Page 1 of 65

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C., 20460

MEMORANDUM Date 12/09/2015

Subject: Registration Review –Preliminary Problem Formulation for Ecological Risk and 

Environmental Fate, Endangered Species, and Drinking Water Assessments for

Chlorophacinone

PC Code: 067707

DP Barcode: 426557

To: Christina Motilall, Chemical Review Manager

Neil Anderson, Branch Chief

Risk Management and Implementation Branch 1

Pesticide Re-evaluation Division (PRD)

From: Christine Hartless, Ph.D., Wildlife Biologist

James Lin, Ph.D., Environmental Engineer

Environmental Risk Branch 2

Environmental Fate and Effects Division

Office of Pesticide Programs

Through: Melissa Panger, Ph.D., Senior Advisor

Ron Parker, Senior Environmental Engineer

Elyssa Arnold, Risk Assessment Process Leader

Brian Anderson, Branch Chief

Environmental Risk Branch 2

Environmental Fate and Effects Division

Office of Pesticide Programs

The Environmental Fate and Effects Division (EFED) has completed the preliminary problem 

formulation (attached) for the ecological risk, environmental fate, endangered species, and 

drinking water assessments to be conducted as part of the registration review of the rodenticide 

chlorophacinone. 

The problem formulation draws on information from both open literature and studies submitted 

by the technical registrants in response to data requirements. This document is intended to 

provide an overview of what is currently known regarding the environmental fate and ecological 

effects associated with chlorophacinone and outlines uncertainties regarding attributes of the 

parent compound and its transformation products. It describes the preliminary ecological risk 

hypothesis and the processes that will be used during the completion of drinking water and

ecological risk assessments in support of registration review. This document also recommends 
Page 2 of 65

studies that should be included in a data call-in (DCI) to address uncertainties surrounding the 

environmental fate and potential ecological effects of chlorophacinone.
Page 3 of 65

Preliminary Problem Formulation for the Environmental 

Fate and Ecological Risk, Endangered Species, and Drinking 

Water Assessments in Support of the Registration Review of 

Chlorophacinone

2-[2-(4-chlorophenyl)-2-phenylacetyl]indan-1,3-dione

(CAS 3691-35-8)

(PC Code 067707)

Environmental Risk Branch II

Environmental Fate and Effects Division

Christine Hartless, Ph.D., Wildlife Biologist

James Lin, Ph.D. Environmental Engineer

Reviewed by:

Melissa Panger, Ph.D., Senior Advisor

Ron Parker, Senior Environmental Engineer

Elyssa Arnold, Risk Assessment Process Leader

Brian Anderson, Branch Chief

U. S. Environmental Protection Agency

Office of Pesticide Programs

1200 Pennsylvania Ave., NW

Mail Code 7507P

Washington, DC 20460

December 9, 2015
Page 4 of 65

Table of Contents

1 EXECUTIVE SUMMARY..................................................................................................................................5

2 INTRODUCTION ............................................................................................................................................5

3 USE CHARACTERIZATION ..............................................................................................................................6

4 CONCLUSIONS FROM PREVIOUS RISK ASSESSMENTS....................................................................................9

4.1 ENDANGERED SPECIES ASSESSMENTS .......................................................................................................................9

4.2 REREGISTRATION ELIGIBILITY DECISION...................................................................................................................10

4.3 NEW USE ASSESSMENTS......................................................................................................................................11

4.4 DRINKING WATER ASSESSMENT .............................................................................................................................12

5 ENVIRONMENTAL FATE AND TRANSPORT .................................................................................................. 12

6 RECEPTORS ................................................................................................................................................. 15

6.1 TOXICITY SUMMARY ...........................................................................................................................................15

6.2 SECONDARY TOXICITY..........................................................................................................................................17

6.3 INCIDENT DATABASE REVIEW................................................................................................................................20

7 EXPOSURE PATHWAYS OF CONCERN.......................................................................................................... 20

8 ANALYSIS PLAN........................................................................................................................................... 21

8.1 STRESSORS OF CONCERN......................................................................................................................................21

8.2 MEASURES OF EXPOSURE.....................................................................................................................................21

8.3 MEASURES OF EFFECT .........................................................................................................................................30

9 ENDANGERED SPECIES ASSESSMENT .......................................................................................................... 30

10 ENDOCRINE DISRUPTOR SCREENING PROGRAM......................................................................................... 30

11 PRELIMINARY IDENTIFICATION OF DATA GAPS........................................................................................... 31

11.1 FATE ...........................................................................................................................................................31

11.2 EFFECTS.......................................................................................................................................................31

12 REFERENCES ............................................................................................................................................... 35

APPENDIX A: LABEL USE INFORMATION FOR CHLOROPHACINONE BASED ON BEADS SUMMARY REPORT.......... 44

APPENDIX B: SUMMARY OF ECOTOXICITY DATA FOR CHLOROPHACINONE......................................................... 48

APPENDIX C. SCREENING LEVEL MODELS TO EVALUATE POTENTIAL IMPORTANCE OF DRINKING WATER AND 

INHALATION EXPOSURE PATHWAYS.................................................................................................................... 55

