Question from Bonnie
Formaldehyde is typically used in clothing to minimize wrinkles. It can be found even in 100% cotton clothing particularly if it is something that wrinkles easily like a dress shirt. Here is one older study that tests several clothing items (pg 36) and as you can see there is formaldehyde found in 100% cotton as well as many types of cotton/synthetic blends. What it also shows is that items that are prone to wrinkling are more likely to test higher in formaldehyde. Given that a sweater is less likely to wrinkle it may not contain formaldehyde regardless of the material but I can’t tell you that for certain. You can call the companies and ask them but they are not required to disclose that information. If the item has a chemical odor that is an indicator (but not definitive) that it contains formaldehyde.
I wish that there was a standard rule of thumb that could tell more definitively what has it and what does not, but that is not the case.