First, let’s go over what formaldehyde is. Formaldehyde is a toxic chemical used in keratin treatments. As reported by the American Cancer Society, this element is a carcinogen and can cause burning sensations in the eyes, nose and throat. It can also cause coughing, wheezing, water eyes, nausea, skin irritation and cancer. In addition, Health Canada has put a restriction on the limit of formaldehyde in smoothing treatments in Canada since 2011 as a result of some health scares in the industry. Stylists and clients are protected from high levels of exposure to formaldehyde fumes caused by the high temperatures of the flat iron during the process.