APPENDIX D. WILDLIFE MORTALITY INCIDENTS ATTRIBUTED TO USE OF CHLOROPHACINONE........................... 58
Page 5 of 65

1 Executive summary

The Environmental Fate and Effects Division (EFED) has completed the preliminary problem 

formulation for the ecological risk, environmental fate, endangered species, and drinking water 

assessments to be conducted as part of the registration review of chlorophacinone. The problem 

formulation describes the methods planned to be used during the completion of drinking water 

and ecological risk assessments in support of registration review and provides an overview of the 

environmental fate, ecological effects, and potential risks associated with the use of 

chlorophacinone as well as uncertainties unique to risk assessment of chlorophacinone. This 

document also identifies additional studies that would be beneficial to the conduct of an 

ecological risk assessment. 

Data needs for ecological effects are:

 Avian acute oral toxicity test (850.2100), one passerine species

 Avian acute oral toxicity test (850.2100), one carnivorous species

 Data evaluating toxicity and/or bioaccumulation of chlorophacinone in terrestrial 

invertebrates

Additionally, an Earthworm Subchronic Toxicity Test (850.3100), has been submitted and is 

currently under review (MRID 47383002). If this study is determined to be invalid, EFED 

recommends requesting a new earthworm study. No additional data are needed for 

environmental fate assessment at this time.

2 Introduction

Chlorophacinone is an indandione anticoagulant rodenticide. Anticoagulants are vitamin-K 

antagonists that disrupt normal blood-clotting mechanisms and induce capillary damage. It 

uncouples oxidative phosphorylation depressing hepatic synthesis of prothrombin and clotting 

factors VII, IX and X and, it causes direct damage to capillary permeability. Typically, death is 

delayed for four to ten or more days after a lethal dose is ingested, and animals may continue to 

feed and move about until shortly before death. Death results from hemorrhage, and exposed 

animals may exhibit behavior that may make them more susceptible to predation (Cox and 

Smith, 1992). This may result in secondary exposure to predatory animals. Chlorophacinone is 

metabolized by vertebrate animals that have eaten bait, but some is sequestered in various body 

tissues for days or weeks. 

The anticoagulant rodenticides registered in the United States have been grouped into "firstgeneration" (warfarin, chlorophacinone, diphacinone) and "second-generation" (brodifacoum, 

difenacoum, bromadiolone, difethialone) compounds. Although there is overlap in their 

metabolic and toxicological properties, second-generation anticoagulants tend to be more acutely 

toxic than are the first-generation anticoagulants, and they are retained longer in body tissues.

The greater potency and duration of action of long-acting anticoagulant rodenticides is attributed 

to their: (i) greater affinity for vitamin K(1)-2,3-epoxide reductase; (ii) ability to disrupt the 

vitamin K(1)-epoxide cycle at more than one point; (iii) hepatic accumulation; and (iv) unusually 

long biological half-lives due to high lipid solubility and enterohepatic circulation (Watt et al.

2005).
Page 6 of 65

EFED evaluated the most recent ecological risk assessments for chlorophacinone in association 

with the updated toxicity, exposure, and usage information to determine if sufficient data are 

available and if further updates are needed to support registration review. In addition, EFED 

considered the latest Agency science policies and risk assessment methodologies. The structure 

of chlorophacinone, as well as the chemical names and other identifiers can be found in the 

chemical identity table in Section 5 of this document. 

3 Use Characterization

Table 1 summarizes the Section 3 labeled use patterns and bait concentrations for given groups 

of target species. Details for individual products are not included; however, this table provides 

characterization for the expected use patterns of chlorophacinone. In addition to the Section 3 

labels, there are currently nine Section 24C labels for 0.005% chlorophacinone baits targeting:

 California and montane voles, California ground squirrels, chipmunks, black tailed 

jackrabbits, and muskrats in California; 

 Norway rats, roof rats, Polynesian rats, and house mice in Hawaii; 

 voles in Idaho (aerial application); 

 Columbian and Richardson’s ground squirrels in Montana; 

 mountain beaver in Oregon and Washington; and

 meadow and mountain voles in Washington (aerial application).

In addition, there are two Section 24C labels for 0.01% chlorophacinone baits targeting

California Ground Squirrels, California voles, montane voles, pocket gophers, deer mice, and 

house mice in California.

Since there is no national level usage data for this chemical, no Screening Level Usage Analysis 

(SLUA) is available for chlorophacinone (067707). Appendix A lists the maximum use patterns 

for the labeled use sites. The table is based on the “EFED Table 1 Report,” which is a part of the 

Label Use Report Package created by BEAD in support of Registration Review (USEPA, 2015). 

