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EPA Seeks Comment on Proposed Decision to Register Enlist

Comment period extended until June 30, 2014.

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On April 30, 2014, the EPA made available for a 30-day public comment period a proposed regulatory decision to register Enlist Duo containing glyphosate and the choline salt of 2,4-D for use in controlling weeds in corn and soybeans genetically engineered (GE) to tolerate 2,4-D. Weeds are becoming increasingly resistant to glyphosate-based herbicides and are posing a problem for farmers. If finalized, this action would provide an additional tool to reduce the spread of glyphosate resistant weeds. To ensure that Enlist Duo successfully manages weed resistance problems, the proposal would impose requirements on the manufacturer including robust monitoring and reporting to EPA, grower education and remediation and would allow EPA to take swift action to impose additional restrictions on the manufacturer and the use of the pesticide if resistance develops.

We are making this action available for public comment because the choline salt of 2,4-D, which is less prone to drift and volatilization than its other forms, is not currently registered for these uses. Glyphosate, however, is already registered for several varieties of GE soybeans and corn. Since no new use pattern and no new exposures for glyphosate are being considered with this registration action, no further assessment is needed for glyphosate.

2,4-D is one of the most widely used herbicides to control weeds. 2,4-D has been registered for many years in the United States and is registered in dozens of countries, such as Canada, Mexico, Japan, 26 European Union Members, and many member countries of the Organisation for Economic Co-operation and Development (OECD).

Public comments on the EPA’s proposed regulatory decision must be submitted by June 30, 2014, to EPA docket EPA-HQ-OPP-2014-0195 at www.regulations.gov. After the comment period closes, EPA will review all of the comments and reach a final decision, which the Agency expects to issue in late summer or early fall.

On This Page

  1. What do EPA reviews of Enlist Duo show?
  2. Why is EPA taking this action?
  3. What are the current registered uses of 2,4-D and glyphosate?
  4. Is 2,4-D the same thing as “Agent Orange” defoliant?
  5. How does EPA’s work relate to what USDA/APHIS is doing in this area?
  6. How have the two Agencies (EPA and USDA) been working together?
  7. What is the status of USDA’s decision?
  8. Why is EPA taking this action before USDA makes a decision on the genetically-engineered seed?
  9. How will EPA minimize spray drift in this proposed decision?
  10. How does today’s proposal address the issues of herbicide-resistant weeds?
  11. When/How will EPA reach its final regulatory decision?

Questions and Answers

  1. What do EPA reviews of Enlist Duo show?

    On the basis of protective and conservative human health and ecological risk assessments for the proposed new uses of Enlist Duo, EPA confirmed the safety of the use for the public, agricultural workers and non-target species. These assessments support our proposed decision to allow the use of the 2,4-D choline salt formulation. The Agency’s risk assessments also included an assessment of risks from the 2,4-D choline salt to endangered species, as required by the Endangered Species Act, and found that there would be no effect on listed species from this active ingredient in the proposed use area when the product is used according to label directions.

    This finding is consistent with the pesticide risk assessments that EPA has performed on 2,4-D.  For instance, EPA did a comprehensive review of 2,4-D in 2005, and once more in 2012 as a result of a petition and new state of the art reproductive studies required by EPA and now again in 2014 on the choline salt of 2,4-D in response to this application to modify the registration.

    Glyphosate is already registered for these uses and did not undergo further review as part of the assessment for this pesticide product. However, glyphosate currently is in the registration review process and an endangered species analysis will be part of that process.



  2. Why is EPA taking this action?

    The Agency received applications from Dow AgroSciences requesting the use of a new, lower volatility formulation of the choline salt of 2,4-D and glyphosate on genetically engineered (GE) corn and soybeans. Concurrent with the EPA regulatory process, the U.S. Department of Agriculture received applications from Dow AgroSciences to introduce into the U.S. market, GE corn and soybeans to tolerate exposure to 2,4 D. These GE corn and soybean plants are the first developed to be resistant to 2,4-D and are intended to provide farmers with new plants to help address the problem of weeds that have developed resistance to other herbicides.

    Weeds are becoming increasingly resistant to glyphosate-based herbicides and are posing a problem for farmers. If finalized, this action will provide an additional tool to reduce the spread of glyphosate resistant weeds. The EPA is proposing to require a stewardship plan including robust education, monitoring, and a remediation program to ensure that use of Enlist Duo successfully manages weed resistance problems.



  3. What are the current registered uses of 2,4-D and glyphosate?

    The active ingredient 2,4-D is registered in pesticide products to control broadleaf weeds in a variety of field, fruit and vegetable crops and for use on turf, lawns, rights-of-way, aquatic sites and forestry sites. Additionally, 2,4-D is registered as a plant growth regulator in citrus.

