1.5—Bt Cotton is Safer for workers than pesticides

Indian cotton laborers suffered from allergy symptoms due to unknown causes.

See Genetic Roulette’s False Claims at Bottom of Page

Analysis of Peer-Reviewed Research:The claims that Bt cotton caused allergies and other illnesses have been circulating for the last four or five years in India.  No published study has documented that these stories are actually true and even the NGO that makes the claims makes them with some caution.  Jeffrey Smith chooses to repeat the claims without any verification because they serve his purpose.  Common sense tells us that with  half of the world’s cotton being Bt-cotton and with millions of people handling it on a daily basis, if it caused adverse effects we would know about it by now.  Bt also has a more than 50-year history of safe use as a pesticide (see section 3.4).

  1. Millions of people who handle Bt cotton have not reported allergies or other problems. Genetically modified insect protected cotton is grown by some 3.8 million small-scale farmers in India and 7.1 million in China (2007). There are–somewhat surprisingly given the widespread use–no other known reports of an association between allergy and Bt cotton among these farmers. Crude Bt preparations that contain toxins, spores and whole bacteria have been used in very large quantities around millions of people with only the most infrequent adverse reactions noted (Seigel, 2001; Betz and others 2000; Whalon and Wingerd 2003)
  2. Bt cotton is probably safer for farm workers. There is well-substantiated evidence that these Bt cotton varieties have reduced the exposure to harmful synthetic pesticides and cases of pesticide poisoning caused among small farmers in China.  The World Health Organization tells us that more than 250,000 farmers die every year from pesticides; many of these poisonings may be self-inflicted (WHO, 2006).  Bt cotton reduces pesticide use 80-95% (Brooks and Barfoot, 2007).
  3. This claim is based on a hearsay report from anti-GM activists. The report quoted by Jeffrey Smith comes from a self-proclaimed anti-GM activist organization, however, they do label their report as preliminary and note that it is only based on interviews with a very small number of people.  Smith is more bold in his claims than self-admitted opponents of the technology.
  4. No real medical evidence is presented. No evidence that Bt cotton caused these allergies is presented. The reader is also not told if workers experienced these reactions when working with non-GM cotton or before GM-cotton was developed.
  5. Genetic Roulette ignores published studies. Numerous safety studies have failed to detect any adverse effect from Bt cotton that now constitutes more than half of the world’s cotton.  Bt cotton has caused a 80-95 percent decrease in pesticide use.


Siegel JP (2001). The Mammalian Safety of Bacillus thuringiensis– Based Insecticides. J. Invert. Pathol.  77:13-21

Betz FS, Hammond BG, and Fuchs, RL. (2000). Safety and advantages of Bacillus thuringiensis-protected plants to control insect pests. Regulatory Toxicology and Pharmacology 32:156-177. A key review which summarizes the uses of Bt proteins to control insect pests in agriculture.

Importantly provides key data substantiating the ~million-fold safety margins for Bt proteins Whalon ME, Wingerd BA (2003).

Bt: Mode of action and use Archives of Insect Biochemistry and Physiology, 54: 200-211

Brookes, G., Barfoot, P. 2007. Global impact of biotech crops: Socio-economic and environmental effects, 1996-2006.

AgBioForum, 11: 21-38. Available on the World Wide Web: www.agbioforum.org.

WHO 2006 www.who.int/mediacentre/news/notes/2006/np24/en/

Genetic Roulette Falsely Claims: Workers exposed to Bt cotton developed allergies

  1. Agricultural laborers and six villages who picked up GM Bt cotton reported reactions of the skin, eyes, and upper respiratory tract.
  2. Some laborers required hospitalization.
  3. Employees at a cotton gin factory take antihistamines every day.
  4. One doctor treated about 250 cotton laborers.

A preliminary study involving interviews of some 23 people identified allergies in cotton laborers from several villages of India.