The chemical found in Aqua Dots toys during the 2007 recall was 1,4-butanediol.
Aqua Dots were small colored beads that bonded when moistened, allowing children to create designs. In 2007, investigators found that some beads had been manufactured with 1,4-butanediol instead of the intended less-toxic chemical.
When swallowed, 1,4-butanediol can be metabolized into compounds with effects resembling those of gamma-hydroxybutyrate, or GHB. Reported symptoms included unconsciousness, seizures, breathing problems, and coma. The toys were recalled internationally, and the incident prompted scrutiny of manufacturing and chemical substitution in imported products.
Aqua Dots are sometimes mistakenly associated with melamine, the contaminant involved in a separate 2008 Chinese milk-powder scandal. The two recalls involved different products and different chemicals.