans to submit a consumer product safety commission violation report against Stanley for its 20 oz. children’s tumblers that she says is experiencing the same issue as the larger cup.

"If a company is manufacturing a product with lead, the lead becomes exposed and a human, especially a child, might interact with that. That’s not acceptable. We need to demand that the company stop using lead or that they make the product in a way that the lead does not become exposed," Rubin said.

Rubin has been an advocate in speaking out against the use of lead for more than 15 years. She says her children live with various lead-related disabilities after her family was exposed during renovations to their home.

"If I had it my way, we would ban lead in all products," said Rubin.