Atmosphere

Air toxics and indoor air quality in Australia

State of knowledge report
Environment Australia, 2001
ISBN 0 6425 4739 4

Part C: Factsheets (continued)

Formaldehyde (methyl aldehyde)

Substance name: Formaldehyde (methyl aldehyde)
CASR number: 50-00-0
Molecular formula: CH2O
Synonyms: Formalin; methylene oxide; methyl aldehyde; methanal; HCHO; formic aldehyde; oxomethane; formol; oxymethylene; morbicid; veracur; methylene glycol; formalin 40; BFV; fannoform; formalith; FYDE; HOCH; karsan; lysoform; superlysoform; oxomethylene; methan 21; melamine-formaldehyde resin

Physical and chemical properties

In pure form, formaldehyde is a gas but it is often used in aqueous form. It is a colourless, highly flammable liquid or gas with a pungent odour detectable at 1 part per million. It is miscible with water, acetone, benzene, diethyl ether, chloroform and ethanol.

Boiling point (pure): -19.2°C
Melting point (pure): -117°C

Formaldehyde is incompatible and reactive with strong oxidisers, alkalis and acids, phenols, and urea. Poisonous gases are produced if it catches on fire. It is very reactive, combines with many substances, and polymerises easily (Merck, 1997). It reacts violently with perchloric acid, aniline, performic acid, nitromethane, magnesium carbonate, and hydrogen peroxide. Aqueous formaldehyde is corrosive to carbon steel but is not corrosive in the vapour phase.

Common uses

The primary uses for formaldehyde are for the production of urea-formaldehyde resins, phenol-formaldehyde resins, plastics, and intermediates. Urea-formaldehyde resins and phenol-formaldehyde resins are used primarily as adhesives in the manufacture of particleboard, fibreboard and plywood; for moulding, paper treating and coating, textile treating, surface coating; and for foams for insulation. Most of the formaldehyde used for the production of intermediates is in the manufacture of acetylenic chemicals; smaller quantities are used in the production of pentaerythritol, hexamethylenetetramine, and urea-formaldehyde concentrates. Formaldehyde has miscellaneous uses in agriculture for seed treatment, soil disinfection, and as an insecticide and fungicide; as a reagent in analysis; in waterproof and greaseproof concrete and plaster; as a drying agent and preservative in cosmetics; in room fumigants; as a chemical intermediate for dyes, surface-active agents, and processing aids; in embalming, as a preservative and hardener of tissues; in histopathology; as a biocide in drilling fluids; as a stabiliser in gasoline; in leather tanning; as a corrosion inhibitor in metal industries; in paper industries as a chemical intermediate for wet-strength and other paper-treating resins; as a photographic film hardener; as a starch modifier; to modify fibres in textiles; and in wood preservatives.

Formaldehyde is also used as a treatment for athlete's foot, in cough drops, skin disinfectants, mouthwashes, spermaticide creams, as a disinfectant for vasectomies and root canals, and formerly to sterilise certain cysts prior to surgical removal. In veterinary medicine, it is used as an antiseptic and fumigant in the treatment of tympany, diarrhoea, mastitis, pneumonia, and internal bleeding; in association with iodine, it is used as a coccidiostat in chickens. It is also used as a synthetic tanning agent, in water treatment and as a bactericide in paints in Australia.

Sources of emissions

Point sources

Manufacturing plants that produce or use formaldehyde or substances that contain formaldehyde are sources of formaldehyde. Catalytic cracking, coking operations, and fuel combustion are major sources from refineries. Stone, clay, and glass production use fuel combustion sources such as boilers, furnaces, and engines in the manufacturing processes that generate formaldehyde. Formaldehyde is used in urea-formaldehyde and phenol formaldehyde resins, copper plating solutions, and incinerators.

Diffuse sources, and point sources included in aggregated emissions data

Formaldehyde is released from products such as carpets and pressed-wood products that contain it. It is both directly emitted into the atmosphere and formed in the atmosphere as a result of photochemical oxidation of reactive organic gases in polluted atmospheres containing ozone and nitrogen oxides.

Natural sources

Formaldehyde occurs in forest fires, animal wastes, microbial products of biological systems, and plant volatiles. It can also be formed in seawater by photochemical processes.

Mobile sources

Vehicular exhaust is a source of formaldehyde.

Consumer products that may contain formaldehyde

Formaldehyde may be present in glues, fibreboard and particleboard, furniture, textiles and some insulation. Formaldehyde-based resins are used in pressed wood, cotton permanent press, grocery bags, and waxed paper. Detergents, cosmetics, and other domestic chemicals contain formaldehyde as an antimicrobial agent (shampoos, bubble baths, and hair conditioners)

Health effects

How might I be exposed to formaldehyde?

Exposure can be by inhalation of fumes, particularly indoors, where concentrations can build up due to poor ventilation. In general, indoor environments consistently have higher concentrations than outdoor environments, because many building materials, consumer products and fabrics emit formaldehyde. It is also possible to eat or drink products contaminated by or containing formaldehyde or to be exposed via skin contact.

By what pathways might formaldehyde enter my body?

Formaldehyde can enter the body by inhalation of fumes, contact with solutions containing formaldehyde or by eating or drinking foods containing formaldehyde. The effects may be different for different forms of exposure.

Health guidelines

National Occupational Health and Safety Commission (NOHSC):

Formaldehyde is listed as a substance under review for irritant effects by the NOHSC.

Australian Drinking Water Guidelines (NHMRC and ARMCANZ 1996):

What effect might formaldehyde have on my health?

Exposure to formaldehyde irritates the eyes, nose, and throat, and can cause skin and lung allergies. Higher levels can cause throat spasms and a build-up of fluid in the lungs, leading to death. Contact can cause severe eye and skin burns, leading to permanent damage. These may appear hours after exposure, even if no pain is felt. Formaldehyde can cause an asthma-like allergy. Future exposures can cause asthma attacks, with shortness of breath, wheezing, cough, and/or chest tightness. Repeated exposures may cause bronchitis, with symptoms of cough and shortness of breath. Formaldehyde is classified by the NOHSC as a Category 2 carcinogen (substance that should be regarded as if it is carcinogenic to humans).

Environmental effects

Environmental fate

Formaldehyde is slightly persistent in water, with a half-life of 2–20 days. About 99% of formaldehyde will eventually end up in air; the rest will end up in the water. As well as being directly emitted to the atmosphere, formaldehyde is formed as a result of photochemical reactions between other chemicals in already polluted air. These reactions may account for most of the formaldehyde in the air in some areas.

Environmental transport

Formaldehyde is transported in air in water and in contaminated soils.

Environmental guidelines

There are no national guidelines.

What effect might formaldehyde (methyl aldehyde) have on the environment?

Chronic toxic effects may include shortened lifespan, reproductive problems, lower fertility, and changes in appearance or behaviour. Chronic effects can be seen long after the first exposures. Formaldehyde has high chronic toxicity to aquatic life. Formaldehyde may cause cancer and other chronic effects in laboratory rodents. Birds and terrestrial animals exposed to formaldehyde could show similar effects. There are not enough data to evaluate or predict the long-term effects of formaldehyde to plants.

Key

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