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101-536: Formaldehyde is classified as a carcinogen and can cause respiratory and skin irritation upon exposure. Formaldehyde is more complicated than many simple carbon compounds in that it adopts several diverse forms. These compounds can often be used interchangeably and can be interconverted. A small amount of stabilizer , such as methanol , is usually added to suppress oxidation and polymerization . A typical commercial-grade formalin may contain 10–12% methanol in addition to various metallic impurities. "Formaldehyde"

202-442: A microwave oven for 2–3 minutes before grilling shortens the time on the hot pan, and removes heterocyclic amine (HCA) precursors, which can help minimize the formation of these carcinogens. Frying, grilling or broiling food at high temperatures, especially starchy foods, until a toasted crust is formed generates acrylamides . This discovery in 2002 led to international health concerns. Subsequent research has however found that it

303-555: A chemical necessary in synthesizing PETN , a high explosive: An aqueous solution of formaldehyde can be useful as a disinfectant as it kills most bacteria and fungi (including their spores). It is used as an additive in vaccine manufacturing to inactivate toxins and pathogens. Formaldehyde releasers are used as biocides in personal care products such as cosmetics. Although present at levels not normally considered harmful, they are known to cause allergic contact dermatitis in certain sensitised individuals. Aquarists use formaldehyde as

404-470: A common state. The trimer 1,3,5-trioxane, (CH 2 O) 3 , is a typical oligomer. Many cyclic oligomers of other sizes have been isolated. Similarly, formaldehyde hydrates to give the geminal diol methanediol , which condenses further to form hydroxy-terminated oligomers HO(CH 2 O) n H. The polymer is called paraformaldehyde . The higher concentration of formaldehyde—the more equilibrium shifts towards polymerization. Diluting with water or increasing

505-575: A contributing factor in stomach cancer: in Japan, where very salty pickled foods are popular, the incidence of stomach cancer is high. Preserved meat such as bacon, sausages, and ham increases the risk, while a diet rich in fresh fruit, vegetables, peas, beans, grains, nuts, seeds, herbs, and spices will reduce the risk. The risk also increases with age. Hydrogen cyanide 12.9 (in DMSO) Hydrogen cyanide (formerly known as prussic acid )

606-519: A defense mechanism, as do certain insects, such as burnet moths and the larvae of Paropsisterna eucalyptus . Hydrogen cyanide is contained in the exhaust of vehicles, and in smoke from burning nitrogen-containing plastics . HCN has been measured in Titan's atmosphere by four instruments on the Cassini space probe , one instrument on Voyager , and one instrument on Earth. One of these measurements

707-488: A factor of ~3.5. HCN has been used to analyze a variety of species and processes in the interstellar medium. It has been suggested as a tracer for dense molecular gas and as a tracer of stellar inflow in high-mass star-forming regions. Further, the HNC/HCN ratio has been shown to be an excellent method for distinguishing between PDRs and X-ray-dominated regions (XDRs). On 11 August 2014, astronomers released studies, using

808-466: A few. CERCLA identifies all radionuclides as carcinogens, although the nature of the emitted radiation ( alpha , beta , gamma , or neutron and the radioactive strength), its consequent capacity to cause ionization in tissues, and the magnitude of radiation exposure, determine the potential hazard. Carcinogenicity of radiation depends on the type of radiation, type of exposure, and penetration. For example, alpha radiation has low penetration and

909-482: A high incidence of colon cancer. Dietary increases in total fat or saturated fat result in elevated DCA and LCA in feces and elevated exposure of the colon epithelium to these bile acids. When the bile acid DCA was added to the standard diet of wild-type mice invasive colon cancer was induced in 56% of the mice after 8 to 10 months. Overall, the available evidence indicates that DCA and LCA are centrally important DNA-damaging carcinogens in colon cancer. Stomach cancer

1010-417: 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. Carcinogen A carcinogen ( / k ɑːr ˈ s ɪ n ə dʒ ən / ) is any agent that promotes

1111-647: A living organism ( in vivo ) muscarinic cholinergic stimulation actually decreases HCN production. Leukocytes generate HCN during phagocytosis , and can kill bacteria , fungi , and other pathogens by generating several different toxic chemicals, one of which is hydrogen cyanide. The vasodilatation caused by sodium nitroprusside has been shown to be mediated not only by NO generation, but also by endogenous cyanide generation, which adds not only toxicity, but also some additional antihypertensive efficacy compared to nitroglycerine and other non-cyanogenic nitrates which do not cause blood cyanide levels to rise. HCN

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1212-488: A major source of carcinogens with an estimated 666,000 annual fatalities worldwide attributable to work related cancers. According to NIOSH , 3-6% of cancers worldwide are due to occupational exposures. Well established occupational carcinogens include vinyl chloride and hemangiosarcoma of the liver, benzene and leukemia , aniline dyes and bladder cancer , asbestos and mesothelioma , polycyclic aromatic hydrocarbons and scrotal cancer among chimney sweeps to name

1313-670: A positive correlation between exposure to formaldehyde and the development of leukemia , particularly myeloid leukemia . Nasopharyngeal and sinonasal cancers are relatively rare, with a combined annual incidence in the United States of < 4,000 cases. About 30,000 cases of myeloid leukemia occur in the United States each year. Some evidence suggests that workplace exposure to formaldehyde contributes to sinonasal cancers. Professionals exposed to formaldehyde in their occupation, such as funeral industry workers and embalmers , showed an increased risk of leukemia and brain cancer compared with