Prior to the registration review assessment, the label review will be updated.
Page 7 of 65

Table 1. Overview of Section 3 Labels for Chlorophacinone 

Target Species % a.i. Bait form General Use pattern Use Sites Maximum application rate and reapplication interval

House mouse (Mus 

musculus), 

Roof rat (Rattus rattus), 

Norway rat (Rattus 

norvegicus), Cotton rat 

(Sigmodon hispidus),

Meadow vole, (Microtus 

pennsylvanicus), Eastern 

harvest mouse 

(Reithrodontomys humuli),

White-throated woodrat 

(Neotoma albigula), Golden 

mouse (Ochrotomys nuttalli),

Southern plains woodrat 

(Neotoma micropus),

Polynesian rat (Rattus 

exulans), and/or Mexican 

woodrat (Neotoma mexicana)

0.005

Bait block, 

pellet, treated 

grain, place 

pack

Use indoors and within 100 

feet of man-made structures. 

Must use bait station for 

outdoor above ground use or 

when children or non-target 

mammals or birds can access 

the bait. Some labels restrict 

use indoors. Some labels 

permit use in sewers. Some 

labels permit use in rat 

burrows. Some labels permit 

use >100 ft from buildings 

(for along fence lines, gullies, 

railroads, etc.)

Indoor and 

within 100 feet 

of man-made 

structures 

(residential, 

commercial, 

agricultural, 

industrial, public 

buildings, 

ships/boats)

Refill/replace bait boxes as needed. 

House mouse, Norway rat, 

and Roof rat 0.2 Tracking powder

Use indoors or in rat burrows 

leading indoors.

Indoor or in rat 

burrow leading 

indoors.

For House mice use at the rate of 1 oz. 

powder per 2.5 sq. ft. of runway area. For 

Norway and Roof rats use at the rate of 2 oz. 

powder for 2,5 sq. ft. of runway area. Repeat 

treatment if burrows are reopened. Maintain 

powder in treated areas for at least 20 days. 

Repeat treatment when infestation recurs. 

Where a continuous source of infestation is 

present, establish permanent tracking powder 

stations and replenish the powder as needed.

Pocket gopher (Geomys spp. 

and Thomomys spp.) 0.005 Pellet or treated grain

Applied underground to 

burrow system by hand or by 

mechanical burrow builder

Lawns, golf 

courses, alfalfa 

fields, rangeland, 

orchards and 

groves, and noncrop areas

Maintain a constant supply of bait for long as 

there is gopher activity.
Page 8 of 65

Vole (Microtus spp.) Hand spot bait, mechanical 

ground broadcast

Orchards, noncrop areas, 

nurseries, tree 

and forestry 

plantations.

Broadcast application – apply 10 lbs. 

product/acre with 2nd application one month 

later, if needed. For some labeled sites, max 

application rate of 20 lbs 

product/acre/application and 40 lbs 

product/acre/year.

Black tailed prairie dog 

(Cynomys ludovicianus)

Place 1/4 cup bait at least 6 

inches into burrow

Rangeland and 

adjacent noncrop areas

If needed, may make second application 

several weeks or months later. 
Page 9 of 65

4 Conclusions from Previous Risk Assessments

The Agency has conducted previous ecological risk assessments on chlorophacinone that serve 

as a basis for this problem formulation. They are briefly summarized below. 

4.1 Endangered Species Assessments

An endangered species risk assessment for chlorophacinone was completed in 2010 (USEPA 

2010). This ecological risk assessment and effects determination was specific to Rozol Prairie 

Dog Bait (EPA Reg. No. 7173-286) to address potential product-specific risks raised in pending 

litigation, Defenders of Wildlife v. U.S. EPA1. In this assessment, a “may affect, and likely to 

adversely affect” (LAA) determination was made for the following federally listed species: 

grizzly bear (Ursus arctos horribilis), American burying beetle (Nicrophorus americanus), Salt 

Creek tiger beetle (Cicindela nevadica lincolniana), California condor (Gymnogyps 

californianus), whooping crane (Grus americana), Eskimo curlew (Numenius borealis), northern 

Aplomado falcon (Falco femoralis septentrionalis), black-footed ferret (Mustela nigripes), 

Chiricahua leopard frog (Rana chiricahuensis), jaguar (Panthera onca), Gulf Coast jaguarundi 

(Herpailurus yagouaroundi cacomitli), Canada lynx (Lynx Canadensis), Preble’s meadow 

jumping mouse (Zapus hudsonius preblei), ocelot (Leopardus pardalis), Mexican spotted owl 

(Strix occidentalis lucida), piping plover (Charadrius melodus), New Mexican ridge-nosed 

rattlesnake (Crotalus willardi obscurus), Sonora tiger salamander (Ambystoma tigrinum 

stebbinsi) black-capped vireo (Vireo atricapilla), golden-cheek warbler (Dendroica 

chrysoparia), and gray wolf (Canis lupus). In addition, the assessment found the action was

expected to result in modification of designated critical habitat for the Salt Creek tiger beetle, 

whooping crane, Canada lynx, Preble’s meadow jumping mouse, Mexican spotted owl, piping 

plover, and New Mexican ridge-nosed rattlesnake because these critical habitats overlap with the 

use area of Rozol Prairie Dog Bait. 

