Document ID: EPA-HQ-OPP-2015-0803-0035
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2021-07-30T04:00Z

Dimethenamid and Dimethenamid-p
                                       
                     Interim Registration Review Decision
                               Case Number 7223
                                       
                                       
                                   June 2021
                                       
                                       
                                                                   Approved by:
 

Mary Elissa Reaves, Ph.D.

Director

Pesticide Re-evaluation Division
                                                                          Date:
   06/29/2021
                                       
                                       
                                       
			
                               Table of Contents

I.	INTRODUCTION	3
Updates Since the Proposed Interim Decision was Issued	4
Summary of Public Comments on the Draft Risk Assessments and Agency Responses	4
II.	USE AND USAGE	7
III.	SCIENTIFIC ASSESSMENTS	8
A.	Human Health Risks	8
B.	Ecological Risks	9
C.	Benefits Assessment	9
IV.	INTERIM REGISTRATION REVIEW DECISION	10
A.	Risk Mitigation and Regulatory Rationale	10
1.	Respirators--Applications to Hops and Nursery Sites	10
2.       Spray Volume--Nursery Applications	11
3.       Prohibition of Application Equipment--Field Crops	12
4.	Spray Drift Management	12
B.	Label Updates	13
1.       Glove Statement	13
2.	Ground and Surface Water Advisories; Spilled Granules	13
3.	Separating Lentils from Dry Beans	13
4.	Non-Target Organism Advisory Statement	13
C.	Environmental Justice	13
V.	Herbicide Resistance Management	14
A. Tolerance Actions	14
B. Interim Decision Review Decision	16
C. Data Requirements	16
VI.	NEXT STEPS AND TIMELINE	17
A.	 Interim Registration Review Decision	17
B.	Implementation of Mitigation Measures	17
Appendix A: Labeling Changes Needed for Dimethenamid/-p Products	18

INTRODUCTION
	
This document is the Environmental Protection Agency's (EPA or the Agency) Interim Registration Review Decision (ID) for dimethenamid and dimethenamid-p (PC Code 129051 and 120051; Case 7223) and is being issued pursuant to 40 CFR §§ 155.56 and 155.58. (In this ID, the Agency uses a shorthand when referring to dimethenamid and dimethenamid-p together unless otherwise noted: dimethenamid/-p. If reference is made to one or the other active ingredient in Case 7223, the Agency uses either "dimethenamid" or "dimethenamid-p," as appropriate). A registration review decision is the Agency's determination whether a pesticide continues to meet, or does not meet, the standard for registration in the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). The Agency may issue, when it determines it to be appropriate, an interim registration review decision before completing a registration review. Among other things, the interim registration review decision may determine new risk mitigation measures are necessary, lay out interim risk mitigation measures, identify data or information required to complete the review, and include schedules for submitting the required data, conducting the new risk assessment and completing the registration review. Additional information on dimethenamid/-p, can be found in EPA's public docket (EPA-HQ-OPP-2015-0803) at www.regulations.gov. Since 2000, all new crop use registrations for this case have been for dimethenamid-p, and therefore this document focuses primarily on the active ingredient dimethenamid-p.

FIFRA, as amended by the Food Quality Protection Act (FQPA) of 1996, mandates the continuous review of existing pesticides. All pesticides distributed or sold in the United States must be registered by EPA based on scientific data showing that they will not cause unreasonable risks to human health or to the environment when used as directed on product labeling. The registration review program is intended to make sure that, as the ability to assess and reduce risk evolves and as policies and practices change, all registered pesticides continue to meet the statutory standard of no unreasonable adverse effects. Changes in science, public policy, and pesticide use practices will occur over time. Through the registration review program, the Agency periodically re-evaluates pesticides to make sure that as these changes occur, products in the marketplace can continue to be used safely. Information on this program is provided at http://www.epa.gov/pesticide-reevaluation. In 2006, the Agency implemented the registration review program pursuant to FIFRA § 3(g) and will review each registered pesticide every 15 years to determine whether it continues to meet the FIFRA standard for registration.

The EPA is issuing an ID for dimethenamid/-p so that it can (1) move forward with aspects of the registration review that are complete and (2) implement interim risk mitigation (see Appendix A). The Agency is currently working with the U.S. Fish and Wildlife Service and the National Marine Fisheries Service (collectively referred to as, "the Services") to improve the consultation process for national threatened and endangered (listed) species for pesticides in accordance with the Endangered Species Act (ESA) § 7. Therefore, although EPA has not yet fully evaluated risks to federally-listed species, the Agency will complete its listed species assessment and any necessary consultation with the Services for dimethenamid/-p prior to completing the dimethenamid/-p registration review. Likewise, the Agency will complete endocrine screening for dimethenamid/-p, pursuant to the Federal Food, Drug, and Cosmetic Act (FFDCA) § 408(p), before completing registration review. 

Dimethenamid was first registered in the United States in 1993, whereas dimethenamid-p was first registered in the U.S. in 1999. Products containing these active ingredients are registered as selective, systemic herbicides for the control of sedges, annual grasses, and broadleaf weeds in a wide range of agricultural and non‐agricultural use sites. Both dimethenamid and dimethenamid-p are used on major agricultural use sites including crops such as field corn, grain sorghum, soybean, dry beans, peanuts, and potatoes. Both are registered for use on grass grown for seed. Dimethenamid-p is also used on major non‐agricultural use sites including landscape and grounds maintenance areas, tree plantations, turf‐grass areas, golf courses, ornamental gardens, and commercial ornamental production sites. Since 2000, all new FIFRA Section 3 crop use registrations have been formulated with dimethenamid‐p. According to the classification of herbicides, dimethenamid/‐p belong to the family of chloroacetamide herbicides.
 
This document is organized into five sections: Introduction, which includes this summary and a summary of public comments and EPA's responses; Use and Usage, which describes how and why dimethenamid/-p is used and summarizes data on its use; Scientific Assessments, which summarizes EPA's risk and benefits assessments, updates or revisions to previous risk assessments, and provides broader context with a discussion of risk characterization; Interim Registration Review Decision, which describes the mitigation measures to address risks of concern and the regulatory rationale for EPA's PID; and, lastly, Next Steps and Timeline for completion of this registration review.

