Also known as methanal, oxomethane, methylene oxide, methylaldehyd and oxymethyline, formaldehyde is a colourless gas. Highly flammable, it can be identified by its pungent, bothersome odour. While formaldehyde occurs naturally inside the human body, most human exposure comes from outside sources. When combined with the chemical urea, the resulting compound is known as urea formaldehyde.
The U.S. Environmental Protection Agency (EPA) reports that some pressed-wood products are constructed using bonding agents that contain urea formaldehyde resins. Many of these items are made for use inside the home. For example, carpenters prefer medium-density fiberboard when building drawers, cabinets and furniture. Although urea formaldehyde strengthens the adhesive holding pressed-wood products together, there has been some discussion over its safety. When compared to other products containing urea formaldehyde, such as particleboard and plywood panelling, medium-density fiberboard releases the most formaldehyde into the atmosphere. The EPA warns that exposure to formaldehyde causes breathing difficulties, irritation to the eyes, nose and throat, or even cancer in humans as well as animals.
The American Contact Dermatitis Society reports that many fabrics, including rayon, corduroy, cotton blends and wrinkle-resistant fabrics, are typically treated with formaldehyde resins, such as urea formaldehyde. By treating fabrics with urea formaldehyde, the garment industry can offer consumers clothing that does not cling, wrinkle, shrink or hold static. Urea formaldehyde also ensures that fabric resists stains, perspiration, moths and mildew. Fabrics also hold colour better when treated with urea formaldehyde. Although garments treated with the chemical offer the same health risks as pressed wood products, washing garments multiple times can reduce the amount of urea formaldehyde contained inside them. However, washing garments will not reduce the risk to individuals who are already sensitive to formaldehyde.
Home expert Jon Eakes explains that foam insulation containing urea formaldehyde was banned for use in Canada as well as the U.S. during the early 1980s. The material was believed to emit dangerous levels of formaldehyde, causing health risks to families whose homes contained urea formaldehyde foam insulation (UFFI). However, researchers concluded that formaldehyde levels found inside the home are more likely to emerge from a range of sources, such as cigarette smoke, than from UFFI. Since then, the U.S. has changed its position on the material and has deemed it legal for sale once again. UFFI remains one of the most popular choices in home insulation, blocking air drafts. When installed in environments containing sufficient ventilation and low humidity levels, UFFI does not pose any significant health risks.