An endangered species risk assessment was completed in 2011 (USEPA 2011) to address 

potential risk to the Salt marsh harvest mouse (SMHM) (Reithrodontomys raviventris), San 

Joaquin Kit Fox (SJKF) (Vulpes macrotis mutica), Alameda Whipsnake (AW) (Masticophis 

lateralis euryxanthus), and California Tiger Salamander (CTS) (Ambystoma californiense) for 

which chlorophacinone was alleged to be of concern in a complaint made by the Center for 

Biological Diversity against United States Environmental Protection Agency on May 30, 2007 

(Case No: 07-2794-JCS). Based on the best available information, the Agency made a “May 

Affect, and Likely to Adversely Affect” determination for the SMHM, SJKF, AW, and CTS 

from the all uses of chlorophacinone. Additionally, the Agency determined that there was the 

potential for modification of designated critical habitat for the AW and CTS from the use of 

chlorophacinone.

 

1

 Defenders of Wildlife v. U.S. EPA, Case No. 09-1199 (D.C. Cir., 2009); Defenders of Wildlife v. Jackson, Case 

No. 09-cv-1814 (D.D.C., 2009); NRDC v. U.S. EPA, Case No. 10-cv-1063, (D.D.C., 2010). 
Page 10 of 65

4.2 Reregistration Eligibility Decision 

The Reregistration Eligibility Decision (RED) for chlorophacinone was published in 1998 as part 

of the rodenticide cluster (USEPA, 1998b). The RED found that all uses of chlorophacinone 

except for field rodenticide uses involving baits with chlorophacinone concentrations greater 

than 0.005% were eligible for reregistration. In addition, the RED found that all rodenticides 

must incorporate an indicator dye and a bittering agent. Both these measures were intended to 

help reduce human exposure. Other mitigation measures included improved label language 

regarding placement of bait stations around buildings, submission of information on poisonings, 

restricted use classification of tracking powders and baits, and the formation of a stakeholder 

group to investigate safer use technologies. 

“Potential Risks of Nine Rodenticides to Birds and Nontarget Mammals: a Comparative 

Approach” (USEPA 2004b) evaluated primary and secondary exposure of chlorophacinone, 

among other rodenticides, to birds and mammals. This assessment determined that the 

greatest risk of chlorophacinone use to non-target animals is via primary and secondary 

exposure to mammals. Risk associated with primary and secondary exposure to birds, 

however, was also of concern. These elements provide the general framework for this 

assessment and are supported through the calculation of RQs in this assessment. The study 

also specified a number of factors contributing to uncertainty in assessing anticoagulant 

rodenticides. Those factors that contributed the most uncertainty were: (1) missing data, 

including acute, chronic, and secondary toxicity as well as data regarding retention of some 

active ingredients in the liver, blood, and other body tissues; (2) the variable quality and 

quantity of existing data on metabolism and retention times in rodents and non-target 

species; (3) specific use information by formulation, including typical amounts applied by 

use site, seasonally, and annually; distances applied from buildings; amounts used in rural 

versus urban areas; use by Certified Applicators versus homeowners and other non-certified 

applicators; and other such relevant information; (4) information on the number and species 

of birds and non-target mammals frequenting baited areas and the likelihood of their finding 

and consuming bait or poisoned primary consumers in the various use areas; (5) methods to 

determine liver concentration(s) and total body burdens of rodenticide that would 

corroborate death or even if such a cause-effect relationship is appropriate (e.g., the 

“threshold of toxicity” concentration); (6) not accounting for the impacts of sub-lethal 

effects on reproduction and non-target mortality (e.g., clotting abnormalities, hemorrhaging, 

stress factors including environmental stressors, such as adverse weather conditions, food 

shortages, and predation); (7) not accounting for bioaccumulation of repeated sub-lethal 

exposures to bait or poisoned rodents utilized as food by predators and scavengers; and (8) 

lack of incident reporting. All of the above issues remain as uncertainties for this 

assessment.

In 2008, EPA released the Risk Mitigation Decision for Ten Rodenticides (RMD) (EPA 2008, 

Docket ID EPA-HQ-OPP-2006-0955). Chlorophacinone products were included in the list of ten 

rodenticides addressed in this document. The focus of this decision was:

1) To minimize children’s exposure to rodenticide products used in homes by requiring 

that all rodenticide bait products marketed to general and residential consumers be 
Page 11 of 65

sold only with bait stations, with loose bait (e.g., pellets and meal) as a prohibited bait 

form. 

2) To reduce wildlife exposures and ecological risks, by requiring sale and distribution 

limits intended to prevent general consumers from purchasing residential use bait 

products containing four of the ten rodenticides that pose the greatest risk to wildlife 

(the second generation anticoagulants – brodifacoum, bromadiolone, difenacoum, and 

difethialone). Moreover, bait stations will be required for all outdoor, above-ground 

uses of these second generation anticoagulants.

