EPA says mosquito spray safe
Wednesday, August 10, 2005
By Gregg Sherrard Blesch
Trucks rolled through a handful of Southland communities Sunday night spraying a fine mist intended to kill airborne mosquitoes on contact.
The sight might lead chemical-wary residents to wonder if they're going to get sick from breathing or swallowing poison, a sucker's trade for a lower risk from West Nile virus.
As of Tuesday night, infection with the mosquito-borne virus had officially sickened seven Illinoisans this year. Three years ago, it hit 884 people in Illinois, killing 67.
Though the insecticide used in this area has its doubters, the U.S. Environmental Protection Agency has ruled that it poses very little risk to humans in the concentration that's sprayed.
Chicago and Cook County have hired Roselle-based Clarke Mosquito Control to apply a product called Anvil, its own patented brew of a common variety of insecticide.
Health officials target the areas that have yielded the highest numbers of infected mosquitoes in traps, which this year have included parts of Chicago's Southwest Side, Evergreen Park and Oak Lawn.
South and southwest suburbs that were sprayed Sunday will get a second round sometime next week. Chicago will order more spraying depending on whether West Nile continues to spread.
Anvil's active ingredient is sumithrin, a synthetic made to mimic a bug-killing chemical that occurs naturally in chrysanthemums. It's dissolved in mineral oil and sprayed in a fine mist.
According to Clarke, you don't have to hide inside when the trucks come down your street — they only spray between dusk and dawn, starting at 8 p.m.
Illinois doesn't require communities to notify residents before spraying, although most put out news releases and some use mass-dialing systems to let them know. Some communities, including Chicago, recommend that people with asthma or other respiratory problems avoid direct contact with the spray.
"If you had asthma and were standing right next to a truck while it was spraying, you might trigger an attack," Chicago Health Department spokesman Tim Hadac said.
"We're only using a tablespoonful of Anvil for every acre," Hadac added. "Nonetheless, it is a toxin, and people are always advised to limit their exposure to toxins."
Anvil's class of insecticide is considered one of the least poisonous to people and other mammals, according to the EPA.
Direct exposure can cause an asthmatic reaction or skin rash, but the chemical won't build up in the body because it breaks down quickly in the respiratory and digestive systems.
To stop mosquitoes from breaking it down before it kills them, Anvil's recipe also includes piperonyl butoxide, which is likewise considered by the EPA to pose little danger humans.
But the federal government's rosy risk assessment isn't persuasive to opponents of spraying.
Dr. Khian Liem, director of the South Cook County Mosquito Abatement District, has drawn criticism for refusing to spray.
He says there's no proof that the spray is very effective in killing mosquitoes — they're only killed if they happen to be in the air when and where the trucks spray — so it's not worth the unknown health risk to humans.
In response to the EPA's findings on the chemicals, Liem says: "Look at the (Food and Drug Administration). They approved Vioxx and Celebrex. You know what happened."
Liem's board on Monday succumbed to pressure from county, state and federal agencies to start spraying, but he's not the only public health official who is against the practice.
Some U.S. communities, including Washington, D.C., don't spray, citing the questionable effectiveness in fighting West Nile paired with the mere possibility that it triggers asthma.
"They don't believe the risk of the virus is worth exposing a vulnerable population to the unknown effects of the chemicals," said Shawnee Hoover of Beyond Pesticides, a Washington-based group that encourages alternatives to pesticides.
For the EPA's fact sheet on pyrethroid insecticides, visit http://www.epa.gov/pesticides/factsheets/pyrethroids4mosquitos.htm.
For more information on West Nile virus, go to http://www.idph.state.il.us/envhealth/wnv.htm.
Gregg Sherrard Blesch may be reached at firstname.lastname@example.org or (708) 633-5962
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