A Win for West Nile -- By Two Rats

By Steven Milloy
Copyright 2000 New York Post
May 12, 2000

Will two rats jeopardize use of the insecticide malathion to control mosquitoes carrying the deadly West Nile virus? Or have New York City politics and hysterical chemophobes beaten the rats to the punch?

Malathion was the chemical sprayed across the city last summer to kill infected mosquitoes. Transmitted to humans, the virus can cause encephalitis. Last summer's outbreak killed seven people and sickened 62.

As mosquito season nears, an ill-timed and scientifically questionable EPA report may cripple the city's ability to protect public health.

The U.S. Environmental Protection Agency just released its preliminary risk assessment for malathion. The EPA says the scientific evidence on malathion constitutes "suggestive evidence of carcinogenicity but not sufficient to assess human carcinogenic potential."

In plain English: There is no evidence malathion causes cancer in humans; but, as it turns out, two laboratory rats more than expected got cancer when given unrealistically high doses of malathion.

Malathion's manufacturer, Cheminova Inc., maintains the two "extra" tumors aren't related to malathion. But the company never had a chance to press its contention with the EPA because of a secretive decision-making process.

The EPA decision was made by agency staff on its Cancer Assessment Review Committee. The EPA let Cheminova submit written documents to the Committee, but allowed no oral presentation and held the committee's deliberations in secret. It says 11 of 16 committee members voted for the "suggestive" classification, overriding some members' objection that the two "extra" tumors were not related to treatment with malathion.

The EPA decision is even more inexplicable given that malathion is known to not be mutagenic - it does not alter DNA to cause cancer - and malaoxon, a structurally-related chemical, does not cause cancer in laboratory rats.

New York politicians are already pressing the panic - and political - button. Rep. Gary Ackerman (D-Queens) said, "They [the city] kept assuring us [malathion] was safe. The city downplayed it. We have no way of knowing how many people got sick because of malathion." Rep. Joe Crowley (D-Queens) said "[The] mayor was wrong. This is not safe."

But Mayor Giuliani has beaten Ackerman and Crowley to the punch, already having pledged not to use malathion while the EPA review is ongoing.

Malathion is toxic - to mosquitoes. Aerial applications of malathion are estimated to result in skin exposures to adults and toddlers that are 3,400 times lower than the level of concern, according to the EPA. The margin is 25,000 times for toddlers' hand-to-mouth activities.

Hysteria, now aided by more EPA junk science, has got the best of New York City possibly at the expense of public safety. Let's hope there is no need for malathion this year - or that politicians have the good sense to use it when needed.

Steven Milloy is the publisher of Junkscience.com and an adjunct scholar at the Cato Institute.