1414-466: A protein to form methylol , which loses a water molecule to form a Schiff base . The Schiff base can then react with DNA or protein to create a cross-linked product. This reaction is the basis for the most common process of chemical fixation . Formaldehyde is readily oxidized by atmospheric oxygen into formic acid . For this reason, commercial formaldehyde is typically contaminated with formic acid. Formaldehyde can be hydrogenated into methanol . In

1515-477: A role in signal transduction between neuronal cells ( neurotransmission ). Moreover, increased endogenous neuronal HCN production under opioids was seemingly needed for adequate opioid analgesia , as analgesic action of opioids was attenuated by HCN scavengers. They considered endogenous HCN to be a neuromodulator . It has also been shown that, while stimulating muscarinic cholinergic receptors in cultured pheochromocytoma cells increases HCN production, in

1616-588: A significant danger to human health. In 2011, the US National Toxicology Program described formaldehyde as "known to be a human carcinogen". Concerns are associated with chronic (long-term) exposure by inhalation as may happen from thermal or chemical decomposition of formaldehyde-based resins and the production of formaldehyde resulting from the combustion of a variety of organic compounds (for example, exhaust gases). As formaldehyde resins are used in many construction materials , it

1717-454: A significant number of authors. Contrary to this view, it is considered organic by other authors, because hydrogen cyanide belongs to the class of organic compounds known as nitriles which have the formula R−C≡N , where R is typically organyl group (e.g., alkyl or aryl ) or hydrogen . In the case of hydrogen cyanide, the R group is hydrogen H, so the other names of hydrogen cyanide are methanenitrile and formonitrile. Hydrogen cyanide

1818-539: A significant source of formaldehyde in homes. The eyes are most sensitive to formaldehyde exposure: The lowest level at which many people can begin to smell formaldehyde ranges between 0.05 and 1 ppm. The maximum concentration value at the workplace is 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

1919-587: A treatment for the parasites Ichthyophthirius multifiliis and Cryptocaryon irritans . Formaldehyde is one of the main disinfectants recommended for destroying anthrax . Formaldehyde is also approved for use in the manufacture of animal feeds in the US. It is an antimicrobial agent used to maintain complete animal feeds or feed ingredients Salmonella negative for up to 21 days. Formaldehyde preserves or fixes tissue or cells. The process involves cross-linking of primary amino groups . The European Union has banned

2020-645: A wider assessment of the occupational hazards of chemicals. The European Union classification of carcinogens is contained in the Regulation (EC) No 1272/2008. It consists of three categories: The former European Union classification of carcinogens was contained in the Dangerous Substances Directive and the Dangerous Preparations Directive . It also consisted of three categories: This assessment scheme

2121-605: Is carcinogenic, if received in sufficient doses. For most people, ultraviolet radiations from sunlight is the most common cause of skin cancer. In Australia, where people with pale skin are often exposed to strong sunlight, melanoma is the most common cancer diagnosed in people aged 15–44 years. Substances or foods irradiated with electrons or electromagnetic radiation (such as microwave, X-ray or gamma) are not carcinogenic. In contrast, non-electromagnetic neutron radiation produced inside nuclear reactors can produce secondary radiation through nuclear transmutation . Alcohol

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2222-412: Is a United Nations initiative to attempt to harmonize the different systems of assessing chemical risk which currently exist (as of March 2009) around the world. It classifies carcinogens into two categories, of which the first may be divided again into subcategories if so desired by the competent regulatory authority: The National Toxicology Program of the U.S. Department of Health and Human Services

2323-491: Is a chemical compound with the formula HCN and structural formula H−C≡N . It is a highly toxic and flammable liquid that boils slightly above room temperature , at 25.6 °C (78.1 °F). HCN is produced on an industrial scale and is a highly valued precursor to many chemical compounds ranging from polymers to pharmaceuticals. Large-scale applications are for the production of potassium cyanide and adiponitrile , used in mining and plastics, respectively. It

2424-459: Is a linear molecule , with a triple bond between carbon and nitrogen . The tautomer of HCN is HNC, hydrogen isocyanide . HCN has a faint bitter almond -like odor that some people are unable to detect owing to a recessive genetic trait . The volatile compound has been used as inhalation rodenticide and human poison, as well as for killing whales. Cyanide ions interfere with iron-containing respiratory enzymes. Hydrogen cyanide

2525-683: Is a carcinogen of the head and neck, esophagus, liver, colon and rectum, and breast. It has a synergistic effect with tobacco smoke in the development of head and neck cancers. In the United States approximately 6% of cancers and 4% of cancer deaths are attributable to alcohol use. Chemicals used in processed and cured meat such as some brands of bacon, sausages and ham may produce carcinogens. For example, nitrites used as food preservatives in cured meat such as bacon have also been noted as being carcinogenic with demographic links, but not causation, to colon cancer. Cooking food at high temperatures, for example grilling or barbecuing meats, may also lead to

2626-853: Is a common precursor to 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 plastics , 1,4-butanediol , and methylene diphenyl diisocyanate . The textile industry uses formaldehyde-based resins as finishers to make fabrics crease-resistant. When condensed with phenol , urea , or melamine , formaldehyde produces, respectively, hard thermoset phenol formaldehyde resin, urea formaldehyde resin, and melamine resin. These polymers are permanent adhesives used in plywood and carpeting . They are also foamed to make insulation , or cast into moulded products. Production of formaldehyde resins accounts for more than half of formaldehyde consumption. Formaldehyde

