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Formaldehyde, a colourless, pungent-smelling gas, can cause watery eyes, burning sensations in the eyes and throat, nausea, and difficulty in breathing in some humans exposed at elevated levels (above 0.1 parts per million). High concentration of formaldehyde may trigger asthma attacks in susceptible people. There is evidence that some people can develop a sensitivity to formaldehyde. Formaldehyde has also been shown to cause cancer in animals and is a known carcinogen (may cause cancer in humans). Health effects from exposure to formaldehyde include eye, nose, and throat irritation; wheezing and coughing; fatigue; skin rash; severe allergic reactions. May also cause other effects listed under "organic gases." EPA's Integrated Risk Information System profile -
How Formaldehyde Affects Your Body:
Formaldehyde can affect you when you breathe its vapours and/or touch the liquid. Because formaldehyde reacts quickly with body tissues, it mainly affects sites of direct contact, such as the lungs and eyes and skin. The most common effect of mild overexposure is irritation of the eyes, nose, throat, and skin, as described below.
Eyes, Nose, and Throat:
The eyes, nose, and throat are irritated by formaldehyde vapours at levels as low as 1 part formaldehyde per million parts of air (1 part per million, or 1 "ppm" - see "Legal Exposure Limits"). Low-level exposure can cause teariness, redness, and burning of the eyes, sneezing and coughing, and sore throat. Liquid formaldehyde solutions contacting the eyes can damage the cornea, possibly causing blindness.
Exposure to formaldehyde vapours produces varied effects; some people have irritant symptoms at very low levels, while others can tolerate higher levels with little or no reaction. Some common effects of formaldehyde vapours on the eyes, nose, and throat are described below:
High levels (5-30 ppm and higher) can severely irritate the lungs, causing chest pain and shortness of breath.
Repeated exposure to formaldehyde can cause asthma. Symptoms of asthma include chest tightness, shortness of breath, wheezing, and coughing. Repeated exposure to formaldehyde and/or other respiratory irritants may also increase your chances of contracting pneumonia or bronchitis. Formaldehyde's long-term effects on the lungs are not fully understood but may cause permanent damage.
Formaldehyde solutions can destroy your skin's natural protective oils. Frequent or prolonged skin contact with formaldehyde solutions can cause dryness, flaking, cracking, and dermatitis (skin rash). Skin contact can also cause an allergic reaction (redness, itching, hives, and blisters). Studies show that as many as one in twenty workers who are regularly exposed to formaldehyde develop an allergic skin reaction.
Formaldehyde causes cancer in test animals. Some studies have suggested that formaldehyde exposure can cause cancer of the lungs and respiratory tract in humans. The International Agency for Research on Cancer considers formaldehyde a probable human carcinogen. Formaldehyde is classed as a carcinogen under California's Prop 65.
The effects of formaldehyde on the reproductive system have not been well studied. In limited studies, formaldehyde did not harm pregnancy in female animals or affect the reproductive function of male animals. We do not know whether formaldehyde can affect pregnancy or reproductive function in humans; however, exposures that do not cause other symptoms probably will not affect pregnancy or reproductive function. Click for a full in depth report dealing with the toxic effects of formaldehyde
Formaldehyde is a toxic chemical used in industry in the manufacture of glues and is also used as a preservative in cosmetics, vaccines and for embalming bodies. Formaldehyde mixes easily with water but will not mix with oil or grease. It is common to find formaldehyde in aqueous cosmetic formulations such as shampoo, conditioner, shower gel, liquid hand wash and bubble bath, even products designed for children such as bubble bath and baby shampoo have formaldehyde in them!
4.2 Short-term exposure
In a 4-week study, Wistar rats (10 per sex per dose) received formaldehyde in
drinking-water at doses of 0, 5, 25, or 125 mg/kg of body weight per day. Rats
receiving the highest dose showed lowered food and liquid intake, histopathological
changes in the stomach (i.e., focal hyperkeratosis of the forestomach, moderate
papillomatous hyperplasia), and, in males only, lowered total protein and albumin
levels in plasma. The NOAEL was 25 mg/kg of body weight per day (Til et al., 1988;
Oral doses of 0, 50, 100, or 150 mg/kg of body weight per day in rats and 0, 50, 75, or
100 mg/kg of body weight per day in dogs for 91 days had no effect on haematology,
clinical chemistry, urinalysis, or gross microscopic pathology. Depression in body
weight gain was observed in both species at the highest dose levels and in male rats
given 100 mg/kg of body weight per day (Johannsen et al., 1986).
6.2 Treatment and control methods and technical achievability
Concentrations of formaldehyde in water, which arise mainly from the oxidation of
natural organic matter during ozonation and chlorination (see section 1.4), may be
reduced by changes to disinfection practice or by GAC treatment to below 0.03
Biological filtration, using dual media sand/GAC or sand/anthracite coal as media,
has been evaluated for the removal of aldehydes, including formaldehyde. Pilot filters
were operated at 14 m/h (EBCT 2.1 min), receiving raw water following preozonation,
coagulation, and sedimentation. Two types of virgin GAC (wood- and
coal-based) were used. The influent concentration of formaldehyde to the filters
(typically 7-12 mg/litre) was reduced by 50% after <32, <15, and 8 days for
anthracite, coal-based GAC, and wood-based GAC, respectively. For the same media,
80% removal was achieved after 36, 18, and 15 days. GAC developed biological
activity sooner than anthracite and was also a better bio-support medium (Krasner et
A study of full-scale treatment plants in France showed that formaldehyde
concentrations increased to 2-4 times the raw water levels (1-25 Î¼g/litre) following
ozonation. Subsequent GAC filtration reduced formaldehyde concentrations to about
the raw water levels (Jammes et al., 1995).
Anthracite/sand biological pilot filters (EBCT 7 min) gave approximately 85%
removal of formaldehyde from a feed concentration of about 10 Î¼g/litre. Backwashing
using chlorinated water (1 mg of chlorine per litre) gave poorer removal than
backwashing with non-chlorinated water (Miltner et al., 1995). In a study with sand
filters operated with different contact times, formaldehyde levels were reduced by
60% after a 2-min EBCT, but no further removal occurred with EBCTs up to 7 min
During the 1970s, urea-formaldehyde foam insulation (UFFI) was used in many homes. However, few homes are now insulated with UFFI. Homes in which UFFI was installed many years ago are not likely to have high formaldehyde levels now. Pressed-wood products containing formaldehyde resins are often a significant source of formaldehyde in homes. Other potential indoor sources of formaldehyde include cigarette smoke and the use of unvented fuel-burning appliances, such as gas stoves, wood-burning stoves, and kerosene heaters.