Updates Since the Proposed Interim Decision was Issued

In March 2021, EPA published the PID for dimethenamid/-p. In this ID, there is one change to what was proposed in the PID. The proposed requirement that applications of dimethenamid/-p impregnated fertilizer be made at a minimum of 300 pounds of per acre has been removed, as explained in the Summary of Public Comments below, in Section III.A, and in Dimethenamid and Dimethenamid-p: Response to the USDA Comment on the Mixer/Loader Risk of Concern on the Human Health Draft Risk Assessment, posted to the public docket. With the addition of the response to comments document, this ID finalizes the Agency's draft supporting documents Dimethenamid/-p. Human Health Risk Assessment for Registration Review and Dimethenamid/-p: Ecological Risk Assessment for Registration Review, which also are available in the public docket.

Summary of Public Comments on the Draft Risk Assessments and Agency Responses 

During the 60-day public comment period for the dimethenamid/-p PID, which opened on March 18, 2021 and closed on May 17, 2021, the Agency received public comments from four respondents. The Agency considers all the public comments to be substantive and they are summarized below, along with the Agency's responses to the comments. The Agency thanks all commenters and has considered the comments in developing this ID.

Comments Submitted by BASF (Document ID - EPA-HQ-OPP-2015-0803-0028): 

Comment: BASF, the sole registrant for dimethenamid/-p, submitted comments stating that it concurs with the mitigation measures that EPA proposed in the PID. BASF also provided additional comments relating to pollinator data requirements and the toxicity of dimethenamid-p to bees both on an acute and chronic exposure basis. Since dimethenamid-p is typically applied before crop emergence or very early in the growing season, the risk of bee exposure during flowering stages of crops is very low. Additionally, BASF referenced a European residue study that has not been submitted to EPA, which BASF claims provides evidence that dimethenamid-p is not likely to accumulate, and low exposure to pollinators is expected. BASF does not agree that higher-tier bee studies are needed as risks to pollinators are low.

EPA Response: All data requirements from the registration review DCI have been satisfied with the exception of the Tier II and III honeybee data. EPA has determined that these data are needed for dimethenamid/-p, based on potential risk concerns identified by the Agency following review of the Tier I honeybee studies. The Agency will consider the European study if BASF makes it available.

Comment submitted by the United States Department of Agriculture (USDA; Document ID - EPA-HQ-OPP-2015-0803-0033):

Comment: USDA generally expressed support for the mitigation measures that were proposed in the dimethenamid/-p PID including label clean-up, the addition of a non-target organism statement, and spray drift and herbicide resistance management labeling. USDA agreed that adding the proposed requirement for PF-10 respirators and application volume restrictions for certain handlers should not pose an exceptional burden for growers. 

USDA commented that the mitigation proposed in the PID for impregnated fertilizer is not the best approach for mitigating risks to workers. The Agency proposed that an increased minimum amount of fertilizer be applied on a per-acre basis, in order to reduce the concentration of dimethenamid/-p in the fertilizer and the exposure of handlers impregnating fertilizer with the herbicide. USDA expressed concern that the proposed mitigation could result in growers applying more fertilizer than is typically needed. The proposed approach also could increase production costs for growers. USDA recommended revisiting the risk assessment for impregnating fertilizers using updated Agricultural Handler Exposure Task Force (AHETF) data, which includes new unit exposure values for the fertilizer impregnation scenario. USDA believes the data support a lower risk estimate for mixer/loaders impregnating fertilizer with liquid formulations of pesticides. Alternatively, USDA suggested that EPA could limit the amount of dry bulk fertilizer handled in a workday, or consider requiring the use of both a closed system and increased Personal Protective Equipment (PPE) for those handlers. 

EPA Response: The Agency has considered these comments from USDA on fertilizer impregnated with dimethenamid/-p. The Agency began using the unit exposure values from the new AHETF database in May 2021, after the dimethenamid/-p PID was published. The unit exposure value used in the original assessment was 0.083 μg/lb ai and resulted in a Margin of Exposure (MOE) of 670. The new unit exposure value is 0.011 μg/lb ai, and results in an MOE of 5,100. The Level of Concern (LOC) is 1000, and MOEs below the LOC represent potential risks of concern. Thus, the risks associated with this scenario are no longer considered to be of concern. Based on the update for this scenario, there is no need for labels to be revised to change the minimum number of pounds of dimethenamid/-p impregnated fertilizer to be applied per acre, as originally proposed by the Agency.   
Comment submitted by the Center for Biological Diversity (CBD; Document ID- EPA-HQ-OPP-2015-0803-0034):
Comment:  CBD's comments focus on the EPA's duty to consult with the Services on the registration review of dimethenamid/-p in accordance with the Endangered Species Act (ESA). The CBD comments mention various aspects of the risk assessment process, specifically use of the best available data, including all necessary data and studies, particularly to develop listed species risk assessments, and evaluation of effects on listed species and their designated critical habitat. CBD also expressed concern regarding the rigor of the agency's preliminary determinations regarding the effects of dimethenamid/-p on listed species and their designated critical habitat for the dimethenamid/-p registration review. In addition, CBD expressed concern about effects on pollinators and other beneficial insects, effects on human health or environmental safety concerning endocrine disruption, and any additive, cumulative or synergistic effects of the use of the pesticide. 

EPA Response:  EPA has reviewed CBD's comments and is addressing many of the concerns regarding listed species as part of its ongoing collaborative work with the Services and USDA to improve the consultation process for listed species for pesticides in accordance with the Endangered Species Act (ESA) § 7. The EPA will address concerns specific to dimethenamid/-p particularly with regard to pollinators, ESA, and endocrine disruption, in connection with the development of its final registration review decision for this pesticide. The EPA is currently developing an agency policy on how to consider claims of synergy being made by registrants in their patents. On September 9, 2019, the EPA released an interim process for public comment, available at regulations.gov in docket EPA-HQ-OPP-2017-0433. After the agency has received and considered public comment on the proposed policy, and once that policy has been finalized, the EPA will consider its implications on the EPA's final decision for dimethenamid/-p.

Comment submitted by National Agricultural Aviation Association (NAAA; Document ID:
EPA-HQ-OPP-2015-0803-0032):

Comment: NAAA stated the overall importance of aerial applications and the advantages of aerial applications over other forms of application. While NAAA supports the proposed spray drift mitigation language for aerial applications, NAAA described the need for clear label language regarding the specific altitude above which temperature inversions are not of concern. NAAA states it is currently collaborating with the USDA-Agricultural Research Service (ARS) Aerial Application Technology Research Unit to conduct a literature review on the matter.  

