2 residential pet exposure and the second section addresses the request for an alternatives

assessment.

I. 2,4-D and Residential Pets

During the public comment period on NRDC’s petition, Beyond Pesticides raised an

issue unrelated to those raised in the NRDC petition. Specifically, Beyond Pesticides is concerned about the use of 2,4-D fo r lawn care and the possible associ ation of cancer in pets due to this exposure. In support of its claim that there is a rela tionship between 2,4-D treated lawns and canine cancer, Beyond Pesticides cited seve ral studies (Glickman et al. 2004, Hayes et al. 1991, Hayes et al. 1995, Re ynolds et al. 1994).

EPA evaluated the studies cited by Beyond Pest icides and the studies do not change the Agency’s current conclusions. The two studi es conducted by Hayes et al. in 1991 and 1995 focused on an epidemiological ev aluation (i.e., case control study) of the relationship between 2,4-D use on lawns and the incidence of mali gnant lymphoma in companion dogs. This evaluation used a hospital-based recall questionnaire approach. There were several criticisms of this paper which were addressed in 1995 by Hayes et al., including issues associated with the exposure assessment process and the uncertain ties associated with low odds ratios. 6 The authors acknowledged major weaknesses with the studies were a lack of environmental or personal sampling and possible recall bias. Further, significant uncertainty exists due to the lack of exposure data. In addition, the 2005 RED required that, in order for a product to be eligible for reregistration, label language n eeded to be added restricting pe t access to treatment areas during and immediately after applicati on. All labels now have this language, which changes the use patterns that existed during the time of the Ha yes studies in the early 1990s because now pets

should not be in the treatment ar ea during or immediately after app lication. Further, the authors

concurred with several commenters that the st udies do not prove that 2,4-D exposure in a home environment is a cause of malignant lympho ma in companion dogs. Therefore, Hayes et al does not impact the Agency’s previous assessment.

Reynolds et al. 1994 attempted to supplement Ha yes et al. by attemp ting to refine the ability to predict exposures from lawn herbicides like 2,4-D by collecting exposure characteristics using an interv iew/questionnaire approach an d by monitoring of 2,4-D in pet urine. They concluded that ga thering data via owner questionna ires could be a good surrogate predictor of exposure. Among 44 dogs potentially exposed to 2,4- D-treated lawns an average of 10.9 days after application, 2,4-D c oncentrations greater than or equal to 10.0 μg/l were found in 33 dogs (75%) and concentrations of ≥ 50 μg/l were found in 17 (39%). Among 15 dogs with no known exposure to a 2,4-D-treated lawn in the previous 42 days, 4 (27%) had evidence of 2,4-D in urine, one at a concentration of ≥ 50 μg/l . The odds ratio for the association between exposure to a 2,4-D-treated lawn and the detection of ≥ 50 μg/l 2,4-D in urine was 8.8 (95% confidence interval, 1 .4-56.2). Dogs exposed to lawns treated within 7 days before urine collection were more than 50 times as likely to have 2,4-D at concentrations ≥ 50 μg/l than dogs with exposure to a lawn treated more than one week previously (odds ratio = 56.0; 95% confidence interval, 10.0- 312.2). The highest mean concentration of 2,4-D in urine (21 3 mg/l) was found in dogs sampled

6 U.S. EPA, 2,4-D: Evaluation of Data Identified In NRDC Petition and Associated Documents (March 27, 2012) at 65-66 (hereinafter HED).3 within two days after application of the herbicid e. The authors indicate d that these findings demonstrate that dogs living in a nd around residences with recent 2,4-D lawn treatment, absorb

measurable amounts of the herbicide for several da ys after application and, thus, may constitute a useful animal model for evaluating the effects of herbicides on the inducti on of lymphoid cancer. EPA believes the use of interviews/questionnaires may have some utility as a surrogate means of predicting exposures in epidemiologi cal research. However, with re gard to the specific issue of establishing a model specific to 2,4-D exposure and cancer induction the results are incomplete and have considerable uncertainty, which is consis tent with the findings of the investigators who

concluded that additional research on this matter is needed. 7

In summary, the studies cited by Beyond Pe sticides, in its comments to support its assertion that 2,4-D has been shown to indu ce lymphoma in pets, did not address key uncertainties (lack of sampling, timing of the stud ies, and recall bias) in the study results. In particular, Beyond Pesticides failed to note the re latively weak association between exposure and lymphoma onset described by Hayes et al. Furt her, because these studies were conducted prior to the risk mitigation measure identified in the RED, and now reflected on all 2,4-D product labels (i.e., limiting pet access during and immedi ately following application), the resulting new use patterns should result in re duced exposure. As such, while the Agency concurs that perhaps additional research is warranted, it does not believe that there is evidence of critical animal

health issues which warrant cha nges to its current conclusions.

C. Alternatives Assessment for 2,4-D

Beyond Pesticides and New York State’s Depart ment of Environmental Conservation and Department of Health submitted comments stating that a comprehensive evaluation of alternatives to 2,4-D is needed. They assert that the evaluation should include a comparison of environmental fate characteristics, applic ation rates and methods, efficacy, and risks (incorporating both toxicologica l properties and estimated expos ures) to public health and nontarget organisms. These commenters felt that there are viable organic lawn management practices that eliminate the need for 2,4-D, as we ll as non-chemical alterna tives to be considered.

Generally, the Agency does not assess alternatives where it has not identified any risks of concern. Where a pesticide has no risks of concern, it is unnecessary to consid er the risk profiles of alternative pesticides in determining wh ether the pesticide being assessed will cause

unreasonable adverse effects on the environment. Further, EPA may not deny registration to a pesticide because it is non-essen tial. See 7 U.S.C. § 136a(c)(5).

EPA evaluated the studies cited in the Petit ion and public comments and concluded that the studies do not alter the Agency’s current c onclusion that 2,4-D does not present a risk of concern. Many of the studies and th eir deficiencies are specifically addressed in this response or in EPA’s separate Order addressi ng tolerances. EPA’s complete an alysis of all the studies cited in the Petition and public comments can be found in the EPA’s 2,4-D: Evaluation of Data Identified In NR DC Petition and Associated Documents located in docket number EPA-HQOPP-200-0877. Because the studies cited by the Pe tition and in public comments do not alter the

7 Id.4 Agency’s conclusions that 2,4-D does not present a risk of con cern, the Agency does not believe it is appropriate or necessary to conduct an alternatives assess ment at this time.