View source for Formaldehyde

{{About|the chemical compound|the 1993 rock album|Formaldehyde (album)}}
{{chembox
| Watchedfields = changed
| verifiedrevid = 311260797
| Name = Formaldehyde
| ImageFile = Formaldehyde-2D.svg
| ImageSize = 120px
| ImageFileL1 = Formaldehyde-3D-balls-A.png
| ImageSizeL1 = 120px
| ImageFileR1 = Formaldehyde-3D-vdW.png
| ImageSizeR1 = 120px
| IUPACName= methanal
| OtherNames = formol, methyl aldehyde, methylene oxide, methanal
| Section1 = {{Chembox Identifiers
| InChI = 1/CH2O/c1-2/h1H2
| CASNo = 50-00-0
| CASNo_Ref = {{cascite}}
| EC-number = 200-001-8
| ChemSpiderID = 692
| RTECS = LP8925000
| ATCCode_prefix = P53
| ATCCode_suffix = AX19
| ATCvet = yes
| SMILES = C=O
}}
| Section2 = {{Chembox Properties
| Reference = <ref>{{RubberBible62nd|pages=C–301, E-61}}.</ref>
| C=1|H=2|O=1
| Appearance = colorless gas
| Solubility = very high (''see text'')
| MeltingPt = -92 °C (pure) <br /> −15 °C (37% solution)
| BoilingPt = -21 °C (pure) <br /> 96 °C (37% solution)
| Dipole = 2.33 [[Debye|D]]
}}
| Section3 = {{Chembox Structure
| MolShape = trigonal planar
}}
| Section7 = {{Chembox Hazards
| ExternalMSDS = [http://www.ilo.org/public/english/protection/safework/cis/products/icsc/dtasht/_icsc02/icsc0275.htm ICSC 0275]
| EUIndex = 605-001-00-5
| EUClass = Toxic ('''T''')<br/>[[Carcinogen|Carc. Cat. 3]]
| RPhrases = {{R23/24/25}} {{R34}} {{R40}} {{R43}}
| SPhrases = {{S1/2}} {{S26}} {{S36/37/39}} {{S45}} {{S51}}
| NFPA-H = 3
| NFPA-F = 2
| NFPA-R = 2
| FlashPt = flammable gas
| Autoignition = 430 °C (806 °F)
|  ExploLimits = 7–73%
 }}
| Section8 = {{Chembox Related
| OtherFunctn = [[acetaldehyde]]<br/>[[propionaldehyde]]
| Function = [[aldehyde]]s
| OtherCpds = [[methanol]]<br/>[[formic acid]]
}}
}}

'''Formaldehyde''' (systematic name: '''methanal''') is an [[organic compound]] with the [[chemical formula|formula]] CH<sub>2</sub>O. As the simplest [[aldehyde]], it is an important precursor to many other chemical compounds, especially for polymers. In 2005, annual world production of formaldehyde was estimated to be 23 million tons (46 billion pounds).<ref name=Ullmann>Günther Reuss, Walter Disteldorf, Armin Otto Gamer, Albrecht Hilt “Formaldehyde” in Ullmann's Encyclopedia of Industrial Chemistry, 2002, Wiley-VCH, Weinheim. {{DOI|10.1002/14356007.a11_619}}</ref> In view of its widespread use, toxicity and volatility, exposure to formaldehyde is a significant consideration for human health.<ref name="IARC">{{citation | contribution = Formaldehyde | url = http://monographs.iarc.fr/ENG/Monographs/vol88/mono88-6.pdf | pages = 39–325 | title = Formaldehyde, 2-Butoxyethanol and 1-''tert''-Butoxypropan-2-ol | series = IARC Monographs on the Evaluation of Carcinogenic Risks to Humans 88 | publisher = International Agency for Research on Cancer | location = Lyon, France | year = 2006 | isbn = 92-832-1288-6}}. {{11thRoC|file=s089form|name=Formaldehyde (gas)}}.</ref>

