### SMM Amended RED - Comments Regarding Buffers
Jack Cain to: Russell Wasem 01/27/2010 06:18 PM
Cc: Jim Tompkins, Thomas Moriarty

History: This message has been replied to.

Dear Rusty,

Thank you for taking the time to speak with me this past Thursday regarding the Amended Sulfometuron Methyl (SMM) RED, and your invitation to submit in writing the concerns we discussed specific to the subject of buffers.

I would first like to commend you and the many others within EPA for acting in response the large number of Public Comments received following the initial publication of the SMM RED. The Amended RED clearly reflects your considerations and DuPont is especially pleased with the revised Environmental Hazards labeling requirements. The new statements address our shared stewardship concern for off-site movement, and will only serve to further emphasize existing label precautions.

We would like to address two concerns related to the buffer text as currently required in the Amended RED. The first pertains to use site applicability, and the second is in regard to intent. Following is our rationale as to why the buffers set forth in the Amended RED should not be applicable to right of way, railroad, or industrial site applications, and not established opposite crops.

SMM containing products are applied to a variety of agricultural (crop) and non-agricultural sites. Forested areas including conifer and hardwood crop plantations, and rangeland (crop) restoration sites are generally characterized as large plot areas similar to many agricultural row crop sites. However, over 50% of SMM containing product applications are actually made to non-agricultural sites described as roadway, utility, pipeline and railroad Right-Of-Ways (ROW), and industrial sites. The Environmental Fate and Effects Risk Assessment that issued on November 28, 2007 specifically noted in the section entitled Identification of Uncertainties and Their Impact on the Risk Assessment that “There are a variety of Vegetation Management uses on sites that are less clearly defined than agricultural crops and have disjoint or unusual treatment area configurations. (e.g.: as with rights of way and railroad uses, or industrial site grounds).” In this same Assessment, spot spraying was categorized as a method of application in forestry sites, but not on ROW sites. In the context of buffers we believe this was a significant oversight.

The current requirements for aerial application buffers of 75 feet, broadcast ground application buffers of 50 feet, and spot spray ground application buffers of 30 feet were all predicated directly or indirectly on results obtained using the AgdriftTM model. Input parameters of use rate and droplet size were varied, but in all instances an agricultural application site scenario was modeled. For aerial applications the model employed an application swath width of 60 feet, and 20 (adjacent) flight lines (a total treatment area width of 1200 feet). Ground modeling was comprised of a swath width of 45 feet and 20 applied swaths (a total treatment area width of 800 feet). Also, in a footnote to the ground model it was noted that “For ground application scenarios the AgdriftTM tier Imodel is restricted to using Fine to Medium coarse ( d roplet sizes), and can not model Very coarse, which is required.”

A Railroad ROW seldom exceeds a total width of 100 feet, or 50 feet from
center line to either side of the rail bed. These sites are treated with single swath applications which typically extend 10 to 20 feet each side of center line. The untreated balance of the ROW may serve as a buffer but it is not uncommon for growers to plant agricultural crops on the untreated portions of these easements based on prior experiences including minimal injury due to herbicide ROW application. The sides of primary roadways are also treated with single swath applications that seldom extending more than 25 feet beyond the side of the road. Secondary road treatment areas are considerably smaller. In ROW application scenarios where the use of a boom may be obstructed by a sign post, guardrail, etc., or there is a recognized risk to adjacent areas, applications are augmented by hand held spot spraying. These spot treatments are made around the base of the obstruction and extended only a few feet in width. A typical guardrail application only extends 1 to 2 feet each side of the rail. These spot spray applications to ROW sites are completely dissimilar to agricultural applications where a treatment may encompass up to 20% of each treated

acre.

The disparity of using the AgdriftTM model for large plot vs. ROW applications needs to be recognized when establishing buffers on labels. Otherwise, a much needed use of SMM will be substantially curtailed or eliminated. DuPont is supportive of buffers when applications are made to large plot sites consistent with the model, but respectfully submits that ROW and Industrial site applications do not even begin to approximate the modeled scenarios. The risk to adjacent non-target species from ROW and Industrial site applications is significantly less, and the buffers that have been established based on agricultural use scenarios should not be applied to these sites.

The EFED Risk Assessment for SMM identifies the "Basis for Direct Effect Concerns" to terrestrial and semi-aquatic plants as the: “Endangered species LOC is exceeded for terrestrial plants”, and the "Basis for Indirect Effect Concerns" is: “Potential concerns from shifts in plant community structure and function due to/from selective impacts on plant species.” The Assessment also notes that “plants are the primary producers upon which the succeeding trophic levels depend.” The LOC’s that were presented in the Risk Assessment were derived from study data on five aquatic vascular and non-vascular species, and ten terrestrial monocots and dicots. DuPont agrees with EFED that the sensitivities of these various surrogate species are a Basis for Concern that legitimizes the requirement for buffers opposite aquatic plants, their habitats, and any threatened or endangered species. But there is no environmental concern to warrant the establishment of buffers opposite all crops.

In my previous correspondence of January 8, 2010 I called your attention to a number of errors and ambiguities including the matter of requiring "Very coarse or coarser" vs. Extremely coarse nozzles for all applications. I had anticipated these matters might be addressed prior to the issuance of an SMM Data Call-In (DCI). However, as I am now it receipt of the SMM DCI, I would encourage the Agency to resolve these items before a registrant seeks a label amendment action in accordance with them. I would also hope that the issues raised herein regarding buffers may be similarly resolved.

Sincerely,Jack Cain DuPont Crop Protection
Stine-Haskell Research Center

1090 Elkton Rd. Newark, DE 19711 jack.cain@usa.dupont.com
Office: 302 366-6417

Cell: 610 316-5006

Fax: 302 351-6841

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