MONDAY, Sept. 15, 2003 (HealthDayNews) -- If you're trying to ward off the West Nile virus by lighting mosquito repellant coils, you may be unwittingly exposing yourself to cancer-causing chemicals.
Researchers from the University of California at Riverside recently tested more than 50 mosquito repellant coils purchased in Indonesia and at several Asian markets in California, and found they contained varying levels of a pesticide, S-2, that releases cancer-causing particles when burned.
Of more concern was that the researchers found S-2 in samples of mosquito coils purchased in California. S-2 shouldn't be in any products sold in the United States because it's banned by the U.S. Environmental Protection Agency either as a main or secondary ingredient, according to the study. Not surprisingly, the coil labels didn't disclose the presence of S-2.
Results of the study appear in the September 2003 issue of Environmental Health Perspectives.
"Mosquito coils can be an effective pest management tool, but ingredients like S-2 shouldn't be there," says study author Bob Krieger, an extension toxicologist at the University of California in Riverside. In the United States, says Krieger, domestically produced mosquito coils are also available and shouldn't contain S-2.
"S-2 appears on shelves in Asian markets in the U.S. from time to time. There are a lot of unknowns about this product," says Krieger, who believes that more study on this chemical's effect on health should be done because coils containing S-2 are widely used in Asia. According to the study, millions of people in China use mosquito coils, and in Indonesia, as many as 7 billion coils are purchased every year.
While not all mosquito coils sold in Asia contain S-2, Krieger says many do, and the coils are often burned indoors for long periods of time in Asian households.
"A common pattern of use is to burn mosquito coils overnight to keep kids from getting mosquito bites," Krieger says.
When products containing S-2 are burned, they release a potent lung carcinogen called bischloromethyl ether (BCME), according to the study. What isn't known, according to Krieger, is how much or how little exposure to these products is necessary to cause cancer.
With the emergence of West Nile, concern over mosquito-borne illness is likely to increase the sale of products like mosquito coils, conclude the authors.
Cindy Mannes, the director of public affairs for the National Pest Management Association (NPMA) says that concern about West Nile is already increasing the number of calls pest management companies are getting for mosquito control services.
"Consumers don't believe that mosquitoes are just a nuisance. They believe they're a health threat," she says.
While the NPMA doesn't recommend specific consumer pest control products, Mannes says there's a lot you can do to control the number of mosquitoes in and around your home. First, she says, eliminate all sources of standing water. Make sure gutters drain properly, empty birdbaths and drain kiddy pools daily. Fix any broken window screens and use screening with 18-by-18 strands per square inch to ensure that no bugs can get through. Other options include spraying pesticide for adult mosquitoes and using larvicide to limit breeding.
She also recommends calling a local pest management company to assess your property for mosquito breeding sites. She says many companies don't charge for an initial consultation.
Krieger recommends that anyone purchasing mosquito coils check the label to be sure they're not using a product with S-2 -- though, as this study found, labels are no guarantee that S-2 isn't an ingredient.
More information
To learn more about preventing West Nile virus, go to the U.S. Centers for Disease Control and Prevention. For more information on controlling mosquitoes, try the National Pest Management Association.
