EPA Expected To Approve Toxic Pesticide

Approval For New Farm Fumigant Likely Despite Concerns About Health Risks

(AP)  The Environmental Protection Agency is expected within days to approve a new toxic fumigant for use by fruit and vegetable farmers, despite opposition from California regulators, prominent scientists and environmental and farmworker groups.

The agency intends to register methyl iodide as a substitute for the pesticide methyl bromide, which is being phased out by international treaty, according to government officials familiar with the decision. The new product is MIDAS, a methyl iodide compound manufactured by Tokyo-based Arysta LifeScience Corp.

Its EPA approval is due by Friday, said the officials, who spoke on condition of anonymity because they were not authorized to discuss the decision publicly.

EPA spokesman Dale Kemery said only that a decision will be announced later this week.

Anticipating EPA's approval, 54 scientists and physicians are urging EPA Administrator Stephen Johnson to block the move for health-related reasons or to permit a panel of independent scientists to scrutinize EPA's safety analysis. They include six chemistry Nobel Prize winners.

"We are concerned that pregnant women and the unborn fetus, children, the elderly, farm workers and other people living near application sites would be at serious risk" from fumigated fields, the group said in a letter to Johnson. They described the newer fumigant as "one of the more toxic chemicals used in manufacturing."

The deadly fumigant is injected into the soil to kill pests before planting tomatoes, strawberries and other crops in agricultural states like California and Florida. It is not applied directly to fruits and vegetables, so experts do not contend consumers are at risk from eating crops where the fumigant is used.

EPA's analysis evaluated possible buffer zones around fields and concluded that bystander exposure would not be significant. It said farmworkers could protect themselves sufficiently with respirators.

Internal documents obtained by The Associated Press indicate use of the fumigant may be approved on an interim basis and later reviewed after new safety restrictions are set for a group of fumigants already in use.

California is conducting its own review and would have to approve methyl iodide before farmers there could use it, said Glenn Brank, spokesman for the state Department of Pesticide Regulation.

"It's extremely toxic," Brank said. "We are concerned about whether or not this can be used safely."

The state last year criticized EPA's scientific analysis. Facing other objections, including some from its own scientists, EPA subsequently decided against approval and said it would revisit the matter this year.

EPA evaluated animal studies that linked methyl iodide inhalation to fetal death, respiratory lesions, thyroid toxicity and neurotoxicity, and thyroid tumors in rats. It concluded the chemical was not likely cancerous in humans "at doses that do not alter rat thyroid hormone homeostasis."

California, however, classifies the fumigant as a carcinogen. Studies also show chronic exposure can harm the central nervous system, lungs, skin and kidneys.

Growers welcome new alternatives to methyl bromide, which broadly annihilates soil pests and weeds but is banned under the Montreal Protocol, with progressively smaller amounts permitted each year.

Steve Fennimore, a University of California at Davis extension specialist, said MIDAS was the most effective substitute in strawberry and other trials. Georgia researchers are still studying the chemical's effectiveness, according to Charles Hall, executive director of the Georgia Fruit and Vegetable Growers Association.

Florida's tomato industry, weighed down by foreign competition and higher energy costs, also will closely evaluate the new fumigant's cost and how much is needed to be effective, said Reggie Brown, the executive vice president for the Florida Tomato Exchange.

"I wouldn't like to live near a field where it's applied," said Cornell University Professor Roald Hoffmann, a 1981 Nobel winner who was among those urging the EPA to block the approval.

In addition to its toxicity, methyl bromide was widely criticized for depleting the protective ozone layer; methyl iodide does not. Still, the senior scientist with the Pesticide Action Network of North America, Susan Kegley, said the EPA should help farmers move away from toxic chemicals.

[octavianfdlr]

My point exactly. Both methyl bromide and methyl iodide are methylating agents, but the iodide reacts (and is destroyed) more rapidly than the bromide. As a liquid, methyl iodide is easier to control than the gaseous methyl bromide, and will tend to exit the soil more slowly.

[lead_azide]

octavianfdlr:

Well the difference is that iodomethane is much more toxic to mammals than bromomethane. Carcinogenic: iodomethane probably yes, bromomethane probably not.
iodomethane is a liquid at RT (CH3Br is a gas) and a good methylating agent. It tends to methylate DNA which is not so good.

[octavianfdlr]

EPA Expected To Approve Toxic Pesticide

Nice spin! A pesticide is a chemical which kills (poisons) some pest. So a "toxic" pesticide is a chemical which not only poisons some pest, but which can also poison the pest. (Sounds like the word "toxic" was redundant, eh?)

So what is the whole article about? Criticism of this pesticide for being effective!

How does methyl iodide differ from methyl bromide, the "toxic pesticide" it replaces? The article states that the new pesticide does not deplete the protective ozone layer, and the old one does. The article fails to mention that methyl iodide reacts more rapidly with living matter in the soil, so that less of it will released to the remainder of the environment (ozone layer, people living nearby, fish in some body of water, etc.) Furthermore, the reaction product methyl iodide leaves in the soil is iodide -- an essential nutrient with a well-recognized deficiency disease.