Inflatable toys and swimming aids, like bathing rings and armbands, that come with a distinctive smell may predict a range of potentially hazardous substances that are likely to increase the risk of cancer as well as other health issues in kids, researchers have found.

"There are always toys that emit a smell that is described by parents as 'pungent' or even 'somehow seems poisonous'," said Christoph Wiedmer from the Friedrich Alexander Universitat Erlangen-Nurnberg (FAU) in Germany.  Some of these compounds, which include carbonyl compounds, cyclohexanone, phenol and isophorone, might be critical when present in higher concentrations in children's toys.

Cyclohexanone can be harmful if inhaled, phenol is known to be acutely toxic and to presumably have mutagenic potential and isophorone is a category 2 carcinogen, which means that this is a suspect substance in the development of cancer in humans, the researchers said.

For the study, appearing in the journal Analytical and Bioanalytical Chemistry, the team conducted tests using an inflatable beach ball, a pair of swimming armbands and two bathing rings they bought off the shelf from local stores and online suppliers in Germany. The researchers then detected between 32 and 46 odours in each sample, of which up to 13 were quite intense. 

A majority of these odorants were identified and among these were several fatty smelling mono- or di-unsaturated carbonyl compounds and their epoxidised derivatives, but also odouractive organic solvents such as cyclohexanone, isophorone, and phenol.

"Modern products such as toys and children's products are sourced from a wide variety of chemical and physical manufacturing processes, and this complexity often makes it difficult for us to identify those containing contaminants and unwanted substances, and to determine their causes," Wiedmer noted.  "However, we found that in a number of cases our noses can guide us to 'sniff out' problematic products," Wiedmer said.