Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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ENVIRONMENTAL PROTECTION AGENCY [OPP-xxxx; FRL-xxxx]

Notice of Intent to Cancel and Notice of Denial of Registrations for Certain Rodenticide Bait

Products AGENCY: Environmental Protection Agency

ACTION: Notice of Intent to Cancel and Notice of Denial.

SUMMARY: This Notice announces the Agency's intent to cancel the registrations of 20 rodenticide bait products. EPA has determined th at all 20 of these rodenticide products cause

unreasonable adverse effects on the environment becau se they are in the form of loose bait or bait blocks without bait stations conforming to the standards identified in EPA’s 2008 Risk Management Decision (RMD), and are sold fo r residential consumer use in controlling commensal rodents in and around buildings. EPA bases this determination on data and other information showing that these products cause unreasonable risks to children, companion and domesticated animals, and non-target wildlife.

Further, EPA has determined that eleven of these 20 rodenticid e products also cause

unreasonable adverse effects on the environment b ecause they contain the active ingredients

brodifacoum or difethialone and are sold for residential consumer use. EPA bases this

determination on data and other information s howing that these produc ts cause unreasonable adverse effects to non-target wi ldlife. All of the 20 products subject to this Notice are in physical forms that cause unreasonable risks, and eleven of these products also cause unreasonable risks owing to the combination of their composition and use pattern. EPA is therefore issuing this Notice of Intent to Can cel pursuant to section 6(b) of the Federal Insecticide, Fungicide and Rode nticide Act (FIFRA). In add ition, this Notice announces the Agency’s denial of certain pending applications for registration for certain rodenticide bait products for the same reasons as the proposed cancellations. Effectiv e the date of final cancellation, EPA will not allow further sale or di stribution of existing stocks of products subject

to this Notice. After cancel lation, producers, distributors a nd commercial applicators holding existing stocks would also beco me subject to FIFRA section 6(g) reporting requirements.

DATES: Requests for a hearing by an affected re gistrant or applicant must be received by the Hearing Clerk at the address gi ven below on or before [insert date 30 days after date of publication in the FEDERAL REGISTER], or with in 30 days of receipt of this Notice by the registrant or applicant, whichever occurs late r. Requests for a hearing by any other adversely affected party must be received by the Hearing Clerk on or before [insert date 30 days after date of publication in the FEDERAL REGISTER].

ADDRESSES: Requests for a hearing submitted by U.S. Mail must use the following address: U.S. Environmental Protection Agency, Office of Administrative Law J udges, Mail Code 1900L, 1200 Pennsylvania Ave., NW, Wa shington, DC 20460. Please not e that mail deliveries to federal agencies are screened off-site, and this security procedure can delay delivery. Requests for hearing submitted by hand or courier must use the following address: U.S. Environmental Protection Agency, Office of Administrative La w Judges, Franklin Court, Suite 350, 1099 14thRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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St. NW, Washington, DC 20005.

Additional information supporting th is action is available for public inspection from 8 a.m. to 4 p.m., Monday through Friday, except legal ho lidays in: [Public Response and Program Resources Branch, Field Oper ations Division (7506C), Of fice of Pesticide Programs, Environmental Protection Agency, Potomac Ya rd South, 2777 Crystal Drive Arlington, VA.]

FOR FURTHER INFORMATION, CONTACT: By mail: Rusty Wasem, Pesticide Re-evalu ation Division (7508W), Office of Pesticide Programs, U.S. Environmental Protection Agency, 1200 Pe nnsylvania Ave., NW., Washington, DC 20460. Telephone: (703) 305-6979; Email: wasem.russell@epa.gov.

SUPPLEMENTARY INFORMATION:

I. Introduction

This Notice is divided into 12 units. Unit II de scribes the legal authority for this action. Unit III describes the regulatory history leading to today’s notice of intent to cancel and notice of intent to deny. Unit IV describes the scope of the intended cancellations. Unit V summarizes

EPA’s human health and domestic animal concerns with the products subject to this Notice. Unit VI discusses ecological exposure and risk of th e products subject to this Notice. Unit VII examines the benefits of these products and the impact of this proposed cancellation action. Unit VIII presents EPA’s conclusions regarding whether the products subject to this Notice meet the FIFRA registration criteria. Un it IX discusses disposition of existing product stocks. Unit X summarizes the interagency review and review by the FIFRA Scientific Advisory Panel. Unit XI outlines the procedures for implementing the acti ons required by this Notice, as well as the procedures for requesting a hearing. Unit XII provides a list of reference documents.

I. Introduction II. Legal Authority III. Regulatory History IV. Scope of Intended Cancellation and Denials V. Risks Associated with Exposure to R odenticide Products Subject to this Notice (Human and Domestic Animals) VI. Risks Associated with Exposure to Roden ticide Products Subject to this Notice (Non-Target Wildlife)

VII. Benefits VIII. Conclusions Regarding Whether Subj ect Rodenticide Products Meet the FIFRA Registration Criteria IX. Existing Stocks of Cancelled Products X. USDA, HHS and SAP Review

XI. Procedural Matters

XII. ReferencesRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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II. Legal Authority

With minor exceptions not at issue here, as provided in FIFRA sec tion 3(a), a pesticide product may not be lawfully sold or distributed in the United Stat es unless and until the product is registered by EPA. 7 U.S.C. 136a(a). A pestic ide registration is a license allowing a pesticide product to be sold, distributed, and used for speci fied uses in accordance with use instructions, precautions, and other terms and c onditions established by EPA when it grants the registration.

As a general matter, in order to obtain or maintain a registration for a pesticide under FIFRA, an applicant or registrant must demons trate that the pesticide satisfies the statutory standard for registration, section 3(c)(5) of FIFRA. 7 U.S.C. 136a (c)(5). That standard requires, among other things, that the pesticide perf orms its intended function without causing

“unreasonable adverse effects on the environment. ” The term “unreasonable adverse effects on

the environment” is defined under FIFRA section 2(bb) as “any unreasonable risk to man or the environment, taking into account the economic, soci al, and environmental co sts and benefits of the use of any pesticide”. 7 U.S.C. 136(bb). This standard requires a finding that the risks associated with the use of a pesticide are justifie d by the benefits of such use, when the pesticide is used in compliance with the terms and condi tions of registration or in accordance with commonly recognized practices. See Defenders of Wildlife v. Administrator, EPA , 882 F.2d 1294, 1298-99 (8 th Cir. 1989) (describing FIFRA’s required balancing of risks and benefits). The burden of demonstrating that a pesticide product satis fies the statutory criter ia for registration is at all times on the proponents of the initial or continued registra tion, and continues as long as the registration is in eff ect. 40 C.F.R. §164.80(b). See also, Industrial Union Dept. v. American

Petroleum Institute , 448 U.S. 607, 653 n.61 (1980); Stearns Electric Paste v. EPA 461 F.2d 293, (7 th Cir. 1972); Environmental Defense Fund v. EPA , 510 F. 2d 1292, 1297 (D.C. Cir. 1975)).

Under FIFRA section 6(b), the Agency may issue a Notice of Intent to Cancel the registration of a pesticid e product whenever it appears either th at: (1) A pesticide or its labeling or other material required to be submitted does not comply with FIFRA, or (2) when used in accordance with widespread and commonly recognized practice, the pesticide generally causes

unreasonable adverse effects on the environment. 7 U.S.C. §136d (b). If a hearing is requested by an adversely affected person, the final order conc erning cancellation of the product is not issued until after an administrative hearing.

In the cancellation hearing, the Agency has the burden of going forward to present an affirmative case for cancellation. 40 C.F.R. §164.80( a). However, the ultimate burden of proof is on the proponent of the re gistration. 40 CFR §164.80(b); Industrial Union Dept ., 448 U.S. at 653 n. 61; Stearns Electric Paste v. EPA 461 F.2d 293, (7 th Cir. 1972). Once the Agency makes its prima facie case that the risks of the product’s continue d use fail to meet the FIFRA standard for registration, the responsibility to demonstrate that the product meets the FIFRA standard is upon the proponents of continued registration. 40 CFR §164.80(b); Dow v Ruckelshaus , 477 F.2d 1317, 1324 (8 th Cir. 1973).Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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FIFRA Section 3(c)(6) provide s that where EPA determines that an application for registration does not meet the regi stration criteria of section 3(c )(5) for registration, the Agency must publish a notice of denial a nd the reasons therefore. Section 3(c)(6) further provides that upon such notification of the denial , the applicant for registration, or other interested person with the concurrence of the applicant, shall have the same remedies as provided for in section 6.

III. Regulatory History

Many pesticides were originally registered well before EPA came into existence or before EPA identified a complete set of data requirement s sufficient to allow it to determine whether new pesticides met the standard for registrati on. In 1972, Congress theref ore directed EPA to assess all existing pesticides to determine whet her they would qualify for the new standard of registration adopted in the 1972 amendments to FIFRA. This process of assessing existing pesticides against current standards is known as “reregistration”. Congr ess in 1988, established a formal five-phase process for EPA to use in co nducting a comprehensive review of all products registered before 1984 to determine whether thes e products had satisfied all applicable data requirements and the registration criteria of FI FRA section 3(c)(5). See FIFRA section 4(a), 7 U.S.C. § 136a-1(a).

EPA began the Section 4 reregistration process for products intended to control commensal rodents (i.e., house mice ( Mus musculus ), Norway rats ( Rattus norvegicus ), roof rats ( Rattus rattus )) early in the 1990s. These rodents, proba bly originating in Central and Southeast Asia, have been introduced throughout the world by humans (Corrigan 1997; Chiri 2006). These commensal rodents typically live in close associ ation with humans, and are often found in and

around homes as well as commercial establishments (Timm 1994).

The active ingredients in rodenticide produc ts intended to control commensal rodents have different characteristics, but are commonly desc ribed as being of one of three general types: First generation anticoagulants (FGARs)(warfarin, chlorophaci none, diphacinone, pival), second generation anticoagulants (SGARs)(brodifacoum , bromadiolone), and acute toxins (zinc phosphide, bromethalin). 1 In 1991, EPA issued a Reregistra tion Eligibility Decision (RED) for rodenticide products containing th e active ingredient warfarin. In July 1998, after making a comprehensive reassessment of data relating to the use and effects of the remaining rodenticide products subject to reregistration, EPA issued tw o REDs for seven different active ingredients that previously had been registered for rodent co ntrol in both agricultural and residential settings. 63 FR 48729, September 11, 1998. One RED (the “Rodenticide Cluster RED”) contained eligibility decisions for th e ingredients brodifacoum, br omadiolone, chlorophacinone, diphacinone, bromethalin, and pival. EPA also issued a second, stand-alone RED (the “Zinc Phosphide RED”) for the ingredient zinc phos phide. In these 1998 REDs, EPA issued FIFRA section 4(g)(2)(A) determinations that certain rodenticide products woul d not be eligible for

1 Two additional second generation anticoa gulants, difethialone an d difenacoum, and the acute toxin cholecalciferol, were first registered after 1984, and theref ore were not subject to reregistration.Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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reregistration unless their registrants adopted cert ain risk mitigation measures to reduce the risks they posed to human health and the environment.

In the REDs, EPA stated it would form a stakeholder group to “discuss means of significantly reducing exposures” to children. Reregistration Eligibility Decision for the Rodenticide Cluster (July 1998). The stakehol der group was created to “develop workable mitigation measures to adequately protect children from accidental rodenticide exposures.” Id.; see also Rodenticide Stakeholder Workgroup, Recommendations for Managing Rodenticide Exposures to Children in the Home: Subcomm ittee Report to the Pesticide Program Dialogue Committee (PPDC) for consideration by the U.S. Environmental Protection Agency (November 15, 2000) (“the purpose of the [wor king group] is to provide advi ce and recommendations to the EPA on a pesticide exposure is sue involving children”); Id. The group’s objectives included discussing long-term risk reduction measures and “decid[ing] on specific timing and other issues associated with bait dyes [and] bittering agents.” Reregistration Eligibility Decision for Zinc Phosphide (July 1998). In 1999, EPA formed th e Rodenticide Stakeholders Workgroup (RSW) as a subcommittee of the federally-chartered advisory group the Pesticide Program Dialogue Committee (the “PPDC”). 2 The RSW included members from EPA, the United States Consumer Product Safety Commission, the District of Columb ia Department of Hea lth, Maryland Public Interest Research Group, the California Depart ment of Food and Agriculture, the Children’s National Medical Center, the Asso ciation of Poison Control Ce nters, and the National Pest

Control Association.

The findings and recommendations of the RS W are contained in the November 15, 2000 report, Recommendations for Managing Roden ticide Exposures to Children in the Home . EPA adopted those recommendations in a 2001 am endment to the REDs. 66 Fed. Reg. 59,425. One of the recommendations adopted by EPA was to rescind the 1998 RED determination that registrants should add a bitter tast e to their rodenticide bait produc ts that would di ssuade children from eating them. An environmental group succ essfully challenged the 2001 amendment to the RED, and a district court remanded it to EPA. West Harlem Env. Action v. EPA , 380 F. Supp. 2d 289, 294-295 (S.D.N.Y. 2005).

Also, in the 1998 REDs, the Agency concluded that further evaluation of the ecological risks of rodenticides was necessary. As part of this work, the Agency developed a comparative ecological assessment for nine 3 rodenticide active ingredient s. Between October 1999 and December 2001, the comparative risk assessment was drafted by Agency scientists, received both internal and external peer review as well as review by the Roden ticide Registrant Task Force. Based on input from these peer reviews, the comparative risk assessment was revised. There were two public comment periods in 2003 and 2004 and the Agency reviewed and responded to the public comments and revised the risk assessment based upon those comments.

2 The PPDC is the principal stakeholder advisory body to EPA’s Office of Pesticide Programs and was established pursuant to the Federal Advisory Committee Act.

3 The tenth active ingredient, difenacoum was registered in 2007 and therefore, was no t included in the Comparative Analysis or the Proposed Risk Mitigation.Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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In September 2004, the Agency opened Phase 5 of the public partic ipation process by publishing the revised comparative ecological risk assessment, which incorporated new ecological incident data and re flected revisions made in response to public comments on the preliminary version of the assessment. Along with the revised ecological assessment, EPA also published a document discussing the benefits asso ciated with rodentic ide products and EPA’s preliminary position on appropriate risk re duction options. EPA accepted public comments on those documents through January 2005.

In January 2007, EPA issued a draft Risk Mi tigation Proposal for co mment. Based on an evaluation of the ecological risks associated with the use of rodenticide bait products containing these nine active ingredients, a nd consideration of the public health and other important benefits of the use of rodenticide baits, EPA proposed to classify all bait product s containing the active ingredients brodifacoum, bromadiolone , and difethialone as restricted use pesticides. Further, to decrease the possibility of children’s exposur e to rodenticide products used in homes, EPA proposed requiring that all rodentic ide bait products available for sa le to consumers be sold only in tamper-resistant bait stations with solid bait blocks as the only permissible bait form.

EPA took comment on the proposed mitigati on for 120 days and received extensive comments from a wide range of stakeholders. During this comment pe riod, the Rodenticide Registrant Task Force surveyed their constituents in 2007 and reported that in 2004, there were 105 million bait placements and in 2005, the number had increased to 115 million bait placements distributed on the consumer market . Based on anecdotal evidence, EPA believed that the majority of products sold on the consumer market contained brodifacoum and

difethialone. Incident data confirmed that brodi facoum was implicated in a high percentage of non-target wildlife incidents. Incident data strengthened EPA’ s conclusions that if the lower toxicity and less persiste nt active ingredients replaced the high er toxicity and more persistent active ingredients for a portion of this market, there would be signi ficant reduction in the levels of exposure to non-target wildlife. Based on rest rictions some municipali ties place on Restricted Use pesticides and concerns about the additional burdens on the poultry, livestock and pest control operator industries, and recognizing the importance of SG ARs to these industries, EPA decided to employ sale and distri bution limitations – rather than re stricted use classification – to minimize the use of second generation anticoagula nts in settings where the risks outweigh the benefits (i.e., most re sidential settings).

On May 28, 2008, in response to the district c ourt’s remand order, EPA issued the “Risk Mitigation Decision for Ten Rodenticides” (RMD). 4 The RMD explains EPA’s current section 4(g)(2)(A) conclusions about the reregistration eligibility of rodenticides cont aining any of ten

4 The RMD did not reinstate either the bittering agent or indicator dye requirement for a number of reasons. After review of all the available information, EPA concluded that, among other things, neither bittering agents nor indicator dyes would provide risk reduction comparable to a bait station requirement, because neither prevents exposure. At best, bittering agents might reduce consumption, and indicator dyes might provide a signal of an

exposure event.Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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listed active ingredients. Among other things, EPA stat ed that rodenticide baits sold to residential consumers must be packaged in a bait station designed to prevent children, domestic animals and non-target wildlife from being able to co me into contact with bait. RMD at 17-18

. EPA also

stated that rodenticides cont aining “second-generation anticoagul ants” pose significant risks to wildlife and the environment, a nd that rodenticides containing those compounds should only be sold to pest control professi onals and agricultural users—not residential consumers—and then only with additional risk mitigation measures. Id. EPA stated that unle ss a rodenticide product incorporates the risk mitigation measures listed in the RMD, it “would present unreasonable risks

inconsistent with FIFRA” and therefore should not remain registered. RMD at 15.

The RMD announced EPA’s conclusions about rodenticide safety and signaled EPA’s intentions for the future completion of the reregi stration process. But it did not change the legal status of any rodenticide product, now or in the future. EPA did not cancel or suspend any rodenticide registrations at that time, nor did it prohibit the sale of registered rodenticides that did not incorporate the specified mitigation measures . Instead, EPA asked registrants to adopt those mitigation measures voluntarily. Specifically, EPA as ked each registrant to decide by September 2, 2008, whether it intended to adopt the measures. If the manufacturer ag reed to do so, it could submit a request for voluntary cancellation of its ex isting registrations that would not be effective until June 4, 2011. RMD at 26.

By June 4, 2011, most rodenticide registrants had voluntarily amended their registrations or replaced them with new registrations meeting the risk mitigation goals of the RMD, thereby significantly reducing rode nticide risks. Today, only 20 rode nticide products, produced by three registrants (Liphatech, Inc.; R eckitt Benckiser, Inc.; and Spec trum Group Division of United Industries Corporation), fail to meet the risk mitig ation goals of the RMD. As set forth in this Notice, EPA intends to achieve the necessary ri sk reduction identified in the RMD, by cancelling and denying the registrations of rodenticide pr oducts that do not include mitigation measures sufficient to prevent unreasonable ri sks to man and the environment.

Certain rodenticide registrants who have disagreed with the Agency’s positions regarding rodenticides have challenged aspects of the Agency’s actions in two court cases, however,

neither case has addressed the mer its of the scientific, economic, a nd policy questions at issue in this cancellation proceeding. See generally, Reckitt Benckiser, Inc. v. Jackson , 762 F. Supp. 2d 34, 46 (D.D.C. 2011)(concerning the scope of EPA’s authority to pursue enforcement action in lieu of a cancellation proceeding), and Woodstream Corp. v. Jackson , 1:11-cv-00867-JEB (D.D.C filed 5/9/2011)(concerning EPA’s author ity to grant or amend registrations on a conditional basis).

IV. Scope of Intended Cancellation and Denials

For the reasons set forth in Units V, VI, and VII, below, EPA has de termined that certain registered rodenticide bait products, when used in accordance with widespread and commonly recognized practice, genera lly cause unreasonable adverse effects on humans and the environment. Accordingly, EPA is today announcing its intention to cancel the registrations ofRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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the following pesticide products:

Table 1. Pesticide Products Subject to this Notice of Intent to Cancel.

Product EPA Reg. No. Registrant Active Ingredient Form

D-Con Concentrate Kills Rats & Mice 3282-3 Reckitt Benckiser,

Inc. Warfarin Powder

D- Ready Mixed Kills Rats & Mice 3282-4 Reckitt Benckiser,

Inc. Warfarin Bait Bits

D- Mouse Prufe Kills Mice 3282-9 Reckitt Benckiser,

Inc. Warfarin Pellets

D- Pellets Kills Rats & Mice 3282-15 Reckitt Benckiser,

Inc. Warfarin Pellets in Place Pack

Rid-A-Rat Rat & Mouse Killer 8845-39 Spectrum Group,

Div. of United Industries Corp. Warfarin Meal

D- Mouse Prufe II 3282-65 Reckitt Benckiser,

Inc. Brodifacoum Pellets

D- Pellets Generation II 3282-66 Reckitt Benckiser,

Inc. Brodifacoum Pellets

D- Bait Pellets II 3282-74 Reckitt Benckiser,

Inc. Brodifacoum Pellets in Place Pack

D- Ready Mixed Generation II 3282-81 Reckitt Benckiser,

Inc. Brodifacoum Crushed Pellets

D- Mouse-Prufe III 3282-85 Reckitt Benckiser,

Inc. Difethialone Pellets

D- Bait Pellets III 3282-86 Reckitt Benckiser,

Inc. Difethialone Pellets

D- II Ready Mix Baitbits III 3282-87 Reckitt Benckiser,

Inc. Difethialone Crushed Pellets

D- Bait Packs III 3282-88 Reckitt Benckiser,

Inc. Difethialone Pellets in Place Pack

Generation Meal Bait Packs 7173-247 Liphatech, Inc. Difethialone Meal

Difethialone Bait Station 7173-283 Liphatech, Inc. Difethialone Block in non-RMD conforming station

Difethialone 6g Paste Pl Pks 7173-285 Liphatech, Inc. Difethialone Paste

Hot Shot Sudden Death Brand Mouse

Killer 8845-125 Spectrum Group,

Div. of United Industries Corp. Bromethalin Pellets in Place PackRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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Table 1. Pesticide Products Subject to this Notice of Intent to Cancel.