==Forms of formaldehyde==
Formaldehyde is more complicated than many simple carbon compounds because it adopts different forms.  Formaldehyde is a gas at room temperature, but the gas readily converts to a variety of derivatives.  These derivatives generally behave similarly to gaseous formaldehyde and are used in industry.  One important derivative is the cyclic compound [[trioxane]], the "[[trimer (chemistry)|trimer]]" of formaldehyde with formula is (CH<sub>2</sub>O)<sub>3</sub>. When dissolved in water, formaldehyde converts to H<sub>2</sub>C(OH)<sub>2</sub>, a [[diol]] (i.e. a compound with two hydroxy groups).  Aqueous solutions of formaldehyde are referred to as '''formalin'''. "100%" formalin consists of a saturated solution of formaldehyde (this is about 40% by volume or 37% by mass) in water, with a small amount of [[stabilizer (chemistry)|stabilizer]], usually [[methanol]] to limit [[oxidation]] and [[degree of polymerization]]. A typical commercial grade formalin may contain 10–12% methanol in addition to various metallic impurities. The diol also exists in equilibrium with a series of short polymers (called [[oligomer]]s), depending on the concentration and temperature.  The infinite polymer formed from formaldehyde is called paraformaldehyde. The cyclic trimer is called metaformaldehyde (or 1,3,5-trioxane).

==Occurrence==
Formaldehyde is a naturally occurring substance in the environment made of carbon, hydrogen and oxygen. Natural processes in the upper [[Earth's atmosphere|atmosphere]] may contribute up to 90 percent of the total formaldehyde in the environment. Formaldehyde is an intermediate in the oxidation (or [[combustion]]) of [[methane]] as well as other carbon compounds, e.g. [[forest fire]]s, in [[automobile]] exhaust, and in [[tobacco smoke]]. When produced in the atmosphere by the action of sunlight and [[oxygen]] on [[atmospheric methane]] and other [[hydrocarbon]]s, it becomes part of [[smog]]. Formaldehyde has also been detected in outer space (see below).

Formaldehyde, as well as its [[oligomer]]s and hydrates are rarely encountered in living organisms. [[Methanogenesis]] proceeds via the equivalent of formaldehyde, but this one-carbon species is masked as a [[methylene]] group in [[methanopterin]]. Formaldehyde is the primary cause of [[methanol]]'s toxicity, since methanol is metabolised into toxic formaldehyde by [[alcohol dehydrogenase]]. Formaldehyde does not accumulate in the environment, because it is broken down within a few hours by sunlight or by bacteria present in soil or water. Humans metabolize formaldehyde quickly, so it does not accumulate, and is converted to [[formic acid]] in the body.

Small amounts of formaldehyde are produced in case of incomplete combustion of [[methane]] gas.

===Interstellar formaldehyde===
{{Main|Interstellar formaldehyde}}
Formaldehyde was the first [[polyatomic]] [[Organic chemistry|organic]] molecule detected in the [[interstellar medium]]<ref>{{citation | last1 = Zuckerman | first1 = B. | last2 = Buhl | first2 = D. | last3 = Palmer | first3 = P. | last4 = Snyder | first4 = L. E. | year = 1970 | title = Observation of interstellar formaldehyde | journal = Astrophys. J. | volume = 160 | pages = 485–506 | doi = 10.1086/150449}}.</ref> and since its initial detection has been observed in many regions of the [[Milky Way galaxy|galaxy]].  Because of the widespread interest in interstellar formaldehyde it has recently been extensively studied, yielding new extragalactic sources.<ref name="mangum">{{citation | first1 = Jeffrey G. | last1 = Mangum | first2 =  Jeremy | last2 = Darling | first3 =  Karl M. | last3 = Menten | first4 =  Christian | last4 = Henkel | year = 2008 | title = Formaldehyde Densitometry of Starburst Galaxies | journal = Astrophys. J. | volume = 673 | issue = 2 | pages = 832–46 | doi =  10.1086/524354}}.</ref>  A proposed mechanism for the formation is the hydrogenation of CO ice, shown below.<ref name="Woon">{{citation | last = Woon | first = David E. | year = 2002 | title = Modeling Gas-Grain Chemistry with Quantum Chemical Cluster Calculations. I. Heterogeneous Hydrogenation of CO and H<sub>2</sub>CO on Icy Grain Mantles | journal = Astrophys. J. | volume = 569 | pages = 541–48 | doi =  10.1086/339279}}.</ref>

:H + CO → HCO
:HCO + H → H<sub>2</sub>CO (rate constant = 9.2{{e|−3}} s<sup>−1</sup>)

Formaldehyde appears to be a useful probe for astrochemists due to its low reactivity in the gas phase and to the fact that the 1<sub>10</sub>←1<sub>11</sub> and 2<sub>11</sub>←2<sub>12</sub> K-doublet transitions are rather clear.

