Scientists Question Safety Of Apple Moth Pesticide

(CBS 5) The State of California has said the pesticide it plans to spray to eradicate the light brown apple moth is safe. But if their claim is true, why did more than 600 people complain of health effects after the aerial spraying of Monterey and Santa Cruz Counties last year? Two Monterey area scientists told CBS 5 Investigates they have the answer.

To the many people living in Monterey and Santa Cruz Counties, there is no doubt that the pesticide sprayed over their communities caused them health problems.

"The complaints just kept pouring in," said Mike Lynberg, who set up a grass roots hotline.

But state agriculture officials say the spraying is safe. It contains a pheromone encased in tiny plastic microcapsules. A key question is the size of those microcapsules.

Why is that important? Because if those particles are very tiny, 10 microns in size or smaller, experts say they can be inhaled into the deep lungs, where there is a higher risk for causing health effects.

In public documents and meetings, state agriculture officials have repeatedly assured residents that the particles in the spray, on average, are much larger than 10 microns. At a recent Berkeley City Council meeting, state toxicologist Dr. David Ting told residents the average particle size was 90 microns.

But back in Santa Cruz and Monterey, where the spraying already happened, and dozens complained about health effects, two local engineers wondered.

Dennis Knepp and Jeff Haferman, who is also a city council member, decided to try to figure out how big the microcapsules in that spray really were. "We wanted to know how many of these little tiny things there were," said Haferman.

Scientific charts put out by the state show that only a small percentage, just 1.2 percent of the microcapsules are 10 micron size or below. But Haferman wasn't impressed with their work.

"They had done some very rough stuff, just slapped together, with some really crude assumptions," Haferman said.

When Knepp and Haferman did their own analysis, they found potentially many more inhalable particles in the spray. In fact, they say fully half of the particles were 10.1 micron size or below.

"It was obvious from the first glance at this curve, and it was astounding that the CDFA didn't notice that," Knepp said.

Why are the numbers so different? The scientists say because the state did a volume calculation.

Yet in a consensus report last year, state agencies used the Agriculture Department's analysis to justify not doing some health studies, saying, "Since the microcapsule particles are very large by inhalation standards…an inhalation toxicity study would not be useful and was not conducted."

"They were using the fact to justify not performing an inhalation toxicity study," Knepp said.

In a letter to the scientists, an Agriculture Department branch chief defended the state's methodology, saying his estimates show the number of small particles "is not a high concentration" and falls within state air quality standards. And a department spokesman further told CBS 5 Investigates, people "…should be able to breathe the product and not get sick."

But the state has now reversed position, and says it will do an inhalation study.

"It leaves us the question how much can we trust any of the science they've done, and I don't trust them to do future experiments either," Knepp said.

(© MMVIII, CBS Broadcasting Inc. All Rights Reserved.)

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