EPA Response: EPA thanks NAAA for their work with USDA. The Agency will review any additional information submitted regarding the altitude of temperature inversions as it relates to pesticide applications. At this time EPA is not changing the temperature inversion label restriction proposed in the dimethenamid/-p PID.

USE AND USAGE

Dimethenamid/-p are Group 15 herbicides that inhibits very long chain fatty acid synthesis and controls weed seedlings before they emerge. Registered agricultural use sites include dried beans, chickpeas, cotton, corn, fallow lands, garbanzo beans, garlic, hops, horseradish, leeks, lentils, onions, peanuts, potatoes, scallions, shallots, squash, sorghum, soybeans, sugar beets, and grass grown for seed. Dimethenamid-p is also used on major non‐agricultural use sites including landscape and grounds maintenance areas, tree plantations, turfgrass areas, golf courses, ornamental gardens, and commercial ornamental production sites. 
REGISTERED END-USE PRODUCTS include emulsifiable concentrates (EC), granules (G), and as a liquid impregnated onto dry bulk fertilizer formulations. Products can be applied using ground, aerial, backpack/handheld sprayers, and soil incorporation equipment, and liquid impregnated dry bulk fertilizer.

Agricultural Usage

From 2014-2018, an annual average of 210,000 lbs dimethenamid were applied to about 270,000 acres of corn, dry beans/peas, sorghum, soybeans, and sweet corn. Total acres treated accounts for multiple applications to a single acre. In the same period, an annual average of 6,000,000 lbs of dimethenamid-p were applied to about 11,700,000 acres of alfalfa, beans (snap/bush/
pole/green), corn, cotton, dry beans/peas, fallow, garlic, onions, peanuts, peas (fresh/green /sweet), potatoes, pumpkins, sorghum, soybeans, squash, sugar beets, and sweet corn.[2]

Dimethenamid has reported usage for corn, sorghum, soybeans, dry beans/peas, and corn. However, usage data indicate that less than 1 percent of these crops were treated with dimethenamid between 2014-2018. Dimethenamid-p had reported usage for onions, potatoes, sweet corn, garlic, dry beans/peas, sugar beets, corn, soybeans, and squash from 2014-2018. Approximately 40 percent of the onion crop was treated with dimethenamid-p, while only 5 percent of the squash, soybean, and corn crops were treated with dimethenamid-p. Between 10-20 percent  of potatoes, sweet corn, garlic, dry beans/peas, and sugar beets were treated with dimethenamid-p. High percent crop treated values indicate the use of the chemical is beneficial to the grower. Although the greatest number of pounds active ingredient applied and total acres treated were on soybeans and squash, a percent crop treated (PCT) of 5% suggests growers are not relying heavily on dimethenamid-p, but primarily use other active ingredients.

Non-agricultural Usage

Available non-agricultural usage data does not show use of dimethenamid or dimethenamid-p in non-agricultural settings. However, the information available to the Agency dates from 2011-2013 and likely is not representative of current market trends.

SCIENTIFIC ASSESSMENTS

 Human Health Risks 

A summary of the Agency's human health risk assessment was presented in the dimethenamid/-p PID. The Agency used the most current science policies and risk assessment methodologies to prepare a risk assessment in support of the registration review of dimethenamid/-p. For additional details on the human health and drinking water assessments for dimethenamid/-p, see the Dimethenamid/ Dimethenamid-p: Draft Human Health Risk Assessment for Registration Review, and other supporting documents, which are available in the public docket. 

Since the PID was published, the Agency has updated the inhalation unit exposure value for mixer/loaders using closed systems to apply liquid sprays of dimethenamid/-p to fertilizer (i.e., fertilizer impregnation) in commercial facilities. This scenario, as assessed in the original human health risk assessment, resulted in a potential risk of concern for these handlers. After the assessment was completed, the Agency revised the inhalation unit exposure value for the scenario, and the updated MOE is now greater than the LOC; and it is not a risk of concern. The updated assessment for this scenario can be found in Dimethenamid and Dimethenamid-p. Response to the USDA Comment on the Mixer/Loader Risk of Concern on the Human Health Draft Risk Assessment, available on the public docket. 

The Agency did not identify any dietary, residential, bystander, aggregate, or occupational post-application risks of concern. EPA has not made a common mechanism of toxicity to humans finding as to dimethenamid/-p and any other substance and it does not appear to produce a toxic metabolite produced by other substances, so a cumulative assessment was not conducted. Additionally, a cancer risk assessment was not needed or conducted. Most risk estimates for occupational handlers were not of concern for handlers wearing the clothing and PPE required by current labels. Three occupational handler scenarios resulted in MOEs below the LOC of 1,000, representing potential risks of concern:

Mixer/Loader/Applicators applying liquid formulations with mechanically pressurized handguns as drench or soil- and ground-directed application to the following use sites:

    Nursery (ornamentals, vegetables, trees, container stock), MOE=40 (at baseline); 400 when a PF10 respirator is added
    Hops (represented by the orchard/vineyard scenario), MOE = 610 (at baseline); 6100 with a PF10 respirator is added
    Field crop, typical, MOE = 610 (at baseline); 6100 with a PF10 respirator is added

There were eight minor incidents involving products containing dimethenamid/-p and one of moderate severity reported to the IDS. The one of moderate severity involved a female who was sprayed with a product containing dimethenamid (Reg. No. 7969-156) while out running, after which she experienced an asthma attack.

 Ecological Risks

A summary of the Agency's ecological risk assessment was presented in the PID. There were no identified risks of concern to freshwater and estuarine/marine fish (and aquatic-phase amphibians for which freshwater fish serve as surrogates), and freshwater invertebrates. The Agency identified some Risk Quotients (RQs) greater than the LOCs for acute and/or chronic risks for mammals, birds (surrogates for reptiles and terrestrial-phase amphibians), terrestrial invertebrates (honeybees), terrestrial plants, and aquatic plants, suggesting potential risks of concern. 

All reported incidents were to plants and there have been no new incidents reported since the publication of the PWP. Plant incidents were reported for a number of different use sites. For dimethenamid, there were 19 incidents reported between 1997 and 2001. There were eight incidents reported for dimethenamid-p between 2001 and 2014. All 27 incidents were considered to be of "possible" certainty.