2727-764: Is a complex mixture of more than 5,300 identified chemicals. The most important carcinogens in tobacco smoke have been determined by a "Margin of Exposure" approach. Using this approach, the most important tumorigenic compounds in tobacco smoke were, in order of importance, acrolein , formaldehyde , acrylonitrile , 1,3-butadiene, cadmium, acetaldehyde, ethylene oxide, and isoprene. Most of these compounds cause DNA damage by forming DNA adducts or by inducing other alterations in DNA. DNA damages are subject to error-prone DNA repair or can cause replication errors. Such errors in repair or replication can result in mutations in tumor suppressor genes or oncogenes leading to cancer. Breast cancer

2828-457: Is a constituent of tobacco smoke . Hydrogen cyanide has been discussed as a precursor to amino acids and nucleic acids, and is proposed to have played a part in the origin of life . Although the relationship of these chemical reactions to the origin of life theory remains speculative, studies in this area have led to discoveries of new pathways to organic compounds derived from the condensation of HCN (e.g. Adenine ). HCN has been detected in

2929-407: Is also a precursor to polyfunctional alcohols such as pentaerythritol , which is used to make paints and explosives . 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 . Condensation with acetaldehyde affords pentaerythritol ,

3030-707: Is an intergovernmental agency established in 1965, which forms part of the World Health Organization of the United Nations . It is based in Lyon , France . Since 1971 it has published a series of Monographs on the Evaluation of Carcinogenic Risks to Humans that have been highly influential in the classification of possible carcinogens. The Globally Harmonized System of Classification and Labelling of Chemicals (GHS)

3131-514: Is an intermediate in the oxidation (or combustion ) of methane , as well as of other carbon compounds, e.g. in forest fires , automobile exhaust, and tobacco smoke . When produced in the atmosphere by the action of sunlight and oxygen on atmospheric methane and other hydrocarbons , it becomes part of smog . Formaldehyde has also been detected in outer space. Formaldehyde and its adducts are ubiquitous in nature. Food may contain formaldehyde at levels 1–100 mg/kg. Formaldehyde, formed in

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3232-685: Is being phased out in favor of the GHS scheme (see above), to which it is very close in category definitions. Under a previous name, the NOHSC, in 1999 Safe Work Australia published the Approved Criteria for Classifying Hazardous Substances [NOHSC:1008(1999)]. Section 4.76 of this document outlines the criteria for classifying carcinogens as approved by the Australian government. This classification consists of three categories: In this section,

3333-467: Is destroyed in interstellar clouds through a number of mechanisms depending on the location in the cloud. In photon-dominated regions (PDRs), photodissociation dominates, producing CN (HCN + ν → CN + H). At further depths, photodissociation by cosmic rays dominate, producing CN (HCN + cr → CN + H). In the dark core, two competing mechanisms destroy it, forming HCN and HCNH (HCN + H → HCN + H; HCN + HCO → HCNH + CO). The reaction with HCO dominates by

3434-707: Is efficiently recycled back into HCN via the reaction CN + CH 4 → HCN + CH 3 . It has been postulated that carbon from a cascade of asteroids (known as the Late Heavy Bombardment ), resulting from interaction of Jupiter and Saturn, blasted the surface of young Earth and reacted with nitrogen in Earth's atmosphere to form HCN. Some authors have shown that neurons can produce hydrogen cyanide upon activation of their opioid receptors by endogenous or exogenous opioids. They have also shown that neuronal production of HCN activates NMDA receptors and plays

3535-750: Is exploited in ChIP-on-chip or ChIP-sequencing genomics experiments, where DNA-binding proteins are cross-linked to their cognate binding sites on the chromosome and analyzed to determine what genes are regulated by the proteins. Formaldehyde is also used as a denaturing agent in RNA gel electrophoresis , preventing RNA from forming secondary structures. A solution of 4% formaldehyde fixes pathology tissue specimens at about one mm per hour at room temperature. Formaldehyde and 18  M (concentrated) sulfuric acid makes Marquis reagent —which can identify alkaloids and other compounds. In photography, formaldehyde

3636-477: Is formed from aqueous hydrogen cyanide: Hydrogen cyanide was first isolated in 1752 by French chemist Pierre Macquer who converted Prussian blue to an iron oxide plus a volatile component and found that these could be used to reconstitute it. The new component was what is now known as hydrogen cyanide. It was subsequently prepared from Prussian blue by the Swedish chemist Carl Wilhelm Scheele in 1782, and

3737-466: Is formed in interstellar clouds through one of two major pathways: via a neutral-neutral reaction (CH 2 + N → HCN + H) and via dissociative recombination (HCNH + e → HCN + H). The dissociative recombination pathway is dominant by 30%; however, the HCNH must be in its linear form. Dissociative recombination with its structural isomer, H 2 NC , exclusively produces hydrogen isocyanide (HNC). HCN

