Other Indoor Contaminants: Formaldehyde

Formaldehyde is a fascinating compound for a lot of reasons. It is one of the most common chemicals used in all kinds of products. It has been around for decades in products used in the office, home and school. And it recently has been classified as a known carcinogen and the regulating agencies want to reduce exposures by setting very low recommended exposure limits.

A little background is in order, courtesy of the EPA. Formaldehyde (HCOH) is a colorless, flammable, strong-smelling chemical that is used in building materials and many household products. It is used in pressed-wood products, such as particleboard, plywood, and fiberboard; glues and adhesives; permanent-press fabrics; paper product coatings; and certain insulation materials including fiberglass. In addition, HCOH is commonly used as an industrial disinfectant, and as a preservative in mortuaries and medical laboratories. Formaldehyde also occurs naturally in the environment. It is produced in small amounts by most living organisms.

In 1987, OSHA modified the federal standard that reduced the amount of HCOH to which workers can be exposed over an 8-hour workday from 3 ppm to 1 ppm. In May 1992, the standard was amended, and the exposure limit was further reduced to 0.75 ppm. Keep in mind that this is an occupational standard, with the assumptions that exposure is for only 40 hours a week and the exposed population is comprised of healthy, working age adults. The standard is appropriate for industrial and commercial work places where workers know there is exposure.

When you move to residential settings, the assumptions change. The exposures can now be 24/7 and involve the young, elderly and infirm. The threshold numbers are naturally lower. How low? The National Institute of Occupational Health and Safety (NIOSH) has long recommended an exposure limit of 0.016 ppm due the cancer risk, almost 50x lower than the OSHA standard. EPA would like an even lower numbers, especially where young children are involved.

These low levels can be difficult to achieve due to the ubiquitous nature of HCOH in building materials. Our experience indicates that formaldehyde levels in the range of 0.02 to 0.05 ppm are pretty common in residential and office buildings. So what can you do to limit exposures?

The EPA recommends several relatively simple measures. The use of “exterior-grade” pressed-wood and plywood products will limit HCOH exposure in the home. These products emit less formaldehyde because they contain phenol formaldehyde resins, not urea formaldehyde resins. Keep in mind that the exterior grade pressed-wood products such as plywood, paneling, particleboard, and fiberboard are not the same as pressure-treated wood products, which contain chemical preservatives and are intended for outdoor use only. Before purchasing pressed-wood products, including building materials, cabinetry, and furniture, you should ask about the formaldehyde content of these products.  OSHA requires that HCOH levels be disclosed.

Indoor HCOH levels can also be reduced by ensuring adequate ventilation, moderate temperatures, and reduced humidity levels through the use of air conditioners and dehumidifiers. When we talk about ventilation we mean air changes with the use of outdoor air. Most residential (and many commercial) ventilation systems do not provide any outdoor air ventilation. While some commercial units can be modified to provide at least some outdoor air, most residential units cannot. The most practical alternative is to use natural ventilation from windows and doors. Energy efficient homes can make even this alternative a challenge.

If you are considering testing for HCOH levels, make sure your consultant is using a method with an adequate detection limit. Since we are interested in levels in the range of 0.02 ppm, the detection limit should be at least 0.005 ppm to ensure precision and accuracy. Both the NIOSH Method 2016 and EPA Method TO-11 have adequate sensitivity and are available from any credible industrial hygiene consultant. Most direct reading instruments do not have the gusto, so try to avoid wasting your money on this approach.