Page 2 of 6 June 1, 2010, regarding the insecticide amitraz. Specifically, the correspondence from PCRM questions some of the requirements for animal testing for amitraz (Registration Review docket for Amitraz; Docket ID EPA-HQ-OPP-2009-1015), as listed below.

The Agency appreciates the comments of PCRM and has reviewed the suggestions with careful consideration (PCRM comments listed below followed by the Agency’s response).

Comment 1: The Summary Document indicates that the Agency may request a series of animal tests. However, we believe data may already exis t either with the technical registrants or other sources that could fulfill some of the Ag ency’s information needs. We provide some references and encourage the Agency to further explore other areas so as to minimize costs as well as duplicative testing that will cause suffering and death to

hundreds of animals.

• (GLN 870.3100) Sub-chronic (90-day) Oral Toxicity Study in Rats

Response 1: Agency: Thank you for your comment. The Agency is committed to reduce, refine and ultimately replace animals for toxicity testin g where practicable. Toward that goal, the Agency is asking that the toxicity parame ters that would normally be included in a separate sub-chronic oral study be included and covered by an extended one-generation toxicity study protocol. This will save animals and still provide the necessary insight sought from both study types. The Agency has looked at your references and others for areas where additional efficiencies might be rendered; however for the toxicity effects of concern, the Agency believes that the animal tests currently requested are necessary to meet our obligations to ensu re the safety of pesticides under FIFRA, FFDCA and FQPA.

Comment 2:

We recommend that the technica l registrants find the inform ation from the previous study including the necessary individual animal data, in lieu of conducting another study especially since the purpose of this study w ill be to remove the uncertain ty factor that is providing additional protection. Considering that humans are th e most sensitive species tested (according to the Human Health scoping documen t) this should only provide more of a reason to retain uncertainty factor.

We also encourage the company to co mbine this study with the sub-chronic neurotoxicity study (GLN 870.6200) as the Agency recommends.

In advance of performing these dermal repe ated-dose studies, we urge the Agency and the registrants to consider whether extrapolat ing from oral toxicity value is possible, given the current knowledge of the chemical ’s dermal absorption factor and local effects. The Agency should consider requesting in vitro dermal penetratio n testing (see OECD Test Guideline 428 for example) to conf irm this estimate of the extent of dermalPage 3 of 6 penetration likely for Amitraz, instead of in vivo dermal penetration. Results can also be confirmed using bridging data fr om other appropriate organotins.

Finally, we are wondering why the requirements for additional dermal data exist if according to the Summary Document, “Based on the 2.4 g ai pet collar use, all residential exposure scenarios, including toddler dermal and in cidental oral (hand-to-mouth) exposures (MOE of 97), were not of concern to the Agency.” Conducting the dermal toxicity studies listed would have se rious repercussions for the welfare of animals, and flie s in the face of OPP’s move toward more thoughtful data requirements.

• (GLN 870.3200) 21/28-Day Dermal Toxicity

• (GLN 870.3250) Sub-chronic (9 0-day) Dermal Toxicity

Response 2: Agency: As noted in our response to the first comment the Agency is committed to exploring ways to reduce, refine and ultimate ly replace the use of animals for toxicity testing. The Agency has launched efforts to do this by our strategic direction for new pesticide testing and assessment approaches ( www.epa.gov/pesticides/science/testingassessment.html ). And while the Agency is moving in that direction, at th e current time the Agency must follow 40 CFR part 158 that req uires these animal studi es to fully evaluate the hazards of chemicals to humans, esp ecially the young, depending on the human exposure scenarios. Currently, Agency policy is not to accept in vitro dermal absorption data without in vivo supporting data, based on the NAFTA Dermal Absorption Group Position Paper. Studies tailored to human ex posure scenarios are necessary because routeto-route extrapolation from oral exposure ma y not provide data which are protective to humans. In some instances, toxicity from derm al absorption of a chemical is more toxic than from oral absorption, due to liver de toxification of oral chemical exposure; a detoxification system which is bypassed via dermal exposure. Regarding an attempt to build on previous studies, the studies must be for related compounds. Amitraz is not related to organotins and therefore, such studi es cannot be bridged. The Agency would also note that several amitraz products are ma rketed to be applied dermally to animals, thus the animal testing can also serve to pr otect many more animals (livestock and pets)

than those animals utilized in the safety assessments.

Comment 3: Using the following link, under the “Animal T oxicity Studies” tab we found that Hayes,

W.J. et al i summarized many studies for Amitraz including a 21-day dermal study in rabbits, short-term inhalation in rats, 90-da y repeat dose in dogs, and 90-day repeat dose in rats. We implore the Agency to further invest these references. http://toxnet.nlm.nih.gov/cgi-bin/sis/s earch/r?dbs+hsdb:@term+@na+AMITRAZ

• (GLN 870.3465) Sub-chronic (90-da y/28-day) Inhalation Toxicity

Response 3:Page 4 of 6 Agency: Thank you for your suggestion. The Agen cy looked at thes e studies and found

them useful but not sufficient for our need to evaluate all important human exposure

scenarios. The studies described by Hayes were not sufficient to cover the human exposure

scenarios relevant to amitraz use. For exam ple current amitraz exposure scenarios require

sub-chronic inhalation studies due to the use of spray wands for product application to animals, which can generate mists capabl e of being inhaled for intermediate-term durations of exposure. Studies by the rel evant route of exposure and for the relevant exposure duration are important, e.g., inhalati on exposure bypasses liver detoxification processes and is potentially mo re toxic than oral exposures. Furthermore, new studies to be conducted after the 1991 Hayes et al book reflect the most current advances in scientific testing methods, thus potentially providi ng more protective endpoints to humans.

