UFFI foam insulation in an old house (C) Daniel Friedman Formaldehyde Gas & Outgassing Hazards In buildings

  • FORMALDEHYDE GAS SOURCES in BUILDINGS - CONTENTS: Sources of formaldehyde gas or odors in buildings. Formaldehyde gas exposure limits. How to reduce formaldehyde exposure levels in a building. Current sources of formaldehyde gas concerns in buildings. Formaldehyde outgassing health concerns in FEMA trailers provided as temporary housing for Hurricane Katrina victims and in other mobile homes.
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Formaldehyde gas sources in buildings:

This article series describes the health risks of exposure to formaldehyde gas in air or water, and we describe the proper steps to remove formaldehyde gas and formaldehyde gas emitting building products in order to improve indoor air quality in homes, offices, other .

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Common Sources of Formaldehyde Gas in buildings

Particle board with mold (C) Daniel FriedmanThe list of all possible building products, furnishings, and contents that might be sources of formaldehyde would number in the thousands and at best is confusing since the formaldehyde gas emitting properties of different materials and products vary considerably.

Beginning here we describe the principal categories of formaldehyde gas-emitting sources likely to be in buildings in order to help track down possible formaldehyde problem sources that might be addressed after it has been determined that there is a formaldehyde hazard in a particular structure.

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Building Materials or Furnishing Products that Are Common Sources of Indoor Formaldehyde

  1. Cabinets & countertops (some) using particle board, wood composites, or pressed-wood products and possibly in construction adhesives, glues, coatings
  2. Carpeting and carpet padding (some)
  3. Cigarette smoke
  4. Fabrics (some) that are treated with chemicals to add a "permanent press" or wrinkle-resistant property
  5. FORMALDEHYDE in LAMINATE FLOORING - reports that Lumber Liquidator's Chinese produced laminate flooring causing significant formaldehyde outgassing and possibly other laminate flooring products, particularly those produced using medium-density-fiberboard or MDF that appears as the core in many of these products.
  6. FORMALDEHYDE TESTS for FLOORING - discusses testing flooring for formaldehyde outgassing
  7. FORMALDEHYDE in LAMINATE FLOORING - Chinese produced laminate flooring formaldehyde outgassing
    The largest source of formaldehyde in homes today is considered to be composite wood products, also called pressed wood products, made with urea-formaldehyde resins. - AIHA (May 2015) draft on file.
  8. Glues and adhesives (some) using formaldehyde resins
  9. Insulation materials (some) including some foam spray insulating products. See
    • UREA FORMALDEHYDE FOAM INSULATION, UFFI - was UFFI a demonstrable health hazard? what to do about UFFI in buildings. During the 1970s, formaldehyde was used in producing urea-formaldehyde foam insulation (UFFI), which was blown into the walls of many homes in the U.S. and Canada and later banned after elevated levels of formaldehyde were found in a small number of homes. Testing has since shown that, in most cases, any excess formaldehyde was released within a few days of installation. Nonetheless, the material was removed from a large number of homes and banned for several years in the United States and permanently banned in Canada.
    • URETHANE FOAM Deterioration, Outgassing - rate of outgassing from polyurethane foam insulation
  10. Paints or other coatings (some) and some other building finishes
  11. Particle board used in a variety of furniture, furnishings, or other home products, including those produced using medium-density-fiberboard or MDF
  12. Subflooring using particle board or MDF

Table of formaldehyde sources indoors (C) J Wiley, Steven BlissMore information is at Formaldehyde Exposure in Homes: A Reference for State Officials to Use in Decision-making [PDF] from the U.S. CDC.


At FORMALDEHYDE HAZARDS Steve Bliss reports that the most significant source of formaldehyde in homes today is pressed wood products made with urea- formaldehyde resins. These include particle board, interior hardwood paneling, and medium-density fiberboard (MDF), which has the highest concentration of urea- formaldehyde of any pressed wood product.

Table 7-7, excerpted from FORMALDEHYDE HAZARDS, at left lists the Contributions of Formaldehyde to Room Air from various building materials and activities.

[Click to enlarge any image]

For a different point of view, and from a group with special interests in the formaldehyde issue, see "The Formaldehyde Fuss", published by the RV Trade association who brought in their own expert to rebut the health concerns from formaldehyde and to address public perception of formaldehyde risks in RVs and mobile homes such as in the FEMA trailers and other mobile homes - September 2007.

Formaldehyde-emitting building materials

Particle board with mold (C) Daniel FriedmanAt left is an example of mold-contaminated particleboard used as the structure for a kitchen countertop. Pressed-wood products such as particle-board, medium density fiberboard (MDF), as well as plywood, oriented strand board (OSB), and hardwood plywood paneling are among the most likely sources of elevated levels of formaldehyde indoors.

These products tend to be significant formaldehyde sources - at least until their outgassing has diminished over time - because:

In fact many sources including Health Canada explain that

Most formaldehyde in homes comes from building materials used in the home, especially pressed-wood products, such as particleboard, medium density fiberboard, and hardwood plywood panelling. Pressed-wood products that use adhesives containing urea-formaldehyde resins generally release more formaldehyde than those containing phenol-formaldehyde resins.

In general, these products will emit less and less formaldehyde over time. However, it can take weeks, months or even years to stop completely. Formaldehyde levels are, therefore, generally higher in newly built or newly renovated homes. More formaldehyde is also released on hot and humid days, so levels are often higher in the summer. - "Formaldehyde in Indoor Air", Health Canada, retrieved 29 March 2015, original source:

Formaldehyde-emitting furnishings & soft goods

Formaldehyde is used to add permanent press qualities to clothing and drapes and as the adhesive resin in some carpeting [and possibly in some carpet padding], fiberglass insulations, and (depending on where you live) in glass fiber or glass wool insulation.

