The U.K.-based charity Which? tested 11 popular slime products, and found eight contained unsafe levels of boron. The chemical element is found in borax, which gives slime products their stickiness.
Exposure to excessive levels of boron can cause symptoms such as irritation to the skin, diarrhea, vomiting and stomach cramps. And contact with very high levels of boron could impair fertility and harm fetuses in pregnant women, according to the European Commission.
Which? urged parents to “approach slime with caution,” warning most products have minimal safety labeling and information about ingredients. Some products carried the CE safety mark, despite carrying higher than recommended boron levels.
Parents should even be cautious of homemade slime, which has exploded in popularity in the past few years, as some ingredients—such as contact lens solutions—contain borax but recipes don’t list exact quantities.
The European Union limit on boron in consumer products stands at 300mg/kg. The U.S. Consumer Product Safety Commission did not immediately respond to a request for comment regarding the safety limit of boron in products in the U.S.
The researchers named Toysmith Jupiter Juice the worst in the study, as it contained four times the safety limit of boron. It was followed by CCINEE Pink Fluffy Slime, which contained 1000mg/kg, and Cosoro Dodolu Crystal Slime Magic Clay, which contained 980mg/kg. Only Hulk Green Halloween Slime had safe levels of boron.
All of these products could be purchased on Amazon. The online retailer has since removed them from its listings. But Which? raised concerns that such products were previously readily available online.
Amazon did not immediately respond to a request for comment. The retailer told Which?: “All Marketplace sellers must follow our selling guidelines and those who don’t will be subject to action including potential removal of their account. The products in question are no longer available."
Which? sent its findings to the Office for Product Safety and Standards in the U.K., and stated customers are entitled to a refund. However, it is unclear whether this relates to consumers in the U.S..
Nikki Stopford, director of research and publishing at Which?, said in a statement: "If you have school-age kids you’re probably very well aware of the latest slime craze sweeping the playgrounds. Kids love it. Parents buying slime for their children should have peace of mind that these toys are safe, so they will be shocked to find that the health of their children could be put at risk by these slimes."
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