All data requirements from the registration review DCI have been satisfied with the exception of the Tier II and III honeybee data. EPA has determined that these data are needed for this case, based on potential risk concerns identified in the Agency's review of the Tier I honeybee studies.

Since the PID, there have been no changes to the Agency's ecological risk conclusions. For additional details, see the Dimethenamid/-p: Ecological Draft Risk Assessment for Registration Review, which is available in the public docket.

 Benefits Assessment

Dimethenamid-p can be applied both before and after crop emergence which allows growers a longer application window throughout the growing season. Additionally, fertilizer impregnation with dimethenamid-p allows growers to apply an herbicide at the same time that they apply a granular fertilizer which saves a trip over the field and the associated costs. This chemical controls broadleaf and grass weeds such as redroot pigweed, waterhemp spp., and foxtail spp. Of these weeds, waterhemp is widely distributed and difficult to control. Dimethenamid-p is reported to provide up to 12 weeks of residual control in field ornamentals, landscape, and nurseries, and 6-8 weeks of control in container plants (Neal et al., 2017). 

In corn production, growers have several herbicides available to control weeds before they emerge; however, use of dimethenamid-p may slightly lower weed control costs, in comparison to the most likely alternatives. Potential alternatives are more limited in the case for hops, where dimethenamid-p, pendimethalin, and flumioxazin are the only residual herbicides that can be applied during the growing season (non-dormant season). Though growers have several herbicide options for general weed control in nurseries, dimethenamid-p is the only herbicide that can reportedly control marsh parsley and kyllinga. Both dimethenamid-p and 2,4-D can be used to control common woodsorrel in nurseries.

For corn, hops, and nursery grown ornamentals, dimethenamid-p provides a valuable tool for use in herbicide rotational programs for resistance management. 

INTERIM REGISTRATION REVIEW DECISION

 Risk Mitigation and Regulatory Rationale

The Agency has reviewed the uses, risks, and benefits of dimethenamid/-p. As discussed in Section II of this document, dimethenamid/-p poses potential human health and ecological risks of concern from its labeled uses. EPA identified potential risks of concern for some occupational handlers and for some wildlife taxa, and specific risk mitigation measures are needed to address those risks. In addition to these mitigation measures, dimethenamid/-p labels need to be updated to current standards for certain PPE and advisory statements, and to specify that lentils be included as a use site separate from dry beans. 

Respirators--Applications to Hops and Nursery Sites 

To mitigate potential inhalation risks to occupational handlers applying dimethenamid/-p in the field, the Agency is requiring the use of PF-10 respirators (in addition to current PPE requirements on the label) for mixer/loader/applicators of liquid formulations using mechanically pressurized handguns for drench, and soil- and ground directed applications for hops and nurseries. 

The risks from use of dimethenamid/-p on hops are no longer of concern with the addition of the PF-10 respirator. For the nursery scenarios, additional measures are needed, and are described below. 

EPA has required fit testing, training, and medical evaluations for all handlers who are required to wear respirators and whose work falls within the scope of the Worker Protection Statement (WPS). If a dimethenamid/-p handler currently does not have a respirator, an additional cost will be incurred by the handler or the handler's employer, which includes the cost of the respirator plus, for WPS-covered products, the cost for a respirator fit test, training, and medical exam. 

Respirator costs are extremely variable depending upon the protection level desired, disposability, comfort, and the kinds of vapors and particulates being filtered. Based on available information that EPA has, the cost of the respirators (whether disposable or reusable) is relatively minor in comparison to the fit-test requirement under the Worker Protection Standard. The Agency expects that the average cost of a particulate filtering facepiece respirator is lower than the average cost of an elastomeric half mask respirator. The cost of a respirator fit test, training and medical exam was estimated to about $180 annually. However, if a dimethenamid/-p handler typically uses other chemicals requiring a respirator in the production system or as part of the business, additional fit testing is not needed. The handler or employer may only incur the cost of purchasing filters for the respirator on a more frequent basis. Respirator fit tests are currently required by the Occupational Safety and Health Administration (OSHA) for other occupational settings to ensure proper protection. 

EPA acknowledges that requiring a respirator and the associated fit testing, training, and medical evaluation places a burden on handlers or employers. However, the proper fit and use of respirators is essential to accomplish the protections respirators are intended to provide. In estimating the inhalation risks, and the risk reduction associated with different respirators, EPA's human health risk assessments assume National Institute for Occupational Safety and Health (NIOSH) protection factors (i.e., respirators are used according to OSHA's standards). If the respirator does not fit properly, use of dimethenamid/-p may cause unreasonable adverse effects on the pesticide handler.

The Agency has weighed the potential risks to handlers against the potential impacts of using the respirators and has determined that this mitigation measure is warranted. The technical registrants have agreed to require respirators on the affected product labels.

       2.   Spray Volume--Nursery Applications

As noted above, for mixer/loader/applicators treating nursery sites with liquid formulations, using mechanically-pressurized handguns for drench or soil-/ground directed applications and wearing PF-10 respirators, the MOE is 400, relative to the LOC of 1000, and represents a potential risk of concern. To address these residual risks, the registrant will need to reduce handler exposures further, with labeling requiring an increased minimum spray volume. Currently, labels allow a minimum spray volume of 20 Gallons Per Acre (GPA); labeling will be revised to require a minimum of 30 GPA for this scenario. 

Increasing the minimum spray volume will have no effect on the application rate of dimethenamid/-p; applicators can still apply up to the maximum allowed amount of dimethenamid/-p, albeit in a larger spray volume. However, the spray will be more dilute, so handlers will be exposed to less of the pesticide in a day's work. Increasing the spray volume could necessitate that the spray tank be refilled more often. In addition, dependent on field acreage, applicators may need to dedicate more days per year to spray all acres.

The Agency has weighed the potential risks to handlers against the potential impacts of increasing the minimum spray volume in this scenario and has determined that this mitigation measure is warranted. The technical registrants have agreed to implement the change on the affected product labels.
            
       3.  Prohibition of Application Equipment--Field Crops

To mitigate the associated handler risks, labels of products registered for use on field crops will need to prohibit the use of mechanically pressurized handguns for drench, soil- and ground-directed applications to field crops. Since field crops are rarely treated with pesticides using hand-held equipment, economic impacts to the grower are expected to be minimal. The registrants have agreed to implement the change on the affected product labels. 