EPA updated its previous risk assessment findings conducted in support of the May 2008 RMD

through the application of additional effects and exposure data, use of additional exposure 

modeling, and quantitative risk assessment techniques for the four rodenticides subject to the 

Notice of Intent to Cancel (NOIC) (brodifacoum, difethialone, warfarin and bromethalin) and for 

two rodenticides that are likely alternatives (i.e., active ingredients included in products with 

RMD-compliant registrations for commensal rodent control, specifically, chlorophacinone and 

diphacinone; bromethalin has both compliant and non-compliant registrations). To support the 

NOIC, EPA conducted an extensive assessment of the potential for primary and secondary 

effects of the rodenticides under evaluation. This work was brought before the Science Advisory 

Panel (SAP) in 2011 for review; meeting materials are available under docket number EPA-HQOPP-2011-0718. 

4.3 New Use Assessments

The most recent Section 3 New Use assessment was completed in 2011 for a proposed use of 

chlorophacinone on California ground squirrels (CGS) (DP Barcode D377940). The risk 

assessment suggested that chlorophacinone presents a risk to both endangered and nonendangered species of terrestrial animals, including mammals, birds, terrestrial-phase 

amphibians, reptiles, and invertebrates. There was a potential for direct effects to listed terrestrial 

animals (vertebrates and invertebrates) through consumption of bait or prey that have eaten bait. 

Consequently, there is a potential concern for indirect effects upon the listed organisms due to 

decreased prey availability and habitat modification (for individuals that use the CGS burrows). 

After removal of the CGS, many vacant burrows may be available in the treated area. This could 

have either a positive or negative effect on listed species residing in or near the treated areas. 

Risks to aquatic organisms, as well as to aquatic plants, were not expected for this proposed use 

of chlorophacinone. Toxicity data were not available for aquatic or terrestrial plants. However, 

given the mode of action of chlorophacinone, direct toxicity to plants, and thus the risk, is 

expected to be low. Terrestrial plants that rely on animals for pollination and seed dispersal do 

have the potential to experience indirect effects through reduction in the animals that perform 

those functions. 
Page 12 of 65

Data gaps were evaluated at the time of the Section 3 assessment for chlorophacinone on CGS

and were assigned a low or high potential to add value to the ecological risk assessment. While 

still considered data gaps according to 40 CFR Part 158, low potential studies are unlikely to 

change risk determinations because alternate methods and weights of evidence (i.e., acute-tochronic ratio, scaling factors, or consideration of environmentally relevant concentrations 

relative to effects thresholds) may possibly be used in the absence of data. High potential studies 

are needed to better characterize potential risks by eliminating uncertainties for both non-listed

and listed species that cannot be accounted for using alternate methods or weights of evidence.

Studies with a high potential to add value to the risk assessment were:

 Field Testing for Terrestrial Wildlife (850.2500)

 Avian Reproduction Study (850.2300), two species

 Avian Acute Oral Toxicity Test (850.2100), one passerine species. 

Studies with a low potential to add value to the risk assessment are:

 Seedling Emergence, Tier II (850.4225), ten species

 Vegetative Vigor, Tier II (850.4250), ten species

 Soil photolysis (835.2410) 

 Aqueous photolysis (835.2240)

 Aerobic aquatic metabolism (835.4300)

 Anaerobic aquatic metabolism (835.4400)

 Freshwater Fish Early Life-Stage Toxicity Test (850.1400)

 Freshwater Invertebrate Life Cycle Toxicity Test (850.1300)

 Estuarine/Marine Fish Acute Toxicity Test (850.1075)

 Estuarine/Marine Fish Early-life Stage Toxicity Test (850.1400)

 Aquatic Plant Toxicity Test Using Lemna spp.,Tiers I and II (850.4400)

 Algal Toxicity, Tiers I and II (850.5400), four species

Two avian reproduction studies (850.2300) were submitted to the Agency after the Section 3 

New Use assessment was completed, and both have been reviewed. These studies will be 

included in the Registration Review risk assessment (MRIDs 48994001 and 48994002). 

4.4 Drinking water assessment

The previous assessments concluded that due to the application amounts and methods of 

chlorophacinone, the exposure of surface water or ground water is unlikely. No drinking water 

assessments have been conducted.

5 Environmental Fate and Transport 

Chlorophacinone, 2-[2-(4-chlorophenyl)-2-phenylacetyl]indan-1,3-dione, may be considered 

moderately persistent (aerobic soil metabolism half-lives on the order of weeks) and hardly 

mobile (Koc = 20,300 L∙kg-1) in the environment. The major route of dissipation appears to 

aerobic soil metabolism. 

The molecule has two chiral centers, one on the 9 carbon of the indanone and the second at the 
Page 13 of 65

carbon which joins the two phenyl rings (Figure 1). The stereo chemistry at these two chiral 

centers is not known and no data are available to describe the differential stereochemical 

properties. 

Figure 1. Structure of chlorophacinone.

