While the memory foam that comes from the U.S. does not contain toxic ingredients such as formaldehyde or PBDE (polybrominateddiphenylether), it can have somewhat of a new foam type of smell that can stay for a couple of days to a couple of weeks, depending on the foam manufacturer. While this smell does not seem to trigger allergies, it can be a bother initially for people who have sensitivity to smells.
Unfortunately, not all foam is created equal. Many companies will put together the matress in the U.S., but buy the foam overseas to save money. With overseas foam, we cannot be sure of the quality or the composition, so we are very wary of recommending any type that use memory foam not produced in the United States, with the exception of Tempur-Pedic, who has the only high quality Swedish manufacturing facility we know of.