3838-738: Is known to cause stomach cancer and MALT lymphoma . Hepatitis B and C are associated with the development of hepatocellular cancer. HPV is the primary cause of cervical cancer . Tobacco smoke contains at least 70 known carcinogens and is implicated in the development of numerous types of cancers including cancers of the lung, larynx, esophagus, stomach, kidney, pancreas, liver, bladder, cervix, colon, rectum and blood. Potent carcinogens found in cigarette smoke include polycyclic aromatic hydrocarbons (PAH, such as benzo(a)pyrene), benzene , and nitrosamine . Given that populations of workers are more likely to have consistent, often high level exposures to chemicals rarely encountered in normal life, much of

3939-446: Is mandated to produce a biennial Report on Carcinogens . As of August 2024, the latest edition was the 15th report (2021). It classifies carcinogens into two groups: The American Conference of Governmental Industrial Hygienists (ACGIH) is a private organization best known for its publication of threshold limit values (TLVs) for occupational exposure and monographs on workplace chemical hazards. It assesses carcinogenicity as part of

4040-407: Is more toxic than solid cyanide compounds due to its volatile nature. A solution of hydrogen cyanide in water , represented as HCN, is called hydrocyanic acid . The salts of the cyanide anion are known as cyanides . Whether hydrogen cyanide is an organic compound or not is a topic of debate among chemists, and opinions vary from author to author. Traditionally, it is considered inorganic by

4141-651: Is not a hazard outside the body, but emitters are carcinogenic when inhaled or ingested. For example, Thorotrast , a (incidentally radioactive) suspension previously used as a contrast medium in x-ray diagnostics, is a potent human carcinogen known because of its retention within various organs and persistent emission of alpha particles. Low-level ionizing radiation may induce irreparable DNA damage (leading to replicational and transcriptional errors needed for neoplasia or may trigger viral interactions) leading to pre-mature aging and cancer . Not all types of electromagnetic radiation are carcinogenic. Low-energy waves on

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4242-429: Is not likely that the acrylamides in burnt or well-cooked food cause cancer in humans; Cancer Research UK categorizes the idea that burnt food causes cancer as a "myth". Several biologic agents are known carcinogens. Aflatoxin B 1 , a toxin produced by the fungus Aspergillus flavus which is a common contaminant of stored grains and nuts is a known cause of hepatocellular cancer . The bacteria H. Pylori

4343-679: Is obtainable from fruits that have a pit , such as cherries , apricots , apples , and nuts such as bitter almonds , from which almond oil and extract is made. Many of these pits contain small amounts of cyanohydrins such as mandelonitrile and amygdalin , which slowly release hydrogen cyanide. One hundred grams of crushed apple seeds can yield about 70 mg of HCN. The roots of cassava plants contain cyanogenic glycosides such as linamarin , which decompose into HCN in yields of up to 370 mg per kilogram of fresh root. Some millipedes , such as Harpaphe haydeniana , Desmoxytes purpurosea , and Apheloria release hydrogen cyanide as

4444-436: Is one of the more common indoor air pollutants . At concentrations above 0.1 ppm in air, formaldehyde can irritate the eyes and mucous membranes . Formaldehyde inhaled at this concentration may cause headaches, a burning sensation in the throat, and difficulty breathing, and can trigger or aggravate asthma symptoms. The CDC considers formaldehyde as a systemic poison. Formaldehyde poisoning can cause permanent changes in

4545-556: Is produced by paints, varnishes , floor finishes, and cigarette smoking as well. In July 2016, the U.S. EPA released a prepublication version of its final rule on Formaldehyde Emission Standards for Composite Wood Products. These new rules impact manufacturers, importers, distributors, and retailers of products containing composite wood, including fiberboard, particleboard, and various laminated products, who must comply with more stringent record-keeping and labeling requirements. The U.S. EPA allows no more than 0.016 ppm formaldehyde in

4646-413: Is produced via several enzyme-catalyzed routes. Living beings, including humans, produce formaldehyde as part of their metabolism. Formaldehyde is key to several bodily functions (e.g. epigenetics ), but its amount must also be tightly controlled to avoid self-poisoning. Formaldehyde is catabolized by alcohol dehydrogenase ADH5 and aldehyde dehydrogenase ALDH2 . Formaldehyde is a building block in

4747-426: Is the fourth most common cancer [990,000 cases (7.8%), 738,000 deaths (9.7%)]. Helicobacter pylori infection is the main causative factor in stomach cancer. Chronic gastritis (inflammation) caused by H. pylori is often long-standing if not treated. Infection of gastric epithelial cells with H. pylori results in increased production of reactive oxygen species (ROS). ROS cause oxidative DNA damage including

4848-649: Is the most common cancer in the world, both in terms of cases (1.6 million cases; 12.7% of total cancer cases) and deaths (1.4 million deaths; 18.2% of total cancer deaths). Lung cancer is largely caused by tobacco smoke. Risk estimates for lung cancer in the United States indicate that tobacco smoke is responsible for 90% of lung cancers. Other factors are implicated in lung cancer, and these factors can interact synergistically with smoking so that total attributable risk adds up to more than 100%. These factors include occupational exposure to carcinogens (about 9-15%), radon (10%) and outdoor air pollution (1-2%). Tobacco smoke

4949-406: Is the second most common cancer [(1.4 million cases, 10.9%), but ranks 5th as cause of death (458,000, 6.1%)]. Increased risk of breast cancer is associated with persistently elevated blood levels of estrogen . Estrogen appears to contribute to breast carcinogenesis by three processes; (1) the metabolism of estrogen to genotoxic, mutagenic carcinogens, (2) the stimulation of tissue growth, and (3)

