Formaldehyde – a necessary toxic carcinogen?

Formaldehyde is a colourless, flammable gas with a strong smell, that is soluble in water. It is an essential component in the production of most common  consumer items. While commonly associated in most people's minds only with embalming procedures in the funeral industry or with laboratories, this ubiquitous chemical is, in reality, used or found in almost every industry. It is highly unstable when exposed to the atmosphere. It also occurs naturally. It is a by-product of forest fires and incendiary activities such as the incomplete burning of automotive fuels and other fuels such as gas, coal, charcoal and kerosene; burning of wood in stoves or fireplaces; and in tobacco smoke.

Formaldehyde is also found in aspartame, cod fish, caviar, gluten flour, maple syrup, shiitake mushrooms, smoked ham, and instant coffee. It is also found naturally in the environment since it is produced by all living things as a function of the metabolic process.(1)

Formaldehyde is also called formalin, P-formaldehyde. oxymetholone, methanal and methenamine.    

Sources of formaldehyde

Formaldehyde is used in numerous ways – as a preservative, a disinfectant, fungicide and germicide (it is effective against bacteria, fungi and mold), among others. Formaldehyde is also released by preservatives such as 2-bromo-2-nitropropane-1,3 diol, diazolidinyl urea, DMDM hydantoin, imidazolidinyl urea, and quaternium-15. The amount of formaldehyde released depends on the amount of formaldehyde and water content. The release of formaldehyde is affected by both temperature and humidity.

Formaldehye is ubiquitous and used by almost every industry including cosmetics, pharmaceutical, oil and gas, textile, automobile, personal hygiene products, building, pulp and paper, furniture, cleaning products, carpeting, printing, medical, industrial, funeral, dairy, photography, explosives, and electronics to name just a few. 

Health risks

Formaldehyde is considered toxic and carcinogenic. It has been classified since 2004 by the World Health Organization as a known human carcinogen that is associated with nasal, sinus and nasopharyngeal cancers with high levels of exposure.(4,5) It has also been associated with leukemia, particularly myeloid leukemia. Exposure can be through inhalation or contact.    

Formaldehyde is one of the top ten allergens for contact dermatitis.(3) At risk for occupational sensitization are hairdressers, metal workers, brewery and wood workers, newsprint and healthcare workers, farmers, laboratory technicians, painters, photographers, housekeepers, hemodialysis nurses, maintenance workers, cosmetologists, and embalmers. The allergic response can vary from urticaria and contact dermatitis to anaphylaxis.

At moderate levels, formaldehyde is an irritant to the eyes and nose and throat. It is also associated with watery eyes, a burning sensation in the eyes, nose and throat; nausea, skin irritation, respiratory symptoms such as cough, wheeze and it can exacerbate asthma. A number of studies have linked formaldehyde with asthma.(6,7) McGwin and colleagues did a systematic review of the published literature on formaldehyde and asthma and concluded that there is a "significant positive association between formaldehyde exposure and childhood asthma". It  is a trigger of asthma and has been linked to occupational asthma.

Avoidance

A limited number of measures can be taken to reduce exposure to formaldehyde in the home.(8) These include:

  • banning the smoking of tobacco products
  • increasing ventilation in the home
  • maintaining moderate temperatures in homes and offices, since high temperatures encourage off-gassing and the release of greater quantities of formaldehyde
  • reducing humidity with dehumidifiers or air conditioners
  • not burning biofuels
  • not allowing vehicle exhaust inside - no idling cars or gas engines in attached garages or near open windows and doors
  • using exterior-grade pressed-wood products (plywood, panelling, particle board and fibreboard, all of which contain less formaldehyde than similar products generally used indoors) and seal them with a coating of plastic laminate
  • washing all permanent-press items before use, or airing, before use, items that cannot be washed 
  • ensuring that furniture made with MDF is either covered with plastic laminate, or coated on all sides
  • using new electronic devices and computers in well ventilated areas

The ‘new car smell’ found in new cars and in automobile showrooms comes from formaldehyde. New computers, too, give off formaldehyde – because their initial off-gassing tends to be very high, it is recommended that they be allowed to run for a few days in a well-ventilated area.

Conclusion

Formaldehyde can be both an irritant and an allergen. In either case, the best approach is avoidance.  To find an alternative product that does not contain formaldehyde, refer patients to the Contact Allergen Replacement Database (CARD) list on the American Contact Dermatitis Society’s website at www.contactderm.org. It lists over 2500 skin and mouth care products that are cross-referenced to allergens, and it can provide a list of products free of known allergens. Note that membership in the Society may be required in order to  access the database. The Household Products Database maintained by the U.S. Department of Health and Human Services is also helpful if searching for a list of products that contain a known allergen.

Because of its usefulness as a preservative and germicide, formaldehyde can be found in numerous personal and household products, and in the workplace. Avoidance is extremely difficult and challenging since products may not list it as an ingredient –  for instance, body care products that contain less than 500 ppm are not required to list it, or may list it under a variety of synonyms, generic and trade names.

Hence, it may be necessary to advise persons with an allergy to formaldehyde to assume, until proven otherwise, that any new or unfamiliar product they encounter does contain the chemical, and to handle that product accordingly.

References

  1. De Groot A, Flyvholm M, Lensen G, et al. Formaldehyde-releasers: Relationship to formaldehyde contact allergy. Contact allergy to formaldehyde and inventory of formaldehyde-releasers. Contact Dermatitis. 2009;61, 63–85.
  2. Formaldehyde Council. Formaldehyde: facts and background information. http://www.formaldehyde.org/_base/pdf/fact_sheets/11_01_07-FormadehydeFactsandBackground Information.pdf    Accessed September 3, 2010.
  3. Douglas JD. Allergic contact dermatitis: topical preservatives, Part I. Dermatology Nursing © 2010 http://www.medscape.com/ viewarticle/725087_11 Accessed Aug 30, 2010
  4. Formaldehyde and Cancer Risk. http://www.cancer.gov/cancertopics/factsheet/Risk/formaldehyde. Accessed 3 April 2014
  5. Thompson CM, Subramaniam RP, Grafstrom RC. Mechanistic and dose considerations for supporting adverse pulmonary physiology in response to formaldehyde. Toxicol Appl Pharmacol 2008; 233: 355–359.
  6. McGwin G, Lienert J, Kennedy JI. Formaldehyde exposure and asthma in children: a systematic review. Environmental Health Perspectives. 2010;118(3) 
  7. Burton C1, Bradshaw L, et al. Medium-density fibreboard and occupational asthma. A case series. Occup Med (Lond). 2011 Aug;61(5):357-63. doi: 10.1093/occmed/kqr090.
  8. http://www.hc-sc.gc.ca/ewh-semt/air/in/poll/construction/formaldehyde-eng.php. Accessed 4 April 2014