Introduction

This is the Environmental Protection Agency’s (EPA or the Agency) Final Work Plan (FWP) for the registration review of cyphenothrin. The Final Work Plan includes the expected registration review timeline. The FWP also a ddresses public comments received concerning the Preliminary Work Plan (PWP) in the Summary Document which was posted in the cyphenothrin registration review docket (E PA-HQ-OPP-2009-0842) and any ot her comments concerning the initial docket postings. The Summary Document provided information on what EPA knows about the pesticide and what additional risk analyses and data or information the Agency
believes are needed to make a registration review decision.

The Agency is implementing the registra tion review program and will review each registered pesticide every 15 years to determin e whether it continues to meet the Federal Insecticide, Fungicide, and Rode nticide Act (FIFRA) standard for registration. Changes in science, public policy, and pestic ide use practices occur over time. The registration review program is intended to make sure that, as the ab ility to assess risk evolves and as policies and practices change, all registered pesticides contin ue to meet that statutory standard. The public phase of registration review begins when the ini tial docket is opened for e ach case. Information on this program is provided at http://www.epa.gov/oppsrrd1/registration_review/

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Cyphenothrin is a systemic pyrethroid este r insecticide used indoors in household/ domestic dwellings, storage areas, pet living qu arters, ships, processing plants, on horses and dogs; and outdoors on external doorways, window cracks and under porches. Cyphenothrin is registered as a liquid, squeeze-on product for insect control on dogs and horses; as a total release aerosol and fogger for insect co ntrol in indoor residential and commercial settings; and as an aerosol spray for crack and crevice spot treatments around doorways, windows and under porches. Target pests include spid ers, ticks, fleas, beetles, ants, flies, midges, yellow jackets, small flying insects, cockroaches; and other pe sts in domestic, public health and industrial situations. Cyphenothrin was fi rst registered in 1991 and theref ore, it was not subject to a Reregistration Eligibility Decision (RED).

Comments Received on Preliminary Work Plan

On December 16, 2009, EPA opened a 60-day pu blic comment period for the registration review of cyphenothrin. The Ag ency received comments from five parties, which included public interest groups, a techni cal advisory committee, countie s and a water quality control
board.

The County Sanitation Districts of Los Ange les County; the County of Sacramento; the League of California Cities, the California Associ ation of Sanitation Agencies and the California
Water Environment Association Technical Advi sory Committee (TriTAC); and the California Regional Water Quality Control Board requested EPA to evaluate potential impacts from cyphenothrin in both Publicly Owned Treatment Works (POTW) effluent and biosolids in its registration review assessment . The commenters’ claim that the Agency’s down-the drain assessments in reregistration did not fully anal yze the potential impacts to aquatic organisms from the indoor cyphenothrin uses. The comment ers also urge the Agency to address the

2environmental impacts of the cross media transfers of pesticides from waste water to biosolids. In addition, the commenters stated that acute and chronic toxicity da ta for freshwater and
estuarine/marine fish and invertebrates are es sential to perform an adequate down the drain assessment. The commenters also urged EPA to evaluate the cumulative risks to cyphenothrin with other pyrethroids.

BioSpotVictims.org commented on assumptions and application rates in the Agency’s human health residential exposure risk assessment. BioSpotVictims.org claimed that several of the Agency’s assumptions in a 2005 residential exposure assessment were deeply flawed. In addition, BioSpotVictims.org identified a registered cyphenothrin application rate that had not been previously assessed. Bi oSpotVictims.org also commented that the adverse incidents associated with cyphenothrin should be view ed as an environmental justice issue.

Physician’s Committee for Responsible Me dicine’s (PCRM) comme nts strongly support the use of existing DNT studies for cyphenothrin . PCRM also recommends that the Agency request the submission of Quantitative Struct ure-Activity Relationship [(Q)SAR] data for applicable ecological or ma mmalian toxicology endpoints.

After reviewing these comments, the Agency has altered the work plan as follows: (1) The Agency is adding a chronic whole sedime nt toxicity data require ment to address soil metabolism uncertainties. The Agency recomm ends that the whole sediment studies be performed with the amphipod Hyalella azteca because it appears to be more sensitive to pyrethroids than Chironomus tentans ; (2) The Agency is investig ating how to modify its downthe-drain model to more accurately reflect environm ental exposure from indoor pesticides. It is anticipated that a bench scal e study (publically owned treatm ent works (POTW) treatability study (TEP)) of waste water treatment will be required to assess the percentage removed in the biosolids by the treatment, the amount that would degrade, and the amount that would remain in
the waste water. This data would be used to inform removal percentages by waste water treatment, which is an input to the Exposure, Fate Assessment Screening Tool (E-FAST) down the drain model; and (3) Prior to the release of the risk assessment in 2016, the Agency is working with the registrant to develop data a nd, if needed, implement mitigation measures to ensure that the registered c yphenothrin products do not pose risk s. These changes have not
affected the time-line established in the PWP. Fu rther, this document ma kes final the work plan for the cyphenothrin registration review process.

