Formaldehyde and Out-Gassing
| Formaldehyde is an important chemical used widely by
industry to manufacture building materials and numerous household
products. It is also a by-product of combustion and certain other
natural processes. Thus, it may be present in substantial
concentrations both indoors and outdoors.
Sources of formaldehyde in the home include building materials,
smoking, household products, and the use of un-vented, fuel-burning
appliances, like gas stoves or kerosene space heaters. |
Steps to Reduce Exposure
- Use "exterior-grade" pressed wood products (lower-emitting
because they contain phenol resins, not urea resins).
- Use
dehumidifiers and air conditioning to maintain moderate
temperature and reduce humidity levels.
- Increase ventilation, particularly after bringing new sources
of formaldehyde into the home.
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| Formaldehyde, by itself or in
combination with other chemicals, serves a number of purposes in
manufactured products. For example, it is used to add
permanent-press qualities to clothing and draperies, as a component
of glues and adhesives, and as a preservative in some paints and
coating products. |
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 sub-flooring 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.
Other pressed wood products, such as softwood plywood and flake or
oriented strandboard, are produced for exterior construction use and
contain the dark, or red/black-colored phenol-formaldehyde (PF) resin.
Although formaldehyde is present in both types of resins, pressed woods
that contain PF resin generally emit formaldehyde at considerably lower
rates than those containing UF resin.
Since 1985, the Department of Housing and Urban Development (HUD) has
permitted only the use of plywood and particleboard that conform to
specified formaldehyde emission limits in the construction of
prefabricated and mobile homes. In the past, some of these homes had
elevated levels of formaldehyde because of the large amount of
high-emitting pressed wood products used in their construction and
because of their relatively small interior space.
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. Few homes are now being insulated with this
product. 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 levels of formaldehyde now.
Sources of Formaldehyde
Pressed wood products (hardwood plywood wall paneling,
particleboard, fiberboard) and furniture made with these pressed wood
products. Urea-formaldehyde foam insulation (UFFI). Combustion sources
and environmental tobacco smoke. Durable press drapes, other textiles,
and glues.
Health Effects
Formaldehyde, a colorless, pungent-smelling gas, can cause watery
eyes, burning sensations in the eyes and throat, nausea, and
difficulty in breathing in some humans exposed at elevated levels
(above 0.1 parts per million). High concentrations may trigger attacks
in people with asthma. There is evidence that some people can develop
a sensitivity to formaldehyde. It has also been shown to cause cancer
in animals and may cause cancer in humans. Health effects include
eye, nose, and throat irritation; wheezing and coughing; fatigue; skin
rash; severe allergic reactions. May cause cancer. May also cause
other effects listed under "organic gases." EPA's Integrated Risk
Information System profile -
http://www.epa.gov/iris/subst/0419.htm
Levels in Homes
Average concentrations in older homes without UFFI are generally
well below 0.1 (ppm). In homes with significant amounts of new pressed
wood products, levels can be greater than 0.3 ppm.
Steps to Reduce Exposure
- Use "exterior-grade" pressed wood products (lower-emitting because
they contain phenol resins, not urea resins).
- Use
dehumidifiers and air conditioning to maintain moderate
temperature and reduce humidity levels.
- Increase ventilation, particularly after bringing new sources of
formaldehyde into the home.
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Reducing Exposure to Formaldehyde in Homes
Ask about the formaldehyde content of pressed wood products,
including building materials, cabinetry, and furniture before you
purchase them.
If you experience adverse reactions to formaldehyde, you may want
to avoid the use of pressed wood products and other
formaldehyde-emitting goods. Even if you do not experience such
reactions, you may wish to reduce your exposure as much as possible
by purchasing exterior-grade products, which emit less formaldehyde.
For further information on formaldehyde and consumer products, call
the EPA Toxic Substance Control Act (TSCA) assistance line
(202-554-1404).
Some studies suggest that coating pressed wood products with
polyurethane may reduce formaldehyde emissions for some period of
time. To be effective, any such coating must cover all surfaces and
edges and remain intact. Increase the ventilation and carefully
follow the manufacturer instructions while applying these coatings.
(If you are sensitive to formaldehyde, check the label contents
before purchasing coating products to avoid buying products that
contain formaldehyde, as they will emit the chemical for a short
time after application.)
Maintain moderate temperature and humidity levels and provide
adequate ventilation.
The rate at which formaldehyde is released is accelerated by heat
and may also depend somewhat on the humidity level. Therefore, the
use of dehumidifiers and air conditioning to control humidity and to
maintain a moderate temperature can help reduce formaldehyde
emissions. (Drain and clean dehumidifier collection trays frequently
so that they do not become a breeding ground for microorganisms.)
Increasing the rate of ventilation in your home will also help in
reducing formaldehyde levels.
Steps to Reduce Exposure
- Use "exterior-grade" pressed wood products (lower-emitting
because they contain phenol resins, not urea resins).
- Use
dehumidifiers and air conditioning to maintain moderate
temperature and reduce humidity levels.
- Increase ventilation, particularly after bringing new sources
of formaldehyde into the home.
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