Those are sterilized with ethylene oxide gas, which is a CMR-classified substance (cancerogenic, mutagenic, reprotoxic). It has a very low boiling point ~10°C (that's roughly 50°F in 'murica units), which means after few days there is only traces left; that should be harmless when you are not exposed to it regularly. This is, when you trust the frabricators (as they are often produced in third world shitholes) and the qualitiy assurance (which is profit orientated). That being said, testing toddlers is total baloney altogether.