From Wikipedia, the free encyclopedia
Jump to: navigation, search
For the fear of chemistry classes, see Chemistry education.

Chemophobia (or chemphobia or chemonoia[1][2]) is an aversion to or prejudice against chemicals or chemistry. The phenomenon has been ascribed both to a reasonable concern over the potential adverse effects of synthetic chemicals, and to an irrational fear of these substances because of misconceptions about their potential for harm.[3][4] People marketing products react to widespread chemophobia with products marketed with an appeal to nature.

Definition and uses[edit]

There are differing opinions on the proper usage of the word chemophobia. The International Union of Pure and Applied Chemistry defines chemophobia as an "irrational fear of chemicals".[5] According to the American Council on Science and Health, chemophobia is a fear of synthetic substances arising from "scare stories" and exaggerated claims about their dangers prevalent in the media.[6]

Despite containing the suffix -phobia, the majority of written work focusing on addressing chemophobia describes it as a non-clinical aversion or prejudice, and not as a phobia in the standard medical definition. Chemophobia is generally addressed by chemical education[7][8][9][10] and public outreach.[7][4][11]

Michelle Francl has written: "We are a chemophobic culture. Chemical has become a synonym for something artificial, adulterated, hazardous, or toxic." She characterizes chemophobia as "more like color blindness than a true phobia" because chemophobics are "blind" to most of the chemicals that they encounter: every substance in the universe is a chemical.[12] Francl proposes that such misconceptions are not innocuous, as demonstrated in one case by local statutes opposing the fluoridation of public water despite documented cases of tooth loss and nutritional deficit.[13] In terms of risk perception, naturally occurring chemicals feel safer than synthetic ones to most people. Consequently, people fear man-made or "unnatural" chemicals, while accepting natural chemicals that are known to be dangerous or poisonous.[14][15]

The Carcinogenic Potency Project,[16] which is a part of the US EPA's Distributed Structure-Searchable Toxicity (DSSTox) Database Network,[17] has been systemically testing the carcinogenicity of chemicals, both natural and synthetic, and building a publicly available database of the results[18] since the 1980s. Their work attempts to fill in the gaps in our scientific knowledge of the carcinogenicity of all chemicals, both natural and synthetic, as the scientists conducting the Project described in the journal, Science, in 1992:

Toxicological examination of synthetic chemicals, without similar examination of chemicals that occur naturally, has resulted in an imbalance in both the data on and the perception of chemical carcinogens. Three points that we have discussed indicate that comparisons should be made with natural as well as synthetic chemicals.

1) The vast proportion of chemicals that humans are exposed to occur naturally. Nevertheless, the public tends to view chemicals as only synthetic and to think of synthetic chemicals as toxic despite the fact that every natural chemical is also toxic at some dose. The daily average exposure of Americans to burnt material in the diet is ~2000 mg, and exposure to natural pesticides (the chemicals that plants produce to defend themselves) is ~1500 mg. In comparison, the total daily exposure to all synthetic pesticide residues combined is ~0.09 mg. Thus, we estimate that 99.99% of the pesticides humans ingest are natural. Despite this enormously greater exposure to natural chemicals, 79% (378 out of 479) of the chemicals tested for carcinogenicity in both rats and mice are synthetic (that is, do not occur naturally).
2) It has often been wrongly assumed that humans have evolved defenses against the natural chemicals in our diet but not against the synthetic chemicals. However, defenses that animals have evolved are mostly general rather than specific for particular chemicals; moreover, defenses are generally inducible and therefore protect well from low doses of both synthetic and natural chemicals.

3) Because the toxicology of natural and synthetic chemicals is similar, one expects (and finds) a similar positivity rate for carcinogenicity among synthetic and natural chemicals. The positivity rate among chemicals tested in rats and mice is ~50%. Therefore, because humans are exposed to so many more natural than synthetic chemicals (by weight and by number), humans are exposed to an enormous background of rodent carcinogens, as defined by high-dose tests on rodents. We have shown that even though only a tiny proportion of natural pesticides in plant foods have been tested, the 29 that are rodent carcinogens among the 57 tested, occur in more than 50 common plant foods. It is probable that almost every fruit and vegetable in the supermarket contains natural pesticides that are rodent carcinogens.[19]

Causes and effects[edit]

Chemistry professor Pierre Laszlo writes that historically chemists have experienced chemophobia from the population at large, and considers that it is rooted both in irrational notions and in genuine concerns (such as those over chemical warfare and industrial disasters).[3] Professor Gordon Gribble has written that the start of chemophobia could arguably be attributed to Silent Spring, and that subsequent events such as the contamination of Times Beach and the disaster at Bhopal, India only exacerbated the situation.[15]

These events have led to association between the word "chemical" and notions of things that unnatural or artificial and also dangerous, and the opposite has occurred, where goods are marketed as "chemical free" or "natural", to avoid this association, which in turn reinforces the misconception that "chemicals" are unnatural and dangerous.[15][20] The chemical industry has moved to make chemicals used as flavoring or aromas using biotechnology instead of synthetic chemistry, as the products can be marketed as "natural".[21]

According to the American Council on Science and Health, chemophobia is a growing phenomenon among the American public[22] and has reached "epidemic" proportions among the general public.[6] In a book published by the Council, Jon Entine writes that this is in part due to the propensity of people to show alarm at the reported presence of chemicals in their body, or in the environment, even when the chemicals are present in "minuscule amounts" which are in fact safe.[23] Elsewhere, Entine has argued that chemophobia is linked to a precautionary principle in agricultural policy, which could jeopardize the world's ability to feed its ever-expanding population.[24]

