Homemade slime is the latest toy craze that children everywhere are becoming obsessed with. It’s so popular that parents are even throwing “homemade slime” parties in which kids gather to make this goo together. Now, however, some parents are warning others about the dangers that homemade slime poses to their children.

Last year, 11 year-old Kathleen Quinn of Rockland, Massachusetts suffered third degree burns while making homemade slime at a party.

Kathleen had been using Elmer’s school glue and sodium borate (also known as borax) to make the slime when her hands suddenly started to feel hot.

“She was crying in pain,” her mother recalled. “‘My hands hurt; my hands hurt!’ And we looked at them and they were covered in blisters.”

Doctors told Kathleen’s parents that her burns were from extended exposure to borax in the slime.

“It’s [borax] a material that is known to be an irritant to the eyes and to the breathing passages and nasal cavities, respiratory tracts. And it can be an irritant to the skin,” explained Consumer Reports chief scientific officer James Dickerson.

Sadly, what happened to Kathleen has happened to many other children as well, including Deejay Jemmett from Prestwich, Manchester, United Kingdom. Deejay suffered chemical burns from making the slime.

“She is an avid YouTuber and came to ask if she could make some slime,” said her mother, Rebekha D’Stephano. “Within 48 hours, her skin had started to peel off. From there it got worse.”

Deejay’s burns were so bad that she had to be referred to a plastic surgeon.

Over the summer, 6 year-old Riley Godfrey spent three days in the hospital after playing with homemade slime at school. It turned out that his teacher had made the slime using an online recipe which included contact lens solution, which often carries boron compounds.

“I could have lost my son,” said his mother Amy.

Many internet recipes for homemade slime that claim not to use borax still use borax-containing ingredients, like contact lens solution. Dickerson wants to make sure that parents know about the dangers of borax and homemade slime.

“It’s something that should be used solely for its intended purpose as a cleaner or a laundry booster, not as something for children, particularly, young children, to play around with in making things like slime,” he said.

Find out more about Kathleen’s story in the video below.