More than 345,000 children's cups are being recalled due to lead levels that exceed the federal content ban, the U.S. Consumer Product Safety Commission said Thursday.

Soojimus is recalling 8-ounce and 12-ounce models of its Cupkin Double-Walled Stainless Steel Children’s Cups — sold in various colors on Amazon and the Cupkin website from 2018 through earlier this year.

Consumers in possession of the recalled Cupkin cups are urged to stop using them immediately and contact Soojimus for a full refund. No illnesses or injuries related to the recall have been reported to date.

According to Cupkin, liquid in the now-recalled cups is “not exposed to lead due to the double walled construction.” The exposure to lead can occur if the cup bottoms are mistreated, the brand said.

In a response to the recall on its website, Cupkin noted that it initiated the voluntary recall after receiving consumer feedback and conducting additional testing. Lead was not detected during the products' initial development, the brand added.

“When we initially developed these cups, our manufacturing partner confirmed multiple times that absolutely no lead was used in any part of our production process,” Cupkin's message read, adding that the cups were also tested by two separate third-party labs accredited by the CPSC.

“Learning that our manufacturing partner and not one, but two CPSC-accredited labs let us down is a heavy set back both financially and emotionally,” Cupkin continued. “However, no matter the cost...we are going to be as transparent and proactive as possible to resolve this ASAP.”

Soojimus and Amazon will be directly contacting all known purchasers of the recalled Cupkin cups, the CPSC said Thursday. To receive a refund, consumers can submit photographs of the cups showing their destruction and fill out a form on Cupkin's website.

“My wife and I have two little girls. As parents, our intentions with the Cupkin cups were to be lead-free from the beginning,” Max Kang, one of the co-founders of Cupkin, said in an emailed statement to The Associated Press. “I just want all of our customers to know that we take this very seriously and will rebuild from here.”

Kang reiterated that their manufacturer initially confirmed no lead was used in the cups' glass beads, which are placed at the bottom of the products for vacuum sealing. But the manufacturer later admitted fault, he said.

Health officials maintain there is no safe level of lead, which can harm brain development in young children. Kids can be exposed to the metal through bits of old paint, contaminated dust and sometimes drinking water that passes through lead pipes.