Product EPA Reg. No. Registrant Active Ingredient Form

Hot Shot Sudden Death Brand Rat

Killer 1 8845-126 Spectrum Group,

Div. of United Industries Corp. Bromethalin Pellets in Place Pack

Hot Shot Sudden Death Brand Rat &

Mouse Killer 8845-127 Spectrum Group,

Div. of United Industries Corp. Bromethalin Pellets in Place Pack

Hot Shot Sudden Death Brand Mouse

Killer Bait Station 8845-128 Spectrum Group,

Div. of United Industries Corp. Bromethalin Pellets in Place Pack

For the same reasons, EPA is today announcing its denial of applica tions for registration or amended registration of th e following pesticide products:

Table 2. Denied Applications for Registration.

Product EPA Application No. Registrant Active Ingredient Deficiency

D-Con Bait Station

XV Kills Mice 3282-RNU Reckitt Benckiser

Inc. Brodifacoum Consumer Oriented

SGAR Product

D-Con Bait Station

XVI Kills Mice 3282-RNL Reckitt Benckiser

Inc. Brodifacoum Consumer Oriented

SGAR Product

Bromethalin 0.01%

Pellet III 36488-AN Woodstream Corp. Bromethalin Consumer Oriented

Product in a Pelleted Form and Packaged

Without a Bait

Station

Bromethalin Rat

and Mouse Block

III 36488-AR Woodstream Corp. Bromethalin Consumer Oriented Product Packaged

without a Bait Station

In the RMD, EPA identified a number of m itigation measures that, if adopted would make existing rodenticides eligible for reregist ration. With this Notice, EPA proposes to cancel the rodenticide products identified above base d on two of the most significant mitigation measures identified in the RMD: Removing SG ARs from residential consumer products, and assuring that rodenticide products available to residentia l consumers are in a form that securely

fits in included bait stations that meet certa in standards. Although the mitigation measures identified in the RMD are designed to be used in concert, with each measure contributing towards safer outcomes, the prohib ition against loose bait and th e bait station requirement are expected to protect children, domestic animal s and non-target wildlif e from exposures to commensal rodenticides generall y, while the exclusion of SGARs from the homeowner market is expected to reduce environmental loading of SGARs and thereby reduce secondary poisoningsRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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among non-target wildlife. As currently labele d and sold, each of the rodenticide products

identified above cause unreasonable risks to man or the environment owing to their lack of one or both of these mitigation measures. Individu al products may also fail to meet the FIFRA registration criteria for other reas ons, however, in order to focus th is hearing on the most critical risk mitigation issues, the proposed cancellations and the denials are based solely on the presence of second generation anticoagulants in products labeled for residential consumer use in controlling commensal rodents in and around buildings, or any product formulated as loose baits

or bait blocks without bait stations that meet the standards of the RMD, or both.

In this Notice, EPA proposes to cancel the re gistration of 20 products sold in the general consumer market, and denies the applications for registration of four additional products. The scope of this action is very na rrow. There are adequate alternative products on the consumer market and the professional applic ators (including public health o fficials, pest control operators (PCOs), and other occupational applicators) and ag ricultural applicators ar e not affected by this Notice. EPA has expressed concern for more than a decade that children, pets, and non-target wildlife are being unnecessarily exposed to rodentic ides. Most of the children and pet incident concerns are occurring in and around homes, despite mandatory la bel statements requiring use in tamper-resistant (or tamper-proof) bait stations where placements otherwise would be accessible to children, domestic animals, and/or non-target wildlif e. These incidents can be significantly reduced if rodenticide products sold in the ge neral consumer market include bait stations designed to prevent children, domestic animals and non-target wildlife from being able to come into contact with bait. Further, based on the reported incidents of wildlife exposures to rodenticides, EPA has determined that it is ap propriate to limit use of products containing the more toxic and persistent anticoagulants brodifaco um and difethialone. EPA has determined that the risks of use by residential consumers of rode nticides containing brodifacoum and difethialone outweigh the benefits of such use. There are over 30 alternative rodent icide products currently available in the general consumer market that ca n provide effective rodent control, that fully conform to the RMD, and that meet the safety standards required under FIFRA. In addition,

residential consumers also have access to mechani cal control methods as we ll as the services of PCOs who will continue to have access to a broader range of products.

The Notice addresses only rodenticides inte nded to control the rodent species commonly referred to as “commensal” rodents: the Norway (brown or sewer) rat ( Rattus norvegicus ), the roof (black or ship) rat ( Rattus rattus ), and the house mouse ( Mus musculus ). Control of these commensal rodents in sewers, in and around co mmercial buildings, and in connection with agricultural and food processing ope rations, are outside the scope of this Notice, as the only products EPA proposes to cancel are those availa ble for residential consumer use. Products registered for the control of other types of rode nts are also outside the scope of this Notice.

In making the determination that the products subject to this Notice do not meet the FIFRA registration criteria, EPA has relied upon the evidence and analyses demonstrating significant exposure to humans, particularly to children, domestic animals, and non-target

wildlife from the use of consumer use rodentic ide products which are not protected in bait

stations that meet the standard s of the RMD. In addition, th is determination relies upon theRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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substantial and well documented risks to non-targ et wildlife from seconda ry exposures to the active ingredients brodifacoum and difethialone. EPA also considered evidence and analyses relating to the benefits of conti nued use of the rodenticide products identified in this Notice, and has determined that, based on the availability of adequate and affordable alternative rodenticide products and methods of commensal rodent contro l, the benefits linked specifically to the products identified in this Noti ce are, at best, minimal. Ho wever, given the potential for exposure these products pose to ch ildren, coupled with risks to do mestic animals and wildlife in the absence of further mitigati on, EPA believes that this cancella tion action would be warranted even if the anticipated costs of rodent control as a result of th is action were somewhat greater than EPA has estimated. Accordingly, EPA is issu ing this Notice of Inte nt to Cancel and to Deny registrations of the consumer-use commen sal rodenticide products listed in above.

V. Risks Associated with Exposure to Rodent icide Products Subject to this Notice (Human and Domestic Animals )

Hazard Characterization of Rodenticid e Products Subject to this Notice

1.. Effects on Mammals

Rodenticides are designed to kill mammals, so their effects on humans and non-target mammals are qualitatively the same as their effect s on target pests, unlike other pesticides such

as herbicides and certain insecticides where adve rse effects on mammals tend to be different in nature than their effects on target pests. Rodenticides can be di vided into three broad classes in terms of their effects: first generation anticoa gulants, second generation anticoagulants, and nonanticoagulants. The first- and second generati on anticoagulants interfer e with blood clotting and death results from hemorrhage. For both firs t generation and second generation anticoagulants, primary manifestations include nosebleeds, bleeding gums, hema turia, melena, and extensive ecchymoses (bruises). Patients may also have symptoms of anemia, including fatigue and dyspnea on exertion. If the poisoning is severe, the patient may progress to shock and death. SGARs are generally more toxic and more pers istent than FGARs. The non-anticoagulant rodenticides work in different ways to cause de ath. Each of these is discussed below:

• FGARs, such as chlorophacinone, diphacinone , diphacinone sodium salt, warfarin, and warfarin sodium salt, disrupt the production in the liver of vitamin K dependent bloodclotting factors II (proth rombin), VII, IX, and X. Du e to the long half -lives of the vitamin K-dependent clotting factors, the antico agulant effect doesn’t occur in the rodent until after several days of ingestion. The onset of lengthened prothrombin time (PT) from a toxic dose may occur within 24 hours, and reach a maximum in 36-72 hours at a

dose much lower than the dose that can cause hemorrhage (Reigart J.R. et.al, 1999). The agents also increase permeability of capillaries throughout the body, leading to widespread internal hemorrhage. It is noted that chlorophacinone, diphacinone, and diphacinone sodium salt block different bindi ng sites than those blocked by warfarin and

warfarin sodium salt.Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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• SGARs such as brodifacoum, bromadiolone, difenacoum, and difethialone are more acutely toxic than first generation agents a nd can cause lethal effects to rodents in a single dose. Like the first ge neration anticoagulants these ag ents block the formation of the active form of vitamin K, which in turn inhibits the production of coagulation factors

in the liver. These chemicals block the same binding site that wa rfarin and warfarin sodium block, however, second generation anticoa gulants have much longer half-lives in the body (Batten and Bratt, 1990). Similar to the first generation anticoagulants, the toxic effects of these agents usually begin several days after inge stion, because of the long half-life of the co agulation factors.

The non-anticoagulants work in a variety of wa ys and no single common mechanism exists. For example:

• Bromethalin, causes decreased production of ATP in the ce lls of the central nervous system by uncoupling oxidative phosphoryla tion in the mitochondria. Low levels of ATP reduce the efficiency of the enzyme Na/K ATPase, leading to increased

intracellular sodium levels. This in turn dr aws more water into ne uronal cells (cerebral edema) and increases intracranial pressure which can be lethal. Symptoms and signs of cerebral edema include headache, dizzine ss, nausea numbness, weakness, loss of coordination or balance, a ltered level of consciousness, respiratory depression, seizures, and death.

• Cholecalciferol increases calcium absorpti on from food, and mob ilizes calcium from bone which leads to hypercalcemia (inc reased calcium levels in blood). Hypercalcemia can cause formation of calcium crystals in internal organs such as blood vessels, kidneys, stomach wall and lungs (Chavhan S.G., et.al, 2011). Abnormal heart conduction and irregular heartbeats can also occur since the heart tissue is sensitive to changes in blood calcium levels . Symptoms and signs of cholecalciferol poisoning may include fatigue, weakness, na usea, anorexia, headache and irregular heartbeats (Goldfrank et.al, 2010). Acute renal tubular in jury due to hypercalcemia may cause excessive urination, increased wate r intake, protein in urine and increased blood urea levels. Prolonged hypercalcemia may eventually cause kidney failure due to formation of kidney stones and calc ium deposition in kidney tissues.

• Zinc phosphide can quickly produce toxic phosph ine gas when it comes in contact with acids or water. Phosphine is thought to produce toxicity by blocking cytochrome oxidase and, inhibiting oxidative phosphoryla tion which may lead to cell death (Perry H.E., 1998). Most of the tissue damage can o ccur in liver, kidneys and heart. Patients may present with symptoms such as, severe gastrointestinal irritation, nausea, vomiting (with fishy odor), chills, tightness of ch est, difficulty in breathing and cough (from pulmonary edema). Development of liver failure can cause jaundice and excessive hemorrhage. Delirium, convulsions and coma may result from renal tubular damage.

Common cause of death is from ventricular arrhythmias and shock due to myocardial damage (Reigart J.R., 1999).Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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2. Characterization of acute hazard for four rodenticide active ingredients in products subject to this Notice

The products subject to this Notice each contain one of four rodenticide active ingredients: warfari n, brodifacoum, difethialone and br omethalin. Warfarin is a FGAR;

brodifacoum and difethialone are SGARs that are very similar in structure to each other. Bromethalin is not an anticoagulant but an unc oupler of oxidative phosph orylation whose effects are manifested as neurotoxicity. For each of the anticoagulant rodenticides vitamin K 1 is an antidote to poisoning, although for the second gene ration anticoagulants, re peated administration over many days or weeks is often necessary. Sin ce there is no specific antidote for bromethalin poisoning, clinicians and veteri narians treat the symptoms of bromethalin toxicity.

Anticoagulant rodenticides bloc k the production of vitamin K which is essential for the synthesis of several clotting factor s. The first sign of toxicity from poisoning is an increase in the time it takes blood to clot (pro thrombin time). This is not an effect that would be detected immediately because it takes time for the anticoa gulants to clear vitamin K-dependent clotting factors from the blood, nor is it an effect that wo uld be noticed in a home setting, but rather in a medical facility. With a higher dose, symptoms become more noticeable and severe, and include easy bruising and bleeding from almost any tissue such as gums, nose, urinary tract, gastrointestinal tract, etc. In severe cases, there is massive loss of blood leading to death.

Bromethalin is not an anticoagulant and ther e are few symptoms that would be regarded as “signature” effects at low doses. At low dos es, a poisoned individual might exhibit mental confusion or dullness. At higher doses as ce rebrospinal pressure increases there may be indications of weakness in limb strength and at very high doses, death preceded by general paralysis or convulsions.

The acute toxicity of each of the four rodenticides will be discussed briefly below with the focus being on acute toxicity values and other relevant parame ters reported in the studies.

Warfarin. The acute oral LD 50 for warfarin in rats is reporte d as 3 mg/kg (males only - Gaines, T. B. 1969. Toxicol. Appl. Pharmacol. 14, 515- 534, MRID 00049330). Another source indicates

there is considerable vari ability in reported rat LD 50 s for warfarin: “Reported oral LD 50 values for warfarin in rats vary by a considerable magnitude. Values of 11 mg/kg body weight (Lund, 1982), 58 mg/kg body weight (Thomson, 1988) and 58 mg/kg (female) and 323 mg/kg (male) (Hagan & Radomski, 1953) have been reported.” (http://www.inchem.org/documents/ehc/ehc/ehc 175.htm). Another study supports a large difference between the acute toxicity of warf arin to male and female rats with the LD 50 for males reported to be between 450 and 680 mg/kg and the LD 50 for females reported as between 5 and 10 mg/kg (MRID 00143093).

Brodifacoum. The oral (gavage) LD 50 of brodifacoum in rats is 0.42 mg/kg in males and 0.56 mg/kg in females. Signs of toxicity at 0.5 and 0.75 mg/kg included pallor, bleeding from the nose

and/or rectum and/or other sites. Deaths o ccurred in the period from 3-8 days after dosing. PostRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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mortem examination of those animals that died or were sacrificed in extremis and/or showed signs of bleeding, revealed the pr esence of free or clotted blood in the abdominal and/or thoracic cavity. Discoloration or pallor of a number of organs was also observed. These findings are

consistent with the known anticoa gulant activity of brodifacoum. There were no mortalities or signs of toxicity in male and female rats at a dose of 0.25 mg/kg (MRID 42687501). The halflife for brodifacoum in liver is ve ry long – up to 350 days (MRID 42007502).

Difethialone. Difethialone is a SGAR that requires only a single ingestion to be effective. Difethialone and brodifacoum are very close to each other structurally, differing only in the hetero atom in the coumarin ring. Like brodifaco um, difethialone has a long half-life in the body.

The estimated half life of difethialone in rat li ver from a single oral dose at 0.5 mg/kg is 175 days for males and 98 days for females (MRID 42065010) . In an acute lethality study, the oral (gavage) LD 50 of difethialone in rats was 0.55 mg/ kg (males) and 0.58 mg/kg ((females) (MRID 40268903). Animals died in 4-8 days with sympto ms of anticoagulant toxicity. There were no deaths for either males or females at 0.4 mg/kg indicating a very steep dose response curve.

There was a second acute lethal ity study in rats (MRID 40268903) in which 0/10 rats died at 0.4 mg/kg and 10/10 rats died at 0.8 mg/kg. The tw o acute studies are cons istent with each other and support an LD 50 value of 0.55 mg/kg for acute leth ality of difethialone in rats.

Bromethalin. Bromethalin (N-methyl-2,4-dinitro-N- [2,4,6-tribromophenyl]-6-[trifluoromethyl] benzenamine) is not an anticoagulant but an unc oupler of oxidative phosp orylation in which the the most apparent manifestation of toxicity invol ves the central nervous system. It is therefore recommended for use against anticoagulan t resitant mice and rats. The oral LD 50 in rats for bromethalin is reported as 3.2 mg/kg (males), 2.1 mg/kg (females) and 2.6 mg/kg (combined males and females) (MRID 44775101). Anot her study (MRID 00241521) lists the for LD 50 females as (9.1 mg/kg and the LD 50 for males as 10.7 mg/kg).

EPA routinely characterizes the risk to humans posed by pesticides with uses in or around the home. An important pa rt of a residential assessment is consideration of potential “incidental oral” exposure. The incidental oral assessment seeks to determine the exposure and risks to young children who may ingest pesticide that they w ould pick up on their hands (hand to mouth activity), or would be exposed to by mout hing an object with pesticide residue on it, or actually pick up granules of pesticid e formulation scattered around the home.

EPA has developed a quantitative approach to evaluating whether a pesticide poses risks to those who might be exposed as a consequence of pesticide uses. Us ing available toxicity data and other information such as physical and chemical properties of the pesticide, and activity patterns of potentially exposed persons, EPA esti mates a level of exposure that would not cause harm (referred to in this analysis as the “exposur e level of concern”), and compares that level to the amount of exposure people would get as a cons equence of pesticide use. If the estimated exposure exceeds the exposure level of concern, the use of the pesticide poses risks that may or may not be unreasonable, depending on the benefits of the use.Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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EPA relies primarily on toxicity studies conduc ted with laboratory animals to derive exposure levels of concern for pesticide active ingredients. First EPA examines all of the

available hazard studies and identifies the most sensitive toxic effect caused by a pesticide for the route and duration of exposure that matc hes the proposed exposure scenario. For rodenticides, EPA is primarily concerned about the hazards of a single instance of oral exposure. The only acute oral exposure studies availabl e for the subject rodenticides are acute LD 50 studies.

Acute LD 50 studies are not designed to identify sublethal toxic effect s, but instead, to determine the amount of exposure that will cause death to 50% of the test animals after a single exposure.

Because most chemicals cause adverse effects at dose levels well below a lethal dose EPA typically would base a human hea lth risk assessment on toxicity effects more sensitive than the

acute LD 50 . However, in the absence of a more appropriate toxicity data, the acute LD 50 studies

were used as the effect of concern for this assessment.

To derive an exposure level of concern, EPA t ypically divides the point of departure (i.e., the exposure level that corresponds to the to xic effect of concern, here the acute LD 50 ) by appropriate uncertainty factors. The uncertain ty factors are intended to account for possible differences in sensitivity between humans a nd laboratory animals, for differences between humans, and in this case, to acc ount for the likelihood of sublethal adverse effects. Using these uncertainty factors, EPA identifies a level of e xposure that, with reason able certainty, would not

cause harm to humans because the difference be tween predicted exposures and the levels that cause adverse effects is large enough that no harm would reasonably be e xpected. It should be noted that an exposure at a level above the exposure level of concern may not elicit any discernable symptoms, depending on the nature of the effect, the amount of the exposure and the sensitivity of the individual pe rson. To address the possibility that the pesticide may generally be more toxic to humans than animals and the pos sibility that variations in human sensitivity may be greater than seen in the test animals, th e Agency usually applies un certainty factors of at least 100, meaning that in order to be presumed safe, an exposure should be at least 100 times lower than the toxicity endpoint. Often EPA app lies additional uncertainty factors to account for

the absence of a “no observed adverse effect leve l” (NOAEL) and to address other limitations of the toxicity database.

Owing to the paucity of data on sublethal eff ects of the subject rodenticides, EPA can not confidently establish exposure levels of concern for acute human exposure to the subject rodenticides. However, if EPA had a complete toxicity database with appropriate studies of

sublethal effects with clearl y established NOAELs, EPA would apply to that endpoint an uncertainty factor of at least 100 (i.e., a leve l of concern 100 times lower than the LOAEL) for each active ingredient to account fo r interspecies and intraspecies variability. If EPA had all the same studies, but the study showing the most se nsitive toxic effect failed to establish a NOAEL, EPA would, in all likelihood, use an uncertainty factor of 1000. In the present case, all of these uncertainties are present, and moreover, the acute t oxicity effect of concer n (death) is severe and its relationship to sublethal acu te adverse effects is unknown. In view of these uncertainties, EPA is unable to say with confidence that there is any finite level of exposure to the subject

rodenticides that can be consid ered reasonably likely to cause no harm. Nevertheless, with the caveat that this undoubtedly understa tes the risks of sublethal a dverse effects, Table 3 belowRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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shows the LD 50 values for each of the rodenticides and what the exposure level of concern would be if EPA applied an uncertainty factor of 1000 to derive a level of concern based on rat LD 50 s.

Table 3. Surrogate Exposure Level of Concern

Rodenticide LD 50 (mg/kg) Provisional Uncertainty

Factor Surrogate Exposure Level of Concern (mg/kg)
Warfarin 3 mg/kg 1000 0.003 mg/kg Brodifacoum 0.42 mg/kg 1000 0.00042 mg/kg Difethialone 0.55 mg/kg 1000 0.00055 mg/kg Bromethalin 2.6 mg/kg 1000 0.0026 mg/kg

After deriving an exposure level of concern, EPA would estimate potential exposure of different population groups. As is evident from the incident reports a nd corroborated by studies of children’s behavior, young children will pick up and put small amounts of food-like material

into their mouths. In the 1998 Rodenticide Cl uster RED, EPA had cited poison specialist’s estimation that a child weighing 10 kg would cons ume approximately 5 grams of rodenticide bait in one bite (less than a quarter of an ounce). In the current analysis, EPA’s estimate of the potential exposure to children eating a single, 5-gr am bite of rodenticide bait containing any of the active ingredients at issue greatly exceeds possible safe levels, without even considering potential sublethal effects. Table 4 below shows how the estimated child exposure from taking one bite of rodenticide bait compar es to the surrogate exposure leve ls of concern for each of the subject rodenticides.

Table 4. Surrogate Exposure Level of Concern for 5 gm Rodenticide Bait.

Rodenticide % active ingredient in a bait product Rodenticide ingested in a 5 gm bite of bait by a 10 kg child Surrogate Exposure

Level of Concern (UF = 1000) Warfarin 0.025% 0.13 mg/kg 0.003 mg/kg Brodifacoum 0.005% 0.025 mg/kg 0.00042 mg/kg Difethialone 0.0025% 0.0125 mg/kg 0.00018 mg/kg Bromethalin 0.01% 0.05 mg/kg 0.00087 mg/kg

This quantitative analysis based on animal toxi city data is consistent with information from reports of incidents of human poisonings . Children who have accidentally ingested quantities of the subject rodentic ides have displayed symptoms th at are consistent with exposure to toxic levels of these compounds. Symptoms for the anticoagulants include hematological effects such as bruising, and bleeding from gums, nose and ot her tissues. Symptoms from bromethalin poisoning may include effects on cogniti on and paralysis. Th ese effects are clearly

harmful.

