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3 September 2003
Illegal Mosquito Coils Still Sold in U.S., Likely Expose Users to Potent Lung Carcinogen
Study Published Today in Environmental Health Perspectives Finds Legal Use in Asia May Also Be Quite Harmful
[RESEARCH TRIANGLE PARK, NC] Some Chinese-made mosquito coils purchased in the U.S. contain a substance banned for sale in the United States, according to a study published today in the September issue of the peer-reviewed journal Environmental Health Perspectives (EHP). The study also found that the widespread (but legal) use in Asia of these coils, a popular and effective defense against mosquito-borne illnesses, may be subjecting children and others to cancer-causing smoke. It is one of two studies on potential hazards of mosquito coils appearing in this month’s journal.
Researchers from the University of California-Riverside analyzed mosquito coils purchased in various retail outlets in Jakarta and Bandung, Indonesia, in addition to others purchased at several Asian markets in Southern California. The mosquito coils purchased in the U.S. contained octachlorodipropyl ether, known as S-2, a substance not registered for any legal use in the United States. The packaging did not indicate S-2 was an ingredient. Use of those coils likely exposes those around it to bis(chloromethyl) ether, or BCME, an extremely potent lung carcinogen.
“Despite the fact that no pesticide can be sold legally in the United States without federal (and in many states also state) registration, unregistered products do find their way into channels of trade,” the study authors write. “Sales are likely to increase as concern about West Nile virus and other mosquito-borne disease mounts in the United States.”
While the illegal sale of these products in the U.S. is troubling, the legal sale in Asian countries may have even greater health consequences.
“The number of coil users in China is in the millions. In Indonesia alone an estimated seven billion coils are purchased annually,” according to the study. “Coils are often used overnight in sleeping quarters, where elevated exposure may occur as parents seek to protect their children from mosquitoes.”
Commenting on the study, Dr. Jim Burkhart, science editor for EHP, says, “This is one of two studies we’ve published this month on mosquito coils. In both the U.S. and in other countries, we need effective systems for controlling those diseases transmitted by mosquitoes. But this study also shows that we need effective controls against illegal import and the misuse of these products in the U.S. In Asia, it seems clear that people would benefit from a different formulation of these coils, at least until safer mosquito controls can be widely accepted.”
The study authors analyzed samples of various coils by gas chromatographic/mass spectrometric analysis. The samples contained a “remarkable range” of S-2. For example, three samples from Jakarta that indicated S-2 on the label said they contained S-2 at 1.5%. In actuality, the samples contained less than 0.001%, 0.03%, and 0.3%, respectively. Samples purchased in Bandung, however, had more consistent levels.
In 1998, the World Health Organization called for further research on mosquito coils so that the degree of exposure to S-2 and BCME could be determined. To date, these studies have not occurred.
The study was conducted by Robert I. Krieger, Travis M. Dinoff, and Xiaofei Zhang of the Department of Entomology, UC-Riverside.
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Editor’s note: A full copy of the report is available by fax or e-mail (PDF format) to media at no charge. Go to http://www.ehponline.org/press/, call 919-541-2359, or e-mail badams@brogan.com.