==Synthesis and industrial production==
Formaldehyde was first [[Chemical synthesis|reported]] by the [[Russia]]n chemist [[Aleksandr Butlerov]] (1828–86) and was conclusively identified by [[August Wilhelm von Hofmann]].<ref>{{citation | first = J. | last = Read | title = Text-Book of Organic Chemistry | publisher = G Bell & Sons | location = London | year = 1935}}.</ref>

Formaldehyde is produced industrially by the catalytic oxidation of [[methanol]]. The most common catalysts are [[silver]] metal or a mixture of an [[iron oxide|iron]] and [[molybdenum trioxide|molybdenum]] or [[vanadium pentoxide|vanadium]] [[oxide]]s. In the more commonly used FORMOX process methanol and oxygen react at ca.&nbsp;250–400&nbsp;°C in presence of iron oxide in combination with molybdenum and/or vanadium to produce formaldehyde according to the [[chemical equation]]:<ref name="Ullmann"/>
:2 CH<sub>3</sub>OH  +  O<sub>2</sub>   →   2 CH<sub>2</sub>O  +  2 H<sub>2</sub>O

The silver-based catalyst usually operates at a higher temperature, about 650&nbsp;°C. Two chemical reactions on it simultaneously produce formaldehyde: that shown above and the [[dehydrogenation]] reaction:
:CH<sub>3</sub>OH → H<sub>2</sub>CO + H<sub>2</sub>

In principle formaldehyde could be generated by oxidation of [[methane]], but this route is not industrially viable because the formaldehyde is more easily oxidized than methane.<ref name="Ullmann"/>

== Organic chemistry ==
Formaldehyde is a building block in the synthesis of many other compounds of specialised and industrial significance. It exhibits most of the chemical properties of other aldehydes but is more reactive.  For example it is more readily [[oxidation|oxidized]] by atmospheric oxygen to [[formic acid]] (formic acid is found in ppm levels in commercial formaldehyde). Formaldehyde is a good [[electrophile]], participating in [[electrophilic aromatic substitution]] reactions with [[aromatic compound]]s, and can undergo [[electrophilic addition]] reactions with [[alkene]]s and aromatics. Formaldehyde undergoes a [[Cannizzaro reaction]] in the presence of [[base (chemistry)|basic]] [[catalyst]]s to produce [[formic acid]] and methanol.

===Examples of organic synthetic applications===
Condensation with acetaldehyde affords [[pentaerythritol]], a chemical necessary in synthesizing [[PETN]], a high explosive.<ref>{{OrgSynth | first = H. B. J. | last = Schurink | title = Pentaerythritol | prep = cv1p0425 | volume = 4 | pages = 53 | year= 1925 | collvol = 1 | collvolpages = 425}}.</ref> Condensation with phenols gives [[phenol-formaldehyde resin]]s. With 4-substituted phenols one obtains [[calixarenes]].<ref>{{OrgSynth | last1 = Gutsche | first1 = C. D. | last2 = Iqbal | first2 = M. | title = ''p-tert''-Butylcalix&#91;4&#93;arene | prep = cv8p0075 | year = 1993 | collvol = 8 | collvolpages = 75}}.</ref>

When combined with hydrogen sulfide it forms [[trithiane]].<ref>{{OrgSynth | last1 = Bost | first1 = R. W. | last2 = Constable | first2 = E. W. | title = ''sym''-Trithiane | prep = cv2p0610 | volume = 16 | pages = 81 | year = 1936 | collvol = 2 | collvolpages = 610}}.</ref>
:3CH<sub>2</sub>O + 3H<sub>2</sub>S → (CH<sub>2</sub>S)<sub>3</sub> + 3H<sub>2</sub>O

==Uses==
===Industrial applications===
Formaldehyde is a common building block for the synthesis of more complex compounds and materials. In approximate order of decreasing consumption, products generated from formaldehyde include [[urea formaldehyde resin]], [[melamine resin]], [[phenol formaldehyde resin]], [[polyoxymethylene plastic]]s, [[1,4-butanediol]], and [[methylene diphenyl diisocyanate]].<ref name="Ullmann"/> The [[textile industry]] uses formaldehyde-based resins as [[textile finishing|finishers]] to make fabrics crease-resistant.<ref>{{citation | title = Formaldehyde in Clothing and Other Textiles | url = http://www.nicnas.gov.au/Publications/Information_Sheets/Existing_Chemical_Information_Sheets/EC_IS_Formaldehyde_102007_PDF.pdf | series = Existing Chemicals Information Sheet | date = October 2007 | publisher = Australian National Industrial Chemicals Notification and Assessment Scheme | accessdate = 2009-09-01}}.</ref> Formaldehyde-based materials are key to the manufacture of automobiles, and used to make components for the transmission, electrical system, engine block, door panels, axles and brake shoes. The value of sales of formaldehyde and derivative products was over $145 billion in 2003, about 1.2% of the Gross Domestic Product (GDP) of the United States and Canada. Including indirect employment, over 4 million work in the formaldehyde industry across approximately 11,900 plants in the U.S. and Canada.<ref>[http://www.formaldehyde.org/economy/economic_importance/ Economic Importance], ''Formaldehyde Council''. 2009. Accessed on April 14, 2010.</ref>