Physical and chemical properties of chlorophacinone are summarized in Table 3. There is no 

evidence that chlorophacinone degrades by hydrolysis at pHs of 7 and 9. At pH 5, 

chlorophacinone degrades slowly, with a half-life of 232 d. Previous assessments indicated a 

rapid degradation of chlorophacinone by photolysis; however, both of these studies (MRID 

42205502 for aqueous photolysis and MRID 42452301 for soil photolysis) used acetone as a 

solvent to introduce chlorophacinone into the test system. As acetone is a strong photosensitizer, 

the results of these are likely not related to actual photodegradation rates in the environment and 

both studies are now classified as invalid. The half-life values of aerobic metabolic degradation 

in soils are 47.2 days and 17.0 days, respectively for sandy clay loam and sandy loam (MRID 

43159801). Data on aquatic metabolism are not available; therefore, actual persistence in 

water/sediment is not known. However, persistence in aquatic systems is often similar to 

persistence in soil.

Chlorophacinone has two identified minor degradates: o-phthalic acid and p-chlorophenylphenyl 

acetic acid (Table 4.). Both degradates were found in the hydrolysis study at pH 5 and the 

aerobic soil metabolism study. A comparison of the structures of these two degradates with those 

of the parent and other anticoagulant rodenticides suggest that the toxic moiety is no longer 

present in these degradates. 

There were three major degradates, CO2 and two that were not identified. The first unidentified 

degradate was observed at 11.7% in the pH 5 hydrolysis study, and 0.9% from aerobic soil 

metabolism study. The second unidentified degradate was material at the origin of the thin-layer 

chromatograms at 10.5%. Occurrence at the origin of the chromatogram suggests that material 

was either very polar, or very immobile. Often this material is composed of a mixture of 

compounds, so that it may not, in fact be, a single major degradate. Since the structures for these 

degradates are not known, the nature of their toxicity cannot be assessed. 

Chlorophacinone is hardly mobile in the environment based on four batch equilibrium studies. 

Adsorption to soil is significantly correlated with soil organic carbon content with a Koc of 
Page 14 of 65

20,300 L∙kg-1based on the regression of the adsorption coefficient, Kd, with the soil organic 

carbon content (R2 = 99.4%) Due to chlorophacinone’s limited immobility in soil, it is 

reasonable to conclude it is relatively immobile within bait formulations. Chlorophacinone baits 

typically retain the parent compound even after exposure to wet weather and moisture (Merson 

and Byers 1985). This means that movement in the environment will be minimal while 

chlorophacinone is still absorbed to the bait or on eroded sediment. Any material that is 

transported into water bodies by erosion may remain sorbed onto soil particles and settle to the 

bottom of the receiving lake or stream bed. Chlorophacinone has a relatively low octanol-water 

partition coefficient of 94, and consequently is not expected to bioaccumulate. The vapor 

pressure is also low (3.58 x 10-6torr), indicating that chlorophacinone is not expected to 

volatilize. 

Table 3. Physical-chemical Properties of Chlorophacinone 

Study Value and units Source

CAS Number 3691-35-8

SMILES Code c12ccccc1C(=O)C(C(=O)C(c3ccccc3)(c4cc(Cl)ccc4))

C2(=O)

Molecular weight 374.81 calculated

Hydrolysis pH 5: 232 d

pH 7: no evidence of degradation

pH 9: no evidence of degradation

MRID 42205501

Solubility 3.43 mg/L @ 25oC MRID 42237401

Aerobic Soil Metabolism T1/2 = 47.2 days; sandy clay loam

T1/2 = 17.0 days; sandy loam

MRID 43159801

Soil Water Partition 

Coefficient 

Sassafras sand: Kf = 56; 1/n = 1.09

Hesperia loam: Kf = 126; 1/n = 1.23

Sequatchie sandy clay loam: Kf = 183; 1/n = 1.22

Sharkey clay: Kf = 1000; 1/n = 1.14

Koc = 20,299 L∙kg-1

MRID 42666001

MRID 42205503

Vapor pressure 3.58 x 10-6torr MRID 42237401

Henry’s law constant 5.12 x 10-7atm∙m3∙mol-1calculated

Kow 94.5 MRID 42237401
Page 15 of 65

Table 4. Major and minor chlorophacinone degradates and the maximum amounts 

found in degradation studies.

Compound Hydrolysis Aerobic Soil Metabolism

o-phthalic acid 0.7% @ 30 d 9.8% @70 d

p-chlorophenylphenyl acetic 

acid

0.4% @ 14 d 5.4% @ 14 d

Unknown 1 11.7% @ 14 d (pH 5) 0.9% @ 30 d

Unknown 2 -- 10.5% @ 30 d

CO2 -- 64% @ 70 d

6 Receptors

6.1 Toxicity Summary

Table 5 provides a summary of the taxonomic groups and the surrogate species tested to 

characterize the potential acute and chronic ecological effects of chlorophacinone. In addition, 

the table provides a preliminary overview of the potential acute toxicity of chlorophacinone by 

providing the acute toxicity classifications. No ecotoxicity data are available for any degradates 

of chlorophacinone.

