Formaldehyde was one of the first preservatives used in cleaning products, and it has been identified as a known carcinogen, or cancer-causing agent. Many companies do not intentionally add formaldehyde, but it can still be present in formulas. Some chemicals called “formaldehyde donors” can break down and degrade over time into formaldehyde. By purchasing products with all ingredients listed on the label, you can see formaldehyde or formaldehyde donors, such as such as dimethyl-dimethylhydantoin (DMDMH), imadazolidinyl urea, diazlidinyl urea, sodium hydroxyl or methyl glycinate. We do not use formaldehyde or formaldehyde donors in any of our ECOS products.