       4.  Spray Drift Management 

The Agency has determined that consistent spray drift management labeling is needed to address some of the potential risks of concern to terrestrial vertebrates, invertebrates, and plants, as well as aquatic plants, associated with the use of dimethenamid/-p. The label changes described in this ID are needed to reduce off-target spray drift and establish a baseline level of protection against spray drift that is consistent across all dimethenamid/-p products. Reducing spray drift will reduce the extent of environmental exposure and risk to non-target plants and animals. Although the Agency is not making a complete endangered species finding at this time, these label changes are expected to reduce the extent of exposure and may reduce risk to listed species whose range and/or critical habitat co-occur with the use of dimethenamid/-p. 

Specific spray drift mitigation language needs to be included on all dimethenamid/-p product labels for products applied by liquid spray application. This language includes mandatory, enforceable statements that supersede any existing language already on product labels (either advisory or mandatory) covering the same topics. Dimethenamid/-p registrants also need to standardize all advisory spray drift language on dimethenamid/-p product labels. Existing advisory language left on labels must not contradict or modify the new mandatory spray drift label language. Elements of the mandatory and advisory spray drift language are detailed in Appendix A, and include maximum release heights, wind speed restrictions, prescribed droplet sizes, and application restriction during temperature inversions.

In addition to including the spray drift restrictions on dimethenamid/-p labels, all references to volumetric mean diameter (VMD) information for spray droplets are to be removed from all dimethenamid/-p labels where such information currently appears. The new language above, which cites ASABE S572 for ground boom equipment and ASABE S641 for aerial equipment, eliminates the need for VMD information.

As explained in the PID, the Agency has determined that a maximum release height of 4 feet allows adequate coverage for the majority of nozzles. EPA does not anticipate any negative impacts to growers from the new language. Likewise, the wind speed restrictions allow greater flexibility for users, and the droplet size range should have little to no effect on the efficacy of dimethenamid/-p. Growers who use products with labels that do not address temperature inversions or have advisory language to will be affected by such labeling. It could result in delays to intended applications and, more generally, reduce the amount of time users have to apply dimethenamid/-p. Management of production activities will be more complex. Potentially, growers could switch to a different active ingredient that does not have this restriction, which could be costly and potentially difficult to obtain in a short period of time. However, consistent labeling on temperature inversions generally is being implemented through registration review for the pesticides to which it applies. 

 Label Updates

No adverse economic impacts are anticipated due to adoption of the label changes summarized in the following section (Section IV.B.). 

       1.  Glove Statement

For product labels requiring that chemical-resistant gloves be worn, glove requirements need to be made consistent with Chapter 10 of the Label Review Manual. In particular, references to specific categories in EPA's chemical-resistance category selection chart need to be removed, and product labels need to specify the appropriate types of gloves to use. For example, chemical-resistant glove statements in the label should remove "such as" language and not state the solvent category, but rather add all acceptable glove types that provide high-level chemical resistance for the solvent category, as mentioned in Table 3 of Chapter 10 of the Label Review Manual. This minor clarification does not fundamentally change the PPE that workers are currently required to use.

Ground and Surface Water Advisories; Spilled Granules

Updates to the ground and surface water advisories that are currently on dimethenamid/-p labels also are needed, along with an advisory statement about cleaning up spilled granules. These label changes will address, in part, the potential risks posed by the use of dimethenamid/-p to natural resources, aquatic organisms, birds, and mammals.

Separating Lentils from Dry Beans

Additionally, lentils need to be listed as a separate crop on labels that mention them, as they are not considered by the Agency to fall under the definition of "dry beans." See Appendix A for additional details. 

Non-Target Organism Advisory Statement

Labels need to reflect the addition of a non-target organism advisory to dimethenamid/-p product labels. The protection of pollinating organisms is a priority for the Agency, and dimethenamid/-p has the potential to impact forage and habitat of pollinators and other non-target organisms. The non-target organism advisory language shown in Appendix A addresses these concerns.

Herbicide Resistance Management 

On August 24, 2017, EPA finalized a Pesticide Registration Notice (PRN) on herbicide resistance management. Consistent with the Notice, EPA is proposing the implementation of herbicide resistance measures for existing chemicals during registration review, and for new chemicals and new uses at the time of registration. In registration review, herbicide resistance elements will be included in every herbicide PID. 

The development and spread of herbicide resistant weeds in agriculture is a widespread problem that has the potential to fundamentally change production practices in U.S. agriculture. While herbicide resistant weeds have been known since the 1950s, the number of species and their geographical extent, has been increasing rapidly. Currently there are over 250 weed species worldwide with confirmed herbicide resistance. In the United States, there are over 155 weed species with confirmed resistance to one or more herbicides.

Management of herbicide resistant weeds, both in mitigating established herbicide resistant weeds and in slowing or preventing the development of new herbicide resistant weeds, is a complex problem without a simple solution. Coordinated efforts of growers, agricultural extension, academic researcher, scientific societies, pesticide registrants, and state and federal agencies are required to address this problem.

EPA is requiring measures for the pesticide registrants to provide growers and users with detailed information and recommendations to slow the development and spread of herbicide resistant weeds. This is part of a more holistic, proactive approach recommended by crop consultants, commodity organizations, professional/scientific societies, researchers, and the registrants themselves. 

C. Tolerance Actions

The Agency has determined that the tolerance expressions for dimethenamid/-p, as currently captured in 40 CFR §180.464, are not in accordance with the Agency's Interim Guidance on Tolerance Expressions. For 40 CFR §180.464(a), EPA is anticipating a change to the tolerance expression so that it reads: 

   Tolerances are established for residues of dimethenamid (2-chloro-N-(2,4-dimethyl-
   3-thienyl)-N-(2-methoxy-1-methylethyl)acetamide) or dimethenamid-P (2-chloro-N-(2,4-
   dimethyl-3-thienyl)-N-[(1 S)-2-methoxy-1-methylethyl]acetamide), including its metabolites and degradates, in or on the commodities in the table below. Compliance with the tolerance levels specified below is to be determined by measuring only dimethenamid or dimethenamid-P as the sum of its R- and S-isomers in or on the commodity.