In sum, EPA’s analysis shows that, unl ess use and exposure patterns are changed, children could easily ingest quantities of the subj ect rodenticides that would contain sufficient amounts of active ingredient to ex ceed levels that EPA would cons ider safe. Consequently, EPARodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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could not conclude that exposure to the subject rodenticides was reasonably certain not to cause

harm.

The rodenticide active in gredients in products subject to this Notice are designed to kill rodents and are known poisons to all mammals, so the number of studies concerning their effects in humans is understandably limited. Much of th e information on their potential risk to humans

and domestic animals comes from the numerous reported incidents detailing the frequent exposure of children to roden ticides, and the serious conse quences (including prolonged veterinarian care and death) to companion animal s. These incidents are discussed in the next

sections

3. Human Incident Data

EPA generally relies on toxici ty studies conducted on animals and exposure information based on the pesticide’s use pattern when registering a pesticide. After a pesticide is registered; however, human observational data about the effect s and exposure of registered pesticides may be collected and analyzed. In assessing the risks of products subjec t to this Notice, EPA analyzed human observational data, or incidents, from the following sources:

• summary data from the American Associ ation of Poison Control Centers (AAPCC),

• Human incident (poisoning) data from such s ources as OPP’s Incident Data System (IDS) database,

• NIOSH Sentinel Event Notification Syst em for Occupational Risks (SENSOR),

• the Agency-sponsored National Pesticide Information Center (NPIC),

• California’s Pesticide Incident Surveillance Program (PISP), and

• Additional review of the open literature.

Incident information can provide important information about actual real-world exposures and risks associated with pesticide products. In cident data are collected systematically, but differently, by a number of or ganizations. The databases used by the Agency differ with respect to such issues as coverage , certainty/confidence, fields/parameters reported, and usability. These five pesticide incident da ta sources in combination with additional data from the open literature provide useful content and historical perspec tive. Various other comparable sources of data are available (e.g. th e Bureau of Labor Statistics, emergency room outpatient surveillance, etc.) bu t are believed to be of limited additional utility and were not relied upon for the development of this Notice. Information from all 5 databases and open literature is provided in the Rode nticides Tier II: Review of Human Incidents, November 1, 2011 Memorandum; however, in regard to childre n’s exposures to house hold products such as rodenticide baits, the AAPCC reports are the most applicable and complete, and are therefore the focus of this discussion. By looking across the data sources which were used, the Agency is confident that the data are adequate and appropria te for the discerning of trends and patterns inRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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incident poisonings associated with the followi ng rodenticides used for commensal rodent control in bait form: brodifacoum, bromadiolone , bromethalin, chlorophacinone, cholecalciferol, difethialone, diphacinone, diphaci none sodium salt, warfarin, wa rfarin sodium salt, and zinc phosphide. Although these incide nt reporting databases can pr ovide important information regarding the frequency, distri bution and severity of adverse effects, they are far from comprehensive. EPA estimates that only one qua rter of the total number of pesticide poisoning incidents are reported to th e AAPCC or state counterparts . (Blondell and Spann, 06/03/1999, D256673).

American Association of Po ison Control Centers (AAPCC)

The American Association of Poison Contro l Centers (AAPCC) is a non-profit, national organization founded in 1958 that represents the poi son control centers of the United States and the interests of poison prevention and treatment of poisoning. All of the calls to a poison control center are answered by a medical professional trained to answ er questions about poisons. Additionally, AAPCC reports prov ide clearly summarized inform ation on pesticide incidents within the context of other poisoning even ts. AAPCC produces an annual summary report giving statistics and information on all the poisonings reported to poison control centers in a calendar year. AAPCC ranks the severity of human exposure incidents as follows:

• Death,

• Major - symptoms are life-thr eatening or result in residual disability or disfigurement (coma, cardiovascular instabil ity, repeated seizures),

• Moderate – symptoms are more pronounced, pr olonged, or more of a systemic nature than minor symptoms with no residual disabi lity. Usually some form or treatment is indicated (high fever, disorientation),

• Minor – symptoms are minimal with no residua l disability (skin irritation, drowsiness, mild gastrointestinal symptoms), or

• None – patient developed no symptoms as a result of exposure.

A. Observed Human Exposures and Resultant Health Effects

1. Prevalence

When looking across human incident data s ources, as well as the open literature,

rodenticides are found to be involved in numerous reported incidents, es pecially those involving children less than 6 years old. While all the sources (IDS, NPIC, PISP, NIOSH SENSOR) demonstrated that humans are being exposed to r odenticides, it is most ev ident in the Agency’s

examination of the AAPCC rodenticide data fr om 1999 to 2009. These data showed that an average of 17,000 human exposures to rodenticides were reported annually. Approximately 85% (i.e., approximately 15,000 per year) of these 17,000 exposures occurred to children under 6 years old over the 11 year period analyzed. Ap proximately 16% of all reported exposures to pesticides in the AAPCC data are related to r odenticide exposure. A pproximately 26% of all reported pesticide exposures among children under 6 in the AAPCC data are related toRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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rodenticide exposure. Although incident data ge nerally do not specify which products were the subject of the reported exposures, very few ,if any, consumer rodenticide products available on the market during this timeframe included bait sta tions intended to preven t children’s exposure.

While certain AAPCC data are publicly ava ilable through 2010, EPA purchased access to the raw data and ancillary information for the years 1999 to 2005. More detailed analysis of

AAPCC raw data from 1999 to 2005 of the childre n’s exposures to rodenticides, demonstrates that approximately 3,686 children less than 6 years ol d were treated at a h ealth care facility for the seven year period analyzed. The analysis al so demonstrates that on average for this seven year period approximately 128 cases per year (o r 1%) of the exposures to children result in a medical outcome classified by the AAPCC as minor, moderate or major. Also, of all pesticiderelated cases involving children less than 6 y ears old from 1999 to 2005, approximately 39% of

those seen in a health care faci lity are related to rodenticide exposure and 13% of hospitalization cases are related to rodenticide exposure. Fo rtunately, no deaths to children under 6 years old have been reported in these AAPCC data from 1999 to 2010.

2. Circumstances

Incidents involving children appear to resu lt primarily from their picking up unprotected baits in the home. This may result from failure to follow label directions to keep bait away from children, though in some cases, baits might ha ve been moved by rodents from appropriate placement locations. In some cases it appears that parents underestimate places their children are capable of accessing. In other ca ses, it appears that these chil dren were visiting a different environment (such as grandparents, friends, or neighbor’s) and their parent or guardian was

unaware that the baits were accessible. Most in cidents involving adults appear to be due to

suicide or malicious inte nt. Accidental exposures, although rare , occasionally occur for adults.

Approximately 85% (i.e., approximately 15,000 per year) of the 17,000 AAPCC exposures to rodenticides occurred to child ren under 6 years old over the 11 year period analyzed. Rodenticide exposure incidents are more likely to involve children than exposure incidents associated with any ot her category of pesticides (Tab le 5). Out of all reported pesticide-related exposure incidents to child ren under 6 years old, for all pesticides, approximately 26% of the exposures are due to rodenticides.

Table 5. Ratio of Exposures to Children <6 years old to Number of Single Exposures per Pesticide Category in AAPCC from 1999-2009

Pesticide Category % Exposures to Children

disinfectants 55%

Fungicides 25%

Herbicides 26%

insecticides 41%

organophosphates 29%Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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Table 5. Ratio of Exposures to Children <6 years old to Number of Single Exposures per Pesticide Category in AAPCC from 1999-2009

Pesticide Category % Exposures to Children

other pesticides 65%

rodenticides 85%

3. Resultant effects

The majority (92%) of the rodenticide e xposures reported to AAP CC do not result in significant symptoms based on those cases whic h received follow up to determine medical outcome. While exposures to rodenticides genera lly result in no detected clinical signs in children, the Agency believes that the numb er of non-symptomatic exposure incidents is unacceptably high because of the social costs as sociated with evaluating and treating children who might have been exposed.

Nevertheless, severe outcomes from human e xposures to rodenticides do occur. Despite the relatively low number of symptoma tic cases, looking at AAPCC data from 1999-2005, rodenticide-related exposures are much more lik ely to receive medical treatment accounting for 39% of all pesticide-related cases seen in a hea lth care facility and 13% of all hospitalized cases involving children less than 6 years old. From 1999-2005, 894 cases were reported having minor, moderate, or major effects (Table 6). Fo r cases reporting moderate or major effects, the most common effect reported was hematological , 37% and 55% respective ly. These symptoms are likely a result from anticoagulant rodenticid es’ abilities to interfer e with blood clotting and are likely the result of rodenticide exposure.

* the categories are not mutually exclusive (i.e. a pers on could report both a neurological and renal symptom) *there were no reported cardio symptoms. Table 6. AAPCC Reported Exposure Symptoms for Symptomatic Children Less Than 6 Exposed to Rodenticide from 1999-2005

Level

of

Effect Total Expo

sures Reported Exposure Symptoms*

Neurological Ocular Renal Respiratory Misc. Dermal GI Hematological

Minor

effect 727 15 (2%) 17 (2%) 0 20 (3%) 180 (25%) 18 (2%) 277 (38%) 36(5%)

Moder

ate
effect 147 7 (5%) 1 (1%) 4 (3%) 2 (1%) 22 (15%) 8 (5%) 34 (23%) 55 (37%)

Major

effect 20 1 (5%) 0 0 2 (10%) 5 (25%) 2 (10%) 4 (20%) 11 (55%)Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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4. Effects on Domestic Animals

A Hazard to Domestic Animals and EPA’s Approach to Assessing Ongoing

Health Effects on Pets

Rodenticides have much the same effects on domestic animals as they do on humans and on target mammals, as discussed above, although species may differ somewhat in sensitivity.

EPA generally relies on toxici ty studies conducted on animals and exposure information relevant to the pesticide’s use pattern when initia lly registering a pesticide. After a pesticide is registered; however, observational data about the effects and exposure of registered pesticides may be collected and analyzed. In assessing the risks of products subject to this Notice, pet observational data, or incidents, from the following sources were analyzed:

• Information from the National Animal Poison Control Center (APCC), the Pet Poison Helpline, and the open literature.

• OPP’s Incident Data Sy stem (IDS) database,

• the Agency-sponsored National Pesticide Information Center (NPIC),

Animal Poison Control Center and Pet Poison Helpline The American Society for the Prevention of Cruelty to Animals (ASPCA) Animal Poison Control Center (APCC) is a 24 hours a day, 365 da ys a year resource for animal poison-related emergencies. Calls to the APCC are triaged by sp ecially trained veterinary toxicologists. The Pet Poison Helpline, another po ison reporting center which is available throughout the U.S., Canada and the Caribbean, is managed by veterina ry specialists who also help triage animal poisoning events. The veterinary specialists include board-certified veterina ry internal medicine emergency critical care specialists, and veterinary toxicologists.

OPP Incident Data System (IDS)

The OPP IDS database of pet exposure informati on includes reports of al leged incidents from various sources, including FIFRA Section 6-(a)-( 2) reports from registrants and reports from other environmental agencies a nd individual consumers. The ID S exposure severity types for domestic animals, as define d by 40 CFR 159.184, are as follows:

• DA – Death – if the domestic anim al died or was euthanized;

• DB – Major – if the domestic animal exhi bited or was alleged to have exhibited symptoms which may have been life-threate ning or resulted in re sidual disability;

• DC – Moderate – if the domestic animal e xhibited or was alleged to have exhibited symptoms which are more pronounced, more pr olonged or of a more systemic nature than minor symptoms and included some treat ment and return to pre-exposure state;

• DD – Minor – if the domestic animal was alle ged to have exhibited symptoms, but theyRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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were minimally bothersome and resolved rapidly;

• DE – Unknown – if symptoms are unknown or not specified. 5

National Pesticide Information Center (NPIC)

NPIC is a cooperative effort between Oregon State University and EPA which is funded by EPA to serve as a source of objective, scie nce-based pesticide info rmation and respond to inquiries from the public and to incidents. NP IC receives approximately 25,000 calls per year, with about 4000 of these being related to pest icide exposure incidents. NPIC collects the

information about the incidents a nd records that information in a database. NPIC is a source of national incident information; but generally recei ves fewer reports than IDS. Regardless, NPIC can provide an additional source of incident information. Unlik e IDS, incidents reported to NPIC are assigned a certainty classification, wh ich helps ascertain whether the exposure and reported outcome are related.

B. Ongoing Pet Exposure and Resultant Health Effects

1. Prevalence

The American Society for the Prevention of Cruelty to Animals (ASPCA) Animal Poison Control Center (APCC) website identifies the top ten pet toxins of 2010 based on the number of calls received. Out of the approximately 167,000 phone calls about pet expos ures they received during 2010, rodenticides were li sted as the third most freque nt reason for calls to the APCC (after human medications and inse cticides). Another 24-hour hotli ne, the Pet Poison Helpline, in

2009 identified rodenticides as the third most common toxin involved in dog poisonings (after

chocolate and insect bait stati ons) and the fourth most common t oxin involved in cat poisonings (after lilies, canine permethrin inse cticides and household cleaners).

Both the IDS and NPIC data indicate that the number of repor ted incidents of pet exposure to rodenticides is incr easing over time. However, differe nt rodenticides are associated

with this increase in the different databases.

IDS reports that the number of reported pet exposures involving first-generation anticoagulants and non-anticoagulant rodentic ides was relatively stable from 1999 to 2009, whereas reported exposures involving second-ge neration anticoagulant r odenticides (chiefly bromadiolone) increased over time, from approxi mately 200 per year to approximately 1400 per year, primarily in the moderate, minor and unknown outcome categorie s. The overall upward trend may be a result of increase d usage or increased reporting, ra ther than an increase in the likelihood that use of a product results in an incident.

5 Some exposures are classified as “D” in IDS, which is a classification used before 1998 (at which point reporting requirements were updated) or used to indicate the severity is undetermined; as the focus of this assessment is on incidents occurring in 1999 or later, we assume all “D” exposures are “DE” and have undetermined severity.Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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By contrast, NPIC reports th at the number of reported pet exposures involving first- and second-generation anticoagulants was relativel y stable from 1999 to 2010, whereas reported exposures involving non-anticoagul ants (chiefly zinc phosphide) increased over time, from approximately 5 per year to approximately 180 per year. Although as r odenticide bait, zinc phosphide is not registered for commensal rode nt control in and ar ound homes. The major consumer use for zinc phosphide is outdoors for mole and vole control.

2. Circumstances

From the narrative information available re garding these incident s and the literature review, it appears that many pets gain access to baits placed in and around homes. EPA believes the main reason these incidents are occurring is because loose baits and bait blocks without petresistant bait stations are being pl aced in areas accessible to pets.

3. Resultant effects

The IDS data reflect that although most inci dents appear to result in lower severity outcomes, there were a substantial number of fatalities (1209) and major outcomes (565) from 1999 to 2009. The report lists two times more fata lities than major outcomes; which may be due to pet owners being more likely to report fatalities. Th is indicates that rodenticides cause about 160 of the severe (death or major effect) domestic animal incidents that ar e reported every year, which EPA believes is likely to significantly und erestimate the actual number of incidents.

The IDS data also allows rodenticide active ingredients to be ra nked according to the severity of domestic animal incidents reported. Although the data may be influenced by market share, focusing on those exposures resulting in severe outcomes provides an indication of the hazard of a particular active ingr edient. The rodenticid e with the highest number of incidents ranked DA (death) and DB (major) over the pe riod 1999-2010 was brodifacoum (710 incidents), followed by bromadialone (355), bromethalin (292 ) and diphacinone and its sodium salt (262). Together, the second generation anticoagulants brodifacoum and bromadialone accounted for 60% of the major and fatal domestic animal inci dents (DA+DB) attributed to rodenticides.

Comparing the total number of major and fata l incidents (DA+DB) pe r active ingredient, and as a percentage of total incidents for that same active ingredient provides a way to judge whether a particular active ingredie nt is more or less likely to caus e serious adverse effects. For example, brodifacoum is involved in about twice as many fatalities as bromadialone, but fewer exposures overall (about 70% as many as bromad iolone), suggesting grea ter potential for an exposure resulting in a high severity outcome is greater when exposed to brodifacoum.Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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Table 7: IDS - Rodenticides as a Percentage of Severe Outcomes, 1999-2009

Rodenticide Category Percentage of Death + Major Incidents out of Total Exposure

Count Total Exposure

Count

Diphacinone and diphacinone, sodium salt
First-generation 22% 1,192

Warfarin and warfarin,

sodium salt 22% 151

Chlorophacinone 21% 29

Brodifacoum

Secondgeneration 22% 3,229

Bromadiolone 8% 4,661

Difethialone 13% 144

Difenacoum 27% 11

Bromethalin
Nonanticoagulant 12% 2,460

Zinc phosphide 18% 258

Cholecalciferol 23% 209

VI. Non-Target Wildlife Risks Associated wi th Exposure to Rodenticide Products Subject

to This Notice

This discussion summarizes the ecological risk concerns that form part of the basis of EPA’s decision to cancel and deny registrations for the commensal rodent control products identified above in this notice. EPA has update d its previous risk assessment findings conducted in support of the May 2008 RMD through the applic ation of additional effects and exposure data, use of additional exposure modeling, and quantita tive risk assessment te chniques for the four rodenticide active ingredients (bro difacoum, difethialone, warfarin and bromethalin) contained in products subject to this Notice and for two r odenticides (chlorophacinone and diphacinone) that are potential alternatives to brodifacoum and difethialone in the consumer rodenticide market.

Rodenticide baits are intended to be lethal to rodents and a few other small mammals, but they are not selective to target species. Mammals and birds are vulnerable to adverse effects, including mortality, from rodenticides, althoug h different species and individuals may have differing sensitivities. Rodenticide exposures and mortalities have been documented for mammals and birds that are primary and secondary consumers.

For the purpose of the ecological risk asse ssment, primary exposure was defined as nontarget organism consumption of rodenticide tr eated bait. Use of rodenticide baits around structures is likely to result in primary e xposures among non-target wi ldlife. Many factors influence which non-target animals might be exposed directly to baits. For instance, birds and mammals that are attracted to seeds and grains may consume grain-based rodenticide baits and baits in forms similar to seeds and grains. Some non-target animals will readily consumeRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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rodenticide baits that have a block form. E xposure has been reported for a number of species that are primary consumers of bait, includi ng quail, turkeys, squi rrels, opossums, raccoons, skunks, and deer.

Secondary consumers were defined in the eco logical risk assessment as those animals that prey upon or scavenge primary consumers of bait. Rodenticide baits also pose potential secondary risks, because predators and scavengers are likely to be attracted to dead or dying rats, mice, and poisoned non-target animals. In ad dition, secondary consumers may also consume

commensal rodent baits that cont ain flavorings that might appeal to carnivores and omnivores. Secondary exposure has been documented in a nu mber of secondary consumer species including larger mammals such as bobcats and foxes, and nu merous bird species such as hawks, eagles and

owls.

The EPA assessment does not evaluate potential risks to aquatic organisms or plants. Exposure to aquatic organisms is assumed to be negligible relative to potential exposures to

terrestrial animals for commensal rodent contro l via the evaluated consumer use products given that (1) direct application to wate r is unlikely to occur; (2) spray dr ift of baits is not expected; (3) large, contiguous areas are not expected to be trea ted; and (4) leaching of rodenticides from baits is limited. Direct risk to terrestrial plants wa s presumed low given the modes of action of the

evaluated rodenticides.