When reacted with phenol, urea, or melamine formaldehyde produces, respectively, hard thermoset phenol formaldehyde resin, urea formaldehyde resin, and melamine resin, which are commonly used in permanent adhesives such as those used in [[plywood]] or [[carpet]]ing. It is used as the [[wet strength|wet-strength]] resin added to sanitary paper products such as (listed in increasing concentrations injected into the paper machine headstock chest) facial tissue, table napkins, and roll towels. They are also foamed to make [[Thermal insulation|insulation]], or [[casting|cast]] into moulded products. Production of formaldehyde resins accounts for more than half of formaldehyde consumption.

Formaldehyde is also a precursor to polyfunctional [[alcohol]]s such as [[pentaerythritol]], which is used to make [[paint]]s and [[explosive]]s. Other formaldehyde derivatives include [[methylene diphenyl diisocyanate]], an important component in [[polyurethane]] paints and foams, and [[hexamine]], which is used in phenol-formaldehyde resins as well as the explosive [[RDX]]. Formaldehyde has been found as a contaminant in several bath products, at levels from 54–610&nbsp;ppm: it is thought to arise from the breakdown of preservatives in the products.<ref>{{citation | title = No More Toxic Tub: Getting Contaminants Out Of Children’s Bath & Personal Care Products | url = http://safecosmetics.org/downloads/NoMoreToxicTub_Mar09Report.pdf | publisher =  Campaign for Safe Cosmetics |date=March 2009}}.</ref>

===Disinfectant and biocide===
An aqueous solution of formaldehyde can be useful as a disinfectant as it kills most [[bacterium|bacteria]] and fungi (including their spores). It is also used as a [[preservative]] in [[vaccine]]s. Formaldehyde solutions are applied topically in medicine to dry the skin, such as in the treatment of [[wart]]s. Many aquarists use formaldehyde as a treatment for the parasites ''[[Ichthyophthirius multifiliis]]'' and ''[[Cryptocaryon irritans]]''.<ref>{{citation | first = Ruth | last = Francis-Floyd | title =  Use of Formalin to Control Fish Parasites | url = http://edis.ifas.ufl.edu/VM061 | publisher = Institute of Food and Agricultural Sciences, University of Florida | date = April 1996 | format = {{Dead link|date=April 2010}}}}.</ref>

Formaldehyde is used to inactivate bacterial products for toxoid vaccines (vaccines that use an inactive bacterial toxin to produce immunity). It is also used to kill unwanted viruses and bacteria that might contaminate the vaccine during production.<ref>Center for Disease Control: Vaccines</ref> [[Urinary tract infection]]s are also often treated using a derivative of formaldehyde (methenamine), a method often chosen because it prevents overuse of antibiotics and the resultant development of bacterial resistance to them.  Some topical creams, cosmetics and personal hygiene products also contain derivatives of formaldehyde as the active ingredients that prevent the growth of potentially harmful bacteria.

===Tissue fixative and embalming agent===
Formaldehyde preserves or [[Fixation (histology)|fixes]] tissue or cells by reversibly cross-linking primary [[amino group]]s in proteins with other nearby nitrogen atoms in protein or [[DNA]] through a -CH<sub>2</sub>- linkage. This is exploited in [[ChIP-on-chip]] transcriptomics experiments.  Formaldehyde is also used as a denaturing agent in [[RNA]] gel [[electrophoresis]], preventing RNA from forming secondary structures.

Formaldehyde solutions are used as a [[Fixation (histology)|fixative]] for [[microscopy]] and [[histology]]. Formaldehyde-based solutions are also used in [[embalming]] to disinfect and temporarily preserve human and animal remains. It is the ability of formaldehyde to fix the tissue that produces the tell-tale firmness of flesh in an embalmed body. In post mortem examinations a procedure known as the "sink test"  involves placing the lungs of an animal in an aqueous solution of formaldehyde; if the lungs float it suggests the animal was probably breathing or able to breathe at the time of death.

Formaldehyde solutions are commonly used as a biological preserving medium, usually for smaller specimens.

