FACT SHEET: ALTERNATIVE RESIN BINDERS FOR PARTICLEBOARD, MDF & WHEATBOARD May 2008

PAGE 1 OF 6

Urea formaldehyde-based 

resins have been the 

standard binders used 

to glue the particles 

together in many 

composite wood products, including 

particleboard, wheatboard, and medium 

density !berboard (MDF). In recent years, 

however, concerns have been rising 

about the risks of cancer and bronchial 

health impacts from formaldehyde.

1

Several market factors are driving 

major changes in the composition and 

technology of these resins. Pressure from 

the green building movement through 

market selection and certi!cation

programs, plus emissions regulations 

from the California Air Resources Board 

(CARB), are moving manufacturers to

look for ways to reduce formaldehyde 

emissions or eliminate formaldehyde 

entirely from formulas. 

Thisfactsheet evaluates health hazards

associated with each of the major binder

technologies. Manufacturers are currently

using or undertaking research and

development into four major approaches

to reduce the problem of exposure to

formaldehyde from composite wood

binders:

1) Modi!ed urea formaldehyde resins with

scavenger additives,such as melamine,

to reduce the rate of emissions of

formaldehyde;

2) Alternate formaldehyde resins,such as

phenol formaldehyde, which cure at the

factory during manufacture and hence

have much lower formaldehyde emissions

in use than urea formaldehyde;

3) Alternate fossil fuel-based binders

containing no added formaldehyde,such

as methylene diphenyl diisocyanate (MDI);

and

4) Alternate binders based on renewable

resource materials,such assoy "our.

Formaldehyde–based 

Binders

There are three types of formaldehydebased binders currently on the market.

Formaldehyde is a known carcinogen,

respiratory irritant and hazardous

component ofsmog. For more detailed

description of formaldehyde and its

health hazardsrefer to“Health Hazards

of Formaldehyde Found in Building

Materials”at http://www.healthybuilding.

net healthcare/index.html.

Alternative Resin Binders 

for Particleboard,

Medium Density Fiberboard 

(MDF), and Wheatboard

There are many concerns about the use of the term “formaldehyde free”

in marketing or otherwise describing building products. A wide range 

of materials, including wood and paper, naturally emit very small 

trace amounts of formaldehyde. Therefore for clarity, we exclusively 

use the term “no added formaldehyde”instead of “formaldehyde free”

to describe these products.

NOTE
Written and produced by Healthy Building Network. 

Production funded by the Global Health and Safety Initiative 

with the support of Health Care Without Harm. PAGE 2 OF 6

Urea Formaldehyde

Composite wood using binders

composed of urea formaldehyde (UF)

2

were determined by the CARB to be

signi!cantsources of formaldehyde

emissionsin buildings due to the fact

that urea formaldehyde continuesto

cure throughout itslifetime, out gassing

formaldehyde in the environment for

long periods after manufacture and

installation.

3

Urea Formaldehyde and 

Scavenger Additives

Urea formaldehyde-based resins can

be directly mixed with additives called

scavengers, which bind with the urea

formaldehyde to reduce emissions.

Melamine and hexamine are the most

common added scavengers. Alternatively,

the board may be treated after pressing

with a scavengersuch as anhydrous

ammonia or varioussolid ammonium

compounds.

4 Scavengers can reduce

formaldehyde emissions by 2 to 10 times,

but cannot eliminate it. Signi!cant quality

control isrequired in manufacturing

to maintain these reductionsin mass

production of the !nished product.

Furthermore, while reducing the rate

of emission of formaldehyde from

composite wood and providing short

term improvements, it is not clear if

scavengers extend the time over which

the formaldehyde emitsfrom the board.

Asthere is no threshold below which

formaldehyde has no carcinogenic

e#ect, this analysis does not focus on the

scavenger alternative.

Phenol Formaldehyde 

Phenol formaldehyde (PF)

5 haslong

been used in composite wood products

designed for exterior use due to its higher

water resistance than urea formaldehyde.

Phenol formaldehyde resultsin 90%

lessformaldehyde emissionsthan urea

formaldehyde, but does not completely

eliminate formaldehyde emissions

altogether.

6Phenol formaldehyde

formulations, like urea formaldehyde

formulas, are derived from formaldehyde

and hence share the same occupational

exposure concerns. Additionally, the

aromatic hydrocarbon, phenol,

7 that is

used to make phenol formaldehyde,

is on its own a chemical of concern.

Finally, phenol formaldehyde islisted as

a suspected immunotoxicant under NIH’s

Database on Hazardous Chemicals and

Occupational Diseases.