    Residents and commercial applicators may use 2,4-D on home lawns. 2,4-D is one of the most widely used herbicides to control weeds.

    The active ingredient glyphosate is a non-selective herbicide and is widely used to control weeds in agricultural crops and non-agricultural sites and is registered for use on a variety of fruit, vegetable, and field crops as well as for aquatic and terrestrial uses. Glyphosate is also registered for use on glyphosate-resistant (transgenic) crop varieties such as canola, corn, cotton, soybeans, sugar beets, and wheat. Labeled uses of glyphosate include over 100 terrestrial food crops as well as other non-food sites including forestry, greenhouse, non-crop, and residential.



  4. Is 2,4-D the same thing as “Agent Orange” defoliant?

    No. “Agent Orange” was a mixture of two different herbicides 2,4,5-T and 2,4-D – as well as kerosene and diesel fuel. Agent Orange contained high levels of dioxin, a contaminant found in 2,4,5-T that causes cancer and other health concerns in people. EPA cancelled all use of 2,4,5-T in 1985 because of these risks.

    In evaluating this requested use, the Agency performed a thorough and conservative safety review for any potential human health and environmental risks associated with the expanded use of 2,4-D on these GE plants and also explicitly considered any possible risks from any formulation contaminants.



  5. How does EPA’s work relate to what USDA/APHIS is doing in this area?

    The U.S. Department of Agriculture (USDA) is responsible for determining whether to allow the sale of seeds that have been genetically engineered. EPA regulates the pesticide used on those seeds or crops under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and the pesticide residues remaining in or on food from those uses under the Federal Food, Drug, and Cosmetic Act (FFDCA).



  6. How have the two Agencies (EPA and USDA) been working together?

    The two agencies are working closely to ensure a thorough scientific review of the potential impacts on human health and the environment associated with the proposed uses and have shared information and assessments to inform both agencies’ respective regulatory decisions.



  7. What is the status of USDA’s decision?

    In January 2014, the USDA made available for public comment a Draft Environmental Impact Statement (EIS) on the 2,4-D tolerant seeds that evaluates the potential environmental impacts of its regulatory decision regarding these GE crops. Please see www.regulations.gov for more information for Docket ID: APHIS-2013-0042.

    USDA’s Animal and Plant Health Inspection Service (APHIS) is evaluating the comments submitted on its draft EIS and its proposed regulatory decision. If the final plant pest risk assessment concludes, as did the preliminary one, that these new GE plants do not pose a plant pest risk to agricultural crops or other plants in the United States, APHIS would deregulate them; that is, determine that those GE plants may be sold without further USDA regulatory control.



  8. Why is EPA taking this action before USDA makes a decision on the genetically-engineered seed?

    EPA is not making a final pesticide registration decision before USDA makes a decision on the genetically-engineered seed. In their recent Draft Environmental Impact Statement, USDA concluded that the deregulation will not pose a plant pest risk.


  9. How will EPA minimize spray drift in this proposed decision?

    EPA has determined that use of the choline salt of 2,4-D in the Enlist Duo product would reduce volatility and off-site movement of the herbicide compared to other forms of 2,4-D. To ensure there is reduced off-target movement, the EPA’s proposed registration decision pertains only to the same formulation as that employed in Dow’s drift studies. In addition, the proposed registration decision requires a 30-foot in-field buffer zone to help minimize spray drift from the intended use area. The proposed label also specifies that Enlist Duo cannot be applied when the wind speed is over 15 mph. No aerial applications would be permitted.


  10. How does today’s proposal address the issues of herbicide-resistant weeds?

    The EPA is concerned about the possibility that using Enlist Duo could result in the spread of weeds resistant to 2,4-d. Therefore, we are also proposing special additional requirements to address this concern. The proposal would impose requirements on the manufacturer including robust monitoring and reporting to EPA, grower education and remediation and would allow EPA to take swift action to impose additional restrictions on the manufacturer and the use of the pesticide if resistance develops.

    These provisions would require Dow to conduct a robust stewardship program including active monitoring and swift steps to remediate weed resistance. It would allow the EPA to modify the registration quickly and easily to impose additional measures to manage resistance if needed. The label would also contain information on resistance management consistent with the Weed Science Society of America’s Best Management Practices (BMPs) for comprehensive resistance management approaches.



  11. When/How will EPA reach its final regulatory decision?

    It is difficult for the Agency to project when the final regulatory decision will be reached and published. We anticipate receiving information and comments on this proposed decision. After consideration of public comments, we will make our final regulatory decision in coordination with USDA’s final regulatory decision regarding the corn and soybean GE plants. We project a final regulatory decision later in 2014 – perhaps late summer or early fall.

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