Parents are being warned that some children’s slime products may contain up to four times the legal amount of a chemical which can cause convulsions and sickness.
Consumer group Which? tested 11 products, and found that eight of them breached EU regulations on the amount of boron they contain.
Boron is found in borax, the ingredient commonly used in slime manufacture to give the product its stickiness.
Which? said that Toysmith Jupiter Juice had more than four times the permitted level of boron with 1400mg/kg.
This was followed by CCINEE Pink Fluffy Slime, which was found to contain 1000mg/kg, and Cosoro Dodolu Crystal Slime Magic Clay, which was found to contain 980mg/kg.
One product purchased on the online marketplace, Hulk Green Halloween Slime, met the standard.
Slime from high street retailers, The Works and Smyths, were also found to be safe.
Large quantities of boron can be poisonous. Symptoms include include skin inflammation and peeling, tremors, convulsions, headaches, diarrhoea, vomiting, and even depression.
Nikki Stopford, director of research and publishing at Which?, said: “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.
“There must be fundamental changes to the product safety system.
“Manufacturers must stop making unsafe products and the Government and retailers simply have to do a far better job of getting anything identified as a risk off the shelves and out of people’s homes.”
All the products which failed the tests were bought from the online retailer Amazon. All have now been removed from their UK website, although some are still available from the US site.
An Amazon spokesperson said: “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.”