5050-423: Is used globally as a fumigant against many species of pest insects that infest food production facilities. Both its efficacy and method of application lead to very small amounts of the fumigant being used compared to other toxic substances used for the same purpose. Using HCN as a fumigant also has less environmental impact, compared to some other fumigants such as sulfuryl fluoride , and methyl bromide . HCN

5151-431: Is used in low concentrations for the process C-41 (color negative film) stabilizer in the final wash step, as well as in the process E-6 pre-bleach step, to make it unnecessary in the final wash. Due to improvements in dye coupler chemistry, more modern (2006 or later) E-6 and C-41 films do not need formaldehyde, as their dyes are already stable. In view of its widespread use, toxicity, and volatility, formaldehyde poses

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5252-544: Is weakly acidic with a p K a of 9.2. It partially ionizes in water to give the cyanide anion, CN . HCN forms hydrogen bonds with its conjugate base, species such as (CN )(HCN) n . Hydrogen cyanide reacts with alkenes to give nitriles. The conversion, which is called hydrocyanation , employs nickel complexes as catalysts. Four molecules of HCN will tetramerize into diaminomaleonitrile . Metal cyanides are typically prepared by salt metathesis from alkali metal cyanide salts, but mercuric cyanide

5353-547: The Atacama Large Millimeter/Submillimeter Array (ALMA) for the first time, that detailed the distribution of HCN, HNC , H 2 CO , and dust inside the comae of comets C/2012 F6 (Lemmon) and C/2012 S1 (ISON) . In February 2016, it was announced that traces of hydrogen cyanide were found in the atmosphere of the hot Super-Earth 55 Cancri e with NASA's Hubble Space Telescope . On 14 December 2023, astronomers reported

5454-457: The Cannizzaro reaction , formaldehyde and base react to produce formic acid and methanol, a disproportionation reaction . Formaldehyde reacts with many compounds, resulting in hydroxymethylation : The resulting hydroxymethyl derivatives typically react further. Thus, amines give hexahydro-1,3,5-triazines : Similarly, when combined with hydrogen sulfide , it forms trithiane : In

5555-485: The Karlsruhe Congress . The compound was identified as an aldehyde by August Wilhelm von Hofmann , who first announced its production by passing methanol vapor in air over hot platinum wire. With modifications, Hoffmann's method remains the basis of the present day industrial route. Solution routes to formaldehyde also entail oxidation of methanol or iodomethane . Formaldehyde is produced industrially by

5656-634: The Organisation for the Prohibition of Chemical Weapons . Perhaps its most infamous use is Zyklon B (German: Cyclone B , with the B standing for Blausäure – prussic acid; also, to distinguish it from an earlier product later known as Zyklon A), used in Nazi German extermination camps during World War II to kill Jews and other persecuted minorities en masse as part of their Final Solution genocide program. Hydrogen cyanide

5757-711: The United States Environmental Protection Agency (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 associated with nasal sinus cancer and nasopharyngeal cancer . Studies in 2009 and 2010 have also shown

5858-462: The carbon–oxygen bond and around 1.11 Å for the carbon–hydrogen bond , while the H–C–H bond angle is 117°, close to the 120° angle found in an ideal trigonal planar molecule . Some excited electronic states of formaldehyde are pyramidal rather than planar as in the ground state . Processes in the upper atmosphere contribute more than 80% of the total formaldehyde in the environment. Formaldehyde

5959-423: The chemical equation : The silver-based catalyst usually operates at a higher temperature, about 650 °C. Two chemical reactions on it simultaneously produce formaldehyde: that shown above and the dehydrogenation reaction: In principle, formaldehyde could be generated by oxidation of methane , but this route is not industrially viable because the methanol is more easily oxidized than methane. Formaldehyde

6060-516: The comae of comets C/2012 F6 (Lemmon) and C/2012 S1 (ISON) . Formaldehyde was discovered in 1859 by the Russian chemist Aleksandr Butlerov (1828–1886) when he attempted to synthesize methanediol ("methylene glycol") from iodomethane and silver oxalate . In his paper, Butlerov referred to formaldehyde as "dioxymethylen" (methylene dioxide) because his empirical formula for it was incorrect, as atomic weights were not precisely determined until

6161-522: The electromagnetic spectrum including radio waves , microwaves , infrared radiation and visible light are thought not to be, because they have insufficient energy to break chemical bonds. Evidence for carcinogenic effects of non-ionizing radiation is generally inconclusive , though there are some documented cases of radar technicians with prolonged high exposure experiencing significantly higher cancer incidence. Higher-energy radiation, including ultraviolet radiation (present in sunlight ) generally

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6262-480: The electroplating of those metals. Via the intermediacy of cyanohydrins , a variety of useful organic compounds are prepared from HCN including the monomer methyl methacrylate , from acetone , the amino acid methionine , via the Strecker synthesis , and the chelating agents EDTA and NTA . Via the hydrocyanation process, HCN is added to butadiene to give adiponitrile , a precursor to Nylon-6,6 . HCN

6363-460: The interstellar medium and in the atmospheres of carbon stars . Since then, extensive studies have probed formation and destruction pathways of HCN in various environments and examined its use as a tracer for a variety of astronomical species and processes. HCN can be observed from ground-based telescopes through a number of atmospheric windows. The J=1→0, J=3→2, J= 4→3, and J=10→9 pure rotational transitions have all been observed. HCN

