Monosodium Salt of Methanearsonic Acid

What is the regulatory status of MSMA?

Regulatory Information


In January 2009, the technical registrants of the organic arsenicals manufacturing-use products reached agreement with the U.S. Environmental Protection Agency (EPA) according to which MSMA has been allowed to be used on cotton, as well as some other use applications, including golf courses, sod farms and highway rights-of-way.  The registrants agreed to eliminate and phase out products of disodium methanearsonate (DSMA), calcium acid methanearsonate (CAMA), and cacodylic acid and its sodium salt, and modify certain uses of MSMA, including use on residential lawns, forestry, non-bearing fruit and nut trees, and citrus orchards. That phase out has begun, and no sales or distribution of MSMA for these particular uses is allowed, although use of existing stocks of MSMA is acceptable.


According to theagreement, the reregistration of MSMA use on cotton was contingent on the development and acceptance of confirmatory data demonstrating that no residues of inorganic arsenic are likely to remain in the meat and milk of animals fed cotton by-products. These data were provided to EPA in 2010.


EPA notes that there are certain mitigation measures required for MSMA use on cotton to protect water resources. Pre-plant cotton use was deleted. The cotton use has been limited to two post-emergent applications per year of two pounds active ingredient per acre each, cotton growers must maintain a 50-foot buffer zone around permanent water bodies.


As part of the agreement with EPA on continued uses of MSMA, EPA agreed to conduct a scientific review of any new toxicity or benefits data in 2013.  The Organic Arsenical Products Task Force (OAPTF) believes that the review of the science and the evaluation of additional benefits information will provide sufficient information to permit the continued use of MSMA for these applications.


At EPA’s request, all MSMA labels were revised to say that the use of the product would be terminated in 2013. This statementhas been removed since February 2013 and the product continues to be used beyond 2013.


Agreement with U.S. EPA For Continued Use of MSMA, January 27, 2009 (click here for the full Agreement)


Status of MSMA Registration, October 31, 2008

Organic Arsenical Products Task Force (OAPTF)  ·  P.O. Box 33856  ·  Washington, D.C.  ·  20033-0856  ·  1-877-221-2442


About This Site : The Organic Arsenical Products Task Force (OAPTF) appreciates your interest in learning more about our products and our activities. Please note that the information contained in this site is offered as a service of the OAPTF and is not intended to replace, alter, or supplement specific product labeling, warranties, claims, or related information pertinent to any member company’s products. Questions about a specific product should be directed to the manufacturer of that product.


site design: great work web design