Several European countries restrict the use of formaldehyde, including the import of formaldehyde-treated products and embalming. Starting September 2007, the European Union banned the use of formaldehyde due to its carcinogenic properties as a [[biocide]] (including embalming) under the [[Biocidal Products Directive]] (98/8/EC).<ref>[http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:31998L0008:EN:HTML Directive 98/8/EC of the European Parliament and of the Council of 16 February 1998 concerning the placing of biocidal products on the market]. ''OJEU'' L123, 24.04.1998, pp.&nbsp;1–63. ([http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CONSLEG:1998L0008:20080926:EN:PDF consolidated version to 2008-09-26])</ref><ref>[http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:32003R2032:EN:HTML Commission Regulation (EC) No 2032/2003 of 4 November 2003 on the second phase of the 10-year work programme referred to in Article&nbsp;16(2) of Directive&nbsp;98/8/EC of the European Parliament and of the Council concerning the placing of biocidal products on the market, and amending Regulation&nbsp;(EC) No&nbsp;1896/2000]. ''OJEU'' L307, 24.11.2003, p.&nbsp;1–96. ([http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CONSLEG:2003R2032:20070104:EN:PDF consolidated version to 2007-01-04])</ref> Countries with a strong tradition of embalming corpses, such as Ireland and other colder-weather countries, have raised concerns. Despite reports to the contrary,<ref>{{citation | first = Alkesh | last = Patel | url = http://www.webwire.com/ViewPressRel.asp?aId=41468 | title = Formaldehyde Ban set for 22 Sept 2007 | publisher = WebWire | date = 2007-07-04}}.</ref> no decision on the inclusion of formaldehyde on Annex&nbsp;I of the Biocidal Products Directive for product-type&nbsp;22 (embalming and taxidermist fluids) had been made {{as of|2009|9|lc=on}}.<ref>{{citation | url = http://ecb.jrc.ec.europa.eu/esis/index.php?GENRE=ECNO&ENTREE=200-001-8 | title = European chemical Substances Information System (ESIS) entry for formaldehyde | accessdate = 2009-09-01}}.</ref>

===Miscellaneous applications===
Formaldehyde is a common component of many uses.  Formaldehyde, along with 18&nbsp;[[Concentration#Molarity|M]] (concentrated) [[sulfuric acid]] (the entire solution often called the [[Marquis reagent]]), is used as an [[MDMA]] (the drug ecstasy) "testing kit" by such groups as [[Dancesafe]] as well as MDMA consumers. The solution alone cannot verify the presence of MDMA but reacts with many other chemicals that the MDMA tablet itself may be adulterated with. The reaction itself produces colors that correlate with these components.

In photography, formaldehyde is still used in low concentrations for [[C-41 process|process C-41]] (color negative film) stabilizer in the final wash step,<ref>{{citation | url = http://www.kodak.com/global/en/service/Zmanuals/z131.shtml | title = Process C-41 Using Kodak Flexicolor Chemicals – Publication Z-131 | publisher = Kodak | accessdate = 2009-09-01}}.</ref> as well as in the [[E-6 process|process E-6]] pre-bleach step, to obviate the need for it in the final wash.

Formaldehyde is used extensively in the woodworking and cabinet-making industries. Formaldehyde is used in the glues which bond particle-board together. The particle board is used underneath wood veneer and plastic laminate. Cabinets, bank counters, and veneered and laminated woodwork all use particle board containing formaldehyde under the plastic laminate and wood veneer.

== Safety ==
Occupational exposure to formaldehyde by inhalation is mainly from three types of sources: [[Thermal decomposition|thermal]] or [[chemical decomposition]] of formaldehyde-based resins, formaldehyde emission from [[aqueous]] solutions (for example, embalming fluids), and the production of formaldehyde resulting from the [[combustion]] of a variety of organic compounds (for example, exhaust gases). Formaldehyde can be toxic, allergenic, and carcinogenic.<ref name="IARC"/>  Because formaldehyde resins are used in many construction materials it is one of the more common indoor air pollutants.<ref>{{citation | title = Indoor Air Pollution in California | publisher = Air Resources Board, California Environmental Protection Agency | date = July 2005 | url = http://www.arb.ca.gov/research/indoor/ab1173/rpt0705.pdf | pages = 65–70}}.</ref> At concentrations above 0.1&nbsp;ppm in air formaldehyde can irritate the eyes and [[mucous membrane]]s, resulting in watery eyes.<ref>{{citation | title = Formaldehyde | url = http://www.osha.gov/SLTC/formaldehyde/index.html | publisher = Occupational Safety and Health Administration | date = August 2008 | accessdate = 2009-09-01}}.</ref> Formaldehyde inhaled at this concentration may cause headaches, a burning sensation in the throat, and difficulty breathing, as well as triggering or aggravating asthma symptoms.<ref>{{citation | title = Formaldehyde Reference Exposure Levels | url = http://www.oehha.ca.gov/air/hot_spots/2008/AppendixD1_final.pdf#page=128 | publisher = California Office Of Health Hazard Assessment |date=December 2008}}.</ref><ref>{{citation | title = Formaldehyde and Indoor Air | publisher = Health Canada | url = http://www.hc-sc.gc.ca/iyh-vsv/environ/formaldehyde_e.html | date = August 2005 | accessdate = 2009-09-01 | isbn = 0815511299}}.</ref> Studies by the National Academy of Sciences and the Institute of Medicine failed to show an association between formaldehyde exposure and asthma.<ref name="Dupont"/>

