Methyl iodide's toxic saga continues

California's approval of a dangerous and controversial agricultural chemical, methyl iodide, came further into question last week when new documents showed the fumigant's registration process was flawed. The documents, which were made public as part of a lawsuit challenging the state's approval of the chemical, show the state's Department of Pesticide Regulation cut and pasted calculations from different risk assessments in order to come up with a less stringent set of restrictions on the chemical's use.

One of the released documents, a memo [PDF] from one disapproving DPR scientist chastised the agency for its cut-and-paste approach to calculations determining how big buffer zones should be to protect public health:

"It is not scientifically credible to select a value or assumption from one (risk assessment calculation) and combine it with a value or assumption from another," the scientist wrote.

Methyl iodide, a multipurpose fumigant that sterilizes the soil by killing everything living in it, was proposed for use as a substitute for methyl bromide, a fumigant with similar properties that depletes the ozone layer. Methyl bromide, used in growing California strawberries as well as other vegetable and nut crops, has been undergoing a phaseout as part of the Montreal Protocol. But methyl iodide is no benign replacement: it's been linked to thyroid cancer, neurological damage, and late-term miscarriages.
Environmental and health activists have long questioned California's rationale for approving methyl iodide over the warnings of DPR's own scientists. Although industry influence was suspected in the decision, there was no proof until these documents came to light, showing that DPR managers changed recommended exposure levels to suit the preferences of methyl iodide's manufacturer, Arysta LifeScience. As reporter Nathan Rice wrote in his recent High Country News story:

A lack of understanding about exactly how DPR arrived at its final exposure standards has helped spark rampant speculation about political influence and corporate pressure. The agency is reluctant to talk about its process, citing the pending lawsuit. Two lead DPR scientists who warned of methyl iodide's risks have since left; both declined to comment. Director Warmerdam resigned from the agency and took a job at the Clorox Company.

Earthjustice, a nonprofit environmental law group, sued DPR in an attempt to reverse the state's approval of the chemical. That court case is where the documents showing DPR manipulated data were first released.

In related news, it turns out the fumigant methyl iodide is supposed to replace, methyl bromide, has its own problems. On Thursday, the Environmental Protection Agency reached a settlement [PDF] on California's use of methyl bromide, which they say disproportionately impacted Latino schoolchildren by being sprayed in higher quantities near schools with primarily Latino students. From 1995-2001, methyl bromide was approved in such as way as to allow spraying near schools with predominately Latino children.   The settlement admits to this discrimination, although it does not offer compensation to the children adversely affected. As a result of the settlement, DPR has agreed to install additional monitors for methyl bromide near those schools and conduct outreach to the Latino community around pesticide use and safety.

Anti-methyl iodide activists, who recently flash-mobbed California Gov. Jerry Brown's Facebook and Twitter accounts in addition to staging protests at the state Capitol, hope the EPA-DPR settlement on methyl bromide will push Brown to reconsider methyl iodide's approval. While there are no signs that's going to happen, with revelations like this, the Earthjustice case against methyl iodide's rushed approval appears to grow ever stronger.

Stephanie Paige Ogburn is the online editor at High Country News.

Image of California strawberries courtesy Flickr user benkataro.