August 2008

Volume 17, Number 8

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Green Topics

All About Formaldehyde

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Image: Amie Walter

When we hear “formaldehyde,” a lot of us probably think of the liquid preserving frogs awaiting dissection, back in high school. That liquid, called formalin, is a solution of about 40% formaldehyde and 60% water. Formaldehyde is a simple organic compound, consisting of carbon, oxygen, and hydrogen. At atmospheric temperature and pressure it is a colorless gas with a distinctive, pungent odor. It occurs naturally, though generally at concentrations no higher than 0.03 parts per million (ppm).

Formaldehyde is also manufactured and used for a wide range of products, including adhesives, paints, fabrics, paper products, and even cosmetics. The very first plastic—bakelite, invented in 1905—was a polymerized phenol formaldehyde, and modifications of that compound are still widely used. Formaldehyde is prevalent enough that it rates its own trade association to sing its praises.

Formaldehyde is an important constituent in most manufactured wood and laminate products. Due largely to its low cost and light color, urea formaldehyde (UF) is the most common binder for interior-grade wood products, such as particleboard, medium-density fiberboard (MDF), and hardwood plywood. Unfortunately, the formaldehyde in UF binder is not very tightly locked up, so a lot of it is released into the air.

Phenol formaldehyde (PF) is used as a binder in exterior-grade wood products, such as plywood, oriented-strand board (OSB), and glulam beams. It is also a common resin in hard-surface countertop materials, such as those used in lab desks, it is the most common binder used in fiberglass insulation, and it is foamed to create some poured-in foam insulation materials. A related compound, melamine formaldehyde (MF) is used in plastic laminate and overlay materials. Formaldehyde is more tightly bound in PF and MF than it is in UF, reducing emissions.

Though useful, formaldehyde is harmful to our health. According to the U.S. Consumer Product Safety Commission, at concentrations in the air above 0.1 ppm, formaldehyde can cause irritation of the eyes, nose, and throat; nausea; chest tightness; coughing and wheezing; skin rashes; and allergic reactions. Over long periods of exposure, formaldehyde also likely causes cancer, according to the U.S. Environmental Protection Agency, and it can cause a variety of other problems.

Since 1985, the U.S. Department of Housing and Urban Development (HUD) has regulated formaldehyde emissions from wood-panel products made for use in manufactured homes, with a maximum allowable formaldehyde concentration of 0.4 ppm, when tested according to ASTM E-1333-96. The LEED Rating System awards a point for avoiding UF binders in wood products.

In 2007, the California Air Resources Board (CARB) finalized a new air quality rule regulating formaldehyde (see EBN Vol. 16, No. 6). This rule phases in maximum allowable formaldehyde concentrations for five types of manufactured wood panels, based on the same ASTM test standard HUD uses. Phase I, to take effect in January or July 2009, sets maximum concentrations ranging from 0.08 to 0.21 ppm; Phase II, to become effective between January 2010 and July 2012, sets limits of 0.05 to 0.13 ppm. The CARB standards will likely cause a phaseout of UF binders.

Comments (1)

1 More info on formaldehyde and posted by Tom Lent on 07/29/2008 at 08:09 pm

Thanks for an excellent primer. The Healthy Building Network recently completed analyses of the range of formaldehyde and alternative binders used in composite wood and a variety of other building products. For further information refer to factsheets entitled "Formaldehyde Found in Building Materials" and a variety of other factsheets and product lists on alternative binders for particle board and insulation. These and more related factsheets on chemicals in building materials can be found on the HBN website at

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July 29, 2008