The primary exposure concern is for the workers in the industries producing or using formaldehyde. As far back as 1987, the U.S. EPA classified it as a ''probable human carcinogen'' and after more studies the [[WHO]] International Agency for Research on Cancer (IARC), in 1995, also classified it as a ''probable human carcinogen''.  Further information and evaluation of all known data led the IARC to reclassify formaldehyde as a ''known human carcinogen'' <ref name="International Agency for Research on Cancer, Monographs Vol 88" >{{Citation
  |url=http://monographs.iarc.fr/ENG/Monographs/vol88/index.php
  |title=IARC Monographs on the Evaluation of Carcinogenic Risks to Humans Volume 88 (2006) Formaldehyde, 2-Butoxyethanol and 1-tert-Butoxypropan-2-ol
  |publisher=WHO Press, 2006( English )
  |format=pdf, html
}}</ref> associated with nasal sinus cancer and [[nasopharyngeal cancer]], and possibly with [[leukemia]] in June 2004<ref name="NCI" >{{Citation
  |url=http://www.cancer.gov/cancertopics/factsheet/Risk/formaldehyde
  |title=Formaldehyde and Cancer Risk
}}</ref>.

The [[United States Environmental Protection Agency]] (EPA) allows no more than 16&nbsp;ppb formaldehyde in the air in new buildings constructed for that agency.<ref>{{citation | title = Testing for Indoor Air Quality, Baseline IAQ, and Materials | url =  http://www.epa.gov/rtp/new-bldg/environmental/s_01445.htm | publisher = Environmental Protection Agency | format = {{Dead link|date=April 2010}}}}.</ref>  A U.S. Environmental Protection Agency study found a new home measured 0.076 ppm when brand new and 0.045 ppm after 30 days.<ref>Residential Indoor Air Formaldehyde Testing Program: A Pilot Study," M. Koontz, et al, prepared for U.S. EPA, 1996</ref> The [[Federal Emergency Management Agency]] (FEMA) has also announced limits on the formaldehyde levels in trailers purchased by that agency.<ref>{{citation | last = Evans | first = Ben | title = FEMA limits formaldehyde in trailers | publisher = Boston.com | date = 2008-04-11 | accessdate = 2008-09-04 | url = http://www.boston.com/news/nation/washington/articles/2008/04/11/fema_limits_formaldehyde_in_trailers/}}.</ref>  The EPA recommends the use of “exterior-grade” pressed-wood products to limit formaldehyde exposure since pressed-wood products containing formaldehyde resins are often a significant source of formaldehyde in homes.<ref name="NCI"/>

For most people, irritation from formaldehyde is temporary and reversible, though formaldehyde can cause allergies and is part of the standard patch test series. People with formaldehyde allergy are advised to avoid [[formaldehyde releasers]] as well (''e.g.'', [[Quaternium-15]], [[imidazolidinyl urea]], and [[diazolidinyl urea]]).<ref>{{citation | title = Formaldehyde allergy | url = http://dermnetnz.org/dermatitis/formaldehyde-allergy.html | series = DermNet NZ | publisher =  New Zealand Dermatological Society | date = June 2009 | accessdate = 2009-09-01}}.</ref> Formaldehyde has been banned in cosmetics in both [[Sweden]] and [[Japan]].{{Citation needed|date=February 2008}} The eyes are most sensitive to formaldehyde exposure: The lowest level at which many people can begin to smell formaldehyde is about 0.3 ppm. In controlled chamber studies, individuals begin to sense eye irritation at about 0.5 ppm; 5 to 20 percent report eye irritation at 0.5 to 1 ppm; and greater certainty for sensory irritation occurred at 1 ppm and above. While some agencies have used a level as low as 0.1 ppm as a threshold for irritation, the expert panel found that a level of 0.3 ppm would protect against nearly all irritation. In fact, the expert panel found that a level of 1.0 ppm would avoid eye irritation—the most sensitive endpoint—in 75-95% of all people exposed.<ref name="Dupont">[http://www2.dupont.com/Plastics/en_US/assets/downloads/processing/FETEG_Facts.pdf Formaldehyde and Facts About Health Effects] (PDF). ''Formaldehyde Epidemiology, Toxicology and Environmental Group''. August 2002. Accessed on April 25, 2010.</ref>

