Under a memorandum of agreement (MOA) between the EPA and ArystaLifeScience North America, all domestic agricultural uses of iodomethane (methyl iodide), a popular fumigant sold by Arysta as Midas®, will be voluntarily terminated by the company as of December 31, 2012.  The EPA has also agreed to Arysta’s request to cancel federal registration of iodomethane.  The MOA allows the company to continue to distribute iodomethane for international use.  

Methyl bromide alternative

Iodomethane was introduced by Arysta as an alternative to methyl bromide.  Methyl bromide can persist in the atmosphere for years and endangers the earth’s protective ozone layer.  In contrast, iodomethane is highly volatile and dissipates once airborne in 4 to 8 days. 

The EPA registered iodomethane in 2007 as a preplant soil fumigant to control pests in soil where fruits, vegetables, ornamental plants, and turf are to be grown.  Arysta reported that Midas was being applied to about 15,000 acres of land in 12 states.  At the recommended usage of 175 pounds per acre, that amounted to a release to the environment of about 2.7 million pounds of Midas.

Earthjustice petition

That level of distribution resulted in an unacceptable risk to public health, declared Earthjustice in its March 2010 petition to the EPA to suspend and cancel all registrations for iodomethane.  The petition summarized a significant amount of research indicating that the fumigant poses a serious, immediate, and unacceptably high probability of serious harm. 

For example, Earthjustice noted that California has listed iodomethane as a carcinogen under Proposition 65.  Animal studies showed that the substance led to malignant brain and cervical tumors.  Iodomethane is also a severe neurotoxicant, causing permanent neurological damage in those exposed, said Earthjustice. In addition, it is toxic to the thyroid, disrupting the normal production of thyroid hormones that control metabolism, immune functions, and growth and development in infants and children, the group added.  Moreover, iodomethane’s volatility and water solubility means its broad use in agriculture will “guarantee substantial releases to air, surface waters, and groundwater and will result in many people being exposed,” said Earthjustice.

Contrary views were presented to the EPA by CropLife America (CLA), which claimed that iodomethane was far safer than methyl bromide, that no alternatives have gained market acceptance, and that the benefits of its use far outweighed any disadvantages.

Cancellation order forthcoming

Notwithstanding CLA’s support, on March 20, 2012, Arysta announced the immediate suspension of product sales for all formulations of Midas in the United States.  “The decision was made as part of an internal review of the fumigant and its economic viability in the U.S. marketplace,” said Arysta.

The EPA says it will publish a cancellation order for iodomethane with the following conditions:

• Arysta is prohibited from distributing or selling existing stocks of end-use products unless sale or distribution is for proper disposal or is solely for import.
• Persons other than Arysta are prohibited from distributing or selling existing stocks of Arysta’s end-use products unless the sale or distribution is for proper disposal, return to Arysta, or is intended solely for export.
• No person may use any existing stocks of any of Arysta’s end-use products. 

Arysta also carries a technical product registration for iodomethane, which will be cancelled by the EPA effective December 1, 2015 under the MOA.

EPA’s notice of registration cancellation of iodomethane was published in the November 21, 2012, FR.