For 40 CFR §180.464(c), the Agency is anticipating a change to the tolerance expression to read: 

   Tolerances with regional registrations. Tolerances are established for residues of dimethenamid (2-chloro-N-(2,4-dimethyl-3-thienyl)-N-(2-methoxy-1-methylethyl)acetamide) or dimethenamid-P (2-chloro-N-(2,4-dimethyl-3-thienyl)-N-[(IS)-2-methoxy-1-methylethyl]acetamide), including its metabolites and degradates, in or on the commodities listed in the table below. Compliance with the tolerance levels specified below is to be determined by measuring only dimethenamid or dimethenamid-P as the sum of its R- and S-isomers in or on the commodity.

No change to the established tolerance definition (parent only) is anticipated.

As outlined in the PID, the Agency anticipates some changes to the tolerances for dimethenamid/-p, as shown in Table 1. These changes relate to commodity definitions, and the addition or removal of tolerances. The Agency intends to undertake tolerance actions pursuant to its Federal Food, Drug Cosmetic Act (FFDCA) authority in a process separate from this registration review.

Table 1. Tolerance Summary for Dimethenamid and Dimethenamid-p. (40 CFR §180.464(a)).
                                  Commodity/
                         Correct Commodity Definition
                          EstablishedTolerance (ppm)
                          Anticipated Tolerance (ppm)
                                   Comments
                              40 CFR §180.464(a)
Beet, sugar, dried pulp
0.01
Remove
Residues are covered by the tolerance established for the raw agricultural commodity, beet, sugar, roots (0.01 ppm).
Beet, sugar, molasses
0.01
Remove

Cassava, bitter, leaves
--
0.01
Tolerances in/on these commodities are required due to registered use on crop subgroup 1C. The tolerance in/on beet, garden, tops or beet, sugar, tops[1] (0.01 ppm) applies.
Cassava, sweet, leaves
--
0.01

Lentil, dry, seed
--
0.01
A tolerance in/on this commodity is required due to registered use on lentils. No data for pea are available. The tolerance in/on bean, dry, seed (0.01 ppm) applies.
Onion, Welsh
0.01
Remove
The established tolerance in/on onion, green (0.01 ppm) also applies to Welsh onion.
Sweet potato, leaves
--
0.01
Tolerances in/on these commodities are required due to registered use on crop subgroup 1C. The tolerance in/on beet, garden, tops or beet, sugar, tops[1] (0.01 ppm) applies.
Tanier, leaves
--
0.01

Taro, leaves
--
0.01

Turnip, greens
0.1
Remove
The only registered use of dimethenamid/dimethenamid-P on turnip (EPA Reg. No. 7969-156) is clearly for the root crop, turnip. 
Yam, true, leaves
--
0.01
A tolerance in/on this commodity is required due to registered use on crop subgroup 1C. The tolerance in/on beet, garden, tops or beet, sugar, tops (0.01 ppm) applies.  

D. Interim Decision Review Decision

In accordance with 40 CFR §§ 155.56 and 155.58, the Agency is issuing this Interim Registration Review Decision. Except for the Endocrine Disruptor Screening Program (EDSP) and the Endangered Species Act (ESA) components of this case, the Agency has determined that, in order for dimethenamid/-p to meet the standard for registration: (1) submission of required Tier II and Tier III honeybee data, and (2) changes to the affected registrations and their labeling are needed at this time, as described in Section III.A and Appendix A.

In this Interim Registration Decision, the Agency is making no human health or environmental safety findings associated with the EDSP screening of dimethenamid/-p, nor is it making a complete endangered species finding. Although the Agency is not making a complete endangered species finding at this time, the mitigation described in this document is expected to reduce the extent of environmental exposure and may reduce risk to listed species whose range and/or designated critical habitat co-occur with the use of dimethenamid/-p. The Agency's final registration review decision for dimethenamid/-p will be dependent upon the result of the Agency's ESA assessment and any needed § 7 consultation with the Services and an EDSP FFDCA § 408(p) determination.

E. Data Requirements

A Generic Data Call-In (GDCI) was issued for each active ingredient, dimethenamid and dimethenamid-p, for data needed to conduct the registration review risk assessments. All data requirements from the registration review DCIs have been satisfied with the exception of the Tier II and III honeybee data for dimethenamid. EPA has determined that these data are needed, based on potential risk concerns identified in the Agency's review of the Tier I honeybee studies. The outstanding higher Tier pollinator studies are:

 Non‐guideline (Tier II): Semi‐field testing for pollinators (tunnel or colony feeding studies)
 Non‐guideline (Tier II): Field trial of residues in pollen and nectar
 OCSPP 850.3040 (Tier III): Field testing for pollinators

The Agency does not anticipate calling-in any new, additional data for registration review of dimethenamid/-p at this time.

F. Environmental Justice

EPA seeks to achieve environmental justice, the fair treatment and meaningful involvement of all people, regardless of race, color, national origin, or income, in the development, implementation, and enforcement of environmental laws, regulations, and policies. To help address potential environmental justice issues related to registration review decisions, the Agency sought information when the docket for dimethenamid registration review was first open on any groups or segments of the population who, as a result of their location, cultural practices, or other factors, may have atypical, unusually high exposure to dimethenamid/-p compared to the general population or who may otherwise be disproportionately affected by the use of dimethenamid/-p as a pesticide. The Agency solicited information on environmental justice when the dimethenamid/-p docket first opened but did not receive any information during the public comment period pertaining to environmental justice concerns. Therefore, this ID has not assumed that there are environmental justice concerns for dimethenamid/-p.  

 IV. NEXT STEPS AND TIMELINE 

A.  Interim Registration Review Decision

A Federal Register Notice will announce the availability of this Interim Registration Decision for dimethenamid/-p. A final decision on the dimethenamid/-p registration review case will occur after: (1) an EDSP FFDCA § 408(p) determination, and (2) an endangered species determination under the ESA and any needed § 7 consultation with the Services.

B.  Implementation of Mitigation Measures 

Once the Interim Registration Review Decision is issued, the dimethenamid/-p registrants must submit amended labels that include the label changes described in Appendix A. The revised labels and requests for amendment of registrations must be submitted to the Agency for review within 60 days following issuance of the Interim Registration Review Decision in the docket. 