8 

MDI and pMDI

Polymeric MDI (pMDI)

9 isthe primary

technical/commercial form of methylene

diphenyl diisocyanate (MDI).

10 11 MDI

and pMDI are used in the production of

polyurethane foam as well asfor binders.

MDI and pMDI are produced from

aniline,

12 formaldehyde,13 14 and a large

number of other chemicals, including

MDI and benzene.

15 The bulk of the

scienti!c information assessing the health

or environmental hazards of MDI/pMDI

involve the use of MDI in the production of

polyurethane foam.

16

Health impacts—cancer

The International Agency for Research

on Cancer (IARC) classi!es MDA (4,4’-

methylenedianiline,

17 an aniline building

block of MDI, as a probable human

carcinogen (Group 2B).

18 While IARC

has not classi!ed aniline as a human

carcinogen, both the EPA19 and California

Proposition 6520 have done so. The

National Institute of Health’s National

Toxicology Program (NTP)statesthat

MDA isreasonably anticipated to be a

human carcinogen.

21 MDA islisted in

California’s Proposition 65 as a known
FACT SHEET: ALTERNATIVE RESIN BINDERS FOR PARTICLEBOARD, MDF & WHEATBOARD May 2008

PAGE 3 OF 6

carcinogen22 and is a cardiovascular,

kidney, and neurodevelopmental toxicant

in the Registry of Toxic E#ects of Chemical

Substances.

23

Studiesrecently are !nding emerging

evidence that the solvent benzene, used

to produce MDI, is not only a volatile

organic compound, but may also be linked

to leukemia, multiple myeloma, prostate

cancer, and non-Hodgkinslymphoma.

24

Health impacts—non-cancer

MDI is a member of a class of chemicals

known asisocyanates. Isocyanatesin

general are skin irritants, as well as eye,

mucous membrane, and respiratory tract

irritants.

25 The primary adverse e#ect on

humansfrom MDI is asthma and then

secondarily contact dermatitis, as well as

hypersensitivity pneumonitis(HP). Acute

inhalation exposure to aniline at high

levels can result in respiratory problemsin

humans.

26

Occupational exposures

Isocyanates are a class of chemicals

implicated in workplace exposures

and occupational health. The U.S.

Environmental Protection Agency

(EPA)says,“exposure to isocyanatesis a

leading cause of occupational asthma

worldwide.”27 Researchers have found

isocyanate-induced asthma showing

up in 5–10% of workersin diisocyanate

production facilities,

28 5–25% in

polyurethane production plants,

29 and

5–30% in polyurethane seat cover

operations.

30 The Center for Disease

Control’s(CDC) National Institute on

Occupational Safety and Health (NIOSH)

regulates MDI occupational exposures.

31

User exposures

Actual test data islimited, but indications

are that once MDI is cured, the emissions

from the product are insigni!cant

and not comparable to the hazards of

formaldehyde binder emissions. Like

epichlorohydrin, below, the issue with MDI

is occupational exposure in the making of

the resin binder itself.

Emerging alternatives: 

Soy-Based Binders

Columbia Forest Products made headlines

in 2006 with announcement of PureBond,®

its new soy-based resin technology.

This was a !rst break from the industry

dependence on resinsthat use a form

of formaldehyde in the resin or as a

feedstock, replacing it with a resin based

upon a renewable resource (soy "our). It is

!rst being utilized as a binder in hardwood

plywood panels and is currently being

tested for use in other composite wood

products.

The soy "our component is a renewable

resource and, while notstudied

extensively as a building material

component, it is not expected to have

health impacts assigni!cant asthe

formaldehyde and MDI-based binders. Soy

products can cause allergic reactionsin

some people and contain plant estrogens.

The compounds are, however, expected

to be completely destroyed in processing

and not be present in the proteins used in

the adhesive.

32

PureBond does, however, have another

primary component—Kymene—with

problematic feedstocks. Kymene

is produced using polyamideepichlorohydrin (PAE)

33 resin, which in

turn is manufactured from a chemical

known as epichlorohydrin, or chloropropyl

oxide. Kymene resin is manufactured

by Hercules Chemical and previously

primarily marketed as a resin in paper
Written and produced by Healthy Building Network. 

Production funded by the Global Health and Safety Initiative 

with the support of Health Care Without Harm. PAGE 4 OF 6

manufacturing.

34

Epichlorohydrin35

Epichlorohydrin36 is a highly volatile and

unstable liquid epoxide. It is prepared

from propene, found in coal gas or

synthesized by cracking petroleum,

which is chlorinated to allyl chloride.