Chlorophacinone is moderately toxic to birds on an acute oral basis, practically highly toxic to 

birds on a subacute dietary exposure basis, and very highly toxic to mammals on an acute oral 

exposure basis. Data on the toxicity of chlorophacinone to terrestrial plants have not been 

submitted to the Agency. 

Technical grade chlorophacinone is classified as highly toxic to freshwater fish and invertebrates 

on an acute exposure basis. Acute estuarine/marine fish and invertebrate data as well as chronic 

exposure effect data to chlorophacinone for fish and invertebrates have not been submitted to the 

Agency. In addition, no acceptable or supplemental toxicity data for aquatic plant studies have 

been submitted to the Agency. 

O

OH

O

HO

O

OH

Cl
Page 16 of 65

Table 5. Most Sensitive Test Species Evaluated for Assessing Potential Ecological Effects 

of Chlorophacinone.

Taxonomic 

Group Study Type Tested Species Toxicity Endpoint

Acute Toxicity 

Classification/

NOAEC most 

sensitive endpoint(s)

MRID and 

Classification

Birds1

Acute oral

Northern 

bobwhite

Colinus 

virginianus

LD50 = 258 mg a.i./kg-bw

Slope = 2.88

Moderately toxic.

Mortalities occurred 

≤5 days after gavage, 

observed 30 days

41513101 

(Acceptable)

Dietary Northern 

bobwhite

LC50 = 56 mg a.i./kg-diet

Slope = 1.49

Highly toxic. 

Mortalities occurred 

≤9 days after test start, 

observed 30 days

41513102

(Acceptable)

Chronic

Mallard duck 

Anas 

platyrhynchos

NOAEC = 0.046 mg a.i./kgdiet

NOAEC based on 

reduction in mean 14-

day survivor weights 

at 0.096 and 0.96 mg

a.i./kg-diet treatment 

levels

489904002

(Acceptable)

Mammals

Acute oral 

(single dose)

Black-tailed 

Prairie Dogs 

Cynomys 

ludovicianus

LD50 = 1.94 mg a.i./kg-bw 

Very highly toxic.

Single dose, 

mortalities occurred 9 

to 22 days after dosing

47333601

Supplemental 

Acute oral 

(5-day 

exposure, 

multiple 

doses)

Laboratory Rat

Rattus norvegicus

5-day LD50 = 0.8 mg 

a.i./kg-bw

Multiple dose; doses 

of 0.16 mg a.i./kg-bw 

were administered 

daily for 5 consecutive 

days equal the LD50 

dose.

Ashton, et al. 

(1986)

Supplemental 

(Qualitative )

Dietary 

(5-day 

exposure)

Laboratory Rat LC50 = 1.14 mg a.i./kg-diet

Slope = 7.19

Mortalities occurred 

4-9 days after test 

start, animals 

observed 9 days.

Teeters 1981 

(TNM 117)3

(Supplemental)

Chronic4 Rabbit Developmental NOAEL = 

10 μg/kg-bw/day 

Developmental 

Gavage Exposure

(daily from days 7 to 

19 of gestation)

Endpoint based lack 

of sufficient 

fetuses/litters at the 

higher dose levels as 

high maternal 

mortality was 

observed.

43570801

(Acceptable)

Terrestrial 

invertebrates

Acute 

contact 

Honey bee No data

Earthworm

LC50 > 1000 mg ai/kg-soil

NOAEC (mortality) = 

309 mg ai/kg-soil

NOAEC (weight 

change) < 95 mg 

ai/kg-soil

47383002

Under review

Freshwater 

fish2

Acute

Rainbow trout 

(Oncorhynchus 

mykiss) 

96-hr LC50 = 452 μg/L 

(416, 494)

Slope = 16.3 (9.3, 23.2)

highly toxic 42356103

(Acceptable)

Chronic No data

Freshwater 

invertebrates

Acute

Water flea 

(Daphnia magna)

48-hr EC50 = 640 μg/L 

(538, 808)

Slope = 5.1 (2.8, 7.4)

highly toxic 42356101

(Acceptable)

Chronic No data
Page 17 of 65

Table 5. Most Sensitive Test Species Evaluated for Assessing Potential Ecological Effects 

of Chlorophacinone.

Taxonomic 

Group Study Type Tested Species Toxicity Endpoint

Acute Toxicity 

Classification/

NOAEC most 

sensitive endpoint(s)

MRID and 

Classification

Estuarine/

marine fish

Acute and 

Chronic No data

Estuarine/

marine 

invertebrates

Acute and 

Chronic No data

Terrestrial 

plants

Seedling 

emergence

No data

Vegetative 

vigor No data

Aquatic 

plants and 

algae

Vascular No data

Nonvascular No data

1 Birds represent surrogates for terrestrial-phase amphibians and reptiles.

2 Freshwater fish are used as surrogates for aquatic-phase amphibians.

3 Teeters, W.R. (1981) Chlorophacinone technical: Toxicity to Laboratory Rat: Test No. 117. (U.S. Environmental Protection 

Agency, Pesticides Regulation Div., Agricultural Research Center, Animal Biology Laboratory, unpublished report.)