Registrants must submit a cover letter, a completed Application for Registration (EPA form 8570-1) and electronic copies of the amended product labels. Two copies for each label must be submitted, a clean copy and an annotated copy with changes. In order for the application to be processed, registrants must include the following statement on the Application for Registration (EPA form 8570-1):

"I certify that this amendment satisfies the requirements of the dimethenamid/-p Interim Registration Review Decision and EPA regulations at 40 CFR Section 152.44, and no other changes have been made to the labeling of this product. I understand that it is a violation of 18 U.S.C. Section 1001 to willfully make any false statement to EPA. I further understand that if this amendment is found not to satisfy the requirements of the dimethenamid/-p Interim Registration Review Decision and 40 CFR Section 152.44, this product may be in violation of FIFRA and may be subject to regulatory and/or enforcement action and penalties under FIFRA."

Within the required timeframe, registrants must submit the required documents to the Re-evaluation section of the EPA's Pesticide Submission Portal (PSP), which can be accessed through the EPA's Central Data Exchange (CDX) using the following link: https://cdx.epa.gov/. Registrants may instead send paper copies of their amended product labels, with an application for a fast-track, Agency-initiated non-PRIA label amendment to Lauren Weissenborn at one of the following addresses, so long as the labels and application are submitted within the required timeframe: 

      VIA US Mail
USEPA Office of Pesticide Programs 
Pesticide Re-evaluation Division 
Mail Code 7508P
1200 Pennsylvania Ave NW 
Washington, DC 20460-0001
      VIA Courier 
Pesticide Re-evaluation Division 
c/o Front End Processing
Room S-4910, One Potomac Yard 
2777 South Crystal Drive 
Arlington, VA 22202-4501

Appendix A: Labeling Changes Needed for Dimethenamid/-p Products

                                  Description
                  Label Language for Dimethenamid/-p Products
                              Placement on Label
                               End-Use Products
--------------------------------------------------------------------------------
Mechanism of Action 
Note to registrant:
 --------------------------------------------------------------------------------
   Include the name of the ACTIVE INGREDIENT in the first column (choose one)
 --------------------------------------------------------------------------------
   Include the word "GROUP" in the second column
 --------------------------------------------------------------------------------
   Include the MECHANISM OF ACTION CODE in the third column (for Herbicides this is the Site of Action)
 --------------------------------------------------------------------------------
   Include the type of pesticide (i.e., HERBICIDE) in the fourth column. 
                                       
--------------------------------------------------------------------------------
DIMETHENAMID 
--------------------------------------------------------------------------------
or
--------------------------------------------------------------------------------
DIMETHENAMID-P
--------------------------------------------------------------------------------
GROUP
--------------------------------------------------------------------------------
15
--------------------------------------------------------------------------------
HERBICIDE
                                       
Front Panel, upper right quadrant.
All text should be black, bold face and all caps on a white background, except the mode of action code, which should be white, bold face and all caps on a black background; all text and columns should be surrounded by a black rectangle.
        Updated Gloves Statement -- if gloves are required by the label
                                       
Note to registrant:

Update the gloves statements to be consistent with Chapter 10 of the Label Review Manual. In particular, remove reference to specific categories in EPA's chemical-resistance category selection chart and list the appropriate chemical-resistant glove types to use. 

In the Personal Protective Equipment (PPE) within the Precautionary Statements and Agricultural Use Requirements, if applicable
Respiratory Protection for labels allowing use in Nurseries and on Hops, which do not prohibit application with a mechanically pressurized handgun
                                       
Note: Registrants should adjust the PPE statement depending on the uses allowed in the end-use product label.
"Mixers, Loaders, and Applicators using mechanically-pressurized handguns when applying to nursery sites (ornamentals, vegetables, trees, container stock) and/or hops also must"

[Note to registrant: If your end-use product only requires protection from particulates only (low volatility), use the following language]

"Wear a minimum of:
 a NIOSH-approved elastomeric half mask respirator with organic vapor (OV) cartridges and combination N1, R, or P filters; OR
 a NIOSH-approved gas mask with OV canisters; OR
 a NIOSH-approved powered air purifying respirator with OV cartridges and combination HE filters."

*Drop the "N" option if there is oil in the product's formulation and/or the product is labeled for mixing with oil-containing products.

[Note to registrant: For respiratory protection from organic vapor and particulates (or aerosols), use the following language:]

"Wear a minimum of a NIOSH-approved elastomeric half mask respirator with organic vapor (OV) cartridges and combination N*, R, or P filters; OR a NIOSH-approved gas mask with OV canisters; OR a NIOSH-approved powered air purifying respirator with OV cartridges and combination HE filters."
In the Personal Protective Equipment (PPE) within the Precautionary Statements
                         Requirements for Non-WPS Uses
Respirator fit testing, medical qualification, and training 
Using a program that conforms to OSHA's requirements (see 29 CFR Part 1910.134), employers must verify that any handler who uses a respirator is:
 Fit-tested and fit-checked,
 Trained, and 
 Examined by a qualified medical practitioner to ensure physical ability to safely wear the style of respirator to be worn. A qualified medical practitioner is a physician or other licensed health care professional who will evaluate the ability of a worker to wear a respirator. The initial evaluation consists of a questionnaire that asks about medical conditions (such as a heart condition) that would be problematic for respirator use. If concerns are identified, then additional evaluations, such as a physical exam, might be necessary. The initial evaluation must be done before respirator use begins. Handlers must be reexamined by a qualified medical practitioner if their health status or respirator style or use-conditions change. 
Upon request by local/state/federal/tribal enforcement personnel, employers must provide documentation demonstrating how they have complied with these requirements."
Precautionary Statements under the heading "Hazards to Humans and Domestic Animals"
                         Non-target Organism Advisory
"NON-TARGET ORGANISM ADVISORY: This product is toxic to plants and may adversely impact the forage and habitat of non-target organisms, including pollinators, in areas adjacent to the treated site. Protect the forage and habitat of non-target organisms by following label directions intended to minimize spray drift."
Environmental Hazards section of the label, under the general heading "Precautionary Statements" 
                            Surface Water Advisory
"Do not apply directly to water, or to areas where surface water is present or to intertidal areas below the mean high water mark. Do not contaminate water when disposing of equipment washwater or rinsate. Drift and runoff may be hazardous to aquatic organisms in water adjacent to treated areas. This product may impact surface water quality due to runoff of rainwater. This is especially true for poorly draining soils and soils with shallow ground water."

