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Pesticide News Story: Organic Arsenicals Agreement

For Release: February 10, 2009

EPA has reached an agreement in principle with the major manufacturers of the organic arsenicals MSMA, DSMA, CAMA, and cacodylic acid and its sodium salt. This voluntary agreement steadily removes all organic arsenical pesticide uses, except the use of MSMA on cotton, from the market and implements new restrictions to better protect drinking water resources. Phasing out these uses is expected to accelerate the transition to new, lower risk herbicides.

Under the agreement, many uses, including use on residential lawns, will be canceled by the end of this year. For products used on cotton and products phased out after 2009, new use restrictions and mitigation measures will be added to increase protections to water resources

In the Agency’s 2006 Reregistration Eligibility Decision (RED), EPA concluded that all uses of the organic arsenicals were ineligible for reregistration. Following application, these pesticides convert over time to a more toxic form in soil, inorganic arsenic, and potentially contaminate drinking water through soil runoff. At that time, EPA believed that inorganic arsenic also could enter the human food supply through the meat and milk of animals fed cotton by-products treated with MSMA. In completing the RED, EPA determined that the aggregate dietary risks from food and drinking water combined did not meet the food safety standard.

During the last two years, stakeholders have submitted additional data indicating that no residues of inorganic arsenic are likely to remain in the meat and milk of animals fed cotton by-products that have been grown in fields treated with MSMA, or in food crops that are rotated with cotton that has been treated with MSMA. Cotton growers also have documented the increasing spread of Palmer amaranth or pigweed, a glyphosate-resistant and economically significant pest, which only MSMA controls at present.

In light of this new information, the agreement allows for reregistration of MSMA use on cotton, contingent on the development of confirmatory data. If these data are not submitted by the August 2010 due date, or if they do not confirm the current scientific understanding, EPA will proceed to cancel the cotton use. The Agency is also rescheduling the Registration Review of MSMA to begin in 2013. At that time, MSMA’s risks and benefits will be reevaluated considering any new toxicity information and the availability of new, lower-risk herbicides that should be entering the market.

EPA will amend the 2006 Organic Arsenicals RED to reflect the provisions of the agreement. Public comment opportunities will be provided when the Agency publishes Federal Register notices announcing its receipt of registrants’ requests for voluntarily cancellation of uses.

The organic arsenicals agreement and related information will be available at www.regulations.gov in Docket EPA-HQ-OPP-2006-0201 and on the reregistration chemical pages for these pesticides at http://www.epa.gov/pesticides/reregistration/status.htm. For additional information, please contact Tom Myers, Office of Pesticide Programs, (703) 308-8589. The press should contact Dale Kemery, Office of Public Affairs, (202) 564-7839.

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