In the United Kingdom, Sense About Science produced a leaflet aimed at educating celebrities about science, in which it said that humans carry only small amounts of "chemical baggage" and that it is only because of advances in analytical chemistry that we can detect these traces at all.[25]

Philip Abelson has argued that the practice of administering huge doses of substances to animals in laboratory experiments, when testing for carcinogenic potential, has led to public chemophobia by raising unjustified fears over those substances' effect on humans. He sees an opportunity cost in the "phantom hazards" such testing conjures, as it distracts from attention on known hazards posed to human health.[26]

See also[edit]


  1. ^ Ropeik, D. (2015). "On the roots of, and solutions to, the persistent battle between "chemonoia" and rationalist denialism of the subjective nature of human cognition". Human & Experimental Toxicology. 34 (12): 1272. doi:10.1177/0960327115603592. 
  2. ^ "Chemonoia: the fear blinding our minds to real dangers". BBC News. 25 February 2016. 
  3. ^ a b Laszlo, Pierre (2006). "On the Self-Image of Chemists, 1950-2000". International Journal for Philosophy of Chemistry. 12 (1): 99. 
  4. ^ a b Shim, Soon-Mi; Seo, Sun Hee; Lee, Youngja; Moon, Gui-Im; Kim, Min-Shik; Park, Ju-Hee (July 2011). "Consumers' knowledge and safety perceptions of food additives: Evaluation on the effectiveness of transmitting information on preservatives". Food Control. 22 (7): 1054–1060. doi:10.1016/j.foodcont.2011.01.001. 
  5. ^ "IUPAC glossary of terms used in toxicology (2nd edition)" (PDF). International Union of Pure and Applied Chemistry. Retrieved October 20, 2016. 
  6. ^ a b Entine, Jon (18 January 2011). Scared to Death: How Chemophobia Threatens Public Health. American Council on Science and Health. 
  7. ^ a b Hartings, MR; Fahy, D (23 August 2011). "Communicating chemistry for public engagement.". Nature chemistry. 3 (9): 674–7. PMID 21860452. 
  8. ^ Smith, Robert B.; Karousos, Nikolaos G.; Cowham, Emma; Davis, James; Billington, Susan (March 2008). "Covert Approaches to Countering Adult Chemophobia". Journal of Chemical Education. 85 (3): 379. doi:10.1021/ed085p379. 
  9. ^ Smith, David K. (14 October 2014). "iTube, YouTube, WeTube: Social Media Videos in Chemistry Education and Outreach". Journal of Chemical Education. 91 (10): 1594–1599. doi:10.1021/ed400715s. 
  10. ^ Morais, Carla (13 January 2015). "Storytelling with Chemistry and Related Hands-On Activities: Informal Learning Experiences To Prevent "Chemophobia" and Promote Young Children's Scientific Literacy". Journal of Chemical Education. 92 (1): 58–65. doi:10.1021/ed5002416. 
  11. ^ Fielding, Kelly S.; Roiko, Anne H. (September 2014). "Providing information promotes greater public support for potable recycled water". Water Research. 61: 86–96. doi:10.1016/j.watres.2014.05.002. 
  12. ^ Michelle M., Francl (7 February 2013). "Curing chemophobia: Don't buy the alternative medicine in 'The Boy With a Thorn in His Joints'". Slate. Retrieved 27 March 2013. 
  13. ^ Francl, Michelle (2013). How to Counteract Chemophobia (Thesis). Nature Chemistry. 
  14. ^ Ropeik, David (2010). How risky is it, really?: Why our fears don't always match the facts. New York: McGraw-Hill. pp. 92–96. ISBN 978-0071629690. 
  15. ^ a b c Gribble, Gordon (2013). "Food Chemistry and Chermophobia". Food Chemistry. 5 (2): 177–187. doi:10.1007/s12571-013-0251-2. Retrieved 27 March 2015. 
  16. ^ Carcinogenic Potency Project Official Website
  17. ^ National Center for Computational Toxicology (NCCT) DSSTox Official Website
  18. ^ Publicly available Toxnet database from US NLM
  19. ^ Gold L.S.; et al. (1992). "Rodent carcinogens: Setting priorities" (PDF). Science. 258: 261–265. doi:10.1126/science.1411524. 
  20. ^ Balzani, Vincenzo; Venturi, Margherita (2014). Chemistry: Reading and Writing the Book of Nature. Royal Society of Chemistry. p. 214. ISBN 9781782620020. 
  21. ^ Dioniosio, AP (2012). "Chapter 11: Natural Flavorings from Biotechnology for Food and Beverages". In Baines, David; Seal, Richard. Natural food additives, ingredients and flavourings. Oxford: Woodhead Publishing. p. 232. ISBN 9780857095725. 
  22. ^ "Consumer Education Group Hosts Call to Discuss Evidence of Growing Chemophobia Among American Public" (Press release). 17 January 2011. Retrieved August 2013.  Check date values in: |access-date= (help)
  23. ^ Entine (January 2011), p. 38.
  24. ^ Jon Entine (16 April 2011). Crop Chemophobia: Will Precaution Kill the Green Revolution?. Government Institutes. p. 72. ISBN 978-0-8447-4363-9. Retrieved 21 August 2013. 
  25. ^ "Science for Celebrities" (PDF). Sense About Science. Archived from the original (pdf) on August 29, 2007. 
  26. ^ Abelson, P. (1990). "Testing for carcinogens with rodents". Science. 249 (4975): 1357. Bibcode:1990Sci...249.1357A. doi:10.1126/science.2402628. PMID 2402628. 

Further reading[edit]