Why is it Nasty?
Formaldehyde is a very toxic chemical and at high enough levels, can even be lethal. When humans are repeatedly exposed to formaldehyde at low levels the chemical can cause irratation and have toxic or carcinogenic effects. It may suprise you to learn that formaldehyde is present in many common household products even though it is not listed anywhere on the product label. There are many common preservatives that work by releasing formaldehyde over time which is a very potent biocide. Without reasearching each ingredient indepth, it is impossible to recognize these formaldehyde releasing preservatives by their chemical name.
How do I find it?
Formladehyde releasing preservatives are tricky to spot, as they can come from a variety of chemical classes and their chemical names are diverse. The easiest way to avoid these toxic chemicals is to watch out for some of the most commonly used nasties in this class: Bronopol, Diazolidinyl Urea, Disteardimonium Hectoride, DMDM hydantoin, Imidazolidinyl Urea, Methylene Glycol, Nitromethylidynetrimethanol, and Quaternium-15. Another way to spot safer options is to look for the “formaldehyde free” claim on a product.