The use of the cleaning product borax in the making of slime, a process that has gained popularity on social media recently, has prompted concern following reports that it causes burns.
Borax, also known as sodium borate, is used in several household cleaning materials such as stain removers and deodorizers. But recently, students taking part in the growing trend of creating their own slime — boosted by platforms like Instagram — have been mixing the cleaning ingredient with water, glue and food coloring to create the stretchy substance.
But the trend may have a harmful side effect.
The Guardian reported that the use of borax, a mild irritant, has concerned parents after reports emerged that it caused burns on multiple children.
In February, one mother shared photos on Facebook showing burns on her daughter’s hands that she said she got after making slime using instructions on YouTube.
This year, Elmer’s glue reported that it had more than doubled its sales in December and grew overall in the second half of 2016 because of the slime-making trend.
This article originally appeared on Fortune.com