Environmental Hazards section of the label, under the general heading "Precautionary Statements"
                            Ground Water Advisory 
                   (specify Dimethenamid or Dimethenamid-p)
"[Dimethenamid or Dimethenamid-p] is known to leach through soil into groundwater under certain conditions as a result of label use. This chemical may leach into groundwater if used in areas where soils are permeable, particularly where the water table is shallow."
Environmental Hazards section of the label, under the general heading "Precautionary Statements"
                           For granular formulations
"Granules exposed on soil surface may be hazardous to wildlife. Cover or collect granules spilled during loading".
Environmental Hazards
                        Herbicide Resistance Management
                                       
                                       
                                       
Include resistance management label language for herbicides from PRN 2017-1 and PRN 2017-2 (https://www.epa.gov/pesticide-registration/pesticide-registration-notices-year)
   

Directions for Use, prior to directions for specific crops under the heading "WEED RESISTANCE- MANAGEMENT"
                  Labels allowing use on lentils or dry beans
The labels of all products registered for use on lentils should be revised to list lentils as a separate use site from dry beans.
                              Directions for Use
                  Labels of liquid products allowing use on 
nursery sites (ornamentals, vegetables, trees, container stock) that do not prohibit use with a mechanically pressurized handgun)
Applications to nursery sites (ornamentals, vegetables, trees, container stock) must be made using at least 30 gallons per acre when applications are made using mechanically- pressurized handguns. 

             Directions for Use in the directions for nursery uses
Spray Drift Management Application Restrictions for all products delivered via liquid spray application and allow aerial application
"MANDATORY SPRAY DRIFT MANAGEMENT
Aerial Applications: 
 --------------------------------------------------------------------------------
   Do not release spray at a height greater than 10 ft above the ground or vegetative canopy, unless a greater application height is necessary for pilot safety.
    Applicators are required to select a nozzle and pressure that deliver a medium or coarser droplet size (ASABE S641). 
    If the windspeed is 10 miles per hour or less, applicators must use (1/2) swath displacement upwind at the downwind edge of the field. When the windspeed is between 11-15 miles per hour, applicators must use (3/4) swath displacement 
    Do not apply when wind speeds exceed 15 mph at the application site. If the windspeed is greater than 10 mph, the boom length must be 65% or less of the wingspan for fixed wing aircraft and 75% or less of the rotor diameter for helicopters. Otherwise, the boom length must be 75% or less of the wingspan for fixed-wing aircraft and 90% or less of the rotor diameter for helicopters."
Directions for Use, in a box titled "Mandatory Spray Drift Management" under the heading "Aerial Applications" 
Placement for these statements should be in general directions for use, before and use-specific directions for use
Spray Drift Management for products that are applied as liquids and allow ground boom applications
"MANDATORY SPRAY DRIFT MANAGEMENT
Ground Boom Applications: 
 --------------------------------------------------------------------------------
   User must only apply with the release height recommended by the manufacturer, but no more than 4 feet above the ground or crop canopy.
    Applicators are required to select a nozzle and pressure that deliver a medium or coarser droplet size (ASABE S572).
    Do not apply when wind speeds exceed 15 mph at the application site. Do not apply during temperature inversions."
Directions for Use, in a box titled "Mandatory Spray Drift Management" under the heading "Ground Boom Applications"
Advisory Spray Drift Management Language for all products delivered via liquid spray application
"SPRAY DRIFT ADVISORIES
THE APPLICATOR IS RESPONSIBLE FOR AVOIDING OFF-SITE SPRAY DRIFT.
BE AWARE OF NEARBY NON-TARGET SITES AND ENVIRONMENTAL CONDITIONS.

IMPORTANCE OF DROPLET SIZE
An effective way to reduce spray drift is to apply large droplets. Use the largest droplets that provide target pest control. While applying larger droplets will reduce spray drift, the potential for drift will be greater if applications are made improperly or under unfavorable environmental conditions.

Controlling Droplet Size  -  Ground Boom (note to registrants: remove if ground boom is prohibited on product labels)
:: Volume - Increasing the spray volume so that larger droplets are produced will reduce spray drift. Use the highest practical spray volume for the application. If a greater spray volume is needed, consider using a nozzle with a higher flow rate.
:: Pressure - Use the lowest spray pressure recommended for the nozzle to produce the target spray volume and droplet size.
:: Spray Nozzle - Use a spray nozzle that is designed for the intended application. Consider using nozzles designed to reduce drift.

Controlling Droplet Size  -  Aircraft (note to registrants: remove if aerial application is prohibited on product labels)
:: Adjust Nozzles - Follow nozzle manufacturers' recommendations for setting up nozzles. Generally, to reduce fine droplets, nozzles should be oriented parallel with the airflow in flight.

BOOM HEIGHT  -  Ground Boom (note to registrants: remove if ground boom is prohibited on product labels)
For ground equipment, the boom should remain level with the crop and have minimal bounce.

RELEASE HEIGHT - Aircraft (note to registrants: remove if aerial application is prohibited on product labels)
Higher release heights increase the potential for spray drift. 

SHIELDED SPRAYERS
Shielding the boom or individual nozzles can reduce spray drift. Consider using shielded sprayers. Verify that the shields are not interfering with the uniform deposition of the spray on the target area.

TEMPERATURE AND HUMIDITY
When making applications in hot and dry conditions, use larger droplets to reduce effects of evaporation.

TEMPERATURE INVERSIONS
Drift potential is high during a temperature inversion. Temperature inversions are characterized by increasing temperature with altitude and are common on nights with limited cloud cover and light to no wind. The presence of an inversion can be indicated by ground fog or by the movement of smoke from a ground source or an aircraft smoke generator. Smoke that layers and moves laterally in a concentrated cloud (under low wind conditions) indicates an inversion, while smoke that moves upward and rapidly dissipates indicates good vertical air mixing. Avoid applications during temperature inversions. 

WIND
Drift potential generally increases with wind speed. AVOID APPLICATIONS DURING GUSTY WIND CONDITIONS.
Applicators need to be familiar with local wind patterns and terrain that could affect spray drift."
Directions for Use, just below the Spray Drift box, under the heading "Spray Drift Advisories"
Advisory Spray Drift Management Language for all products that allow liquid applications with handheld technologies
"SPRAY DRIFT ADVISORIES
Handheld Technology Applications: 
 --------------------------------------------------------------------------------
   Take precautions to minimize spray drift."

   
Directions for Use, just below the Spray Drift box, under the heading "Spray Drift Advisories"