A more detailed description of the comments received a nd the Agency’s response to these comments are available in the separa te response memoranda from the Agency’s
Environmental Fate and Effects Division (EFED) and Health Eff ects Division (HED) located in the cyphenothrin registration revi ew docket (EPA-HQ-OPP-2009-0842).

Risk Assessment and Data Needs

The Agency anticipates conducting a comp rehensive ecological risk assessment, including an endangered species risk assessment, for all uses of cyphenothrin. The Agency also anticipates reviewing toxicological studies that are anticipated as being required per registration review and reevaluating the cyphe nothrin endpoints selected for hu man health risk assessment as

3necessary. An updated occupationa l exposure risk assessment may be necessary if toxicological endpoints are revised for inhalation and dermal t oxicity. In addition, the Agency anticipates performing a quantitative residential exposure assessment for all registered uses. Additional data that the Agency anticipates needing to comp lete these assessments are included below.

Ecological Risk:

• The Agency has not previously conducted an ecological risk assessment for cyphenothrin
because its use was considered limited to the indoors. However, Agency policy has changed since the last cyphenothrin registra tion was granted. Current Agency policy dictates an assessment of poten tial ecological pesticide expos ure from washoff of treated pets and runoff from outdoor spot treatments . Therefore, a comp lete ecological risk assessment for all cyphenothrin uses is planned during registration review.

• The ecological risk assessment planned during registration review will allow the Agency to examine whether cyphenothrin’s current us e has “no effect” or “may affect” federally listed threatened or endangered species (lis ted species) or their designated critical habitats. When an assessment concludes that a pesticide’s use “may affect” a listed species or its designated critical habitat, the Agency will consult with the FWS and/or
National Marine Fisheries Service (the Services), as appropriate.

• The Agency anticipates needing the followi ng data in order to conduct a complete ecological risk assessment, including an endangered species assessment, for cyphenothrin:

o GDLN 850.1300 – Aquatic Invertebrate Life Cycle (freshwater)

o GDLN 850.1400 – Fish Early Life-Stage (freshwater)

o GDLN 850.1735 – Whole Sediment: Acut e Freshwater Invertebrates

o GDLN 850.2100 – Avian Acute Oral Toxicity

o GDLN 850.2300 – Avian Reproduction

o GDLN 850.3020 – Honeybee Acute Contact Toxicity

o GDLN 850.4100 – Seedling Emergence

o GDLN 850.4150 – Vegetative Vigor

o GDLNs 850.4400 & 5400 – Aquatic Plant Growth (algal and aquatic vascular plant toxicity)

o GDLN 850.1730 – Fish Accumulation Study

o GDLN 835.2120 – Hydrolysis

o GDLN 835.2240 – Photodegradation in Water

o GDLN 835.4100 – Aerobic Soil Metabolism

o GDLNs 835.1230 and 835.1240 – Leaching and Adsorption/Desorption

o Non-GDLN – Whole Sediment: Chroni c Invertebrates (freshwater) ( Hyalella

azteca )

4o Non-GDLN – Publically Owned Treatment Works (POTW) Treatability Study (TEP)

- The Agency is anticipating requiring a bench scale study of waste water treatment, to assess the percentage removed in the biosolids by the treatment, the amount that would degr ade and the amount that would remain
in the waste water. This data would be used to inform removal percentages by waste water treatment, which is an input to the EFAST down the drain
model.

• For a detailed discussion of the anticipated ecological risk assessment and data needs
refer to the Registration Review – Preliminary Probl em Formulation for Ecological Risk and Environmental Fate, Endangered Species, and Drinking water Assessments for Cyphenothrin , dated December 15, 2009; the Addendum to the Cyphenothrin Registration Review Problem Formulation Data Requirments , dated June 23, 2010; and the Response to Comments on the Registration Review – Preliminary Problem Formulation for Ecological Risk and Envir onmental Fate, Endangered Spe cies, and Drinking Water Assessments for Cyphenothrin document, dated June 10, 2010. These documents are
available in the docket.

Human Health Risk:

• The most recent human health risk assessm ent for cyphenothrin was completed in 2006 to support the following new use: squeeze-on spot treatment for dogs.

• The cyphenothrin toxicity database is not complete. EPA anticipates requiring the following guideline studies to reevaluate toxicological endpoints for cyphenothrin:

o GDLN 870.3250 – 90-Day Dermal Toxicity Study in Rats

o GDLN 870.3700 – Developmental Toxicity Study in Rats

o GDLN 870.3700 – Developmental Toxicity Study in Rabbits

o GDLN 870.6200 – Acute Neurotoxicity Study

o GDLN 870.6200 – Subchronic Neurotoxicity Study

o GDLN 870.6300 – Developmenta l Neurotoxicity Study

o GDLN 870.7800 – Immunotoxicity Study

• The Agency is investigating the need for add itional experimentation, sp ecific to the mode of action and pharmacokinetic characteristics of pyrethroids, to eval uate the potential for increased susceptibility of young organisms. A meeting of the FIFRA Scientific Advisory Panel (SAP) is planned for July 2010. For more information on the pyrethroid developmental neurotoxicity (DNT) requirement, see http://www.epa.gov/oppsrrd1/reevalua tion/pyrethroids-pyrethrins.html

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• EPA has recently determined that, as an alte rnative to the generation and submission of a new Developmental Neurotoxicity (DNT) study, registrants may instead choose to cite the six previously submitted DNT studies for pyrethroid pesticides. A decision regarding the need for an FQPA or ot her database uncertainty/safet y factor required to assure

5protection of infants and children will be ma de following receipt of remaining required toxicity data, and following a final determ ination of the potential for increased susceptibility of these subpopulations to pyrethr oid pesticides based on the results of all available data. The cyphenothr in risk assessment may need to be revised to incorporate
these decisions.