EPA is concerned with both the primary a nd secondary risks to birds and non-target mammals from exposure to the commensal rodent c ontrol products subject to this notice. This concern is based upon consideration of several li nes of evidence, including (1) an assessment of the risks to non-target animals associated with primary exposure to rodenticides; (2) an assessment of the risks of non-target animals th rough secondary exposure to rodenticides; (3) an evaluation of available feeding studies as they relate to secondary exposure risks; and (4) an evaluation of reported wildlife incidents as they relate to primary and secondary mortality events for non-target species in a va riety of land use settings, in cluding urban, suburban, and rural settings. Tables 8, 9, 10 and 11 be low summarize the results of EPA’ s analysis of these lines of

evidence.Rodenticides.  Draft Notice of Intent to Cancel and Denial    11/02/2011~ 26 ~Table 8. RQs from the bird risk assessment: primary exposureof passerine birds to bait and secondary exposure ofpredator/scavenger birds to residues in consumed rodents.Bodyweights (g)BrodifacoumDifeth-ialoneWarfarin(0.025%)Warfarin(0.054%)Chloro-phacinoneDipha-cinoneBrometh-alin

Primary exposure to passerinesSingle day dose RQ20 19.61* 29.80*0.230.50*0.07 0.017.76*100 22.67* 18.39*0.14 0.31 0.04 0.014.76*1000 27.89* 9.22*0.07 0.16 0.02 <0.012.40*Six day dose RQ20 117* 168* 1.36* 2.94*0.40 0.05NA100 135* 104* 0.84* 1.81*0.25 0.03NA1000 166* 52*0.420.91*0.12 0.01NADietary RQNA38* 45*0.400.86* 0.89*0.06 0.48

Secondary exposure to carnivores and scavengersHouse mouse consumption:3 day accumulation in preyRQ100 19.77* 17.09*0.14 0.30 0.04 0.014.06*1000 15.42* 5.42*0.04 0.09 0.01 <0.011.29*5000 12.96* 2.43*0.02 0.04 0.01 <0.010.58*Norway rat consumption: 3day accumulation in preyRQ100 5.25* 4.52*0.04 0.08 0.01 <0.011.07*1000 4.08* 1.43*0.01 0.02 <0.01 <0.01 0.345000 3.43* 0.64*0.01 0.01 <0.01 <0.01 0.15House mouse consumption:6 day accumulation in preyRQ100 39.40* 32.98*0.270.58*0.08 0.01NA1000 30.74* 10.45*0.09 0.19 0.02 <0.01NA5000 25.84* 4.68*0.04 0.08 0.01 <0.01NANorway rat consumption: 6day accumulation in preyRQ100 10.43* 8.73*0.07 0.15 0.02 <0.01NA1000 8.14* 2.77*0.02 0.05 0.01 <0.01NA5000 6.84* 1.24*0.01 0.02 <0.01 <0.01NAHouse mouse consumption:dietary RQNA17.81* 2069*0.19 0.41 0.32 0.02 0.20Norway rat consumption:dietary RQNA4.71* 5.48*0.05 0.11 0.09 <0.01 0.05NA = not applicable ND = no data* RQ exceeds acute risk LOC = 0.50Rodenticides.  Draft Notice of Intent to Cancel and Denial    11/02/2011~ 27 ~Table 9. Additional lines of evidencefrom the bird risk assessment.Bodyweights (g)BrodifacoumDifeth-ialoneWarfarin(0.025%)Warfarin(0.054%)Chloro-phacinoneDipha-cinoneBrometh-alin

Primary exposure to passerinesDays to consumesufficient bait to reachthe LD5020<1 <1 4-5 1-2 16-17 >365 <1100<1<17-8 3-430-31>365 <11000<1<114-15 6-7117-118>365 <1Grams bait consumed toreach the LD50200.3 0.2 25 10 86 >1800 0.71000.9 1.1 160 80 620 >7300 4.210005 15 2100 990 17000 >52000 59

Secondary exposure to carnivores and scavengersNumber of house miceconsumed to reach theLD50: 1 day accum. inprey100<1 <1 38 18 130 820 110002 4 540 250 1800 1200 1650005 27 3400 1600 1200 74000 104Number of Norway ratsto consume to reach theLD50: 1 day accum. inprey100<1 <1 7 3 23 150 <11000<1 <1 97 45 330 2100 35000<1 5 610 280 2100 13000 17Secondary feeding studysummary counts(#mortalities/ #tested)NA 63/149 ND 2/23 0/112 3/34 ND

Incident data summary countsprimary exposureNA 3 0 1 3 1 0secondary exposureNA 164 3 5 3 5 0unknown exposureNA 21 0 0 1 0 0NA = not applicableND = no data* RQ exceeds acute risk LOC = 0.50Rodenticides.  Draft Notice of Intent to Cancel and Denial    11/02/2011~ 28 ~Table 10. RQs from the mammal risk assessment: primary exposure of rodents to bait and secondary exposure ofpredator/scavenger mammals to residues in consumed rodents.Bodyweights (g)BrodifacoumDifeth-ialoneWarfarin(0.025%)Warfarin(0.054%)Chloro-phacinoneDipha-cinoneBrometh-alin

Primary exposure to rodentsSingle day dose RQ15 9.93* 4.30* 8.36* 18.05* 0.82* 1.97* 5.1*35 8.48* 3.67* 7.14* 15.42* 0.70* 1.68* 4.4*1000 4.55* 1.97* 3.83* 8.27*0.380.90* 2.4*Six day dose RQ15 59* 24* 49* 106* 4.7* 11.6* NA35 51* 21* 42* 90* 4.0* 9.9* NA1000 27* 11* 22* 48* 2.1* 5.3* NADietary RQNA94*ND57* 123* 44* 22* ND

Secondary exposure to carnivores and scavengersHouse mouse consumption:3 day accumulation in preyRQ50 11.10* 4.74* 8.81* 19.03* 0.84* 2.49* 4.31*1000 13.78* 5.88* 10.93* 23.61* 1.04* 3.09* 3.53*3000 14.91* 6.37* 11.83* 25.56* 1.12* 3.35* 5.79*Norway rat consumption: 3day accumulation in preyRQ50 2.94* 1.25* 2.33* 5.04*0.220.66* 1.14*1000 3.65* 1.56* 2.89* 6.25*0.270.82* 1.42*3000 3.95* 1.68* 3.13* 6.76*0.300.89* 1.53*House mouse consumption:6 day accumulation in preyRQ50 22.13* 9.15* 17.35* 37.48* 1.63* 4.20* NA1000 27.46* 11.35* 21.53* 46.51* 2.02* 5.21* NA3000 29.72* 12.28* 23.30* 50.33* 2.18* 5.64* NANorway rat consumption: 6day accumulation in preyRQ50 5.86* 2.42* 4.59* 9.92* 0.43 1.11* NA1000 7.27* 3.00* 5.70* 12.31* 0.53* 1.38* NA3000 7.87* 3.25* 6.17* 13.32* 0.58* 1.49* NAHouse mouse consumption:dietary RQNA44.69*ND26.64* 57.54* 20.42* 10.11* NDNorway rat consumption:dietary RQNA11.23*ND7.05* 15.23* 5.41* 2.68* NDNA = not applicable ND = no data * RQ exceeds acute risk LOC = 0.50Rodenticides.  Draft Notice of Intent to Cancel and Denial    11/02/2011~ 29 ~Table 11. Additional lines of evidence from the mammal risk assessment.Bodyweights (g)BrodifacoumDifeth-ialoneWarfarin(0.025%)Warfarin(0.054%)Chloro-phacinoneDipha-cinoneBrometh-alin

Primary exposure to rodentsDays to consume sufficientbait to reach the LD5015<1 <1 <1 <1 1-2 <1 <135<1 <1 <1 <1 1-2 <1 <11000<1 <1 <1 <1 2-3 <1 <1Grams bait consumed toreach the LD50150.3 0.7 0.3 0.2 6 1.1 0.6350.5 1.3 0.7 0.3 9 2.1 1.110006.7 16 8.0 3.7 61 25 13

Secondary exposure to carnivores andNumber of house miceconsumed to reach theLD50: 1 day accum. in prey50<1 <1 <1 <1 3 <1 <110002 5 3 1 27 8 530005 11 6 3 60 18 11Number of Norway rats toconsume to reach the LD50:1 day accum. in prey50<1 <1 <1 <1 <1 <1 <11000<1 <1 <1 <1 5 1 <13000<1 2 1 <1 11 3 2Secondary feeding study summarycounts(#mortalities/ #tested)NA 8/19 ND 9/100 32/55 19/33 0/4

Incident data summary countsprimary exposureNA 41 1 2 3 9 1secondary exposureNA 22 1 0 1 4 0unknown exposureNA 16 0 0 0 0 0NA = not applicableND = no data* RQ exceeds acute risk LOC = 0.50Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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1. EPA’s Deterministic Assessment Approach

In conducting both the primary and secondary risk assessments, EPA utilized its deterministic risk quotient (RQ) method to esti mate risk to non-target mammals and birds

associated with the use of the commensal rodentic ides. The RQ is a unitless value that is the ratio of exposure to the toxicity endpoint. Fo r example, in the contex t of acute avian risk estimates (e.g., mortality), an RQ of 1 would mean th at non-target bird species may be exposed

in the environment to an amount of the pesticide that re sults in mortal ity (specifically, the dose at which 50% of the test species died). EPA comp ares RQs to the Agency’s “levels of concern” (LOC) for non-target species. Th e LOC represents the exposure levels at which, in EPA’s judgment, a pesticide has the potential to cause ri sks of concern to non-target organisms. Thus, when the RQ for a pesticide exceeds the LOC for a particular category of non-target species, the Agency believes there is a risk of concern for speci es in that category. In this assessment, risk quotients were compared with the acute level of concern that EPA regularly uses in assessing risks to non-target species genera lly (LOC = 0.5). Additional levels of concern may also be used to evaluate potential risks to species listed as threatened or endangered (LOC = 0.1); however, for simplicity, this analysis only used the LOC of 0.5. Therefore, conclusions made with respect to the LOC of 0.5 may no t apply to listed species.

Because this deterministic assessment is intended to serve as a screening tool for identifying a potential for adverse effects, it is somewhat limited and conservative by design. As a result, EPA does not believe that the RQs deri ved in this assessment can be used as a precise measure of the magnitude of effects that will occur, but rath er serve as tools for a ddressing whether or not a chemical poses a risk to assessed animals. As a result, direct comparisons between chemicals on the basis of RQs can be misleading. In this asse ssment, the Agency uses other lines of evidence

to characterize the relative risk s of the rodenticides that are subject to this Notice and the

alternatives considered here.

2. Primary Exposure and Risk

a. Methodology

For the purpose of this assessment, primary exposure is defined as non-target organism consumption of rodenticide treated bait. Primary exposure risk is influenced by factors including toxicity, toxicokinetics (chemical absorpti on, distribution and elimination in the body), concentration of active ingredient in the bait, an d availability of bait for consumption. For each of the evaluated chemicals, risk is assessed in several ways:

• single day dose-based exposure to bait base d on allometric equations that allow for differentiation among taxa and body size is compared to acute oral LD 50 toxicity values;

• six day dose-based exposure to bait based on metabolism rate in the body and allometric equations that allow for differentiation am ong taxa and body size is compared to acute

oral LD 50 toxicity values; andRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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• diet-based exposure based on the concentration of chemical active ingr edient in bait in comparison to acute dietary LC 50 values.

Further lines of evidence include an analys is of the number of da ys of bait consumption required to reach the median lethal dose of r odenticide and the amount of bait individuals would

need to consume in order to accumulate the median lethal dose.

For the single-day dose-based exposure met hod, exposure was calcul ated by dividing the dose (in milligrams of active i ngredient) by the body we ight (in kilograms) of the consuming

individual for three standard we ight classes of birds and mammals . Allometric equations that relate food consumption to body weight (W ildlife Exposures Handbook, USEPA 1993) were used to determine potential exposures for t ypical birds and mammals of varying sizes. Allometric equations were used for the gene ric bird and mammal. In addition, allometric equations for passeriform birds and rodent ma mmals were also used as these would best approximate those individuals with high poten tial for consuming bait and they would give conservative exposure estimates. Animal exposur e was determined based on daily food intake rates (dry weight), assuming 100% of their diet consisted of dry bait. It was assumed for this

assessment that the form of the bait would not influence rate of intake or total intake.

Weight-adjusted LD 50 values for birds and mammals were used as the measure of toxicity to non-target species. The toxicity values sele cted for this assessment for birds were the most

sensitive LD 50 values available for Northern bobwhite quail ( Colinus virginianus ) or mallard

duck (Anas platyrhynchos ). The toxicity values selected for this assessment for mammals were

the most sensitive LD 50 values available for the Norway rat ( Rattus norvegicus ). For this assessment, EPA used standard bird (bobwhite quail and mallard duck) and mammal (Norway rat) test species to estimate weight-adjusted LD 50 values for non-target animals. Although there are numerous studies addressing the toxicity of one or more roden ticides in a wide variety of non-target species, these standard test species are the only ones fo r which studies are available on all of the rodenticides of interest; therefore, only these standard test species allowed for comparisons of results among chemicals. However, this method may not be conservative if other non-target species are more sensit ive to rodenticide exposure.

Scaling factors were used to modify the av ailable avian and mammalian toxicity data to account for differences in sensitivity between an imals of different body weights. For example, when using the default scaling factor, smaller bird s are estimated to be more sensitive compared to larger birds. Scaling f actors, derived from Mineau et al . (1996) for birds are used in this assessment, which is consistent with the Agency ’s terrestrial animal risk assessment model TREX v.1.4.1. A chemical-specific scaling factor was available for brodifacoum (0.76) from

Mineau et al . (1996), and for all other chemicals where su ch a specific value is unavailable, the default scaling factor (1.15) was used to adjust the avian LD 50 s. Using additional data, Mineau

et al . (2001) provided an alternativ e scaling factor for brodifacoum (0.88) and a chemicalspecific scaling factor for chlorophacinone (-0.53). Mammalian weight-adjusted LD 50 values were calculated using the “body weight 3⁄4 ” adjustment (USEPA 1995, 2011). EPA’s assessment for primary exposure and risk utilized default we ight classes of birds (s mall (20 g), medium (100Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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g), and large (1000 g)), and mammals (small (15 g) , medium (35 g), and large (1000 g)). These

are the standard bird and ma mmal body weights used in EFED risk assessments (T-REX documentation (version 1.4.1, December 2008).

The six day dose-based exposure assessment utilized the same toxicity information discussed above, but in this assessment RQs we re calculated by estimating body burden based on the assumption that bait was cons umed exclusively for six days . Body burden concentrations (mg a.i./kg-bwt) were based on feeding rates and elimination rates from liver half-life estimates.

For the diet-based primary exposure assessment, EPA evaluated the concentration of a.i. in the bait and the dietary LC 50. The LC 50 (mg a.i./kg-diet) is obt ained from 5-day exposure dietary toxicity studies. RQs are calculated as a ratio of a.i. concentration and the LC 50 . Risk results that agree between this method and the multiple day accumulated dose method described above provide an enhanced degree of confiden ce in risk conclusions for a given chemical.

As noted above, EPA also evaluated further li nes of evidence, including an analysis of the number of days of bait consumption required to reach the median lethal dose of rodenticide

and the mass of bait animals would need to consum e in order to reach the median lethal dose.

The first line of evidence involve d calculation of the number of da ys it would take an individual non-target bird or mammal (assuming the standa rd body weights described above) to reach the

LD 50 through consuming 100% of it s daily diet as bait. The second line of evidence involved calculating the amount of bait that would need to be consumed to be equivalent to the LD 50. These additional lines of evidence represent useful tools for comparing risks among chemicals. The greatest concerns for non-target primary risk are with those pestic ides for which little feeding time or only a small amount of treated mate rial is necessary for mortality to occur. Mortality to non-target primary consumers become less likely when consistent feeding or large amounts of consumption are necessary over a protracted period of time to cause death.

b. Risk Characterization

The risks identified by the determinative analys es and the other lines of evidence for each

of the rodenticides considered in the EPA asse ssment are characterized below. Tables 12 and 13 include the RQs for primary exposures of birds and mammals (respectively) to rodenticides.

These tables also include the estimated number of days required to reach the LD 50 through 100% consumption of bait and the amount of bait equivalent to the LD 50

.Rodenticides.  Draft Notice of Intent to Cancel and Denial    11/02/2011~ 33 ~Table 12. bird risk assessment: primaryexposure of passerine birds to bait.Bodyweights (g)BrodifacoumDifeth-ialoneWarfarin(0.025%)Warfarin(0.054%)Chloro-phacinoneDipha-cinoneBrometh-alin

Risk QuotientsSingle day dose RQ20 19.61* 29.80*0.230.50*0.07 0.017.76*100 22.67* 18.39*0.14 0.31 0.04 0.014.76*1000 27.89* 9.22*0.07 0.16 0.02 <0.012.40*Six day dose RQ20 117* 168* 1.36* 2.94*0.40 0.05NA100 135* 104* 0.84* 1.81*0.25 0.03NA1000 166* 52*0.420.91*0.12 0.01NADietary RQNA38* 45*0.400.86* 0.89*0.06 0.48

Additional lines of evidenceDays to consume sufficientbait to reach the LD5020<1<14-5 1-216-17>365 <1100<1<17-8 3-430-31>365 <11000<1<114-15 6-7117-118>365 <1Grams bait consumed toreach the LD50200.30.225 1086>1800 0.71000.91.1160 80620>7300 4.210005152100 99017000>52000 59NA = not applicable ND = no data* RQ exceeds acute risk LOC = 0.50Rodenticides.  Draft Notice of Intent to Cancel and Denial    11/02/2011~ 34 ~NA = not applicable ND = no data * RQ exceeds acute risk LOC = 0.50Table 13. mammal risk assessment: primary exposure of rodents to bait.Bodyweights (g)BrodifacoumDifeth-ialoneWarfarin(0.025%)Warfarin(0.054%)Chloro-phacinoneDipha-cinoneBrometh-alin

Risk QuotientsSingle day dose RQ15 9.93* 4.30* 8.36* 18.05* 0.82* 1.97* 5.1*35 8.48* 3.67* 7.14* 15.42* 0.70* 1.68* 4.4*1000 4.55* 1.97* 3.83* 8.27*0.380.90* 2.4*Six day dose RQ15 59* 24* 49* 106* 4.7* 11.6* NA35 51* 21* 42* 90* 4.0* 9.9* NA1000 27* 11* 22* 48* 2.1* 5.3* NADietary RQNA94*ND57* 123* 44* 22* ND

Additional lines of evidenceDays to consume sufficientbait to reach the LD5015<1 <1 <1 <1 1-2 <1 <135<1 <1 <1 <1 1-2 <1 <11000<1 <1 <1 <1 2-3 <1 <1Grams bait consumed toreach the LD50150.3 0.7 0.3 0.2 6 1.1 0.6350.5 1.3 0.7 0.3 9 2.1 1.110006.7 16 8.0 3.7 61 25 13Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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RQs exceed the LOC for all mammals exposed to brodifacoum and difethialone. By design, brodifacoum and difethial one represent a lethal primar y risk to non-target small mammals that may eat either loose treated bait or utilize a bait station. However, the quantitative assessment also demonstrates that bait containing these two rodenticides constitutes a primary exposure risk concern for larger mammals as well as all avian size classes – that is, species that are plainly not the intended targ ets of these products. This co nclusion is consistent across all primary exposure risk analyses performed (singl e oral dose, six-day accumulated dose, dietary concentration and the feeding peri od- lethality assessment). EPA’s analysis indicates birds and mammals could attain a lethal dose (LD 50 ) of either brodifacoum or difethialone upon feeding for less than one day on treated bait. The brevity of feeding required to reach a potentially lethal exposure represents an increased opportunity (rel ative to all other rodenticides assessed) for nontarget animals – especially birds -- to chance upo n loose treated bait and consume a lethal dose.

Warfarin, as expected for al l rodenticides, also demonstrates a primary exposure risk

concern to small mammals. The assessment of wa rfarin also indicates a risk to large mammals for all assessment methods employed as well. EP A’s analysis indicates th at feeding on treated bait for less than a day is sufficient to attain a lethal dose in all evaluated size classes of mammals, suggesting a similar opportunity, relati ve to brodifacoum and difethialone, for nontarget mammals to chance upon treated bait and consume a lethal dose. In contrast to brodifacoum and difethialone, warfarin’s primar y exposure risk for birds is limited to small passeriforms and other medium sized birds. Wh ile a single day dose risk assessment suggests only a risk to small passeriforms from the highe st concentration formulation, accounting for the potential for multiple day accumulation on a dose basis expands the concerns to include passeriforms and other small and medium sized bird s at all formulation concentrations assessed. The dietary assessment does not consider body weight as a determinant factor. However, this assessment method still predicts a risk concern at the highest formulation concentration. EPA

estimates that birds would attain a lethal warfarin dose after 1 to 7 days of feeding (0.054% warfarin bait) or after 4-15 days of feeding (0.02 5% warfarin bait). Th is finding suggests that, for birds there is less of an opportunity for consum ing a lethal dose of warfarin by chance when compared with brodifacoum and difethialone, since it would generally require multiple days of feeding on warfarin treated bait to reach a lethal dose in birds.

For bromethalin, as can be expected for a relatively fast acting compound (target mortality occurs 1 to 7 days after initial exposure, Pitt et al . 2011, and registrant submitted studies), acute risk concern levels are exceeded for all mammalian size classes feeding on treated bait regardless of the assessment method EPA em ployed. In addition, bromethalin exceeds risk

concern levels in a ll assessment methodologies with the exception of the dietary exposure methodology. EPA’s analysis indica tes that less than a single day’ s feeding on bromethalin bait

is sufficient to attain a lethal dose in birds and mammals, sugge sting again like brodifacoum and difethialone, that adverse effect s to non-target wildlife are like ly from primary exposure events

with treated bait.

Two anticoagulant alternatives , chlorophacinone and diphacinone, also present primary exposure risk concerns for nearly all mamma l sizes assessed using all primary exposureRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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assessment methods (however, large rodents, greater than 1000 g, consuming chlorophacinone bait for one day are not expected to experience risk concerns). EP A’s analysis indicates that <1 day (diphacinone) and <1 to 3 days (chlorophacinone) of feeding on bait are sufficient to attain

the median lethal dose in mammals. This is no t materially different from the other rodenticides with respect to the opportunity for non-target mammals to chance upon and feed lethally on

treated bait. In contrast to ma mmals, primary avian risk is be low concern levels for these two compounds. This may be a limitation in the analys is of primary exposure models terminating at six days (i.e., longer exposure periods might provide sufficient exposure to bait for adverse accumulation to occur); however, the analysis indicates that, unlike brodifacoum and difethialone, a very consiste nt and protracted feeding pe riod for either diphacinone or chlorophacinone is required to at tain a lethal dose in birds (i.e ., daily feedings over weeks to months).

3. Secondary Exposure and Risk

The toxicity of each of the rode nticides and a variety of fact ors concerning their fate and effects in biological systems influence their poten tial for risk to secondary consumers, i.e., nontarget wildlife that may ingest living or dead an imals that have consumed rodenticide bait. These characteristics can be compared to predict the rodenticid es’ relative potential for such secondary risk. The elimination rate, potential to accu mulate within body tissues, time to death, and toxicity to both primary and secondary consumers influence exposure and risk.

A compound that is rapidly me tabolized or excreted from a primary consumer likely results in a lesser secondary ri sk to non-target predators a nd scavengers than one that accumulates with repeated exposure, even if re peated exposure occurs weeks or months after initial exposure (Eason and Mu rphy 2000). Compounds that more rapidly clear from the body are less likely to pose secondary risk because the r odenticide is less able to accumulate to a level sufficient to affect a secondary consumer. Time to death also influences the potential for exposure, since compounds that kill rapidly would prevent the primary consumer from continuing to eat bait, thereby consuming a dose th at would be toxic to a secondary consumer.

Rodenticides that are slower to cause death also prolong the period when contaminated (and potentially more vulnerable) prey are available to predators. The toxicity of the rodenticide to the secondary consumer would also affect the risk of adverse effects that would result from exposure. Based on these characteristics, rodentic ides that are eliminated more slowly and have greater potential to accumulate within body tissues, take longer to kill the primary consumer, and have greater toxicity to seconda ry consumers are expected to present greater secondary risk. Below is an evaluation of the elimination and accumulation potential for each of the assessed

chemicals.