Comment 4: Hayes et al ii summarizes a pre-natal developmental toxicity in rats and rabbits. Study authors found that “rats who received 12 mg/d ay of Amitraz from day one of pregnancy until the young were weaned at 21 days ol d had a reduced number of young born and alive at day four.” They concluded that, “a lthough there have been reproductive effects observed in laboratory animals at some dose levels, likely human exposures are very much less than those which produced effects. These effects are unlikely in humans under normal circumstances.” A more in-depth summary can be found here: http://pmep.cce.cornell.edu/profile s/extoxnet/24d-captan/amitraz-ext.html

.

Additionally, the following three studies could be used to fulfill the data requirements. The effects of prenatal Amitraz exposure on the physical and behavioral parameters of

rats were studied. iii Then a follow up study was conducte d to determine the effects of postnatal Amitraz exposure on physical and be havioral parameters in rats, whose lactating dams received the pesticide (10 mg/kg) orally. iv The final study investigated the potential adverse effects of Amitraz on the in itiation and maintenance of pregnancy in Sprague-Dawley rats as well as its effects on embryo-fetal development after maternal exposure during the entire pregnancy period. v

• (GLN 870.6200a) Neurotoxicity Battery (acute studies)

• (GLN 870.6200b) Neurotoxicity Ba ttery (sub-chronic studies)

• GLN 870.3700) Pre-Natal Develo pmental Toxicities – Rabbit

Response 4: Agency: Again, thank you for your thoughtful suggestions. They are consistent with the practice of the Agency to take exposure scenar ios into account in our risk assessments and in designing toxicity studies to inform ou r risk assessments. Because amitraz exhibits clinical signs of neurotoxicity and sedation, the Agency concludes that the current studies are insufficient and that, for instance, additi onal detailed neurotoxi city information beyond the behavioral study is necessary to fully ev aluate the hazards of amitraz to humans and ensure safety. These neurotoxicity studies w ill be included in the comprehensive extended one-generation protocol which make s more efficient use of animals.Page 5 of 6 Comment 5: As previously stated we encourage the registrants to combine the (870.3100) 90-Day Oral Toxicity study in rats and the sub-ch ronic neurotoxicity st udy listed, if conducted.

A GHS classification document classifies Amitraz into a category 2 CNS toxicant. vi
“Specific target organs/systemic toxicity following single exposure” and “specific target organs/systemic toxicity following repeated exposure” based on data in animals and humans. The agency should examine these studies to ensure that they will not meet the agencies requirements for this endpoint.

Additionally, a series of studi es investigating the possible neurotoxicity of Amitraz was conducted on Long-Evans rats following acute and short-term repeated exposures to the pesticide. vii Part four of the series assessed th e toxicity syndrome using a functional observational battery in rats. viii

We acknowledge that the two-generation reprodu ction and health fert ility effects study is not listed on the Summary Document but is listed in the Human Health Scoping Document and wanted to clarify what the agency is requesting regarding this matter. We are happy to see that the registrants will incl ude protocols for a modified one-generation reproduction study. Once the study is confirmed it may be used to satisfy data requirements for the DNT study and immunotoxicity studies. Additionally, we found a 3-gene ration reproductive test cond ucted in both rats and rabbits saying that Amitraz is not a reproductive toxicant. ix Again, the Agency should examine these studies to ensure that they will not meet its requirements for this endpoint. If not, then we suppor t use of modified one-genera tion reproduction study in hope it will be used successfully used in re-registration process.

We hope that the reproduction study mentioned above satisfies the immunotoxicity data needs for Amitraz. If it does not, then we recommend investigating a study we found which analyzed the effects of Amitraz in f our-week old outbred male Wistar rats for specific immune functions. X
In conclusion, we have provided the Agency with quite a bit of information regarding existing studies done on animals for the data gaps listed for Amitraz. In our search we found a plethora of information on this pestic ide and encourage the Agency to further investigate our findings (and possibly find even more) within the framework of minimizing duplicative animal tests.

• (GLN 870.6300) Developmen tal Neurotoxicity Study

• (GLN 870.3800) Two Generation Repr oduction and Fertility effects

• (GLN 870.7800) Immunotoxicity

Response 5: Agency: The Agency appreciates PCRM suggestions for data sources to potentially evaluate the safety of amitraz to humans, livestock and pets. The many data sources listedPage 6 of 6 by PCRM will be carefully evaluated for scientific adequacy, quality and relevance during the next risk assessment for amitraz. The Ag ency is working to implement the extended one-generation reproduction study to co nserve animal utilization for toxicology

assessments.

In conclusion, the Agency is striving to mi nimize animal testing with amitraz. In that respect, the Agency has been communicating with the registrant s to develop a very efficient “extended one-generation reproduction protocol” which will greatly minimize replication of testing and animal usage. This protocol w ill combine multiple tests into one combined comprehensive study utilizing the same animals, to greatly conserve an imals. The toxicology

studies that will be combined include reproduction, immunotoxicity, neurotoxicity, developmental, clinical chemistry, hematology, urinal ysis, oral toxicity, etc. It is the mission of the US EPA to protect the public from pollution and ensure chemical safety. Unfortunately, the toxicology data base for amitraz has multiple de ficiencies, thus several animal studies are required to fulfill federal regulations 40 CFR §158.