You can see greenish-yellow binder resin in the photo-micrograph of fiberglass insulation just below.

Fiberglass resin may contain and outgas formaldehyde (C) Daniel Friedman

Our microscopic photograph of fiberglass insulation (above) is discussed in more detail

Interior coatings as formaldehyde sources

Because formaldehyde is used as as a preservative in many paints and coatings these can produce significant off-gassing of formaldehyde (and other VOCs) especially when newly-applied.

Continuing a comment from Health Canada

Other sources of formaldehyde include ... some paints and adhesives, varnishes and floor finishes and permanent press fabrics. - op. cit.

Indoor Combustion as a Formaldehyde Source

Formaldehyde is also a product of combustion found in tobacco smoke and the fumes from gas stoves and other unvented combustion.

Formaldehyde Gas in Mobile Homes & Disaster Housing or FEMA Trailers

Before 1985 formaldehyde gas levels were particularly high in mobile homes because of the combination of use of large amounts of paneling, carpeting, and particleboard, and because of their comparatively small enclosed space.

Formaldehyde products that emit that gas in mobile homes were regulated (and generally reduced) beginning in 1985 when the HUD standard set a limit on particleboard emissions in mobile homes of 0.3 ppm and 0.2 ppm from plywood paneling (based on a standard "large-scale test chamber").

Formaldehyde was reported as a significant problem in FEMA-provided mobile homes or trailers that were provided to people who lost their homes during Hurricanes such as Hurricane Katrina or Hurricane Sandy. In 2012 NBC News reported a $42.6 million class-action lawsuit settlement against the manufacturers of FEMA trailers. Quoting from NBC News:

"More than six years after Gulf Coast victims of Hurricane Katrina began experiencing adverse health effects while living in travel trailers provided by the federal government for temporary housing, a federal judge in New Orleans has given his final approval to a $42.6 million settlement of a class-action lawsuit alleging that the units emitted hazardous levels of the toxic chemical formaldehyde.  - Mike Brunker, David Friedman (photos), NBC News, "Class-action suit against FEMA trailer manufacturers settled for $42.6 million.
As (now first reported in July 2006, residents of the trailers began complaining of headaches, nosebleeds and breathing difficulty shortly after moving into the trailers, which were trucked to the Gulf Coast by the tens of thousands after Katrina and Rita devastated the area in rapid succession in 2005.Air quality tests of 44 FEMA trailers in early 2006 conducted by the Sierra Club found formaldehyde concentrations as high as 0.34 parts per million – a level nearly equal to what a professional embalmer would be exposed to on the job, according to one study of the chemical’s workplace effects.
And government tests on hundreds of trailers in Louisiana and Mississippi announced in 2008 found formaldehyde levels that were, on average, about five times what people are exposed to in most modern homes.
" - NBC News, 28 Sept 2012, retrieved 5/8/15 original source: -fema-trailer-manufacturers-settled-for-426-million

References & Research on Formaldehyde Hazards in Disaster Housing & FEMA Trailers

Urea Formaldehyde Outgassing Sources Continue in Use in Modern buildings

A California study of indoor air quality in recently built homes (3-5 years old) found a similar range: indoor concentration of formaldehyde ranged from 4 ppb to 120 ppb, with a median of 29 ppb. The outdoor formaldehyde concentrations ranged from < 1 ppb to 6.5 ppb with a median of 1.7 ppb. (Offermann, 2009)

As New Zealand building investigator Paul Probett has pointed out (May 2010) that UFFI continues to be a concern as a formaldehyde outgassing source and that building moisture and formaldehyde outgassing appear to have an important relationship:

... We are becoming increasingly concerned here as [UFFI urea formaldehyde foam insulation] off gassing rates ( the company doing installs here uses USA sourced UF foam) do not seem to stabilize as quickly as some literature suggests. Since NIOSH and CDC ... [currently] class Urea Formaldehyde as a carcinogen, [see above] we have elevated concerns.

The other issue is that we are getting anecdotal evidence that when UFFI is wet it breaks down to airborne UF. In addition given your recent FEMA problem with class actions over UF release from emergency accommodation trailers used after Hurricane Katrina- the issue has a new lease of life.
[See "CDC Releases Results Of Formaldehyde Level Tests" below at References.]

We still use UF
[Urea Formaldehyde] in large quantities in particle board here ( 106kg/m3 of UF and about 20kg/m2 of Toluene) and believe we are seeing off gassing of these products from wet ... OSB ... at levels high enough to suggest high risk to long term occupants.

In February 2008, in "CDC Releases Results Of Formaldehyde Level Tests", 14 February 2 [at References}

In "Formaldehyde Exposure in Homes:A Reference for State Officials to Use in Decision-making", [PDF] the U.S. CDC, Department of Homeland Security, FEMA, and the US EPA reported on the past and current level of formaldehyde hazards in buildings.

For a different point of view, and from a group with special interests in the formaldehyde issue, see "The Formaldehyde Fuss", published by the RV Trade association who brought in their own expert to rebut the health concerns from formaldehyde and to address public perception of formaldehyde risks in RVs and mobile homes such as in the FEMA trailers and other mobile homes - September 2007. is an independent publisher of building, environmental, and forensic inspection, diagnosis, and repair information for the public - we have no business nor financial connection with any manufacturer or service provider discussed at our website.

Other Sources of Indoor Formaldehyde Gas & What Gets Rid of Formaldehyde

Other sources of indoor formaldehyde gas emission that continue to generate consumer complaints in some homes (though certainly not with all products) include formaldehyde outgassing from some carpet backings, carpet padding, glues, and fabrics.

Heat and humidity increase the level of emission of gases from building materials in general - therefore these may even be useful in speeding the outgassing process where that step is desirable.



Article Series Contents


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