Accumulation and Elimination

Information available from residue studies in primary consumers indicates that, of the anticoagulants, brodifacoum and difethialone accumula te in body tissues to a greater extent than warfarin, chlorophacinone, and diphacinone. Data from these types of studies are not availableRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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for the neurotoxin, bromethalin, but the duration for primary consumers to feed on bromethalin

bait and accumulate the rodenticid e is limited due to this chemical's rapid mode of action and observations that target animals stop feed ing after a lethal dose is reached.

Available toxicokinetic data also indicate that , of the anticoagulants, brodifacoum is more persistent in animal tissue than all of the other rodenticides considered in EPA’s assessment. In one study, brodifacoum was detected in rat liver s up to 200 days post exposure to a single oral dose of 0.2 mg a.i./kg (Hawkins et al. 1991), and up to 11.7% was detected in livers of rats after 104 weeks following a single dose of 0.15 mg a.i./ kg (Batten and Bratt 1990). Other studies reviewed by the Agency provide further evidence of the long-term retention of brodifacoum in body tissues, and half-lives range up to 307.4 days in liver tissue and 91.7 days in plasma (Vandenbroucke et al. 2008). The study by Vandenbroucke et al. (2008) suggests that difethialone may be much less pe rsistent in the body than brodif acoum, with a liver half-life of 28.5 days and a plasma half-life of 38.9 days.

Data available for difethialone suggest that this rodenticide is not as persistent as brodifacoum. Vandenbroucke et al. (2008) estimate d the elimination half-life in liver as 28.5 days and the half-life in plasma as 38.9 days . Studies submitted to EPA (Belleville 1986 and 1991, MRID#s 42065010 and 42065009 respectively) indicate that the half-lif e of difethialone may be several times greater than Vandenbroucke et al (2008). Bellevi lle (1991) calculated a

half-life for difethialone of 74 days in liver.

Biological persistence data available for warfarin show variation among the species tested; however, most of the information on tissue retention indicates that it is generally less persistent in the body than brodifacoum and difeth ialone. A liver half-life of up to 66.8 days has

been calculated for warfarin in rats (Vandenbroucke et al. 20 08), and other estimates are less

than this value. Most data indicate that the plasma half-lives are less than 1 day.

Available data also show that chlorophacinone and diphacinone are mo re persistent than warfarin, but less persistent than brodifacoum and difethialone. Liver and plasma half-lives for chlorophacinone are 35.4 days and 11.7 days (Va ndenbroucke et al. 2008), respectively and a plasma half-life of 0.4 days has also been calculated (Belleville 1981). Half-lives for diphacinone have been estimated to be shorter in some species (ranging from 3 – 5.43 days), but

liver retention times in cattle were determined to be >90 days (Fisher 2006, Fisher et al. 2003, Bullard et al. 1976).

Available data on the non-antico agulant rodenticide bromethalin suggest that it is rapidly eliminated by the body. While there are no data on the elimination half-l ife of bromethalin in liver, a metabolism study conducted in rats in dicated a plasma half-life of 5.6 days.

Due to the lack of availabl e whole-body elimination data for all assessed rodenticides,

liver half-lives were selected fr om the range of available data as a conservative representation of whole body elimination in animals consuming bait. If liver half-lives were not available, as in the case of bromethalin, the blood plasma half-life was used. In order to allow for comparisonsRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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of half-lives among chemicals, liver half-lives for brodifacoum , difethialone, warfarin, and chlorophacinone from the same study (by Vandenbr oucke et al. (2011)) were selected. Although this approach reduces variability due to differences attributed to laboratories, it is not necessarily the most conservative approach th at could be undertaken. For in stance, the liver half-life value for difethialone that was repor ted by Vandenbroucke (28 days) is lower than provided in other studies (74 days from Belleville, 1991). T hough a liver half-life value is available for diphacinone, it is based on a study on pigs, rather than the rats used in the other studies. There is

some indication from the available half-life studies that species react to anticoagulant rodenticides differently. Therefore, this pig value may overestimate or underestimate the liver

half-life of rats for this chemical. For bromet halin, there are no availabl e data on the liver halflife, so a blood plasma value is used instead. It is uncertain how a blood plasma half-life would

differ from the liver half-life for this chemical. The half-lives that were used to estimate doses of each rodenticide in non-target and target animals are provided in Table 14.

Table 14. Elimination half-lives fo r certain rodenticides based on

elimination rates from liver.

Rodenticide Elimination half-life (days)

Brodifacoum 307.4

Difethialone 28.5

Warfarin 66.8 Chlorophacinone 35.4

Diphacinone 5.5

Bromethalin 5.6*

*Value is based on elimination from blood plasma.

Potential to Accumulate a Lethal Dose

The assessed rodenticides typi cally cause mortality several days after exposure, which may allow target rodents to feed for several days upon rodenticide bait before dying. This can

lead to doses that far exceed the lethal dose. EFED estimated the extent to which an accumulated dose may exceed the median lethal dose of target animals. For warfarin, estimated doses in target rodents were 4 to 17 times the LD 50 at days when mortality was observed in the acute oral toxicity study with th e rat assuming that bait is con tinuously being consumed over the duration of the simulation. For brodifacoum, dife thialone and bromethalin, estimated doses in target rodents ranged from 2 to 82 times the LD 50 . For chlorophacinone and diphacinone, estimated doses ranged from 3 to 13 times the LD 50 . This analysis indicates that target rodents continually consuming anticoagula nt rodenticide bait may contai n doses that are orders of magnitude above the levels that are sufficient to cause mortality. This is of particular concern for secondary consumers that may prey upon targ et rodents because th ey could potentially

receive elevated doses of rodenticid es. Bromethalin is not expected to result in elevated levels in target rodents because one effect of brometha lin poisoning is that the animals stop feeding.Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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a. Assessment Based on Calculated Residues in Prey

(i) Methodology

Exposure for secondary consumers was estimated by calculating the amount of rodenticide in target rodents (i.e ., house mouse and rat) that repres ent potential prey. As with the primary assessment, EPA’s theoretical secondary risk assessment estimated exposure using allometric equations of da ily food intake from the W ildlife Exposure Factors Handbook (EPA 1993). Rodenticide intake base d on consumption of bait by the primary consumers (prey) was calculated for the house mouse (23 g) and Norway rat (485 g). For this analysis, rodenticide accumulation in prey over three different time pe riods (1, 3 and 6 days) was calculated. These time periods were used as representative time pe riods that target rodents may survive after the initial daily dose of a pesticide (based on availabl e toxicity studies) and in order to bracket the

available data from residue studies submitted to the agency and occurring in open literature. Accumulation was determined based on daily food intake rates for the prey, conservatively assuming 100% of their diet consis ted of dry bait. It was assumed that the form of the bait would not influence intake. Based on the assumed weight of the primary consumers, the percent active ingredient in the bait, and daily food intake, the concentration with in the prey animal at the end of a day’s feeding was determined. Accumulati on of rodenticide within the prey animal over time was calculated using an elimination rate constant based on the liver half-lives for each chemical (described above). This analysis is expected to produce a c onservative estimate of

exposure.

In addition to the theoretical estimates of rode nticides in target rodents representing prey of secondary consumers, measured rodenticide c oncentrations in carcasses of rodents were used to represent potential exposure values for secondary consumer s. Although this method of representing concentrations of rodenticides in pr ey of secondary consumers would be expected to be less conservative than the theoretical analys is described in the pr evious paragraph, both analyses produced similar findings.

Dose-based exposure to secondary consumer s was assessed for mammals weighing 50g, 1000g, or 3000g, and birds weighing 100g, 1000g, or 5000g. These weights were selected based on the range of secondary consumers identified in rodenticide incidents in the Environmental Incident Information System (EIIS) database. The generic bird and mammal equations for food intake (Wildlife Exposure Factors Handbook ) were used to calculate the daily rodenticide intake for predator/scavenger birds and mammals consuming house mice and Norway rats exposed to

rodenticide bait for three or si x days. Dose-based RQs were calculated by dividing the dosebased exposure values from the theoretic al estimated dose by the adjusted LD 50 values.

In addition, dietary-based RQ s were calculated for secondary consumers. This was accomplished by dividing the theoretical concentrati ons of rodenticides in target rodents by the

LC 50 values for birds or mammals.Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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Risk Estimation

Based on acute exposure of predator and scaven ger birds to rodenticides accumulated in prey organisms, RQs for brodi facoum and difethialone exce ed the Agency’s acute LOC regardless of assessed weight class, prey orga nism consumed, or accumulation scenario. RQs calculated for warfarin, diphaci none, and chlorophacinone do not exceed the acute LOCs for birds, except for small predator and scavenge r birds consuming prey exposed to the higher concentration of warfarin (0.054%) bait for six days . The results for bromethalin fall in between the two anticoagulant groups, as bromethalin RQs exceed the acute LOC for all predator and scavenger birds consuming small prey animals (i.e., house mice), but do not exceed the acute LOC for large predator and scavenger mammals consuming large prey animals (i.e., Norway rats). When considering dietary- based exposures of predator and scavenger birds to rodenticides, brodifacoum and difethialone RQs exceed the acute LOC, while warfarin, chlorophacinone, diphacinone, and bromethalin RQs do not exceed the acute LOC. Secondary bird RQs are provided in Table 15. Although warfarin, chlorophacinone, and di phacinone RQs for secondary birds do not exceed the acute LOC, there is uncerta inty associated with th ese values. Available data suggest that some predatory birds may be substantially more sensitive to diphacinone exposure compared to the bobwhite quail and mallard ducks that are the source of th e majority of the avian toxicity data. If th is applicable to all secondary consumers exposed to anticoagulant rodenticides, the secondary bird RQs calculated for these chemicals may not be conservative.

For predator and scavenger mammals exposed to rodenticides accumulated in prey, RQs

for all assessed chemicals exceed the acute LO C, except for predator and scavenger mammals exposed to a three day accumulation of chlo rophacinone in large prey animals and small predators/scavengers exposed to six day accumula tion of chlorophacinone in large prey animals. Dietary-based RQs exceed the acute LOC for all assessed rodenticid es; however, dietary toxicity

data in mammals are not available for difethialo ne or bromethalin so these chemicals could not be included in this analysis. Second ary mammalian RQs are pr ovided in Table 16.Rodenticides.  Draft Notice of Intent to Cancel and Denial    11/02/2011~ 41 ~Table 15. RQs from the bird risk assessment: secondary exposure of predator/scavenger birds to residues inconsumed rodents.Bodyweights (g)BrodifacoumDifeth-ialoneWarfarin(0.025%)Warfarin(0.054%)Chloro-phacinoneDipha-cinoneBrometh-alin

Secondary exposure to carnivores and scavengersHouse mouse consumption:3 day accumulation in preyRQ100 19.77* 17.09*0.14 0.30 0.04 0.014.06*1000 15.42* 5.42*0.04 0.09 0.01 <0.011.29*5000 12.96* 2.43*0.02 0.04 0.01 <0.010.58*Norway rat consumption: 3day accumulation in preyRQ100 5.25* 4.52*0.04 0.08 0.01 <0.011.07*1000 4.08* 1.43*0.01 0.02 <0.01 <0.01 0.345000 3.43* 0.64*0.01 0.01 <0.01 <0.01 0.15House mouse consumption:6 day accumulation in preyRQ100 39.40* 32.98*0.270.58*0.08 0.01NA1000 30.74* 10.45*0.09 0.19 0.02 <0.01NA5000 25.84* 4.68*0.04 0.08 0.01 <0.01NANorway rat consumption: 6day accumulation in preyRQ100 10.43* 8.73*0.07 0.15 0.02 <0.01NA1000 8.14* 2.77*0.02 0.05 0.01 <0.01NA5000 6.84* 1.24*0.01 0.02 <0.01 <0.01NAHouse mouse consumption:dietary RQNA17.81* 2069*0.19 0.41 0.32 0.02 0.20Norway rat consumption:dietary RQNA4.71* 5.48*0.05 0.11 0.09 <0.01 0.05NA = not applicable ND = no data* RQ exceeds acute risk LOC = 0.50Rodenticides.  Draft Notice of Intent to Cancel and Denial    11/02/2011~ 42 ~Table 16. RQs from the mammal risk assessment: secondary exposure of predator/scavenger mammals to residues inconsumed rodents.Bodyweights (g)BrodifacoumDifeth-ialoneWarfarin(0.025%)Warfarin(0.054%)Chloro-phacinoneDipha-cinoneBrometh-alin

Secondary exposure to carnivores and scavengersHouse mouse consumption:3 day accumulation in preyRQ50 11.10* 4.74* 8.81* 19.03* 0.84* 2.49* 4.31*1000 13.78* 5.88* 10.93* 23.61* 1.04* 3.09* 3.53*3000 14.91* 6.37* 11.83* 25.56* 1.12* 3.35* 5.79*Norway rat consumption: 3day accumulation in preyRQ50 2.94* 1.25* 2.33* 5.04*0.220.66* 1.14*1000 3.65* 1.56* 2.89* 6.25*0.270.82* 1.42*3000 3.95* 1.68* 3.13* 6.76*0.300.89* 1.53*House mouse consumption:6 day accumulation in preyRQ50 22.13* 9.15* 17.35* 37.48* 1.63* 4.20* NA1000 27.46* 11.35* 21.53* 46.51* 2.02* 5.21* NA3000 29.72* 12.28* 23.30* 50.33* 2.18* 5.64* NANorway rat consumption: 6day accumulation in preyRQ50 5.86* 2.42* 4.59* 9.92* 0.43 1.11* NA1000 7.27* 3.00* 5.70* 12.31* 0.53* 1.38* NA3000 7.87* 3.25* 6.17* 13.32* 0.58* 1.49* NAHouse mouse consumption:dietary RQNA44.69*ND26.64* 57.54* 20.42* 10.11* NDNorway rat consumption:dietary RQNA11.23*ND7.05* 15.23* 5.41* 2.68* NDNA = not applicable ND = no data * RQ exceeds acute risk LOC = 0.50Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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Whole Carcass Residue Analysis

As discussed above, EPA also assessed sec ondary risks by analyzi ng residues in test

animals that had consumed contaminated carcasses. This analysis differs from the theoretical

carcass concentration-based risk assessment in that it makes us e of measured residues in intoxicated target organisms as a basis for dietar y exposure in scavengers and predators. Using

actual animal concentrations eliminates some uncertainty associated with bait feeding, absorption, and elimination rates used in the th eoretical assessment. However, alone, this method is limited by the types and magnitude of r odenticide exposure in th e prey base (i.e., the animals intoxicated at the primary exposure leve l). A concordance of risk conclusions made using this method with conclusions based on the theoretical method allow for more confidence in the risk conclusions overall; howev er, if the empirically-based RQs calculated in this section do not exceed the LOC, risk cannot necessarily be pr ecluded, especially if the theoretically-based RQs do exceed the LOC.

In field and laboratory studies, rodenticide whole-carcass residues were determined in mammals after exposure to bait. Data are avai lable for a variety of small and medium sized mammalian granivores and omnivores exposed to brodifacoum, difethialone, warfarin, chlorophacinone and diphacinone. No data were identified for bromethalin. As with the theoretical assessment, rodentic ide exposure through car cass consumption is calculated as mg a.i./kg-bw, where kg-bw is the kilograms of the c onsuming individual for th ree weight classes of birds and mammals as set forth above. Weight-adjusted LD 50 values for birds and mammals

were then used to calculate risk. For toxic re sponse elicited from the dietary exposure route extended over several days, exposure is measured as mg a.i. residue/kg-diet. Toxicity is measured by the LC 50 obtained from the dietary studies (5 days on treated diet) for birds and

mammals.

The acute LOC was exceeded for secondary exposure risk to birds for brodifacoum and difethialone; however, RQs for secondary exposure risk to birds exposed to warfarin did not exceed the acute LOC. RQs for secondary exposure risk to birds exposed to chlorophacinone or diphacinone on an acute basis did not exceeded the acute LOC. Carnivore/scavenger mammalian RQs for brodifacoum and difethialone exceeded the acute LOC. For warfarin, chlorophacinone, and diphacinone, RQs did not exceed the acute LOC, as shown in Table 17.

Table 17. Secondary Acute RQs based on a Single-dose of Rodenticide through Consumption of Contaminated Carcasses

Predator Birds Mammals

Predator Weight

Class 100 g 1000 g 5000 g 50 g 1000 g 3000 g

Brodifacoum 6.42* 5.01* 4.21* 3.59* 4.46* 4.83*

Difethialone 4.64* 1.47* 0.66* 1.41* 1.75* 1.89*

Warfarin < 0.01 < 0.01 < 0.01 0.26 0.32 0.34

Chlorophacinone < 0.01 < 0.01 < 0.01 0.07 0.08 0.08

Diphacinone < 0.01 < 0.01 < 0.01 0.19 0.23 0.25Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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Table 17. Secondary Acute RQs based on a Single-dose of Rodenticide through Consumption of Contaminated Carcasses

Predator Birds Mammals

Bolded (*) RQs exceed ac ute risk LOC (0.5).

Avian and mammalian RQs based on dietary stud ies are provided in Table 18. Carnivore and scavenger bird RQs for brodifacoum and dife thialone exceeded acute risk LOCs. Warfarin RQs for carnivore and scavenger birds did not exceed any LOCs. RQs for birds exposed to chlorophacinone and diphacinone in their diet do not exceed acute risk LOCs. For carnivore and scavenger mammals, RQs for brodifacoum and warfar in exceed the acute risk LOC. There are no available mammalian dietary da ta for difethialone or brom ethalin. For the alternative rodenticides with conforming labels, mamm alian RQs for chlorophacinone and diphacinone

exceeded the acute LOC.

Table 18. Secondary Dietary RQs based on a 5-day Exposure of Rodenticide through Consumption of Contaminated Carcasses

Birds Mammals

Brodifacoum 5.25* 13.17*

Difethialone 5.54* ND

Warfarin < 0.01 0.67*

Chlorophacinone 0.02 1.39* Diphacinone < 0.01 ND

ND = no data Bolded (*) RQs exceed ac ute risk LOC (0.5).

b. Secondary Feeding Studies

Secondary feeding studies address a number of uncertainties associated with the quantitative dose-based risk estimation methods us ing theoretical or empi rically based prey-base

concentrations estimates of rodenticide. Th e feeding studies empirically account for primary organism feeding, absorption and elimination uncertainties surrounding the theoretical dosebased assessment. They also ac count for uncertainties associated with biological av ailability of rodenticide from consumed prey and assumpti ons of predator/scavenger sensitivity to the rodenticide which are present in both of the dos e-based risk estimation methods. Concordance

between risk conclusions between all three methods constitutes enhanced confidence in the

overall risk conclusions made for predators and scavenging wildlife.

Concerns for secondary risks with brodif acoum are supported by available data from secondary toxicity studies show ing mortality in 63% of predat or/scavenger birds and 42% of predator/scavenger mammals fed brodifacoum cont aminated target organisms. No secondary feeding data are available for difethialone.Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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In the case of warfarin, mammalian sec ondary feeding studies involving mammal predators/scavengers show mixed results and fo r some species the differences extended to a dose-dependent response. No mo rtalities were observed in ra ccoons and European ferrets (no dose dependency and bait concentrations equal to or higher than levels found in US registered products). Other studies showed lethalities in mink, least weasels and dogs, though the results often involved few test organisms. Avian sec ondary feeding studies i nvolved testing of four species. In three of the four species tested there was no observed mortality. Interestingly, the results from feeding tests do not co mpletely parallel the results of the quantitative secondary risk assessment where risks were expected for small bi rds exposed to prey contaminated with higher concentrations of warfarin bait. For example no mortality was observed in the feeding studies with black-billed magpies (~170 g bodyweight) while the risk assessment suggests a concern for a 100 gram bird. Conversely, mortality results we re mixed in larger birds of similar weights (death in barn owls but not in tawny owls both ~400-500 g body weight). These discrepancies may be indicating that allometric relationships for predicting e ffects of warfarin toxicity may incompletely explain the factors contribu ting to species sensitivity variability.

Bromethalin secondary feeding studies are limited to a single cas e. In that study involving domestic dogs fed intoxi cated rats there were no morta lities (n=4). The number of species tested is limited and so there is insuffi cient evidence from these data alone to make definitive conclusions regarding the accuracy of the secondary quantitative risk assessment results. No bird feeding studies were available for bromethalin.

Chlorophacinone secondary toxicity results in clude studies with five mammal species. Mortality responses were variable and ranged fr om approximately 50 percent to 100 percent of individuals tested. In one singl e species, European ferret, di fferent studies yielded highly variable results, ranging from zero to 100 percent mortality. It should be noted again that all

these studies involve a low number of test individuals and differences in perceived sensitivity may be as much a product of low number of i ndividuals as from real differences in toxic response across species. Avian feeding studies with chlorophacinone span 10 species with a wide range of bodyweights (170 to 4400 g). In no cases were mortalities observed. This is consistent with the secondary risk assessment.

Diphacinone secondary feeding data span studies from seven mammal species. The effects range from 0 to 100 percent mortality. Of particular note is the study involving actual secondary feeding with rats. Th is is of note because (1) the se condary exposure risk assessment used a rat acute toxicity endpoint as a surrogate for predators a nd scavengers and (2) the assumed prey item concentrations in the risk assessmen t were 10 to 20 times higher than tested in the feeding study. The feeding study with rats yielded a 50 percent mortality response under conditions of similar toxicity and lower expos ure than modeled conditions showing risk. Looking back on the quantitative risk results, substituting the modeled diphacinone dietary

concentrations with the actual concentrations used in the feeding study would still trigger secondary acute risk concerns. These results are considered supportive of the secondary risk assessment with mammals. Avian feeding studies with diphacinone span five species of varying bodyweights. In three species th ere were no mortalities, consiste nt with the secondary risk assessment results. In the case of two owl species, mortalities were observed contrary to the riskRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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assessment results. As discussed earlier, the toxi city endpoint relied upon in the risk assessment may underestimate the sensitivity of raptoral species to this chemical.

a. Estimation of number of prey animals equal to median lethal dose in secondary animals

As evaluated in the secondary exposure ri sk assessment, residues were estimated and observed to reach levels in target organisms th at, when consumed by predators and scavengers

can result in death. When consid ering those risks among the assesse d rodenticides it is important to consider the likelihood of predators and s cavengers encountering e nough intoxicated target prey to reach potential lethal doses. Furthering the evalua tion of secondary exposure of

rodenticides are the resu lts of analyses of the number of i ndividual target organisms necessary for dietary consumption to achieve a lethal dos e in predators and scavengers. The fewer the number of intoxicated target organisms necessary to reach a lethal dose, the less efficiently and intently a predator or scavenger must locate and consume these organisms to reach lethal body burdens. The analysis considered different bodyweights of predator/scavengers consuming either rats or mice which have ingested ba it for a single day or up to six days. Again, compounds that can present a lethal dose to predat ors and scavengers after consumption of target organisms with only a single day of exposure ar e likely to represent greater opportunities for lethal secondary exposure events than those which require multiple days of target organism

exposure .

