Environmentalists say a newly uncovered memo shows how the California Department of Pesticide Regulation gave in to industry pressure when it approved the controversial soil fumigant methyl iodide for use in California agriculture at levels more than 100 times higher than those its own scientists recommended.
The Feb. 16, 2010, memo by an executive of methyl iodide manufacturer Arysta LifeScience said maximum exposure levels that the state’s scientists had recommended for workers and people who live near agricultural fields were unacceptable to the company because they were too low.
“It is essential to revisit the toxicology assessment to come up with less conservative assumptions,” wrote John Street, the company’s global head of development and registration.
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The memo was addressed to Jim Wells of Environmental Solutions Group, a Sacramento-based consulting firm that Arysta hired to help win regulatory approval for methyl iodide in California. Wells served as director of the Department of Pesticide Regulation in the 1990s.
Street recommended a range of exposure levels Arysta would support and laid out the calculations state pesticide regulation managers could make to arrive at those levels.
Eight months later, DPR managers overruled their own toxicologists – and a panel of expert scientists the department had commissioned to review the toxicologists’ work – and approved the use of methyl iodide at so-called regulatory target levels nearly identical to the lowest levels Street said would be acceptable to Arysta.
“In our view, the February 16 Arysta memo shows that the regulatory target levels DPR management adopted were the result of closed-door discussions with Arysta,” said Earthjustice attorney Greg Loarie.
The memo refers to two days of meetings Arysta held with DPR managers just before Street’s memo was written in February 2010.
Loarie, along with attorneys from California Rural Legal Assistance, has sued the DPR on behalf of environmental and farm worker groups over its approval of methyl iodide. The attorneys plan to file an opening brief in the case this week.
The department declined to comment about the allegations, citing the lawsuit.
“We are not going to litigate this issue in the media,” DPR spokeswoman Lea Brooks wrote in an e-mail. “DPR will respond to the litigants in its reply brief to the court.”
Methyl iodide, which is sold under the trade name Midas, kills weeds and soil pests before crops like strawberries, tomatoes and peppers are put in the ground. It was touted as an urgently needed drop-in replacement for methyl bromide, a soil fumigant that is widely used but is now being phased out under the Montreal Protocol because it depletes the earth’s ozone layer. Methyl bromide’s use must be discontinued by 2015.
An Arysta spokeswoman didn’t respond to questions about the memo, but sent a statement drafted by the company: “DPR considered all data presented – including that of their own staff scientists – before making a final registration decision for MIDAS. Their consideration of available data resulted in final label restrictions significantly more conservative than EPA’s.”
Still, some methyl iodide critics have argued that the DPR put economic and political considerations before science when it registered methyl iodide for use in California.
“The point is Arysta developed a memo which delineated with precise detail the changes that could be made with the risk calculations to make the findings meet their needs, and the DPR decision-makers seemed miraculously to arrive at the same changes,” said Dr. Paul Blanc, a UC San Francisco medicine professor who served on the scientific review committee for methyl iodide.
“These were not science-based changes,” he said.
In determining safe levels for methyl iodide use, DPR scientists included safety factors to account for uncertainties in predicting the chemical’s effects on humans based on animal tests, and because of gaps in knowledge about the potential toxic effects of methyl iodide on the nervous systems of developing fetuses and young children.
Arysta’s memo argued such protective measures were unnecessary and cited studies to back its arguments. DPR managers appeared to agree and removed those safety factors.
DPR toxicologist Jay Schreider said they did so improperly. In an April 2010 memo [PDF], released by Earthjustice in August, Schreider told his supervisor that DPR managers mixed and matched methodologies for calculating risk.
“It is not scientifically credible to select a value or assumption from one and combine it with a value or assumption from another,” Schreider wrote.
Dr. Tom McKone, another scientific review panel member who teaches risk assessment at the UC Berkeley School of Public Health, said it is management’s prerogative to make final decisions on how much risk is acceptable. But he said it’s out of the norm for managers to alter scientists’ calculations.
“It’s highly unusual to come up with numbers that weren’t in the risk assessment,” he said.
Dr. Dale Hattis, a Clark University professor who also served on the scientific review committee, contended that it isn’t clear that DPR managers took advice from Arysta in determining methyl iodide exposure levels because he noted they have never fully laid out their reasoning in writing.
But, he said, “I think there is circumstantial evidence.”
The dispute over the state’s approval of methyl iodide will move to Alameda County Superior Court in January, when Judge Frank Roesch is set to begin hearing the Earthjustice case.
This story originally ran on HealthyCal.org, a nonprofit health journalism group based in Sacramento.