• Based upon the limited nature of the registered outdoor uses of cyphenothrin, the Agency does not anticipate conducting a drinki ng water assessment for cyphenothrin.

• The Agency has no plans to conduct a dietary assessment because there are no registered food uses and dietary exposure is not expected.

• The Agency is currently revising the Resident ial Standard Operating Procedures (SOPs) for treated pets and indoor settings. The Agency anticipates conducting a new quantitative residential exposure assessment, wh ich incorporates the revised SOPs and all cyphenothrin uses.

• The Agency does not anticipate conducting an aggregate assessment because dietary exposure from food and water is not expected.

• Cyphenothrin belongs to the pyrethroid class of insecticides. This class also includes permethrin, cypermethrin, cyfluthrin, de ltamethrin, tau-fluvalinate, and lambdacyhalothrin, among others. EPA develope d a draft science policy document on the proposed common mechanism of to xicity for naturally-occurr ing pyrethrins and synthetic pyrethroids (Proposed comm on mechanism grouping for the pyrethrins and pyrethroids, draft, May 19, 2009 http://www.regulations.gov/search/Regs/hom e.html#documentDet ail?R=09000064809a62df )

. This document was supported by the FIFRA SAP and is available in the docket. See http://www.regulations.gov/search/R egs/home.html#documentDetail?R=0900006480a1f
8d7 . EPA will finalize the policy document on the pyrethroid common mechanism of toxicity taking into account the SAP comments. Pesticides with a common mechanism of toxicity are subject to cumulative risk assessment under the FQPA. Research is on-going by EPA’s Office of Research and Developm ent (ORD) to make improvements to the Stochastic Human Exposure and Dose Si mulation (SHEDS) probabilistic exposure model, which are important for the cumulative risk assessment. EPA ORD is also developing physiologically-based pharmacokineti c models for several pyrethroids. The status of both of these research modeling e fforts will be reviewed by the FIFRA SAP in July, 2010. For information regarding EPA’s effo rts to evaluate the risk to pyrethroids,
See http://www.epa.gov/oppsrrd1/reevaluati on/pyrethroids-pyrethrins.html.

• The Agency does not anticipate conducting an occupational health risk assessment unless endpoints are updated for dermal and inhalation toxicity.

• For a detailed discussion of th e anticipated human health risk assessment and data needs for cyphenothrin please refer to the Cyphenothrin. Human Health Assessment Scoping Document in Support of Registration Review , dated August 20, 2009; and the

6Cyphenothrin. Response to Registrant Co mments on the Registration Review Human Health Scoping Document and Preliminary Workplan , dated June 17, 2010. These
documents are available in the c yphenothrin docket.

Other Data Needs:

• GDLN 830.750 UV/Visible Light Ab sorption – this study is a new data requirement under 40 CFR part 158 (Product Chemistry Data Requirements) for registration of a pesticide (food and non-food uses). The Agency anticipates requiring this study to obtain basic information about the compound’s id entity/composition and the wavelengths at which the compound may be suscepti ble to photochemical degradation.

Timeline

The Agency has created the following estimated timeline for the completion of the cyphenothrin registration review.

Registration Review for Cyphenothrin Projected Registration Review Timeline
Activities Estimated
Year/Month Opening the Docket Open Docket and Public Comment Period December 2009
Close Public Comment February 2010 Case Development Issue Final Work Plan (FWP) June 2010 Issue Data Call-in (DCI) January – March 2011
Data Submission 1 January – March 2015 Open Public Comment Period for Preliminary Risk Assessments July – September 2016
Close Public Comment Period October - December
2016 Registration Review Decision Open Public Comment Period for Proposed Registration Review
Decision January – March 2017
Close Public Comment Period April - June 2017

Final Registration Review Decision & Begin Post-Decision Followup 2017

Total (years) 2 8
1 If the registrants choose to cite the six previously submitted DNT studi es for pyrethroid pesticides, as explained above, rat her than conducting a DNT study with cyphenothrin, this time estim ate will likely be shortened by approximately two years. 2 An assessment of potential cumulative risk from the pyrethro id class of insecticides may impact this time estimate.

7Next Steps

As noted previously, the Agency anticipate s requiring several eco logical effects and human health studies through a Data Call-In (DCI) Notice, expected to be issued in 2011. This
new information will be used to conduct the risk assessments outlined in this FWP for all cyphenothrin uses.

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