37

Epichlorohydrin is a major raw material

used in the manufacture of epoxy and

phenoxy resins. It is also used as a solvent

and in the synthesis of glycerol. Other uses

include as an insect fumigation and as a

chemical intermediate for the formation of

glycidyl acrylate derivatives.

38

Health impacts—cancer

The International Agency for Research on

Cancer (IARC) classi!es epichlorohydrin

as a probable human carcinogen (Group

2A).

39 The National Institute of Health’s

National Toxicology Program (NTP)

statesthat epichlorohydrin isreasonably

anticipated to be a human carcinogen.

40

The chemical islisted in California’s

Proposition 65 as a carcinogen.

41

Health impacts—non-cancer

Epichlorohydrin islisted in California’s

Proposition 65 as a reproductive

toxicant (as well as a carcinogen—see

above). Researchers have found that

epichlorohydrin is acutely toxic to humans

and overexposure can cause severe

damage to the liver, kidneys, eyes, and

respiratory tract.

42 It is also mutagenic

and may cause infertility in men.

43 It is

also regulated in drinking water,

44 as a

hazardous air pollutant,

45 as a pesticide,46

as an air contaminant,

47 and as an aquatic

toxicant.

48

Occupational exposures

NIOSH conducted industry-wide studies of

exposure to epichlorohydrin in the 1970s

and found exposuresin the workplace

well below the PEL and the ACGIHTLV.

Though workplace issues are paramount,

the EPA also regulates epichlorohydrin in

drinking water.

49 Those employed in the

manufacture of epichlorohydrin are likely

to have greatest potential for exposure,

as well asthose working in the Kymene

plants, rather than workers exposed

during the manufacturing of the PureBond

resin itself.

50 CDC’s NIOSH regulates

epichlorohydrin occupational exposure.

51

User Exposure

Columbia Forest Productssaysthat the

epichlorohydrin is completely consumed

in the batch manufacturing process

used to make the resin,so there are

no emissionsfrom the process and no

epichlorohydrin remaining in the !nal

product.

52 The manufacturer hasstated

that the addition and mixing of PAE with

the soy "our is a“closed process”and

therefore manufacturing workers and/or

users do not have contact with the PAE or

the mixed PAE-soy resin.

53 Massachusetts

Toxics Use Reduction Institute (TURI)

concluded in itsstudy of PureBond,

that“[w]hile it eliminates potential

formaldehyde exposures, it doesintroduce

a new potential hazard, epichlorohydrin,

into the lifecycle of building panels. This

hazard is unlikely to threaten building

occupants or workers exposed to the

Kymene resin, but is a potential (although

low) worker and environmental hazard in

the manufacture of the intermediates.”54

Summary Conclusions

At this point in the development of

alternativesto urea formaldehyde

(UF) resinsin particleboard, MDF , and

wheatboard products, there has yet to

be a product that can replace UF that

does not raise some environmental

health concerns.

55 Taking into account

any potential added costs associated

with the production of the alternatives
FACT SHEET: ALTERNATIVE RESIN BINDERS FOR PARTICLEBOARD, MDF & WHEATBOARD May 2008

PAGE 5 OF 6

(some alternative productsrequire more

curing time, which gets built into the

product price), health care institutions

will have to take into account the

health risks, alongside the costs and

performance characteristics of the

productsthemselves, to determine

which alternativesto use in casework.

Alternativesto formaldehyde,such as MDI

orsoy-based resins, appear to virtually

eliminate the exposuresto chemicals

in the curing processesthat continue

after installation in formaldehyde-based

products,signi!cantly reducing user

exposure to hazardous chemicals. These

chemicals do, however, raise occupational

health concernsfor those making the resin

binders.

In summary, the health concerns are as

follows:

1) Modi!ed urea formaldehyde resins

with scavenger additives bind the

formaldehyde better in the wood,

reducing but not eliminating the

formaldehyde emissionsfrom the resin.