===European ban===
There are several web articles claiming that formaldehyde has been banned from manufacture or import into the European Union (EU) under REACH (Registration, Evaluation, Authorization, and restriction of Chemical substances) legislation.  This appears to be misinformation, as official EU chemical databases contradict these claims as of February 19, 2010.  This misconception has gained some ground.  Formaldehyde is not listed in the Annex I of Regulation (EC) No 689/2008 (export and import of dangerous chemicals regulation), nor on a priority list for risk assessment.  However, formaldehyde is banned from use in certain applications (preservatives for liquid-cooling and processing systems, slimicides, metalworking-fluid preservatives, and antifouling products) under the Biocidal Products Directive.<ref>{{citation | title = European Union Bans formaldehyde/formalin within Europe  | publisher = European Commission's Environment Directorate-General | date = September 2007 | url = http://ec.europa.eu/environment/biocides/pdf/070622_withdrawal_notice.pdf | pages = 1–3}}.</ref><ref>{{citation | title = ESIS (European Chemical Substances Information System)  | publisher = European Commission Joint Research Centre Institute for Health and Consumer Protection | date = February 2009 | url = http://ecb.jrc.ec.europa.eu/esis/}}</ref>

===FEMA trailer incidents===
====Hurricane Katrina & Rita====
In the U.S. the [[Federal Emergency Management Agency]] (FEMA) provided travel trailers and mobile homes starting in 2006 for habitation by residents of the U.S. gulf coast displaced by [[Hurricane Katrina]] and [[Hurricane Rita]]. Some of the people who moved into the trailers complained of breathing difficulties, nosebleeds, and persistent headaches. Formaldehyde-catalyzed [[resins]] were used in the production of these homes.

The United States [[Centers for Disease Control and Prevention|Centers For Disease Control and Prevention]] (CDC) performed indoor air quality testing for formaldehyde<ref>[http://www.cdc.gov/niosh/nmam/pdfs/2016.pdf CFC.gov]</ref> in some of the units. On February 14, 2008 the CDC announced that potentially hazardous levels of formaldehyde were found in many of the travel trailers and mobile homes provided by the agency.<ref>[http://www.cdc.gov/nceh/ehhe/trailerstudy/pdfs/SummaryofStudyFindings.pdf Formaldehyde Levels in FEMA-Supplied Trailers<!-- Bot generated title -->]</ref><ref>{{Citation | title = Are FEMA trailers ‘toxic tin cans’? | url = http://www.msnbc.msn.com/id/14011193/from/ET/#storyContinued | author = Mike Brunker | date = 2006-07-25 | publisher = [[MSNBC]]}}</ref> The CDC's preliminary evaluation of a scientifically established random sample of 519 travel trailers and mobile homes tested between Dec. 21, 2007 and Jan. 23, 2008 (2+ years after manufacture) showed average levels of formaldehyde in all units of about 77 parts per billion ([[Parts-per notation|ppb]]). Long-term exposure to levels in this range can be linked to an increased risk of cancer and, at levels above this range, there can also be a risk of respiratory illness. These levels are higher than expected in indoor air, where levels are commonly in the range of 10-20 ppb, and are higher than the Agency for Toxic Substance Disease Registry (ATSDR, division of the CDC) Minimal Risk Level (MRL) of 8 ppb.<ref>[http://www.atsdr.cdc.gov/mrls/index.html ATSDR - Minimal Risk Levels for Hazardous Substances (MRLs)<!-- Bot generated title -->]</ref> Levels measured ranged from 3 ppb to 590 ppb.<ref>[http://www.fema.gov/news/newsrelease.fema?id=42606 FEMA: CDC Releases Results Of Formaldehyde Level Tests<!-- Bot generated title -->]</ref>

FEMA, which requested the testing by the CDC, said it would work aggressively to relocate all residents of the temporary housing as soon as possible. Lawsuits are being filed against FEMA as a result of the exposures.<ref>{{cite news| url=http://www.washingtonpost.com/wp-dyn/content/article/2007/08/08/AR2007080801758.html | work=The Washington Post | title=Suit Filed Over FEMA Trailer Toxins | first=Michael | last=Kunzelman | accessdate=2010-05-02}}</ref>