6464-434: The nervous system 's functions. A 1988 Canadian study of houses with urea-formaldehyde foam insulation found that formaldehyde levels as low as 0.046 ppm were positively correlated with eye and nasal irritation. A 2009 review of studies has shown a strong association between exposure to formaldehyde and the development of childhood asthma . A theory was proposed for the carcinogenesis of formaldehyde in 1978. In 1987

6565-611: The origin of life ." In World War I , hydrogen cyanide was used by the French from 1916 as a chemical weapon against the Central Powers , and by the United States and Italy in 1918. It was not found to be effective enough due to weather conditions. The gas is lighter than air and rapidly disperses up into the atmosphere. Rapid dilution made its use in the field impractical. In contrast, denser agents such as phosgene or chlorine tended to remain at ground level and sank into

6666-473: The trenches of the Western Front's battlefields. Compared to such agents, hydrogen cyanide had to be present in higher concentrations in order to be fatal. A hydrogen cyanide concentration of 100–200 ppm in breathing air will kill a human within 10 to 60 minutes. A hydrogen cyanide concentration of 2000 ppm (about 2380 mg/m ) will kill a human in about one minute. The toxic effect is caused by

6767-461: The 1890s was met by George Thomas Beilby , who patented a method to produce hydrogen cyanide by passing ammonia over glowing coal in 1892. This method was used until Hamilton Castner in 1894 developed a synthesis starting from coal, ammonia, and sodium yielding sodium cyanide , which reacts with acid to form gaseous HCN. HCN is the precursor to sodium cyanide and potassium cyanide , which are used mainly in gold and silver mining and for

6868-550: The Greek word for blue ( Ancient Greek : κύανος ), again owing to its derivation from Prussian blue. The most important process is the Andrussow oxidation invented by Leonid Andrussow at IG Farben in which methane and ammonia react in the presence of oxygen at about 1,200 °C (2,190 °F) over a platinum catalyst: In 2006, between 500 million and 1 billion pounds (between 230,000 and 450,000 t) were produced in

6969-540: The Shawinigan Process, hydrocarbons , e.g. propane , are reacted with ammonia. In the laboratory, small amounts of HCN are produced by the addition of acids to cyanide salts of alkali metals : This reaction is sometimes the basis of accidental poisonings because the acid converts a nonvolatile cyanide salt into the gaseous HCN. Hydrogen cyanide could be obtained from potassium ferricyanide and acid: The large demand for cyanides for mining operations in

7070-501: The US. Hydrogen cyanide is produced in large quantities by several processes and is a recovered waste product from the manufacture of acrylonitrile . Of lesser importance is the Degussa process ( BMA process ) in which no oxygen is added and the energy must be transferred indirectly through the reactor wall: This reaction is akin to steam reforming , the reaction of methane and water to give carbon monoxide and hydrogen . In

7171-510: The action of the cyanide ion, which halts cellular respiration . It acts as a non-competitive inhibitor for an enzyme in mitochondria called cytochrome c oxidase . As such, hydrogen cyanide is commonly listed among chemical weapons as a blood agent . The Chemical Weapons Convention lists it under Schedule 3 as a potential weapon which has large-scale industrial uses. Signatory countries must declare manufacturing plants that produce more than 30 metric tons per year, and allow inspection by

7272-678: The agent's ability to engage directly with DNA. Activation-dependent agents are relatively inert in their original form, but are bioactivated in the body into metabolites or intermediaries capable of damaging human DNA. These are also known as "indirect-acting" carcinogens. Examples of activation-dependent carcinogens include polycyclic aromatic hydrocarbons (PAHs), heterocyclic aromatic amines , and mycotoxins . Activation-independent carcinogens, or "direct-acting" carcinogens, are those that are capable of directly damaging DNA without any modification to their molecular structure. These agents typically include electrophilic groups that react readily with

7373-504: The air in new buildings constructed for that agency. A U.S. EPA study found a new home measured 0.076 ppm when brand new and 0.045 ppm after 30 days. The Federal Emergency Management Agency (FEMA) has also announced limits on the formaldehyde levels in trailers purchased by that agency. The EPA recommends the use of "exterior-grade" pressed-wood products with phenol instead of urea resin to limit formaldehyde exposure, since pressed-wood products containing formaldehyde resins are often

7474-408: The atomic bombs developed by the secret Manhattan Project . Hydrogen cyanide was also the agent employed in judicial execution in some U.S. states , where it was produced during the execution by the action of sulfuric acid on sodium cyanide or potassium cyanide . Under the name prussic acid , HCN has been used as a killing agent in whaling harpoons, although it proved quite dangerous to

7575-729: The bile acids deoxycholic acid (DCA) or lithocholic acid (LCA) induce production of DNA-damaging reactive oxygen species or reactive nitrogen species in human or animal colon cells. Furthermore, 14 studies showed that DCA and LCA induce DNA damage in colon cells. Also 27 studies reported that bile acids cause programmed cell death ( apoptosis ). Increased apoptosis can result in selective survival of cells that are resistant to induction of apoptosis. Colon cells with reduced ability to undergo apoptosis in response to DNA damage would tend to accumulate mutations, and such cells may give rise to colon cancer. Epidemiologic studies have found that fecal bile acid concentrations are increased in populations with

