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

### FEB 2 3 2016
OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION MEMORANDUM
SUBJECT:

FROM:

THRU: BEAD Chemical Profile for Registration Review ofthe Second Generation Anticoagulant Rodenticides: Brodifacoum (112701 ), Bromadiolone (112001 ), Difenacoum ( 119901 ), and Difethialone ( 128967) Colwell Cook, Biologist 

# e**~~** Biological Analysis Branch Elizabeth Hill , Economist 

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TO: Ricardo Jones, Chemical Review Manager Risk Management and Implementation Branch I Pesticide Re-evaluation Division (7508P)
Product Review Panel Date: February 10, 2016

Page 1of 6SUMMARY The second generation anticoagulant rodenticides (SGARs) were developed as a result ofrodents developing resistance to warfarin and other first-generation anticoagulants. The SGARs registered in the U
.S
. include brodifacoum, bromadiolone, difenacoum, and difethialone
. Brodifacoum was first registered in 1979, bromadiolone was registered in 1980, difethialone in 1995 , and difenacoum in 2007. These compounds are registered for the control of commensal rodents and work by interfering with the blood clotting mechanism. The primary use sites for these rodenticides are in and near human habitat, as well as in island eradication programs . INTRODUCTION The Biological and Economic Analysis Division (BEAD) Chemical Profile (BCP) provides an overview ofthe pest management roles and quantitative usage information for SGARs. The BCP includes available public and/or private use and usage data for SGARs and a general discussion ofbiological aspects , intended to describe the role of this chemical in pest management. Additional information on use is available in the SOAR Label Data Report provided in the public docket for this chemical. Information provided in this BEAD Chemical Profile (BCP) may be used by stakeholders (e.g ., users and registrants) , Office of Pesticide Programs (OPP) risk and benefit assessors , OPP risk managers, and the general public during the Registration Review process ofthis pesticide. This document builds upon the data already provided in the Label Use Information System (LUIS) reports that BEAD provides to the Registration Review teams. The document is based on information and data available to BEAD as ofJanuary 15 , 2016
. HISTORY OF BEAD ASSESSMENTS FOR SGARs The SGARs , brodifacoum, bromadiolone, and difethialone , have been assessed several times by BEAD
. The registered SGARs were re-registered in 1998 (EPA, 1998) , but not all registrants agreed to mitigation measures. BEAD conducted several assessments to support the EPA ' s 2008 Risk Management Decision ·for Ten Rodenticides (RMD) (EPA, 2008) , which then included difenacoum (Wasem, 2911). BEAD concluded that chemical rodenticides are a critical component ofrodent management ; there is little difference between the performance of the rodenticide active ingredients; and rodenticides are generally interchangeable and can be considered alternatives to one another for homeowner use (Chiri , 2006; Chiri , et al. 2006 ; Chiri , et al. , 2008)
. Some registrants did not accept the mitigation from the RMD (EPA , 2008). In 2011 , Cook and Hill (2011) considered the impact of cancellation of selected consumer (homeowner) products in support of the Agency ' s proposed Notice of Intent to Cancel (EPA , 2011). Specifically, the mitigation required that SGARs no longer be available in the consumer market, that rodenticides must be sold in block form and packaged with a bait station. The assessment concluded that the incremental costs would be minimal for consumers having to switch from rodenticide products currently available to those that would be in compliance with the mitigation
. Page 2of6A search ofthe BEAD database for previous documents for SGARs indicates that there are no records ofprior Section 18 Emergency Exemption Requests
. Recent Section 18 Emergency Exemption Requests might suggest that a chemical is important for the uses granted in the request ; however, a lack of Section 18 Emergency Exemption Requests is not an indication of the relative importance ofthe chemical.
COMMON FORMULATIONS AND APPLICATION METHODS The second generation anticoagulant rodenticides are formulated mainly as a solid bait, such as pellets , tablets , or blocks. These products must be in locations out ofreach of children, pets , domestic animals , and nontarget wildlife or in tamper-resistant bait stations. Bait stations are mandatory in outdoor, above-ground use . USE SITES Agricultural Use Sites : The SGARs are registered to be used to control rodents in and around agricultural buildings/structures , farm equipment, and in uncultivated agricultural areas. Non-Agricultural Use Sites: The SGARs are registered for use in commercial/institutional/industrial premises/equipment (indoor and outdoor), commercial transportation facilities-nonfeed/nonfood, commercial transportation vehicles , food processing plant premises (nonfood contact), household/domestic dwellings indoor and outdoor premises , and uncultivated nonagricultural areas. They may be used around refuse/solid waste containers
. Brodifacoum, bromadiolone, and difethialone may be used in sewage systems ; however, difenacoum is not registered for this use site.
SGAR USAGE The rodenticide market has been impacted by recent EPA regulation in 2011 , limiting the availability of SGARs to the general public. Although data are not available on SGAR usage, it is known that prior to the 2011 mitigation, brodifacoum was the lead consumer rodenticide , and bromadiolone was the lead professional applicator rodenticide (Kline & Company, 2006; Kline & Company, 2004)
. BIOLOGICAL ASPECTS RELEVANT TO SGARs The SGARs are registered to control primarily commensal rodents, i
.e. Norway rats , roof rats , and house mouse in residential and commercial settings and in and around agricultural buildings. Page 3of6Anticoagulant rodenticides interfere with the blood clotting mechanism, specifically impacting a protein, vitamin K epoxide reductase (Vkor). Vkor converts the vitamin K epoxide back to vitamin K, which is an essential cofactor for several blood clotting factors