====Iowa Floods of 2008====
Also in the U.S., problems arose in trailers again provided by FEMA to residents displaced by the [[Iowa Flood of 2008|Iowa floods of 2008]]. A couple months after moving to the trailers, occupants reported violent coughing, headaches, as well as [[asthma]], [[bronchitis]], and other problems. Tests showed that in some trailers, levels of formaldehyde exceeded the limits recommended by the U.S. [[Environmental Protection Agency]] and [[American Lung Association]].<ref>{{Citation | format = {{dead link|date=July 2010}} | title = How We Tested for Formaldehyde | url = http://www.kgan.com/newsroom/top_stories/videos/kgan_vid_1515.shtml | author = Megan Terlecky | date = 2008-10-24 | publisher = [[KGAN-TV]]}}</ref><ref>{{Citation | title = FEMA disputes formaldehyde study of Iowa trailers| url = http://ap.google.com/article/ALeqM5jQTjw89qkEGgyRpUyURQLnyrPsMwD93V991G0 | author = NIGEL DUARA | date = 2008-10-21 | publisher = [[Associated Press]]}}{{dead link|date=July 2010}}</ref> The associated publicity has resulted in additional testing to begin in November.<ref>{{Citation | format = {{dead link|date=July 2010}} | title = FEMA meets with mobile home residents over health concerns| url = http://www.gazetteonline.com/apps/pbcs.dll/article?AID=/20081025/NEWS/710259952/1006 | author = Cindy Hadish | date = 2008-10-24 | publisher = [[Cedar Rapids Gazette]]}}</ref>

==Contaminant in food==
Scandals have broken in both the [[2005 Indonesia food scare]] and [[2007 Vietnam food scare]] regarding the addition of formaldehyde to foods to extend shelf life.  Foods known to be contaminated include noodles, salted fish, tofu, and rumors of chicken and beer.  In humans, it is known to have a number{{Quantify|date=May 2010}} of detrimental effects and there is limited evidence of a carcinogenic effect.<ref name="IARC"/>
Testing for formaldehyde is by blood and/or urine by [[gas chromatography-mass spectrometry]]. Other methods include infrared detection, gas detector tubes, etc., of which HPLC is the most sensitive <ref>{{Citation| title = formaldehyde testing| url = http://monographs.iarc.fr/ENG/Monographs/vol88/mono88-6A.pdf| author = Moise Ngwa| date = 2010-10-25 | publisher = [[Cedar Rapids Gazette]]}}</ref> In the early 1900s, it was frequently added by US milk plants to milk bottles as a method of pasteurization due to the lack of knowledge regarding formaldehyde's toxicity. This resulted in numerous deaths in both orphanages and homes, particularly in the Midwestern states, where infants were fed the tainted milk, and resulted in a high death rate at several large orphanages in northern America.{{Citation needed|date=June 2010}}

== See also ==
* [[1,3-dioxetane]]

== References ==
{{Reflist|2}}

== External links ==
*{{ICSC|0275|02}} (''gas'')
*{{ICSC|0695|06}} (''solution'')
*{{PGCH|0293}}
*{{NPI|id=45|name=Formaldehyde}}
* [http://www.formaldehyde.org/ Formaldehyde Council] (grouping of producers and industrial users in North America)
* [http://chemsub.online.fr/name/formaldehyde.html Formaldehyde] from ChemSub Online
* [http://www.irsst.qc.ca/files/documents/PubIRSST/RG-473.pdf Prevention guide—Formaldehyde in the Workplace] from the Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST)
* [http://www.cdc.gov/niosh/topics/formaldehyde/ Formaldehyde] from the [[National Institute for Occupational Safety and Health]]
*{{SIDS|id=FORMALDEHYDE|name=Formaldehyde|date=March 2002}}
*{{HSG|id=057|number=57|name=Formaldehyde|date=1991|isbn=92-4-151057-9}}
*{{EHC|89|name=Formaldehyde|date=1989|isbn=92-4-154289-6}}
<!--*{{CICAD|id=40|name=Formaldehyde|date=1992|isbn=92-4-153040-5}}-->
*[http://www.cdc.gov/vaccines/vac-gen/additives.htm CDC Vaccine Additives]
{{Consumer Food Safety}}

[[Category:Aldehydes]]
[[Category:IARC Group 1 carcinogens]]
[[Category:Hazardous air pollutants]]
[[Category:Anatomical preservation]]
[[Category:Occupational safety and health]]

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