7676-750: The carcinogenicity of substances include the National Toxicology Program of the US Public Health Service , NIOSH , the American Conference of Governmental Industrial Hygienists and others. There are numerous sources of exposures to carcinogens including ultraviolet radiation from the sun, radon gas emitted in residential basements, environmental contaminants such as chlordecone , cigarette smoke and ingestion of some types of foods such as alcohol and processed meats . Occupational exposures represent

7777-422: The carcinogens implicated as the main causative agents of the four most common cancers worldwide are briefly described. These four cancers are lung, breast, colon, and stomach cancers. Together they account for about 41% of worldwide cancer incidence and 42% of cancer deaths (for more detailed information on the carcinogens implicated in these and other cancers, see references ). Lung cancer (pulmonary carcinoma)

7878-421: The catalytic oxidation of methanol . The most common catalysts are silver metal, iron(III) oxide , iron molybdenum oxides (e.g. iron(III) molybdate ) with a molybdenum -enriched surface, or vanadium oxides . In the commonly used formox process , methanol and oxygen react at c. 250–400 °C in presence of iron oxide in combination with molybdenum and/or vanadium to produce formaldehyde according to

7979-526: The cell's DNA repair processes fail to identify DNA damage allowing the defect to be passed down to daughter cells . The damage accumulates over time. This is typically a multi-step process during which the regulatory mechanisms within the cell are gradually dismantled allowing for unchecked cellular division . The specific mechanisms for carcinogenic activity is unique to each agent and cell type. Carcinogens can be broadly categorized, however, as activation-dependent and activation-independent which relate to

8080-654: The cumulative scientific evidence regarding the potential carcinogenicity of specific substances. Foremost among these is the International Agency for Research on Cancer (IARC). IARC routinely publishes monographs in which specific substances are evaluated for their potential carcinogenicity to humans and subsequently categorized into one of four groupings: Group 1: Carcinogenic to humans, Group 2A: Probably carcinogenic to humans, Group 2B: Possibly carcinogenic to humans and Group 3: Not classifiable as to its carcinogenicity to humans. Other organizations that evaluate

8181-457: The development of cancer . Carcinogens can include synthetic chemicals , naturally occurring substances, physical agents such as ionizing and non-ionizing radiation , and biologic agents such as viruses and bacteria . Most carcinogens act by creating mutations in DNA that disrupt a cell's normal processes for regulating growth, leading to uncontrolled cellular proliferation. This occurs when

8282-439: 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, converting it to formic acid , so it does not accumulate. It nonetheless presents significant health concerns , as a contaminant . Formaldehyde appears to be a useful probe in astrochemistry due to prominence of the 1 10 ←1 11 and 2 11 ←2 12 K -doublet transitions. It

8383-737: The evidence for the carcinogenicity of specific agents is derived from studies of workers. Selected carcinogens Not in widespread use, but found in: circadian disruption Carcinogens can be classified as genotoxic or nongenotoxic. Genotoxins cause irreversible genetic damage or mutations by binding to DNA . Genotoxins include chemical agents like N-nitroso-N-methylurea (NMU) or non-chemical agents such as ultraviolet light and ionizing radiation . Certain viruses can also act as carcinogens by interacting with DNA. Nongenotoxins do not directly affect DNA but act in other ways to promote growth. These include hormones and some organic compounds. The International Agency for Research on Cancer (IARC)

8484-435: The first time discovery, in the plumes of Enceladus , moon of the planet Saturn , of hydrogen cyanide, a possible chemical essential for life as we know it, as well as other organic molecules , some of which are yet to be better identified and understood. According to the researchers, "these [newly discovered] compounds could potentially support extant microbial communities or drive complex organic synthesis leading to

8585-438: The formation of minute quantities of many potent carcinogens that are comparable to those found in cigarette smoke (i.e., benzo[ a ]pyrene ). Charring of food looks like coking and tobacco pyrolysis , and produces carcinogens. There are several carcinogenic pyrolysis products, such as polynuclear aromatic hydrocarbons, which are converted by human enzymes into epoxides , which attach permanently to DNA. Pre-cooking meats in

8686-412: The general population. Other factors are important in determining individual risk for the development of leukemia or nasopharyngeal cancer. In yeast, formaldehyde is found to perturb pathways for DNA repair and cell cycle. In the residential environment, formaldehyde exposure comes from a number of routes; formaldehyde can be emitted by treated wood products, such as plywood or particle board , but it

8787-558: The incidence of DNA damage and breast cancer risk. Consumption of alcohol has also been linked to an increased risk for breast cancer. Colorectal cancer is the third most common cancer [1.2 million cases (9.4%), 608,000 deaths (8.0%)]. Tobacco smoke may be responsible for up to 20% of colorectal cancers in the United States. In addition, substantial evidence implicates bile acids as an important factor in colon cancer. Twelve studies (summarized in Bernstein et al. ) indicate that

8888-418: The major base alteration 8-hydroxydeoxyguanosine (8-OHdG). 8-OHdG resulting from ROS is increased in chronic gastritis. The altered DNA base can cause errors during DNA replication that have mutagenic and carcinogenic potential. Thus H. pylori -induced ROS appear to be the major carcinogens in stomach cancer because they cause oxidative DNA damage leading to carcinogenic mutations. Diet is also thought to be