Like other urea formaldehyde based resins,

they will o#gasformaldehyde, exposing

occupantsfor long periods of time, just at

lower rates;

2) Alternate formaldehyde resins,such

as phenol formaldehyde, also have lower

formaldehyde emissionsin use, but do

not eliminate emissions altogether. In

addition, they raise occupational health

and safety concerns during the production

process;

3) Alternate fossil fuel-based binders

containing no formaldehyde,such as

methylene diphenyl diisocyanate (MDI),

do not release formaldehyde during

use. They are, however, made from

formaldehyde. In addition, MDI raises

othersigni!cant occupational health and

safety concerns during the production

and manufacturer of the composite wood

products. We were not able to determine

at thistime whether there are su$cient

remediation e#ortsthat can be utilized

in the workplace to reduce occupational

exposure concerns, but hope to be able to

addressthese issuesin future work; and

4) Alternate binders based on renewable

resource materials,such assoy "our,

do not release formaldehyde during

use. What we know of a primary

component, epichlorohydrin, currently

used in combination with the soy "our

in the resin, doesraise some concerns

for occupational heath and safety. The

primary manufacturer of the technology

claimsthat the product is manufactured

in such a way asto reduce occupational

exposure and eliminate potential user

exposure. We were not able to determine

at thistime whether there are su$cient

remediation e#ortsthat can be utilized

in the workplace to reduce occupational

exposure concerns, but hope to address

these issuesin future work.
Written and produced by Healthy Building Network. 

Production funded by the Global Health and Safety Initiative 

with the support of Health Care Without Harm. PAGE 6 OF 6

ENDNOTES

1 Formaldehyde (CAS No. 50-00-0) is also known 

as methanal, methylene oxide, oxymethylene, 

methylaldehyde, or oxomethane and has the chemical 

abbreviation HCHO. For more in depth analysis of 

formaldehyde, see “Health Hazards of Formaldehyde 

Found in Building Materials,” May 2008.

2 CAS No. 9011-05-6

3 California Air Resources Board,“Fact Sheet Proposed 

Airborne Toxic Control Measure (ATCM) to Reduce 

Formaldehyde Emissions from Composite Wood Products”

(http://www.arb.ca.gov/toxics/compwood/background.

htm).

4 California Air Resources Board, Sta! Report: Initial 

Statement Of Reasons For Proposed Rulemaking - 

Adoption OfThe Proposed Airborne Toxic Control Measure 

To Reduce Formaldehyde Emissions From Composite 

Wood Products, April 2007 (http://www.arb.ca.gov/

regact/2007/compwood07/isor.pdf).

5 CAS No. 9003-35-4

6 CARB. Ibid.

7 CAS No. 108-95-2

8 National Institute of Health, “Relational Database of 

Hazardous Chemicals and Occupational Diseases”

(http://hazmap.nlm.nih.gov/hazmapadv.html).

9 CAS No. 101-68-8

10 CAS No. 9016-87-9

11 World Health Organization, “Concise International 

Chemical Assessment Document 27: Diphenylmethane 

Diisocyanate (MDI),” 2000 (http://www.inchem.org/

documents/cicads/cicads/cicad27.htm).

12 CAS No. 62-53-3

13 WHO, Ibid.

14 Massachusetts Toxics Use Reduction Institute (TURI) 

at the University of Massachusetts Lowell (June 2006) 

[hereinafter TURI document], page 4-16 of 456

(http://www.turi.org/library/turi_publications/

"ve_chemicals_study).

15 McRandle, P.W., “What is Polyurethane?”April 2003 

(http://www.thegreenguide.com/doc/ask/poly).

16 U.S. Environmental Protection Agency,Toxicological 

Review Of Methylene Diphenyl Diisocyanate (MDI) (CAS 

No. 101-68-8 and 9016-87-9) In Support of Summary 

Information on the Integrated Risk Information System 

(IRIS) February 1998 (http://www.epa.gov/iris/

toxreviews/0529-tr.pdf).

17 CAS No. 101-77-9

18 International Agency for Research on Cancer (IARC) 

Summaries & Evaluations: 4,4’-Methylenedianiline 

and its Dihydrochloride (Group 2A), Vol. 39, page 

347 (1986) and Suppl. 7 (1987) (p. 66: Group 2B). 

(http://www.inchem.org/documents/iarc/vol39/4,4’-

methylenedianiline.html).

19 US EPA, Integrated Risk Information System – Aniline is 

classi"ed as a Group B2 “Probable Human Carcinogen”

(http://www.epa.gov/IRIS/subst/0350.htm).

20 California Safe Drinking Water and Toxic Enforcement 

Act of 1986 (Proposition 65). (http://www.oehha.org/

prop65/prop65_list/"les/032108list.pdf).

21 National Institute of Health 11th Report on Cancer, 

National Toxicology Program (1998) (http://ntp-server.

niehs.nih.gov/index.cfm?objectid=32BA9724-F1F6-

975E-7FCE50709CB4C932).

22 Proposition 65, Ibid.

23 Registry of Toxic E!ects of Chemical Substances (RTECS) 

cited in Scorecard.org based on a review of RTECS 

conducted by Environmental Defense.