Analyses were conducted to determine the number of rodenticide-intoxicated target organism a predator/scavenger mammal would n eed to consume in order to trigger lethal incidents (Table 19). Based on these analyses , every size predator/scavenger mammal exposed to brodifacoum through consumption of rats woul d only need to consume a fraction of a single target organism to reach lethal endpoint exposures, even if the rat fed on brodifacoum bait for just one day. Comparing brodifacoum results for predator/scavenger mammals to other assessed

rodenticides does not reveal a marked differen ce among the chemicals. Owing to their smaller size, consumption of brodifacoum intoxicated mi ce must be slightly more intensive for the predator/scavengers to r each lethal endpoint exposure (<1 to 5 organisms) as compared to rats. These results are not atypical of the results fo r difethialone, warfarin and bromethalin assessed rodenticides. However, the amount of brodifaco um that must be consumed to reach lethal exposure is substantially lower than diphacinone and chlorophacinone.

Similar analyses were conducted to determine the target organism numbers necessary to trigger lethal incidents in scav enger/predator birds (Table 19 ). Brodifacoum results show consumption of only a fraction of an intoxicated rat, regardless of rat exposure duration, is needed to reach lethal endpoint exposures in all bird sizes modeled. These results with

brodifacoum are similar to results with difeth ialone, but are greater for the other assessed rodenticides, particularly for warfarin. Mouse consumption would have to be higher than rat consumption, though not substantially so (<1 to 5 organisms consumed) for brodifacoum. Again, these results are comparable to difethia lone and slightly lower than bromethalin. However, similar analyses conducted with warf arin, chlorophacinone, and diphacinone reveal that consumption of intoxicated mice must reach much larger levels to reach lethal exposure endpoints. When taken together, these analyses suggests that brodifac oum has a substantiallyRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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greater opportunity than these othe r active ingredients to result in lethal incidents following exposure of a predator/scavenger bird to intoxicated target organisms.

Table 19. Secondary Exposure to Predators and Scavengers: Number of animals

consumed to reach the LD 50 from a 1 day accum. in prey

Body weights (g) Brodifacoum Difethialone Warfarin (0.025%) Warfarin (0.054%) Chlorophacinon

e Diphacinone Brometh

-alin

Secondary Avian Exposure

house

mice 100 <1 <1 38 18 130 821 1

1000 2 4 539 249 1836 11602 16

5000 5 27 3429 1587 11690 73852 104

Norway

rats 100 <1 <1 7 3 23 147 <1

1000 <1 <1 97 45 329 2079 3

5000 <1 5 614 284 2094 13232 17

Secondary Mammalian Exposure

house

mice 50 <1 <1 <1 <1 3 <1 <1

1000 2 5 3 1 27 8 5

3000 5 11 6 3 60 18 11

Norway

rats 50 <1 <1 <1 <1 <1 <1 <1

1000 <1 <1 <1 <1 5 1 <1

3000 <1 2 1 <1 11 3 2

a. Risk Discussion

The assessment of secondary exposure risks fo r wildlife involved a series of assessment methodologies that encompassed both theoretical accu mulation of rodenticides in a prey base as well as empirical measurements of rodenticide re sidues in prey. This assessment concluded that all of the assessed rodenticides pose a risk of mortality to secondary mammals. Some of the rodenticides pose a risk to birds. Based on the analysis of the number of prey organisms that

would have to be consumed in order for predators and scavengers to receive an LD 50 dose, the following general conclusions can be made: 1) brodifacoum, dife thialone, and bromethalin pose greater secondary risk than wa rfarin, chlorophacinone, and diph acinone; however, secondary risk

from bromethalin is somewhat limited due to the lower likelihood of continuous feeding of prey after reaching a lethal threshold, and 2) prey that have accumulated more rodenticide through longer exposure periods pose greater secondary ri sks to predator/scavenger birds and mammals.

4. Incident Findings Related to Pr imary & Secondary Risk Analyses

The quantitative risk assessment does not eval uate the actual potential for wildlife toRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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come into contact with treated bait; it simply evaluates the consequences of exposure. To determine if any documented adverse effects have been reported, indicating complete exposure pathways, EPA looks to available incident and exposure information from a variety of sources, including state and local governments and pesticid e registrants. The majority of available reported incidents for the rodenticides assessed are included in EPA’s Environmental Incident Information System (Version 2.1) EIIS. EPA believes these data offer strong support for the

conclusion that residential use of rodenticides in urban/suburban a nd rural areas provide complete exposure pathways to a variety of wild life and that primary e xposure lethal incidents involving non-target wildlife can occur. Table 20 presents the total number of reported incidents

associated with each of the rodenticides consid ered in EPA’s assessment. Where possible, EPA distinguished between incide nts resulting from primary and secondary exposures.

Table 20. Total Number of Wildlife Incide nts by Rodenticide Ac tive Ingredient and Exposure Type. Incidents occurred between 1971 and 2011.

Rodenticide

Active Ingredient Exposure Type

Primary Secondary Unknown Total

Brodifacoum 44 186 37 267

Birds

3 Mammals

41 Birds

164 Mammals

22 Birds

21 Mammals

16 Birds

188 Mammals

79

Difethialone 1 4 0 5

Birds

0 Mammals

1 Birds

3 Mammals

1 Birds

0 Mammals

0 Birds

4 Mammals

1
Chlorophacinon

e 6 4 1 11

Birds

3 Mammals

3 Birds

3 Mammals

1 Birds

1 Mammals

0 Birds

7 Mammals

4
Diphacinone 10 9 0 19

Birds

1 Mammals

9 Birds

5 Mammals

4 Birds

0 Mammals

0 Birds

6 Mammals

13

Warfarin 3 5 0 8

Birds

1 Mammals

2 Birds

5 Mammals

0 Birds

0 Mammals

0 Birds

6 Mammals

2

Bromethalin 1 0 0 1

Birds

0 Mammals

1 Birds

0 Mammals

0 Birds

0 Mammals

0 Birds

0 Mammals

1

Totals 65 208 38 311

Birds

8 Mammals

57 Birds

180 Mammals

28 Birds

22 Mammals

16 Birds

211 Mammals

100
* Incident counts exclude incidents with certainty levels of “unrelated” and “unlikely,” excludes incidents known to

be associated with intentional misu se, and excludes incidents associat ed with other active ingredients.

In evaluating EPA’s incident database fo r rodenticides, it is important to understand

that incidents that have been re ported likely represents only a frac tion of the incidents that have occurred. Because of the delay between consump tion of a lethal dose and death associated with the rodenticides considered in this analysis, the discovery of animals killed by these rodenticides is typically removed, both spatially and temporally, from the immediate site of rodenticide use. As a result, the cause of death generally is not obvious to persons finding animals killed by theseRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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rodenticides. Only when the mortality is repor ted to an authority, typically a state fish and wildlife office, and that agency c onducts an investigation that dia gnoses the cause of death is an incident linked to rodenticide exposure. The i nvestigating agency may then take tissue samples from the animal, normally from the liver, and ha ve laboratory analyses performed to screen for the presence of various rodenticides, as well as various other pesticides. Only when the residue analysis finds one or more rodent icides in the tissue of the dead animal does the incident become diagnosed as a suspected or confirmed rodent icide incident. Because the linkage between wildlife mortalities and exposure to the rodenticides subject to this Notice depends on thorough investigations, includ ing residue analysis of ti ssue samples, incident re porting rates vary greatly from state to state and likely depend largely on whether the state has the personnel and resources to conduct and report inve stigations. Only two states, Ne w York and California, have had programs that have systematically analyzed and reported wildlife mortality incidents, and thus are responsible for the majority of known rodentic ide incidents. Many states have never reported any wildlife mortality incidents re lated to rodenticides. Given th ese considerations, and the fact that most dead or dying animals are never seen by humans, EPA believes the vast majority of wildlife incidents from exposure to rodenticides go unreported. The general character of the reported incidents for each chemical are briefly discussed below.

Notwithstanding the likely extent of underreporting of wildlif e incidents, the available data do support the quantitative risk assessment’s conclusion th at both primary and secondary exposure to brodifacoum poses lethal risk to a variety of sizes of mammals and birds. Incidents expected to represent likely pr imary exposure to brodifacoum, include a range of non-target mammalian wildlife mortalities, ranging in size fro m chipmunks to white-tailed deer, consistent with the modeled size classes reported to be at risk. For birds, inci dents representing likely primary exposure involved species ranging from robi ns to geese, again consistent with the risk model predictions. Incidents re presenting likely secondary exposur e to brodifacoum range from foxes to mountain lions, consistent with the mode led size classes reported to be at risk. There

were 186 total incidents for brodifacoum attributed to secondary exposure. For birds, incidents likely involving secondary exposure include a variety of raptors, again cons istent with the risk model predictions for larger birds. These incidents occurred in urban/suburban and rural habitats. In sum, incident data indicate that likely lethal events from both primary and secondary exposure to brodifacoum for non-target wildlife can occu r in rural, suburban, and urban environments.

The incident data set for difethialone is much more limited than that for brodifacoum. Analysis of the toxicity and re tention time of difethialone indi cates that it is toxicologically similar to brodifacoum, suggesting th at the lack of observed incident s for this ingredient could be

due to the low use or to other factors not related to risk. Ne vertheless, one lethal incident apparently resulting from direct exposure to dife thialone treated bait ha s been reported, involving Key deer in a suburban environment. This in cident is consistent with the primary risk assessment. There are no reported primary incide nts involving difethialone and bird species, though one should conclude that this finding, co nfounded by low use of the chemical, neither supports nor refutes the primary risk assessment findings. With regard to secondary exposure risk, there is a lethal incide nt involving predatory birds a nd mammals. All the available

difethialone incidents are associ ated with urban/suburban areas.Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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Warfarin incidents with non-target wildlife generally parallel the findings of the quantitative risk assessment for primary exposure to this chemical in that primary exposure incidents have been reported and complete exposure pathways are confirmed. Little can be said regarding the land use characteristics in areas wh ere incidents were repo rted, which is likely a factor of the age of the incident reports. Incidents of secondary poisonings to non-target mammals from warfarin have not been reported; however, reported incident s for birds exposed to warfarin include a variety of raptoral species presumed to be secondary consumers. These secondary exposure incidents are consistent with the quantitative secondary risk assessment and are in partial agreement with the available second ary feeding toxicity studies. Incident data indicate that likely leth al events from secondary exposure to warfarin for non-target wildlife can occur in rural, suburban and urban environments.

The incident data set for primary exposure of animals to bromethalin is limited to a reported mortality of a chipmunk, and this in cident involved a commensal rodent control product. This limited information is consistent with a quantitative risk assessment that indicates a risk to small mammals exposed to treated bait, yet provides little support for the risk assessment predictions for larger mammal. Th ere are no incidents involving bromethalin and bird species expected to involve primary exposure to treated bait materials. There may be an extenuating issue that explains the absence of repo rted incidents for this chemical. As discussed

in the incident section of the ecological risk assessment, bromet halin is not a commonly assayed compound when investigating wildlife mortality inci dents. The incident data set for bromethalin related to secondary exposure of animals is limite d to birds. This limited information can neither support nor refute the mammalian secondary risk assessment but is consistent with the quantitative risk assessment for secondary exposure in birds.

Chlorophacinone incidents of high certaint y involving mammals of likely primary exposure to bait are scarce but in clude reports of mortalities in squirrels (Central Park, New York) which would be in agreement with the pr imary exposure risk assessment predictions for small mammals. Larger mammal incidents attribut able to primary exposure to this chemical are not reported. An incident report with a likely primarily exposed bird (C alifornia quail in an orchard) suggests the possibility that risk from chlorophacinone from primary exposure to birds is greater than indicated in the primary risk assessment. Chlorophacinone incidents of high certainty involving mammals and birds of likel y secondary exposure ar e scarce but include reports of mortalities in wild felids (bobcats) and raptors (red-taile d hawk). The mammal incident is consistent with the secondary ri sk assessment findings. The bird incident is inconsistent with the secondary risk assessment. It may be po ssible that chlorophacinone mirrors diphacinone in terms of the sensi tivity of raptors being possibly greater than the test species employed in the risk assessment (i.e. a 20 fold increase in sensitivity). If the chlorophacinone secondary risk assessment was adjusted for this possible increased sens itivity in raptors the secondary risk conclusions would then be consiste nt with reported incide nts for dietary subacute portions of the analysis but not for the single oral dose analysis. On balance, secondary lethalities to birds may occur but the strength of this prediction for this chemical is limited.

The diphacinone incident data set for mammals is similar to that fo r chlorophacinone, in that the only incident involves a squirrel in an urban setting (Central Par k, New York). Again, asRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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for chlorophacinone, there is a diphacinone incide nt involving a likely primarily exposed bird (turkey), again suggesting a possibl e greater risk to birds than i ndicated in the quantitative risk

assessment. This incident involved birds feedin g in the vicinity of a prairie dog town, not a commensal rodent control operation. Diphaci none incidents of hi gh certainty involving mammals and birds of likely secondary exposure ar e limited but include repor ts of mortalities in wild canids, mustilids and felids (fox, coyote, raccoon, and mountain lion) and raptors (snowy and barred owls, red-tailed hawk). The mammal in cidents are consistent w ith the secondary risk assessment findings. The bird inci dents are inconsistent with th e modeling portions of secondary

risk assessment but consistent with available f eeding studies, especially for owls. If the diphacinone secondary risk assessment was adjust ed for the possible increased sensitivity in raptors the secondary risk conclu sions would still yield risk quotients below concern levels. On balance secondary lethalities to birds may occur but the strength of this prediction for this chemical is limited, though the uncertainty in concl uding the possibility of a lethal risk is less than for chlorophacinone.

5. Implications for Risk Mitigation

The proposed cancellations would limit the avai lability of brodifacoum and difethialone in ways that should limit their use to professiona l applicators in urban and suburban areas. These requirements will reduce the potential for wildlife to encounter these rode nticides since most rodenticide placements in and around buildings or other man-made structures are made with consumer products. As this assessment concludes, these two rodenticides pr esent greater risk to non-target species – primarily to birds – than other commensal rodenticides. While the bait station requirement will mitigate primary expos ure to birds and larger mammals, secondary poisoning remains a concern for wildlife that consume mice and rats. In this regard, brodifacoum and difethialone pres ent a greater risk of secondary poisoning when compared to other commensal rodenticides. Limiting sales of brodifacoum and difethialone in the consumer market will likely cause most consumers to turn to one of the other available rodenticides or to use alternative mechanical controls, thereby re ducing overall use of and wildlife exposure to brodifacoum and difethialone. While the replace ment compounds may still present some risk of secondary poisoning, EPA believes that risk will be greatly reduced.

This notice also seeks the cance llation of certain rodenticide products in the absence of product changes requiring consumer commensal rodent control products to be sold in or with appropriate bait stations and in bait forms that are not readily removable from such stations. While labels of these products may currently direct the consumer to use bait stations to limit exposure to children and wildlife, it is readily apparent that such re strictions have been unsuccessful in preventing harm ful exposures. EPA expects th at the proposed bait station restrictions will reduce the geographic extent of bait dispersal across the landscape. As scattered bait may offer an increased opportunity for casual encounter with rodenticides when compared with a more focally placed bait station moving to ba it stations is likely to result in a reduction of encounters of wildlife directly with rodenticides which may be especially significant for chemicals such as brodifacoum, difethialone, br omethalin and warfarin where only a few feeding episodes are sufficient to cause mortality. Moving to bait stations is also likely to result in a reduction of predatory and scave nger wildlife encounters with intoxicated prey species becauseRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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the number and range of affected prey species should be reduced if less scattered bait is

available. While loose bait will still be availa ble to professional applicators following this action, it is EPA’s belief that professional users (including persons who routinely apply pesticides as a minor part of their job, as well as full-time professional pe sticide applicators) are more likely to choose a method of pest control a ppropriate for the specific circumstances, more likely to appreciate the consequences and liability of pesticide misuse, and are in most cases acutely sensitive to the economic consequences of overuse. For these reasons, EPA believes that pesticides generally pose less risk when applied by professional users than when applied by the general public. In the case of rodenticides containing brodifacoum and difethialone, EPA believes that this difference is significant enough to warrant taking steps to limit access to these products to professional users. Also, the requirement of bait stations and block or paste

formulations will reduce the likelihood of indi scriminant spreading of pellets on the ground which could lead to primary exposures.

In addition to the issue of geographical dist ribution of rodenticide, the requirement for bait stations may further limit acce ss to the bait itself. Bait st ations are optimized for the commensal rodent body size (mice and rats); la rger mammals are physically limited by the station portal size preventing them from reaching the bait within. And for predators that may feed on a variety of sizes of prey species, narrowi ng the sizes of affected exposed prey will likely reduce the proportion of exposed prey in the total di et and so reduce the over all availability of a rodenticide to the predator. In addition, the requirement for bait to be in a form not readily

removable from the stations will further reduce th e opportunity for wildlife to come in contact

with the enclosed bait.

6. Endangered Species Considerations for Rodenticide Active Ingredients

The Agency has concluded that the rodenticides subject to this Notice pose a risk to nontarget wildlife. By extension, these chemicals woul d also pose a risk of direct effects to federally listed threatened and endangered species. Furthe r, potential indirect e ffects to any species dependent upon a species that experiences effect s from use of rodenticide active ingredients cannot be precluded based on the deterministic eco logical risk assessment. These findings are based solely on EPA’s deterministic assessment and, because they do not take into account such factors as whether the species woul d be expected to be exposed to rodenticide activ e ingredients, do not in themselves constitute “may affect” findings under the Endangered Species Act. EPA previously consulted with the Fish and Wildlife Service (the Service) under the Endangered Species Act on certain uses of rodenticides, and in 1993, as part of that consultation, the Service issued a biological opinion finding that a number of rodenticides, includi ng several addressed and analyzed in this action, will likely jeopardize a nu mber of animal species. EPA has not in large measure implemented recommended measures pr ovided in that 1993 opinion, but in March 2005,

initiated informal consultation. That informal cons ultation for the nine rode nticides registered at that time was for the purpose of obtaining technical as sistance in identifying the full suite of listed species that may be affected by the full range of uses of these products, to determine whether further, formal consultation would be necessary and if so, to explore possible mitigation relative to specific species that may be affected. Several reported incide nts have involved Federally listedRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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threatened and endangered species, for example the San Joaquin kit fox and northern spotted owl. In addition, reported incidents in clude the bald eagle, which is protected under the Bald and Golden Eagle Act. While the action EPA is taking in this Notice will likely serve to reduce risks to a number of protected species, this action is not intended to resolve the need for mitigation to address federally listed and other protected specie s. Should EPA determine, as a result of its own further assessment, or through consultation with the Service, that additional restrictions on use are necessary to address adverse impacts to listed an d other protected species or designated critical habitat, EPA may initiate other appropriate action to address such impacts.

VII. Benefits

EPA examined several potential impacts of the proposed cancellation of the rodenticide products identified in th is Notice, including:

• Whether residential consumers can achieve the same level of control over rodent

infestations.

• Whether it may take longer for residential cons umers to achieve cont rol of their rodent problems.

• Whether the cost of rodent control, in cluding non-monetary costs, may increase.

Overall, there is no evidence to conclude that cancellation of these products will result in the loss of a residential consumer’s ability to control commensal rodents, or increase the time required to control commensal rodents. As a result of the proposed can cellation, a majority of residential consumers switching from cancelle d mouse control products to consumer-use rodenticide products that would c ontinue to be available post-can cellation are expe cted to incur incremental costs that range fr om $2 to $12 per infestation, when switching to rodenticide products that conform to the RMD with product s for mouse control accounting for about 90% of rodent control products sales (K line, 2006). The largest propor tion of affected residential consumers (those treating for mouse infestations who currently use loose-form rodenticides) are expected to see an average increase in cost of $1.50 to $3.00 per infestation. Residential consumers currently using rodentic ides for rat control that will co ntinue using rodenticides postmitigation could potentially incur a cost savings or an increase in costs up to $97 per rat
infestation. Lower cost, mechani cal control options are also av ailable, but would entail some additional non-monetary costs, such as disposing of dead rodents. The additional cost is generally less than 2% of the monthly non-housin g income for a family of three at the poverty line, and a considerably sma ller proportion for the majority of residential consumers.

The following provides an overview of the methodology used in EPA’s impact assessment, targeted pests, the use and advantag es of the rodenticide products EPA intends to cancel and their alternatives, a nd expected impacts on households that would be affected by the proposed cancellation.Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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A. Methodology

EPA’s analysis explores the potential impact s incurred by households currently using one of three general types of rodent icide baits: block form rodenticid es sold without bait stations; second generation rodenticides th at are in loose form, such as bait bits, pelle ts, whole grain, meal, and powder, and second generation rodenticid es sold in bait stations. However, EPA’s marketplace survey of prices found no examples of several of the products subject to this Notice, and no examples of FGARs in loose form. SGARs with bait stations were found in two forms. They may be sold as pre-baited, single-use stations (i.e., a single bait sold with the station, which is then discarded), or they may be packaged as a single reusable bait station with multiple bait blocks. The latter are intended for multiple use and may be more relevant to consumers with chronic problems or who use them as part of an exclusion program. Since the single-use and multi-packs seem to have different use pa tterns, EPA considers them separately.