8989-502: The metabolism of the amino acids serine and threonine , is found in the bloodstream of humans and other primates at concentrations of approximately 50  micromolar . Experiments in which animals are exposed to an atmosphere containing isotopically labeled formaldehyde have demonstrated that even in deliberately exposed animals, the majority of formaldehyde-DNA adducts found in non-respiratory tissues are derived from endogenously produced formaldehyde. Formaldehyde does not accumulate in

9090-410: The name of oxygen itself, which is derived from Greek elements that mean "acid-former" and are likewise calqued into German as Sauerstoff ). In 1811, Joseph Louis Gay-Lussac prepared pure, liquified hydrogen cyanide. In 1815, Gay-Lussac deduced Prussic acid's chemical formula. The radical cyanide in hydrogen cyanide was given its name from cyan , not only an English word for a shade of blue but

9191-569: The net negative charge of DNA molecules. Examples of activation-independent carcinogens include ultraviolet light , ionizing radiation and alkylating agents . The time from exposure to a carcinogen to the development of cancer is known as the latency period . For most solid tumors in humans the latency period is between 10 and 40 years depending on cancer type. For blood cancers, the latency period may be as short as two. Due to prolonged latency periods identification of carcinogens can be challenging. A number of organizations review and evaluate

9292-608: The presence of acids, it participates in electrophilic aromatic substitution reactions with aromatic compounds resulting in hydroxymethylated derivatives: When conducted in the presence of hydrogen chloride, the product is the chloromethyl compound, as described in the Blanc chloromethylation . If the arene is electron-rich, as in phenols, elaborate condensations ensue. With 4-substituted phenols one obtains calixarenes . Phenol results in polymers. Many amino acids react with formaldehyde. Cysteine converts to thioproline . Formaldehyde

9393-690: The repression of phase II detoxification enzymes that metabolize ROS leading to increased oxidative DNA damage. The major estrogen in humans, estradiol , can be metabolized to quinone derivatives that form adducts with DNA. These derivatives can cause depurination, the removal of bases from the phosphodiester backbone of DNA, followed by inaccurate repair or replication of the apurinic site leading to mutation and eventually cancer. This genotoxic mechanism may interact in synergy with estrogen receptor-mediated, persistent cell proliferation to ultimately cause breast cancer. Genetic background, dietary practices and environmental factors also likely contribute to

9494-452: The solution temperature, as well as adding alcohols (such as methanol or ethanol) lowers that tendency. Gaseous formaldehyde polymerizes at active sites on vessel walls, but the mechanism of the reaction is unknown. Small amounts of hydrogen chloride , boron trifluoride , or stannic chloride present in gaseous formaldehyde provide the catalytic effect and make the polymerization rapid. Formaldehyde forms cross-links by first combining with

9595-405: 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. Monomeric CH 2 O is a gas and is rarely encountered in the laboratory. Aqueous formaldehyde, unlike some other small aldehydes (which need specific conditions to oligomerize through aldol condensation ) oligomerizes spontaneously at

9696-703: The use of formaldehyde as a biocide (including embalming ) under the Biocidal Products Directive (98/8/EC) due to its carcinogenic properties. Countries with a strong tradition of embalming corpses, such as Ireland and other colder-weather countries, have raised concerns. Despite reports to the contrary, no decision on the inclusion of formaldehyde on Annex I of the Biocidal Products Directive for product-type 22 (embalming and taxidermist fluids) had been made as of September 2009. Formaldehyde-based crosslinking

9797-579: Was in situ , where the Cassini spacecraft dipped between 1,000 and 1,100 km (620 and 680 mi) above Titan's surface to collect atmospheric gas for mass spectrometry analysis. HCN initially forms in Titan's atmosphere through the reaction of photochemically produced methane and nitrogen radicals which proceed through the H 2 CN intermediate, e.g., (CH 3 + N → H 2 CN + H → HCN + H 2 ). Ultraviolet radiation breaks HCN up into CN + H; however, CN

9898-447: Was also used in the camps for delousing clothing in attempts to eradicate diseases carried by lice and other parasites. One of the original Czech producers continued making Zyklon B under the trademark "Uragan D2" until around 2015. During World War II , the US considered using it, along with cyanogen chloride , as part of Operation Downfall , the planned invasion of Japan, but President Harry Truman decided against it, instead using

9999-473: Was eventually given the German name Blausäure ( lit . "Blue acid") because of its acidic nature in water and its derivation from Prussian blue. In English, it became known popularly as prussic acid. In 1787, the French chemist Claude Louis Berthollet showed that prussic acid did not contain oxygen, an important contribution to acid theory, which had hitherto postulated that acids must contain oxygen (hence

10100-573: Was first used as a generic trademark in 1893 following a previous trade name, "formalin". Molecular formaldehyde contains a central carbon atom with a double bond to the oxygen atom and a single bond to each hydrogen atom . This structure is summarised by the condensed formula H 2 C=O. The molecule is planar, Y-shaped and its molecular symmetry belongs to the C 2v point group . The precise molecular geometry of gaseous formaldehyde has been determined by gas electron diffraction and microwave spectroscopy . The bond lengths are 1.21 Å for

10201-446: Was the first polyatomic organic molecule detected in the interstellar medium . Since its initial detection in 1969, it has been observed in many regions of the galaxy . Because of the widespread interest in interstellar formaldehyde, it has been extensively studied, yielding new extragalactic sources. A proposed mechanism for the formation is the hydrogenation of CO ice: HCN , HNC , H 2 CO, and dust have also been observed inside

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