24 Clapp R, Jacobs M, Loechler E, Environmental and 

Occupational Causes of Cancer: New Evidence,

2005-2007, Lowell Center for Sustainable Production, 

University of Massachusetts, Lowell, October 2007.

25 Department of Health and Human Services, Centers for 

Disease Control and Prevention, National Institute of 

Occupational Safety and Health, “A Summary of Health 

Hazard Evaluations: Issues Related to Occupational 

Exposure to Isocyanates, 1989 to 2002”., January 

2004 (http://www.cdc.gov/niosh/docs/2004-116/

pdfs/2004-116.pdf).

26 US EPA Hazard Summary for Aniline, Revised January 

2000. (http://www.epa.gov/ttn/uatw/hlthef/aniline.

html).

27 US EPA, Toxicological Review of MDI (February 1998).

28 US EPA, Ibid.

29 US EPA, Ibid.

30 US EPA, Ibid.

31 National Institute for Occupational Safety and Health, 

“International Chemical Safety Card: MDI.” (http://www.

cdc.gov/niosh/ipcsneng/neng0298.html).

32 Brown, Valerie, “Better Bonding with Beans,”

Environmental Health Perspectives. 2005 August; 113(8): 

A538–A541 (http://www.pubmedcentral.nih.gov/

articlerender.fcgi?artid=1280368).

33 CAS No. 68583–79–9

34 Kymene is marketed as a “wet strength” technology 

to provide strength to paper. See Hercules Paper 

Technologies website at http://ppd.herc.com/

innovations/kymene%C2%AE_wet_strength_

technology.asp.

35 TURI, Ibid. 

36 CAS No. 68583–79–9

37 Chemical Land 21, Arokor Holdings, Inc. (http://www.

chemicalland21.com/petrochemical/EPICHLOROHYDRIN.

htm).

38 O#ce of Environmental Health Hazard Assessment 

(OEHHA), “Chronic Toxicity Summary: Epichlorohydrin 

(1-chloro-2,3-epoxy-propane),” 2000. (http://www.

oehha.ca.gov/pdf/2ApnA_DCB-Isoph.pdf).

39 International Agency for Research on Cancer (IARC)

Summaries & Evaluations: Epichlorohydrin

(Group 2A), Vol. 71 (1999) (p. 603) (http://www.inchem.

org/documents/iarc/vol71/020-epichlorohydrin.html).

40 National Institute of Health, Ibid.

41 Proposition 65, Ibid.

42 National Library of Medicine, “Hazardous Substances 

Data Bank (HSDB).” (http://toxnet.nlm.nih.gov/cgi-bin/

sis/search/f?./temp/~aVEyeS:1.).

43 International Programme On Chemical Safety: 

“Environmental Health Criteria 33” (1984). (http://www.

inchem.org/documents/ehc/ehc/ehc33.htm).

44 U.S. Environmental Protection Agency, Safe Drinking 

Water Act of 1974. and National Primary Drinking Water 

Contaminants Regulations. (http://www.epa.gov/

safewater/contaminants/index.html#listmcl).

45 Title III of the Clean Air Act Amendments of 1990 (http://

www.epa.gov/appcdwww/aptb/hap_list.pdf).

46 Federal Insecticide, Fungicide, and Rodenticide 

Act (FIFRA). (http://a257.g.akamaitech.

net/7/257/2422/01jan20051800/edocket.access.gpo.

gov/2005/pdf/05-22384.pdf).

47 Occupational Safety and Health Agency (OSHA). 

“Chemical Sampling Information Epichlorohydrin.”

(http://www.osha.gov/dts/chemicalsampling/data/

CH_238700.html).

48 World Health Organization, “Epichlorohydrin Health And 

Safety Guide”, International Programme On Chemical 

Safety, Health And Safety Guide No. 8, Geneva 1987 

(http://www.inchem.org/documents/hsg/hsg/hsg008.

htm).

49 Proposition 65, Ibid.

50 Proposition 65, Ibid..

51 National Institute for Occupational Safety and Health, 

“International Chemical Safety Card: Epichlorohydrin”

(http://www.cdc.gov/niosh/ipcsneng/neng0043.html).

52 TURI 2006, page 4-17.

53 TURI 2006, page 4-33.

54 TURI 2006, page 4-35.

55 For detailed information about concerns with UF, please 

see “Health Hazards of Formaldehyde Found in Building 

Materials.” (http://www.healthybuilding.net healthcare/

index.html).