Science

Scientists Stop EPA From Pushing Toxic Pesticide

On Friday — the best day of all for making embarrassing announcements, in the hope that they’ll be lost in the weekend news lull — the EPA delayed its approval iodomethane, a toxic chemical slated for use as a pesticide. The agency didn’t explain the delay, but their announcement came several days after 54 scientists, […]

Sjscooby2_3On Friday -- the best day of all for making embarrassing announcements, in the hope that they'll be lost in the weekend news lull -- the EPA delayed its approval iodomethane, a toxic chemical slated for use as a pesticide.

The agency didn't explain the delay, but their announcement came several days after 54 scientists, including six Nobel Prize winners, wrote a scathing letter to EPA head Stephen Johnson. The text of the letter (pdf) is quoted below. If you want to skip it and go straight to the end of the post, the takeaway is this:* iodomethane warps DNA, scares chemists, and causes brain damage and cancer and kills fetuses -- and that's at the exposure levels you're about to approve -- so what on God's green earth are you THINKING?*

As chemists and physicians familiar with the effects of this chemical, we are concerned that pregnant women and the fetus, children, the elderly, farm workers, and other people living near application sites would be at serious risk if methyl iodide is permitted for use in agriculture (80-275 pounds per acre).

Methyl iodide is a highly reactive chemical used in some industrial processes and in research laboratories for the synthesis of new molecules. Alkylating agents like methyl iodide are extraordinarily well-known cancer hazards in the chemical community because of their ability to modify the chemist’s own DNA, as well as the target molecule in the flask, leading to mutations that are potentially very harmful.
Because of this potential toxicity, chemists who work with this material use the smallest amounts possible and take great precautions to avoid exposure. Because of methyl iodide’s high volatility and water solubility, broad use of this chemical in agriculture will guarantee substantial releases to air, surface waters and groundwater, and will result in exposures for many people. In addition to the potential for increased cancer incidence, U.S. EPA’s own evaluation of the chemical also indicates that methyl iodide causes thyroid toxicity, permanent neurological damage, and fetal losses in experimental animals. EPA’s exposure assessment suggests that the Agency is willing to accept exposures at levels that may cause these effects in humans up to five percent of the time near the application site.

We are skeptical of U.S. EPA’s conclusion that the high levels of exposure to methyl iodide that are likely to result from broadcast applications are “acceptable” risks. U.S. EPA has made many assumptions about toxicology and exposure in the risk assessment that have not been examined by independent scientific peer reviewers for adequacy or accuracy. Additionally, none of U.S. EPA’s calculations account for the extra vulnerability of the unborn fetus and children to toxic insults.
We know that developing organisms are generally more sensitive than adults, yet no additional safety factors were applied to account for this sensitivity, as is usual for most pesticides. In fact, based on results from a questionable model of how the pesticide is detoxified by the body, U.S. EPA has actually decreased the size of the safety factors that typically add some level of protection from exposures to pesticides.

Finally, we are perplexed that U.S. EPA would even consider the introduction of a chemical like methyl iodide into agricultural use.
The Agency has spent a great deal of effort to reduce industrial toxic emissions from chemical manufacturing plants. It is astonishing then that the Office of Pesticide Programs is working to legalize broadcast releases of one of the more toxic chemicals used in manufacturing into the environment.

Now, it might seem that I'm being unfair to the EPA: after all, they got the letter, realized their mistakes, and did the responsible thing.
But not really. As detailed by the Center for Science in the Public
Interest, the letter was written at the last minute after government scientists anonymously told the Pesticide Action Network that their bosses had instructed them to hush up the iodomethane approval. EPA officials knew their consideration of the chemical would be controversial, as they'd actually tried to have it approved a year ago, only to give up after a backlash from public health activists, California's EPA and its own scientists.

Stephen Johnson is, hands down, the worst EPA commissioner ever. And when he leaves office -- with a police escort, preferably, glowering and shouting, "I would have gotten away with it, too, if it hadn't been for those meddling scientists!" -- I'm going to have a party, and you're all invited.

Protest Prompts EPA to Postpone Pesticide Approval [CSPI]

U.S. Delays Approval of Farm Pesticide [Associated Press]

*Common sense disclaimer: Stephen Johnson, pictured in the photograph above, did not actually say those words. If you don't get the reference, at the end of every episode of Scooby Doo, the thwarted villain exclaimed "I would have gotten away with it, too, if it hadn't been for those meddling kids."
*

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