Formaldehyde

Formaldehyde is a colorless, strong-smelling gas. It is an important industrial chemical used to manufacture other chemicals, building materials, and household products. In the home it can be found in glues, wood products, permanent press fabrics, paper product coatings, and certain insulation materials. Its most significant use in homes is as an adhesive resin in pressed wood products. There are two types of formaldehyde resins: urea formaldehyde (UF) and phenol formaldehyde (PF). Building products made with formaldehyde resins can "off-gas", or emit, formaldehyde gas. These products include particle board used as sub-flooring or shelving, fiberboard in cabinets and furniture, plywood wall panels, and foamed-in-place urea-formaldehyde insulation. Some sources that previously contained formaldehyde are either no longer used or have been reformulated to contain less formaldehyde. Incomplete combustion, cigarette smoking, and burning wood, kerosene, and natural gas also release formaldehyde. Thus, it may be present in substantial concentrations both indoors and outdoors.

In homes, the most significant sources of formaldehyde are likely to be pressed wood products made using adhesives that contain urea-formaldehyde (UF) resins. Pressed wood products made for indoor use include: particleboard (used as subflooring and shelving and in cabinetry and furniture), hardwood plywood paneling (used for decorative wall covering and used in cabinets and furniture), and medium-density fiberboard (used for drawer fronts, cabinets, and furniture tops). Medium-density fiberboard contains a higher resin-to-wood ratio than any other UF pressed wood product and is generally recognized as being the highest formaldehyde-emitting pressed wood product.

Formaldehyde is normally present at low concentrations, usually less than 0.06 ppm (parts per million), in both indoor and outdoor air. When present in the air at concentrations at or above 0.1 ppm, acute health effects can occur including watery eyes, burning sensations in the eyes, nose and throat, nausea, coughing, chest tightness, wheezing, skin rashes, and other irritating effects. High concentrations may trigger attacks in people with asthma. There is evidence that some people can develop a sensitivity to formaldehyde. Formaldehyde has caused cancer in laboratory animals and may cause cancer in humans. The cancer risk depends upon amount and duration of exposure.

The rate at which products like pressed wood or textiles release formaldehyde can change. Formaldehyde emissions will generally decrease as products age. When the products are new, high indoor temperatures or humidity can cause increased release of formaldehyde from these products. During the 1970s, many homeowners had urea-formaldehyde foam insulation (UFFI) installed in the wall cavities of their homes as an energy conservation measure. However, many of these homes were found to have relatively high indoor concentrations of formaldehyde soon after the UFFI installation. Studies show that formaldehyde emissions from UFFI decline with time. Therefore, homes in which UFFI was installed many years ago are unlikely to have high concentrations of formaldehyde now.

Exposure to formaldehyde may be decreased by the following measures:

• Purchasing pressed wood products labeled as low-emitting or products made from phenol formaldehyde, such as oriented stand board or softwood plywood.
• Increasing ventilation after bringing new sources of formaldehyde into your home.
• Using alternate products such as lumber, metal, or solid wood furniture.
• Avoiding the use of foamed-in-place insulation containing formaldehyde, especially urea-formaldehyde foam insulation.
• Enclosing unfinished pressed-wood surfaces of furniture, cabinets, or shelving with laminante or water-based sealant.
• Washing durable-press fabrics before use.
• Ensuring combustion sources are properly adjusted.
• Avoiding smoking indoors.
• Maintaining moderate temperatures and low (30% to 50%) relative humidity. The use of dehumidifiers and air conditioning to control humidity and to maintain a moderate temperature can help reduce formaldehyde emissions.