. The SGARs are potent enough that rodents may ingest a lethal dose in a single night's feeding ; however the rodents take nearly a week to die. Therefore, the rodents may obtain doses much larger than necessary for control. Rodents with elevated level of anticoagulants are then a hazard if consumed by non-target wildlife.
ROLE OF SGARs IN PEST MANAGEMENT Rodents may be both public health pests and agricultural pests. Some rodents may carry diseases , or may be injurious to humans. Rodents will consume and contaminate stored food supplies ; disturb soil through their burrowing activities; damage houses and other structures ; and prey on native species , including birds that nest on oceanic islands. These animals are adapted to live in close proximity to humans and therefore have nearly unlimited food and shelter. Rodenticides are a critical component of managing rodent pests. Rodenticide baits are useful for reducing rodent numbers, especially when infestations are high. Many municipalities and communities have integrated pest management programs that employ a combination of sanitation, exclusion, habitat medication, trapping , and baiting (Illinois Department of Public Health, 2005 ; Kass , et al. 2009 ; New York City Department ofHealth and Mental Hygiene , undated ; New York City Department of Health and Mental Hygiene , 2011). Homeowners may control rodents with a combination oftraps (snap or glue) , and baits ; but SGARs are critical to managing rodents in and around agricultural buildings , food manufacturing facilities , and food handling establishments
. In addition, SGARs are needed by Pest Control Operators
. Rodenticides are also necessary to remove invasive rats and mice that have been introduced on oceanic islands to protect native species (Donlan, et al. , 2003 ; Howald, et al. , 2007 ; Department of Interior/ National Park Service, 2000).
INFORMATION THAT MAY BE USEFUL FOR BEAD'S FUTURE WORK ON SGARs BEAD would be interested in learning about preferences of companies and what drives the selection of one SGAR over another SGAR. More details on when and why these SGARs are used would be helpful for future BEAD assessments . REFERENCES: Chiri , A. 2006. Analysis of Rodenticide Bait Use. Memorandum to Kelly Sherman, Special Review and Registration Division
. Chiri , A. , Becker, J. and Kim, J. 2006. Impact Assessment for Proposed Rodenticide Page 4of6Mitigation. Biological and Economic Analysis Division, Office of Pesticide Programs , U.S
. Environmental Protection Agency. Available at: http: //www .regulations.gov /fdmspub1 ic/component /main?main=DocketDetail&d= EPA-HQ-OPP-2006-0955. Chiri , A. , Becker, J. and Rim, E. 2008. Response to Comments submitted to Docket No
. EPA-HQ-OPP-2006-0955 , Proposed Risk Mitigation Decision for Nine Rodenticides. Biological and Economic Analysis Division, Office of Pesticide Programs , U.S
. Environmental Protection Agency
. Cook, C. and E
. Hill. Oct. 31 , 2011. Impact assessment of the draft notice of intent to cancel selected residential consumer rodenticide products to control commensal rodents
. Memorandum to Russell Wasem, PRD. Available at: http: //www.regulations.gov/# !documentDetail;D=EPAHQ-OPP-2011-0718-0013
. Department of the Interior/ National Park Service. 2000. Anacapa Island Restoration Plan, Final Environmental Impact Statement, Channel Islands National Park, Ventura County, CA ; Notice of Availability
. Available at : http ://www.federalregister
.com/Browse/Document/usa/na/fr /2000/ 1 0/ 12/00-26143
. Accessed : February 4 , 2016. Donlan, C
.J ., G. R. Howald, B
. R
. Tershy , D. A. Croll. 2003. Evaluating alternative rodenticides for island conservation: roof rat eradication from the San Jorge Islands , Mexico
. Biological Conservation 114 (1): 29-34. EPA. 1998
. Rodenticide Cluster R.E.D
. Facts. Available at: http: //archive.epa.gov/pesticides/reregistration/web/pdf /21 OOfact. pdf
. EPA. 2008. Risk Mitigation for Ten Rodenticides. May 28 , 2008. Available at: http ://www .regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2006-0955-0764
. EPA. 2011
. Rodenticides
. Draft notice of intent to cancel and denial. Available at: http ://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2011-0718-0017
. Howald , G. , C. J
. Donlan, J
. P
. Galvan , J.C. Russell , J
. Parkes , A. Samaniego, Y
. Wang , D
. Veitch , P
. Genovesi , M
. Pascal , A. Saunders , and B. Tershy
. 2007
. Invasive Rodent Eradication on Islands. Conservation Biology 21(5):1258-1268
. Illinois Department of Public Health. 2005. Prevention and Control : Municipal Rodent Management. Available at: http ://www.idph
.state.il.us/envhealth/pcmunicipal rodents.htm
. Kass , D , W McKelvey , E Carlton, M Hernandez , G Chew, S Nagle , R Garfinkel , B Clarke , J Tiven, C Espino , and D Evans
. 2009
. Effectiveness of an integrated pest management intervention in controlling cockroaches , mice , and allergens in New York City public housing. Environmental Health Perspectives 117(8) : 1219-1225. Page 5of6Kline & Company
. 2006. Consumer Markets for Pesticides and Fertilizers USA: Rodenticides. Kline & Company. 2004
. U.S. Professional Pest Management Market: Rodenticides
. New York City Department of Health and Mental Hygiene
. Undated. Preventing rats on your property - a guide for property owners and tenets. Publication number EHS6356051- 408
.Available at : http ://www.nyc.gov/html/doh/downloads/pdf /pest /rodent
_control.pdf. Accessed: 6/21 /2011
. New York City Department of Health and Mental Hygiene. 2011. Who is responsible for preventing rats? Available at: http: //www .nyc .gov/html/doh/html/rats/responsible.shtml. Accessed: 6/21/2011. Wasem, R. 2011. Regulatory history often rodenticides. Memorandum to Federal Insecticide Rodenticide and Fungicide Act Scientific Advisory Panel. Available at : http: //www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2011-0718-0015
.

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