To assess the impacts of cancelling these three types of products , EPA identifies the target rodents and describes how the products are used. The Agency then identifies available alternatives and compares their performance in te rms of ability and time to achieve control of an infestation. EPA also compares other factor s that may be considered advantageous or disadvantageous, such ease of use and dispositi on of carcasses, and compares control costs. Finally, EPA draws conclusions about the most li kely alternatives that will be used in the absence of the cancelled products an d the impacts of cancellation.

B. Uses of rodenticides

Rodenticides are formulated in baits to make them palatable to rodents. Regardless of form (i.e., block, loose, or in stations), baits placement will essentially be the same. Baits need to be placed in the areas where the rodents are active, typically in their runway, and about 6 to 10 feet apart. It is often difficult to determine just how many rodents have invaded a home, but the amount of droppings helps to inform whether it is a minor infestation or a major infestation. Regardless of the method of control, residentia l consumers need to continually monitor their homes for rodent signs during the course of control operations until signs of rodents are no longer detected. All the rodenticides take about 3 to 5 days to kill and all rodents may not feed immediately. Thus, a typical control program will last from about a week to 10 days.

Effective use of rodenticides depends on a num ber of factors including the size and shape

of the infested area and the size of the infestatio n. Use of multiple bait placements will increase

the likelihood that rodents will find and consume th em. To characterize the likely range of use,

EPA evaluated scenarios for a minor infestation and a major infestation, which would encompass lesser and greater areas and numbers of rodent s. Based on university agricultural extension agencies and government recommendations for home owners to control rodents, EPA concludes that six bait placements (e.g., a block, packet, or ba ited station) would be n eeded in the case of a minor infestation of rodents, and 12 placements would be needed for a major infestation of rodents (CDC 2010; Pierce 1993; Koehler and Kern, 2008; Hovanic et al., 2010; Illinois Department of Public Health undated).Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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C. Advantages of second generation anticoagulants

Many of the rodenticides are anticoagulants , which interfere with the animal’s blood clotting abilities, resulting in it hemorrhaging to death. The first generation anticoagulant rodenticides used in products currently register ed in the U.S. include: warfarin, diphacinone, and chlorophacinone. Baits using these active ingredie nts deliver a lethal dose after multiple small feedings, ( i.e. if the targeted rodent feed s on them for several nights in a row). Consequently, it is important to maintain fresh bait and reduce the av ailability of other food options for rodents to

consume a lethal dose.

Rodenticides known as the second generation an ticoagulant rodenticid es were developed to be effective against rodents resistant to warfarin (Hadler and Shadbolt, 1974; Rowe and Bradfield, 1975; Dubock and Kaukeinen, 1978). Th ey include: brodifacoum, bromadiolone, difethialone, difenacoum, plus others not registered in the U.S. Most second generation anticoagulant bait products are formulated such that rodents that eat enough bait may obtain a lethal dose in one night of feeding on these rodenticides. Theref ore, second generation anticoagulants offer the dual bene fits of greater performance ag ainst rodent populations that are resistant to warfarin , and the pot ential for delivering a lethal dos e in a single night’s feeding. This provides an advantage where alternative f ood sources are ubiquitous, such as agricultural and food processing establishments, and outdoor public health and sanitation situations such as urban alleys and trash collecti on areas. In residential setti ngs, food sources for rodents are generally limited, making multiple feedings on the bait more likely, and the advantage of possibly delivering a lethal dose in a single night’s f eeding less important.

D. Advantages of loose baits and ba it blocks without bait stations

Some rodents may be more wil ling to eat baits in loose form s, including pe llets, grain and

loose meal. Loose baits come in various sizes an d rodents are able to pick them up and eat them like a seed or nut. Loose baits can be easier to pla ce in hard to reach areas than bait stations and bait blocks. Gnawing is a prominent behavior of commensal rodents, and once they recognize a block as food they have no difficulty consuming it. Bait blocks formulated with paraffin, grain and other materials were originally developed fo r use in sewers and other wet and damp areas, where they remain the bait form of choice. Studies have shown no consistent differences in rodents’ consumption of block, pe lleted, or meal formulations. Rodenticide baits must be tested for palatability and meet EPA’s bait acceptance criter ia in order to be registered. Compared to bait blocks in bait stations, bait blocks without ba it stations may be margin ally easier to place as they are smaller in size, and the user does not have to orient a bait station so that its entrance is easily accessible to target rodents. However, bait stations offer countervailing benefits, including protecting the bait from moisture and dust; providing a protected place for rodents to feed, allowing them to feel more secure and consume more bait; keep ing non-target species, including pets, wildlife, and child ren away from toxic baits; and allowing bait to be placed in otherwise difficult locations given weather or potential hazards to non-target animals.Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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E. Alternatives

1. Alternative rodenticides

There are currently more than 30 EPA regist ered consumer use rodenticide products for

commensal rodents that conform to the RMD. The RMD-conforming consumer use products are

listed at http://www.epa.gov/pesticid es/mice-and-rats/rod ent-bait-station.html

.

These products all meet the efficacy testing requirements that EPA has established for registration of rodenticides unde r FIFRA. In order to demons trate the effectiveness of a rodenticide active ingredient, EPA requires (1) acute oral toxicity testing with wild-type rodents of the targeted species; (2) laboratory efficacy sc reening of one or more bait formulations with wild-type rodents of the targeted species; (3) indoor and out door field efficacy trials involving the targeted species in ac tual use situations in di fferent regions of the U.S. 6 These tests are not designed to rank the efficacy of the various roden ticide products, but instead to establish whether each product meets the registration criteria.

a. Pesticidal alternatives to second generation anticoagulants

Pesticidal alternatives to second generati on anticoagulant active ingredients currently

available for residential consumers include fi rst-generation anticoagula nts (chlorophacinone and
diphacinone) and a non-anticoagulant, bromethalin.

There is evidence that rats in certain locations in the U.S. have developed resistance to anticoagulants, primarily warfarin. As there ha s been little screeni ng of commensal rodent populations in the U.S. for anticoagulant resistan ce over the past 30 years, there is little current information on the prevalence of resistance to anticoagulants genera lly, or to specific anticoagulants. Claims of anticoagulant resistance in the wild can be difficult to separate from ineffective rodent control pr actices (e.g., Timm, 1994a, Drummond and Rennison 1973). In addition, the anticoagulants have different chemis tries and therefore, different mechanisms of binding with VKO. Consequently resistance to one anticoagulant does not indicate resistance to other anticoagulants. However, should rodents, resistant to the anticoagulants available to residential consumers, invade a home, products containing a non-anticoagul ant, bromethalin, is

available. Bromethalin causes rodents to cease feeding after a toxic dosage has been ingested, limiting the possibility of target r odents bearing more than a lethal dose. It is effective in small quantities, results in paralysis, and death usually occurs in ab out three days (Corrigan 1997).

b. Rodenticide alternatives to loose baits and blocks without bait stations

Upon cancellation of rodenticide products labeled for residential consumer use in controlling commensal rodents in and around buildings and formulated as loose baits, or bait

blocks without bait stations that meet the sta ndards of the RMD, residential consumers will still

6 General guidance for the design of such studies appears on pages 307-310 of Subdivision G of EPA’s Pesticide Assessment Guidelines, Office of Pesticides and Toxic Substances, Washington, DC, 1982.Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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be able to purchase a variety of registered rodenticides with bait stations that meet the standards of the RMD. Bait-stations have been employed in effective urban rodent control projects for many years, and have also been used in successf ul eradications of commensal rodent species from offshore islands. For several decades, pestic ides registered for use to control commensal rodents have had label statements requiring use in tamper-resistant (or tamp er-proof) bait stations where placements otherwise would be accessible to children, pets, domestic animals, and/or nontarget wildlife.

Depending upon the species being targeted, the de sign of the bait stati on, and the specific control situation, bait applied in bait stations may be accepted less readily than bait applied to burrows or placed in the open. Some rodents (p articularly Norway rats) are wary of any new objects in their environments, and may avoid a newl y introduced bait station for a period of time, about 2 or 3 days. Rodents overcome this neoph obia, and will enter a well-placed bait station and consume the bait. The shelter and protection of bait that the stations provide ultimately may encourage feeding and prolong th e attractiveness of the bait.

2. Mechanical alternatives

Mechanical control of rodents (e .g., snap traps, glue boards, liv e trapping) is effective, especially for mice and when populati ons are relatively small. Snap traps have a long history of use and are an effective way to control mice and rats. Some advantages of snap traps are they are relatively inexpensive, they may be reused, the presence of d ead rodents verifies success, and there is less of an opportunity for odor from de composing rodents as compared to rodenticides because trapped rodents can be quickly located and disposed of daily. Some disadvantages

include the time and effort of baiting and setting the traps; onc e sprung a trap will not work until reset; the user must dispose of dead rodents; and ra ts tend to be more difficul t to trap than mice.

Glue boards have a sticky substance that will catch and hold rodents th at run across them. Some consumers may like the ease of glue boards, since there are no triggers or baits to set. Glue traps may be useful to kill snap trap-war y mice and are sometimes used in conjunction with snap traps (Illinois Department of Public Health, undated). Dampness, dust, and even temperature extremes will diminish the efficacy of the glue boards (Illinois Department of Public Health, undated). Since rodents trapped on glue boards do not die quickly, they can use their urine, feces, and fur to escape (Corrigan 1997). R odents have been observed to use paper, dirt, or leaves to essentially create bridges over the sticky surfaces (Corrigan 1997). CDC (2010) does not recommend glue boards because often th e rodents are not dead, thereby increasing the potential for disease transmi ssion or rodent bites.

There are live traps available on the market for mice and rats. While some live traps use baits to entice rodents to enter, other live traps rely on rodent’s innate curiosity. Several models of these traps have holding spaces can hold mu ltiple rodents. CDC (2010) does not recommend the use of live traps because of increased exposur e to rodents that may harbor diseases. Live traps require that consumers find a nother location to releas e their rodents. Because of the issues of humaneness as well the potenti al for disease transmissions, so me state agencies are beginning to regulate the relocation of live tra pped animals (Witmer and Jojola 2006).Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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3. Professional alternatives

Many residential consumers routinely rely on PCOs to treat their homes for rodents and other pests, even though PCO services are more expensive than do-it-you rself pest control. PCOs have access to rodenticide products contai ning second generation anticoagulants, and to bait blocks and loose baits, that are not subject to this Notice a nd which are expected to remain

available to PCOs for use in areas not accessibl e to children, domestic animals and non-target

wildlife.

F. Effects of Cancellation on Consum ers’ Ability to Control Rodents

Not all control methods are equal. Howeve r, the registered ro denticide bait products meet EPA efficacy standards. The FGARs generally require rodents to feed on them for several nights to acquire a lethal dose, but so long as palatable bait is ava ilable, there is no indication that rodents will not feed multiple times. Rodents may be able to obtain a lethal dose with one night’s feeding on the SGARs. However rodents take 4 to 7 days to die regardless of which anticoagulant they consume. Bromethalin has a di fferent mode of action than the anticoagulants, and rodents usually obtain a leth al dose after one feeding, cease feeding, and die after 1-3 days.

To insure that all rodents have been killed, bait must be left out until all signs of rodents are gone. Thus, all rodenticides will be used for about the same period of time and achieve the same

results. The use of stations has not been show n to adversely affect r odenticide performance.

Snap traps can perform similarly to the rode nticides. Snap traps take somewhat more

effort since the consumer must bait them. As w ith rodenticides, it will generally take several days to eliminate an infestation and traps must be set until all si gns of rodents are gone. Thus, control time is not likely to be substantially different from that of rodenticides. Traps also require that the consumer deal with dead rode nts, which many may find unpleasant. Thus, while the level of control is likely to be similar, there may be non-mone tary costs associated with the

use of these control methods in the absence of the rode nticide products identif ied in this notice.

1. Incremental costs of rodent control

This section summarizes EPA’s analysis comp aring control costs of rodenticides that

would be cancelled to available alternatives. As previously mentione d, product groupings that would no longer be available to residential consum ers after the proposed cancellation (the baseline) include: (1) block form rodenticides, (2) loose form SGARs, (3) single-use SGARs in bait stations, and (4) multi-pack SGARs in bait st ations. Alternative product groupings that

would remain available to residential consumer s after the proposed cancellations are (1) singleuse FGAR/non-anticoagulant rode nticide blocks in bait stations, (2) multi-pack FGAR/ nonanticoagulant rodenticide blocks in bait stations, (3) traditional snap traps, (4) covered snap traps, and (5) glue traps. Prices for electronic and li ve traps were obtained, but since they are not recommended by CDC and there is uncertainty regarding their performance, EPA does not

evaluate them as alternatives. Additionally, the cost for a PCO to treat an infestation is providedRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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in the analysis, but PCOs will not be affected by the proposed cancellations and thus residential consumers using PCOs in the baseline will not be impacted.

For all mouse and rat control methods, the cost of rodent control in a minor infestation is calculated as the price of six placements and the co st of rodent control in a major infestation is the price of 12 placements. A single placement repr esents a single unit of control—i.e., one trap or rodenticide placement as determined by the manufacturer—and EPA assumes for purposes of this analysis that each placement kills one rodent.

Overall, EPA expects that incremental cost s from having to switch from rodenticide products currently available to those that woul d be available post-mitigation will be small. Residential consumers treating for mouse infestations are expected to switch from rodenticides that would no longer be availabl e to similar rodentic ide products that wo uld be available postmitigation. Incremental costs from this change range from $2 to $12 for mouse control.
However, loose-form rodenticides account for a ma jority of rodenticide sales and thus residential consumers using such products make up the larges t proportion of those that will be impacted by the mitigation measures. Therefore, most reside ntial consumers are expected to see an average increase in cost of $1.50 in a minor infesta tion and $3 in a major infestation, or $0.25 per placement. With 90% of rodenticides sales bein g for products that are intended to control mice, EPA concludes that a majority of residential consumers currently using rodenticides will be facing the impacts described above.

For residential consumers treating for rat in festations, incremental costs range from a potential cost savings to $97 per infestation across all alternativ es that would be available postmitigation. As in the case of mouse control, it is expected that most residential consumers are currently using loose-form rode nticides and will incur increm ental costs ranging from $46 in a minor infestation to $92 in a major infestation, or $8 per placement. Only a small proportion of residential consumers are expected to incur thes e costs, however, as rat control products make up 10% of rodenticide sales and only a portion of those sales are for loose-form rodenticides.

Both in the case of mouse and rat control, there ar e lower cost alterna tive control methods that would be available post-mitigation and resu lt in a cost savings, as well as higher cost options. Although switching to alternative methods may result in a cost savings, there may be associated non-monetary costs such as having to dispose of rodent carcasses when using traps. Therefore, EPA expects that consumers currentl y relying on rodenticides would likely incur at least some incremental costs from complying w ith the proposed NOIC. EPA does not expect the proportion of residential consumers relying on PCOs to change as a result of the proposed cancellations, because the proposed cancellations are not expected to affect residential consumers’ ability to control rodents.

2. Socio-Economic Equity Assessment

Changes in the per-unit cost of rodent contro l do not completely describe the impacts that may arise from the proposed cancellations. To place the estimated incremental cost in context, EPA has considered how the proposed cancellations would affect households that are below theRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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poverty-threshold. This concern is not only that such households ha ve less income with which to purchase rodent control products, but also that , as according to the U.S. Census Bureau’s American Housing Survey (2009), households below the poverty-threshold have a greater likelihood of rodent problems.

To assess the per household impacts of can cellation, EPA compares the incremental costs, as presented in the previous section, lik ely to result from the proposed cancellations to household monthly disposable in come (i.e., excluding housing cost s) at the poverty threshold. Monthly income rather than annua l income was considered as rode nt control costs typically are not spread evenly through the year, but are in stead episodic and possibly seasonal. As povertythreshold income varies depending on housing size, this analysis considered income for a threeperson household, which is considered the aver age size household in the United States (U.S. Census Bureau, 2005-2009).

The impact on households at the poverty leve l from switching from control options that would no longer be available under this Notice to similar products that would be available postmitigation was also examined. For mouse control, the average incremental costs for consumers switching from non-RMD conforming rodenticide products to rodenticides th at they would most likely adopt in post-mitigation ranges from a cost savings to 1% of m onthly non-housing income at the poverty threshold for a minor infestation and up to 2% for a major infestation. For rat control, incremental costs for consumers at the poverty-threshold who would no longer be able to use non-RMD conforming rodenticide products range from a potential cost savings to 5% of their monthly non-housing income in a minor infestati on and up to 11% in a majo r infestation

Again, with a majority of rodenticide sale s being for mouse control products, it is expected that impacts on most low-income residential consumers will be equivalent to 1% to 2% of monthly non-housing income.”

VIII. Conclusions Regarding Whether Subject Rodenticide Products Meet the FIFRA Registration Criteria

Despite mandatory label statements requiring use in tamper-resistant (or tamper-proof) bait stations where placements otherwise would be accessible to children, domestic animals, and/or non-target wildlife, each of these groups experience significant rodenticide exposures that

cause risks of adverse effects. The rodenticide products identified in Unit IV of this Notice present significantly greater ri sks to domestic animals and non-target wildlife than other rodenticide products registered for the same uses , owing to various factors. Chief among these factors are the presence of the active ingredie nts brodifacoum and dife thialone and/or the absence of a bait station conforming to the criteria of the RMD in products registered for general

consumer use in the control of commensal rodent s. The exposures to children and risks to the environment caused by the rodenticide products identified in this Notice are unreasonable because they are avoidable through the use of alternative products that are effective and

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A. Cancellation and Denial of Registrations of Rodenticides Containing Brodifacoum and Difethialone and Intended for Residential Consumer Use.

1. Effective alterna tives to brodifacoum and dife thialone are available.

1. Alternative rodenticides are effective

All active ingredients and all or nearly a ll bait formulations containing them that are registered for use to control commensal rodents ha ve met the applicable criteria for registration that EPA has established under FIFRA, including data requirements addressing the effectiveness of the products against target rodents. Produc ts containing first gene ration anticoagulant and non-anticoagulant rodenticides ha ve been registered based on reliable studies demonstrating satisfactory effectiveness against target rode nts. EPA concludes that first generation anticoagulant rodenticides, non-anticoagulant roden ticides, and mechanical traps, when used in combination with prudent sanitation and exclusio n measures, are effective for general consumer

use for the control of commensal rodents in and around buildings.

Although there is some eviden ce that in some situations first generation anticoagulants may be less effective against house mice than br odifacoum and difethialone, first generation anticoagulant products nevertheless demonstrate sufficient effectiveness to control target pests. However, even if there were particular situati ons where certain active i ngredients might be less effective against target rodents, residential c onsumers would still have access to rodenticide products containing alternat ive active ingredients that can provide effective rodent control. In addition, residential consumers could also choose to use traps, or to hire a PCO who would have access to a broader range of control methods.

One advantage of brodifacoum and difethialone over first generation anticoagulants is that brodifacoum and difethialone baits offer the po ssibility of delivering a lethal dose in a single night’s feeding. This may be an important advant age in situations such as agricultural and food processing facilities, where abundant food sources make it unlikely th at rodents will return to a bait placement. However, in residential setti ngs, competing food sources typically are more limited and can be more easily controlled, therefor e the possibility of deli vering a lethal dose in a single night’s feeding is not e ssential in order to achieve sa tisfactory rodent control.

2. Alternative rodenticides are affordable

Most residential consumers w ill see no increase in costs as a result of the proposed removal of rodenticides containing brodifacoum a nd difethialone from the residential consumer market. The majority of residential consumers use mechanical methods of control, which will not be affected by the proposed cancellations. Moreover, residential consumers who rely on rodent control services provided by housing management or PCOs will not be affected by the proposed cancellations. Products containing br odifacoum, difethialone and other SGARs will remain available to PCOs, agricultural users, co mmercial users, and public health officials, who therefore will not experience si gnificant cost increases as a result of cancellation of the rodenticide products identified in this Notice.Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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The only users likely to be affected by th e proposed cancellations are those residential consumers who purchase and use rodenticides fo r control of commensal rodents in and around buildings. These residential consumers are unlikel y to experience significant cost increases as a consequence of the proposed cancellation of br odifacoum and difethialone products because there is currently no significant, consistent difference in the price of rodenticide products based on their active ingredients: Consumer use product s containing brodifacoum and difethialone are not generally priced lower than competing products containing fi rst generation anticoagulants or non-anticoagulant rodenticid es active ingredients. Differences in price appear to be a function of other factors, such as the type of product, p ackaging and brand. Owing to the registration of multiple rodenticide products conforming to the RMD and marketed at prices comparable to those of the brodifacoum and difethialone pr oducts EPA proposes to cancel, these residential consumers are likely to experien ce negligible increases in cost.

3. Residential consumer use of brodifacoum and difethialone ca uses adverse effects to nontarget wildlife and domesticated and compani on animals that could be avoided.

