Low health risk from boron compounds in toy slime and bouncy putty
Boron compounds such as boric acid and borax can be added to viscous "wobbling" masses so that the toy slime slimes properly and the bouncy putty bounces properly. The German Federal Institute for Risk Assessment (BfR) has now investigated the question of whether the boron contained in "wobbling" masses can be expected to have adverse effects on children. The result: it is very unlikely that swallowing boron-containing wobbling mass once will have negative health effects. "Nevertheless, parents should prevent their child from putting the wobbling mass in its mouth to reduce contact with boric acid, but also other chemical substances, to a minimum," says Professor Dr. Dr. Andreas Luch, Head of Department Chemical and Product Safety. "In addition, these toys are usually not suitable for small children under the age of three, so the BfR recommends to comply with the minimum age indicated on the products."
Boron is a semimetal ("metalloid"). It does not occur in the environment in pure form, but in the form of boric acid or its salts, the borates. In wobbling products, boron compounds cross-link long-chain molecules and thus create sticky, soft and elastic properties in modelling clay and toy slime, depending on the composition.
For its health assessment, BfR used surveillance data on the boron release from toy slime provided by Official Control Laboratories of the German Federal States. On this basis, the BfR assessed the uptake through ingestion and via the skin. According to the European Toy Safety Directive 2009/48/EC, no more than 300 milligrams (mg) of boron per kilogram (kg) of toy material may be released from liquid or sticky toys, which includes certain wobbling masses.
The BfR concludes that acute health effects from a single swallowing event of a larger amount of about five grams of wobbling mass are very unlikely. Five grams correspond roughly to a ball with the diameter of a two-euro coin. This applies in the case that the amount of boron released is less than 11 600 mg/kg of toy material. The data submitted by the Federal State authorities to the BfR were below this value. Symptoms of acute boron poisoning would be nausea and vomiting as well as diarrhoea and abdominal pain.
Chronic adverse health effects resulting from daily play with wobbling mass are very unlikely in the view of the BfR provided that less than 2950 mg boron/kg are released. When considering long-term intake, the BfR also took into account background exposures from other sources (drinking water, food, consumer products).
About the BfR
The German Federal Institute for Risk Assessment (BfR) is a scientifically independent institution within the portfolio of the Federal Ministry of Food and Agriculture (BMEL) in Germany. It advises the Federal Government and the States ("Laender") on questions of food, chemicals and product safety. The BfR conducts independent research on topics that are closely related to its assessment tasks.