UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D
.C. 20460 

## OCT 1 42015

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION 

### MEMORANDUM
SUBJECT: BEAD Chemical Profile for Registration Review: Warfarin and Warfarin Sodium Salts (086002 and 086003) Amended 

### FROM:

THRU:

TO: Colwell Cook,

# Entomologist~~ Biological Analysis Branch Biological and Economic Analysis Division (7503P) Arnet Jones, Chief 

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./" Biological and Economic Analysis Division (7503P) CaitlinNewcamp, Chemical Review Manager Risk Management and Implementation Branch II Pesticide Re-evaluation Division (7508P) 

### ProductReview Panel date: July 15, 2015
SUMMARY The Biological and Economic Analysis Division (BEAD) Chemical Profile (BCP) provides an overview ofthe pest management role for warfarin and warfarin sodium salt. Information provided in this BCP may be used by stakeholders (e.g. users and registrants), OPP risk and benefit assessors, OPP risk managers, and the general public during the Registration Review process ofthis pesticide. This amended document corrects the use sites from the earlier version (Cook, 2015). Warfarin and its sodium salt are anticoagulant rodenticides, first registered inthe U.S. in 1950 and 1954, respectively. There are no current active registrations for warfarin sodium salt. There are 13 active end-use product registrations for warfarin; Warfarin is registered for use in
1controlling rodents (e.g. rats, mice, voles, and moles), in and around homes andbuildings, agricultural and animal premises, commercial and industrial sites, and transport vehicles. Warfarin is formulated as granules, pellets/tablets, microencapsulatedpellets, and solution (gel). Itmaybe applied inbait stations orby hand, and a syringe is used to apply the gel formulation into active underground mole burrows. · Warfarin was the first anticoagulant rodenticide to be developed and subsequently is a first generation anticoagulant rodenticide. Anticoagulants interfere with the formation of prothrombin andthus the blood clotting process. This leads to internal bleeding and death. Warfarin, and all the first generation anticoagulantrodenticides, require multiple feeding over several days to reach a toxic dose. Because warfarin was the first rodenticide, there are some populations ofrodents thatmay demonstrate some levelofresistance, butthe extent is not known (Corrigan, 2001; Heiberg, 2009). BEAD has previously assessed rodenticides. Chiri (2006) assessed the pest status ofrodents, integrated pest management ofrodents, and evaluated the use ofrodenticide bait. A second document in 2006 consideredthe cost impacts
.for the Rodenticide Mitigation Decision (RMD) (Chiri, et al., 2006). BEAD (Chiri, et al., 2008) responded to public comments concerning the proposed RMD for nine rodenticides. Later that year BEAD published an addendum to the impact analysis that determined the amended proposed mitigation ofrequiring bait stations would not impose constraints on rodent control programs but could increase costs to residential consumers; althoughhomeowners could switchto less expensive snap traps (Rim, 2008). BEAD published an impact analysis ofmitigations ofthe proposedNotice ofIntent to Cancel selected residential consumerrodenticide products (Cook and Hill, 2011) which reachedthe same conclusion as Rim (2008). BEAD has no available usage data for warfarin. General information onwhy warfarin is · selected over other rodenticides; where it is used; how it is applied; and when it is used would be helpful for assessments.
References: Chiri, A. A. January 23, 2006. Analysis ofrodenticide baituse. BEAD Memorandumto SRRD/Kelly Sherman. Located at:**http://www.regulations.gov/#!documentDetail;D~EPA-HO-** ' 

### 0 PP-2006-0955-0004
. Chiri, A. A., J. Becker, and Jin Kim. Sept. 20, 2006. Impact assessment foi; proposed
· rodenticide mitigation (DP 332577). BEAD Memorandum to SRRD/Kelly Sherman. Located

at: http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2006-0955-0003. Chiri, A. A., J. Becker, and E. Rim. January 3, 2008. Response to comments submitted to DocketNo. EPA-HQ-OPP-2006-0955, proposed risk mitigation decision for nine rodenticides. BEAD Memorandumto SRRD/Kelly Sherman. Located at: http://www.regulations.gov/#!documentDetail;D=EP A-HQ-OPP-2006-0955-0755.
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### Cook, C. 2015. BEAD chemical profile for reregistrationreview: warfarin and warfarin sodium salts (086002 and 086003). BEAD Memorandum to PRD/CaitlinNewcamp, dated July 16, 2015. Corrigan, R. 

### M. 2001. Rodent Control: A Practical Guide for PestManagement Professionals. GIE Media, Cleveland. 351 pp. Heiberg. A-C. 2009. Anticoagulantresistance: a relevant issue in sewerrat (Rattus norvegicus) control? PestManag Sci 65(4):444-449. Rim, E. May 20, 2008. Addendumto impact assessment for proposed rodenticide mitigation (DP 332574). BEAD Memorandum to SRRD/Kelly Sherman. Located at:**http://www.regulations.gov/#!documentDetai~;D=EPA-HQ-OPP-2006-0955-0754.**

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