Wildlife monitoring studies (analysis of animals that died from causes unknown or unrelated to rodenticide poisoning) show that accumulation of br odifacoum residues is prevalent in numerous species of avian and mammalian pr edators and scavengers. Accumulation of difethialone also appears to be fairly prevalent in some areas, especially when considering the relatively low usage of this rodenticide in the United States. Species in which widespread accumulation of anticoagulant rode nticides in liver tissue has been observed include owls, hawks, vultures, mustelids, bobcats, and mountain lions. Notably, rodentic ides are detected in 100% of the great horned owls in central Massac husetts and 100% of mountain lions in southern California. Inasmuch as products containing brodifacoum and dife thialone are only registered for use against commensal rodents in and around build ings and are not register ed for field uses or use against other rodent species, all non-targ et wildlife exposures to brodifacoum and

difethialone are believed to result from commensa l rodent products registered for use in and around buildings. 7 Cancellation of brodifacoum and dife thialone products sold to residential consumers is expected to reduce environmental loading of these highly toxic and persistent chemicals and thereby reduce secondary poisoni ngs among non-target wildlife. Information from multiple lines of evidence (predictions from toxicity and metabolism studies, whole carcass residue studies, secondary feeding studies, a nd wildlife incident reports) indicate that brodifacoum and difethialone accumulate in body ti ssues to a greater extent, and persist for a longer time, than warfarin, chlorophacinone, di phacinone, and bromethalin. The high retention

of brodifacoum and difethialone in the tissue of prey animals, co mbined with their high toxicity, presents significant risks of secondary expos ure to non-target predators and scavengers. Moreover, the potential for target rodents to consume a lethal dose of brodifacoum or difethialone in a single night’s feeding, and then to continue to consume additional bait for 3 to 8 days, can result in rodents with brodifacoum and difethialone body burdens well in excess of the dose lethal to the target pest , and in many cases in excess of the lethal dose for non-target

7 Minor exceptions are brodifacoum and diphacinone products registered to the U.S.D.A. Animal and Plant Health Inspection Service for its use in eliminating non-nativ e rodents from islands where they are disrupting the ecosystem. “Field uses” refers to uses in crop land, non -crop areas, ditch banks, river banks, gullies, irrigation ditches, railroad tracks, fence lin es, buffer strips, garbage dumps, landfills, orchards, and rangelands.Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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predators and scavengers.

Incident data support the quantitative risk assessment’s conclusion that secondary exposure to brodifacoum poses lethal risk to predator and scavenger mammals and birds, notwithstanding the likely extent of underreporting of wildlife incide nts. The incident data set

for difethialone is much more limited than that for brodifacoum, which is not surprising given

difethialone’s lower extent of use in the United States. However, analysis of the toxicity and

retention time of difethialone indicates that its risks to predators and scav engers are more similar to brodifacoum than to warfarin, chlorophacinon e, diphacinone, and brom ethalin, suggesting that

the lack of observed incidents for this ingredient could be due to the low use or to other factors

not related to risk.

All the rodenticides subject to this Notice present primar y poisoning risks to non-target vertebrates. Primary poisoning risk for large non-target mammals and for birds can effectively be eliminated through the use of tamper resistan t bait stations. However, the secondary exposure risk to predators and scavengers cannot be ad equately addressed thr ough bait stations alone. These risks are greater for produc ts containing the second genera tion anticoagulant s brodifacoum and difethialone than for the warfarin, chlorophacinone, diphacinone, and bromethalin. Brodifacoum and (to a lesser extent ) difethialone are widely used by residential consumers, and limiting availability of these chemicals in the consumer market will likely cause most consumers to buy other rodenticides or to use alternative mechanical controls, thereby reducing use and environmental loading of brodifacoum and difethia lone – and hence, secondary exposure risks to non-target wildlife. While switching to alterna tive rodenticides will not completely eliminate secondary exposure risks, EPA belie ves that these risks to wildlif e will be significantly reduced

if brodifacoum and difethialone are not available to residential consumers but are limited to the professional and agricultural markets.

3. Conclusion.

Non-target wildlife exposed to rodenticid es containing brodifacoum or difethialone experience significant adverse effects. These ad verse effects occur despite label statements requiring use in tamper-resistant bait stations wh ere placements otherwise would be accessible to non-target wildlife. Significant numbers of in cidents of secondary rodenticide poisonings of non-target wildlife occur in urban and subur ban areas, suggesting that residential and

commercial uses of rodenticides for commensal r odent control pose significant risk to non-target

wildlife.

These adverse effects could be substantially reduced if the quantity of brodifacoum and

difethialone introduced in to the environment were reduced. While rodenticides containing brodifacoum or difethialone offer advantages over other rodenticides , these advantages are important in certain use situations and less importa nt in others. EPA has determined that control

of commensal rodents in and ar ound buildings by residential cons umers can be satisfactorily accomplished without rodenticides containing eith er brodifacoum or difethialone. EPA has

determined that the level of commensal rode nt control achieved in and around buildings by general consumers can also be achieved using alte rnative methods that significantly reduce risksRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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to non-target wildlife and domestic animals. Th ese alternatives, including registered rodenticide products containing warfarin, chlorophacinone, di phacinone, and bromethalin, and mechanical rodent control devices, are available on the mark et at costs comparable to products containing brodifacoum or difethialone, and, when used in combination with prudent sanitation and exclusion measures, are effective for general consumer use for th e control of commensal rodents in and around buildings.

Inasmuch as rodenticides containing wa rfarin, chlorophacinone, diphacinone, and bromethalin active ingredients and mechanical rodent control devi ces are available, effective, affordable, and cause significantly less risk to the environment, roden ticide products containing brodifacoum or difethialone active ingredients ca use risks that are unreasonable. Accordingly, EPA proposes to cancel the following rodenticide products registered for general consumer use

for the control of commensal r odents in and around buildings:

D- MOUSE PRUFE II, EPA Re g. No. 3282-65 (brodifacoum) D- PELLETS GENERATION II, EPA Reg. No. 3282-66 (brodifacoum) D- BAIT PELLETS II, EPA Reg. No. 3282-74 (brodifacoum)

D- READY MIXED GENERA TION II, EPA Reg. No. 3282-81 (brodifacoum) D- MOUSE-PRUFE III, EPA Reg. No. 3282-85 (difethialone) D- BAIT PELLETS III, EPA Re g. No. 3282-86 (difethialone) D- II READY MIX BAITBITS III, EPA Reg. No. 3282-87 (difethialone) D- BAIT PACKS III, EPA Reg. No. 3282-88 (difethialone) GENERATION MEAL BAIT PACKS, EPA Reg. No. 7173-247 (difethialone) DIFETHIALONE BAIT STATION, EPA Reg. No. 7173-283 (difethialone) DIFETHIALONE 6G PASTE PL PKS, EPA Reg. No. 7173-285 (difethialone)

For the same reasons, EPA denies applications for registration of the following products:

D-CON BAIT STATION XV KILLS MICE, EPA A pplication No. 3282-RNU (brodifacoum)

D-CON BAIT STATION XV KILLS MICE, EPA A pplication No. 3282-RNL (brodifacoum)

B. Cancellation and Denial of Registration of Rodenticides Formulated as Loose Baits, or

Bait Pastes or Blocks Without Bait Stations That Meet the Standards of the RMD, Intended for Residential Consumer Use In Controlling Commensal Rodents In and Around Buildings.

Rodenticides formulated as loose baits (e.g., grain, granules, pellets, meal), paste or bait blocks are directly accessible to children, domestic animals and non-target wildlife, unless they are placed where children, domestic animals and non- target wildlife cannot reach them or unless they are enclosed in secure bait stations. In practice, it is difficult to place rodenticides where children, domestic animals and non-ta rget wildlife cannot reach them . Even if rodenticides are initially well placed, rodents often move them to other locations for la ter consumption, and theRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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new locations may be accessibl e to children, domestic anim als and non-target wildlife.

The primary exposures of children, and risks for domestic animals and non-target wildlife for rodenticides can be substantially reduced if the bait is contained in a bait station that meets

the standards of the RMD. The RMD describes four types of bait varying in terms of resistance to children, dogs, and weather:

• Tier 1 - Tamper-Resistant and Weather-Resista nt: These bait stations are resistant to weather and to tampering by children and dogs . Tier I bait stations meet the tamper

resistance and weather resistance standards se t forth in Pesticide Registration Notice 94- 7, and have also satisfactorily demonstrated the ability to isolate bait from children and dogs in laboratory testing c onforming to EPA protocols.

• Tier 2 - Tamper-Resistant (but not weathe r resistant): Tier 2 bait stations have satisfactorily demonstrated the ability to isol ate bait from children and dogs in laboratory testing conforming to EPA protocols. Tier 2 ba it stations have not met weather resistance standards; therefore, ro denticide bait products that include Tier 2 bait stations must be labeled for indoor use only.

• Tier 3 – Tamper-Resistant for Children Only: Tier 3 bait stations have satisfactorily demonstrated the ability to isolate bait from children in laboratory testing conforming to EPA protocols. Tier 3 bait stat ions have not demonstrated the ability to isolate bait from dogs and have not met weather resistance standa rds; therefore, rode nticide bait products

that include Tier 3 bait sta tions must be labeled for indoor use only and to prohibit placement where the product is accessible to dom estic animals and/or non-target wildlife.

• Tier 4 - Tamper-Resistance Unknown: Tier 4 ba it stations have not been demonstrated to meet the testing standards required of the highe r tiers, however, a Tier 4 bait station must be made of a material of sufficient rigidity su ch that the station is not easily crushed or opened by a child less than 6 year s of age, not easily chewed by target rodents, and not reasonably anticipated to release rodentic ide bait except for bait removed by target rodents and minor quantities of crumbs crea ted by target rodents. Rodenticide bait products that include Tier 4 ba it stations must be labeled for indoor use only and to prohibit placement where the product is accessi ble to children, domestic animals and/or non-target wildlife.

1. Rodenticides in bait stations that meet the standards of the RMD are effective

alternatives to l oose baits and unprotected pastes and blocks.

Studies have shown no consistent differences in rodents’ consumption of block and pelleted or meal formulations. Bait-stations are widely used a nd effective rodent control has been achieved using bait stations in a wide vari ety of circumstances. So me rodents (particularly Norway rats) are wary of any new objects in their environments, and may avoid a newly introduced bait station for a period of time, genera lly about 2 or 3 days. Rodents overcome this neophobia, and will enter a well-placed bait statio n and consume the bait. The shelter and protection of bait that the stations provide ul timately may encourage feeding and prolong the

attractiveness of the bait.Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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2. Rodenticides in bait stations that meet the standards of the RMD are affordable

alternatives to l oose baits and unprotected pastes and blocks.

Most residential consumers will not be affected by the proposed removal of rodenticides formulated as loose baits, paste or blocks withou t bait stations from the residential consumer market. The majority of residential consumers use mechanical methods of control, which will not be affected by the proposed cancellations. Residential consumers wh o use rodent control services provided by PCOs will not be affected by the proposed cancellations. Professional users (such as PCOs, agricultural users, commercial user s, and public health officials) generally have access to tamper-resistant bait stations (required by existing rodenticide labels for use outdoorsand where placements otherwise would be accessible to children, domestic animals, and/or nontarget wildlife) and will continue to have access to many registered rodenticides formulated as loose baits, paste or blocks w ithout bait stations, notwithstandi ng the proposed cancellations. Inasmuch as these professional users will not be affected by the cancellations, neither will

residential consumers who re ly on their services.

The only users likely to be affected by th e proposed cancellations are those residential consumers who purchase and use rodenticides fo r control of commensal rodents in and around buildings. Most of these residential consumer s are likely to experience only modest cost increases as a consequence of the proposed cance llation of rodenticide produc ts registered for the

control of commensal rodents in and around buildings products w ithout bait stations conforming to the RMD criteria, because there are multiple alternative rodenticide products conforming to the RMD and marketed at prices comparable to those of the products EPA proposes to cancel.

For residential consumers currently using non-RMD conforming rodenticide products to control mice, EPA estimates that incremental costs resulting from the proposed cancellations will range from $2 to $12 per infestation. Fo r residential consumer s controlling rats (approximately10% of the consumer rodenticide ma rket), EPA estimates that incremental costs resulting from the proposed cancella tions will range from a potenti al cost savings to $ 97 per infestation. EPA has examined the impacts from these incremental costs against monthly nonhousing income for a family at the poverty thres hold. For mouse control, incremental costs for

control of a minor infestation would be less than 1%, and a major infestation would be approximately 2%, of monthly non-housing income at the poverty threshold. For rat control,

incremental costs for control of minor and major infestations would be 5% and 11%, respectively, of monthly non-housing income at the poverty threshold. These costs would be a significantly lower proportion of in come for the majority of reside ntial consumers. Therefore, the costs associated with the proposed cancellati ons are expected to have little impact on residential consumers. Moreover, mechanical traps offer effective, lower co st rodent control that could result in a cost savings fo r price-sensitive consumers.

3. Loose baits and unprotected pastes and blocks cause adverse effects to children, nontarget wildlife and domesticated and compani on animals that could be avoided.

Bait stations that conform to the standards of the RMD are designed to prevent children,Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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domestic animals and non-target wildlife from being able to come into contact with rodenticides, whereas other product presentations do not ad equately reduce exposur e and ingestion of

rodenticides. Use of a bait station that substa ntially reduces exposure to the bait plainly poses

less risk than alternatives that a llow direct contact with the bait.

Numerous incidents of children being exposed to loose baits and unpr otected blocks have been reported. While most expos ures generally result in no clini cal harm, the numbers of reports of exposed children are troubling. Approximately 85% of the rodenticide exposures reported to AAPCC (i.e., approximately 15,000 per year) occurre d to children under 6 years old. Incidents involving children are predominantly accidental expos ures from picking up baits placed on floors in the home of a parent or guardian. Approximate ly 1% of the incidents of children’s exposure to rodenticides reported to AAP CC are symptomatic (an average of 128 cases per year). While only a small proportion of reported incidents involv e clinical harm, EPA be lieves there are social and economic costs that arise from addressing children’s exposures to rodenticides, including costs to health care facilities, poison control hotlines, and to the families whose children are exposed.

Rodenticides appear to be involved in nu merous reported domestic animal poisonings, which have the potential to result in severe outc omes and/or necessitate veterinary care. In 2010,

APCC identifies rodenticides as the third most li kely cause of pet poisonings and the Pet Poison Helpline identifies rodenticides as the third most common toxi n involved in dog poisonings and

the fourth most common toxin involved in cat poisonings. OPP’s IDS iden tifies two rodenticides (brodifacoum and bromadiolone) in the top 20 pest icides most likely associated with a domestic animal fatality. OPP’s IDS indicates that in recent years there are a bout 2000 reported incidents per year of domestic animals exposed to roden ticides, many of which result in severe outcomes (on average 14% result in death or a major outcome) which may necessitate veterinary care. The IDS data indicate that about 160 severe (death or major effect) domestic animal incidents attributable to rodenticides will be reporte d every year, which EPA believes significantly

underestimates the actual number of incidents.

The various lines of evidence evaluated by EP A have led the Agency to conclude that risks to non-target wildlife from all the rodenticides addresse d in the Notice are significant. There is little question th at wildlife is being exposed to loos e bait products. Incident reports and exposure studies make clear that a wide range of mammalian and avian wi ldlife can come into

contact with the rodentic ides from both primary exposures. EPA’s quantitative assessment and the incident data provide evidence that exposure can and does result in mortality to wildlife. Although many non-target wildlife sp ecies avoid areas of human ha bitation, significant numbers of incidents of both primary and secondary rodenticide po isonings of non-target wildlife occur in urban and suburban areas. This suggests that resi dential and commercial uses of rodenticides for commensal rodent control pose signifi cant risk to non-targ et wildlife.

Moreover, autopsies and biopsie s of predatory and scavenging wildlife consistently show

accumulation of rodenticide residues in liver tissue of numerous predatory and scavenging wildlife species, including owls, eagles, hawks, vultures, mustelid s, bobcats, and mountain lions. Numerous monitoring studies conducted throughout the Unite d States have found secondRodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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generation anticoagulants present in over 85% of individuals of one or more species studied. The prevalence of second generation anticoagulan ts in wildlife regardless of location of

collection indicates that roden ticides used in and around buildi ngs for control of commensal rodents (the only lawful uses of second generation anticoagul ants) affect predatory and scavenging wildlife everywhere.

Bait stations conforming to the RMD can prev ent primary exposures to birds and larger mammals that cannot gain access to the bait. While bait stations cannot prevent secondary exposures to intoxicated prey, bait stations can ensure that int oxicated birds and larger mammals are not available as prey to mammalian and avian scavengers and predators.

4. Conclusion.

The rodenticides subject to this Notice are known poisons to all mammals and birds, and exposure to these rodenticides is widespread among children, domestic animals, and non-target

wildlife. If rodenticides form ulated as loose baits, or pastes or blocks unprotected by bait

stations continue to be availabl e in the residential consumer mark et, these exposures are likely to

continue.

Bait stations conforming to the RMD crit eria can significantly reduce rodenticide exposures among children, domestic animals, and non-target wildlife, co mpared to products without bait stations conforming to the RMD crite ria. EPA has determined that control of commensal rodents in and around buildings by residential consumers can be satisfactorily accomplished without rodenticides formulated as loose baits, or pastes or blocks unprotected by bait stations. Registered rodenticide products that include bait stations that meet the RMD criteria are available on the market at costs compar able to the rodenticide products subject to this Notice, and, when used in combination with prudent sanitation and ex clusion measures, are

effective for the control of commensa l rodents in and around buildings.

Inasmuch as rodenticides in bait stations that meet the standards of the RMD are available, effective, affordable, and cause sign ificantly less risk to ma n or the environment, rodenticide products intended to control comm ensal rodents in and around structures and marketed for general consumer use cause unreasona ble risks unless they in clude a bait station

that meets the standards of the RMD. Accordingly, EPA proposes to cancel the following rodenticide products registered for the control of commensal rodents in and around buildings products without bait stations c onforming to the RMD criteria:

D-CON CONCENTRATE KILLS RATS & MICE, EPA Reg. No. 3282-3 (warfarin)

D- READY MIXED KILLS RATS & MI CE, EPA Reg. No. 3282-4 (warfarin) D- MOUSE PRUFE KILLS MICE, EPA Reg. No. 3282-9 (warfarin) D- PELLETS KILLS RATS & MICE, EPA Reg. No. 3282-15 (warfarin) RID-A-RAT RAT & MOUSE KILLER, EP A Reg. No. 8845-39 (warfarin) D- MOUSE PRUFE II, EPA Re g. No. 3282-65 (brodifacoum) D- PELLETS GENERATION II, EPA Reg. No. 3282-66 (brodifacoum) D- BAIT PELLETS II, EPA Reg. No. 3282-74 (brodifacoum)Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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D- READY MIXED GENERA TION II, EPA Reg. No. 3282-81 (brodifacoum) D- MOUSE-PRUFE III, EPA Reg. No. 3282-85 (difethialone) D- BAIT PELLETS III, EPA Re g. No. 3282-86 (difethialone) D- II READY MIX BAITBITS III, EPA Reg. No. 3282-87 (difethialone) D- BAIT PACKS III, EPA Reg. No. 3282-88 (difethialone) GENERATION MEAL BAIT PACKS, EPA Reg. No. 7173-247 (difethialone) DIFETHIALONE BAIT STATION, EPA Reg. No. 7173-283 (difethialone) DIFETHIALONE 6G PASTE PL PKS, EPA Reg. No. 7173-285 (difethialone)

HOT SHOT SUDDEN DEATH BRAND MOUSE KILLER, EPA Reg. No. 8845-125 (bromethalin)

HOT SHOT SUDDEN DEATH BRAND RAT KILLER 1, EPA Reg. No. 8845-126 (bromethalin)

HOT SHOT SUDDEN DEATH BRAND RA T & MOUSE KILLER, EPA Reg. No. 8845-127 (bromethalin)

HOT SHOT SUDDEN DEATH BRAND MOUS E KILLER BAIT STATION, EPA Reg. No. 8845-128 (bromethalin)

For the same reasons, EPA denies applications for registration of the following products:

BROMETHALIN 0.01% PELLET III, EPA Application No. 36488-AN (bromethalin)

BROMETHALIN RAT AND MOUSE BLOCK III, EPA Application No. 36488-AR (bromethalin)

IX. Existing Stocks of Cancelled Products

FIFRA section 6(a) allows the Agency to pe rmit the continued sale and use of existing stocks of pesticide whose use has been cancelled, to the extent the Administrator determines that

such sale or use would not be inconsistent with th e purposes of this Act. Allowing further sale or distribution of the products identif ied in this Notice would not be consistent with the purposes of FIFRA. First and most important, the continue d sale and distribution of products cancelled pursuant to this Notice result in unreasonable adverse effects on the environment. Second, the regulated community has been on notice since May 28, 2008 that the Agency intended that sale and distribution of these products by registrant s must cease by June 4, 2011. During that period, most registrants have amended existing rodenticide products , or registered new rodenticide products, that cause significantly less risk to the environment, a nd these rodentic ide products are widely available. EPA does not believe it to be consistent with the purposes of FIFRA to continue to put registrants who voluntarily brought safer products to the market at a competitive disadvantage relative to registra nts who declined to improve their products. Accordingly, the

EPA has determined that the continued sale a nd distribution of existi ng stocks of pesticide products cancelled pursuant to this notice shall not be permitted.

Sections 3(c)(2)(B) and 6( e) of FIFRA provide that the question of whether the disposition of existing stocks is consistent with the purposes of FIFRA is a subject to be determined at any suspension or conditional cancellation hearing under those provisions.Rodenticides.  Draft Notice of I ntent to Cancel and Denial    11 /02/2011


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Section 6(b) does not contain similar language, a nd the EPA has determined that the question of the disposition of existing stocks is outside the scope of any heari ng conducted pursuant to FIFRA section 6(b).

X. USDA, HHS and SAP Review

When the Agency intends to issue a Notice of Intent to Cancel, FIFRA section 6(b) requires that it must furnish a draft of that noti ce and an analysis of the impact of the proposed action on the agricultu ral economy to the Secretary of the Department of Agriculture (USDA), and, when a public health use is affected, to the Secretary for Health and Human Services (HHS), for comment at least 60 days prior to issuing the notice. In addition, FIFRA section 25(d) requires the Agency must within the same time period submit the proposed cancellation action to the FIFRA Scientific Advisory Panel (SAP) for comment concerning the impact of the proposed action on health and the environment.

In the event that written co mments are received from the USDA, HHS or the SAP within 30 days of such referral, the Agency must publish those comments and the Agency's response to

the comments with the cancellation notice.

[Insert summary of any USDA, HHS and SAP comments]

XI. Procedural Matters