4 Developmental toxicity study will be used as to evaluate chronic mammalian toxicity as a two-generation rat study is not 

available.

6.2 Secondary Toxicity

Secondary toxicity was evaluated in the laboratory setting by exposing carnivorous birds and 

mammals through the dietary route. Test animals were fed chlorophacinone in whole or ground 

carcasses, which were usually those of rats or mice, or in fortified meat. Most prey animals were 

fed treated bait, although some were dosed orally. Mortality was included as a measurement 

endpoint in all studies. Some studies also reported signs of toxicosis (e.g., bleeding, prolonged 

blood-coagulation time, abnormal behavior, or regurgitation) in surviving test animals. Although 

exposure scenarios, test species, and the number of test animals varied among the studies, 

collectively these studies provide useful information to characterize secondary hazards from 

short-term exposure. Though these types of secondary exposure studies provide information on 

the potential effects from chlorophacinone exposure that may occur under field conditions, it is 

often not possible to quantify the level of exposure (rodenticide residues in primary consumers or 

food consumption by secondary consumers) or the sensitivity of the exposed animals to the 

rodenticide.

No deaths were recorded in the secondary bird exposure studies that involved birds from ten

different species (Table 6); however, many birds exhibited signs of chlorophacinone toxicity 

including instances of external bleeding and internal hematoma, as well as increased blood 

coagulation time. In secondary mammal exposure studies, 27 (49%) of 55 test mammals died 

after feeding on rodents fed chlorophacinone. Species affected included mongoose, coyote, 

European ferret, red fox, and weasel (Table 7). 
Page 18 of 65

Table 6. Observed Effects of Chlorophacinone on Birds Consuming Contaminated Carcasses

Secondary 

species Prey offered to birds No. prey offered daily per bird

No. days birds 

exposed

No. birds 

exposed

No. birds 

dead

No. survivors 

with signs of 

chlorophacinone 

toxicitya

Reference

(MRID)

Barn owl

Rats fed choice of 

0.005% bait or untreated 

bait for 5 days

1-2 10 2 0 0

Mendenhall and 

Pank 1980

MRID # 46750931

Black-billed 

magpie

Rats fed 0.005% bait for 

5 days Ad libitum 5 20 0 0

Baroch 1997

MRID# 44631402

American 

kestrel

Voles fed 0.01% bait 

until dead

1

1 every 3 days

21

61

10

10

0

0

10 (eb/ih)

10 (eb/hi)

Radvanyi et al. 

1988 (E39765)

Red-tailed

hawk

Voles fed 10 g 0.0005% 

bait daily up to 9 days 2 6 5 0 0

Askham 1988

E73126

Askham and Poché

1992

Great horned 

owl

Voles fed 10 g 0.005% 

bait daily up to 9 days 2 6 1 0 0

Tawny owl Mice fed 0.0075% baitb Ad libitum 10 4 0 (ct)

Riedel et al. 1991 Eurasian c

buzzard Mice fed 0.0075% baitb Ad libitum

7

10

5-5-5

d

40

4

6

3

3

0

0

0

0

(ct)

(ct)

(ct)

(ct)

Carrion crow Mice fed 0.0075% baitb Ad libitum 10 4 0 (ct)

Eurasian 

buzzard Mice fed 0.0075% baitb 4 7 4 0 0 Anonymous 1978c

Carrion crow Mice fed 0.0075% baitb 3-4

3

5

12

12

0

0

0

0

Sterner 1978c

White stork Mice fed 0.0075% baitb Ad libitum 

(treated/untreated)

3

14

3

3

0

0

1 or 2 (ct)

1 or 2 (ct)

a

eb = external bleeding; ih = internal hematoma; bl = bleeding (unspecified); ct = increased blood coagulation time; nr = not reported

b baits registered in the U.S. are either 0.005% or 0.01% a.i.

c Cited in US EPA (2004) Potential Risks of Nine Rodenticides to Birds and Nontarget Mammals: a Comparative Approach and Joermann 1998

d the 3 5-day treatment periods are separated by 3 days when the birds were fed untreated mice
Page 19 of 65

Table 7. Observed Effects of Chlorophacinone on Mammals Consuming Contaminated Carcasses

Secondary 

species

Prey offered to 

mammals

No. prey offered 

daily per 

mammal

No. days 

mammals 

exposed

No. 

mammals 

exposed

No. 

mammals 

dead

No. survivors 

with signs of 

chlorophacinone 

toxicitya

Reference

(MRID)

Mongoose Rats fed 0.005% bait 

for 5 days 1

1

3

5

6

7

9

10

1

1

2

1

1

1

1

0

1

2

1

1

1

1

nr

no survivors

no survivors

no survivors

no survivors

no survivors

no survivors

Pank and Hirata 

1976

MRID# 2467

Coyote

Ground squirrels fed 

15 g of 0.01% bait for 

6 days

1 5 7 3 0

Marsh and Howard 

1986

MRID# 42760902

European 

ferret

Rats fed 0.005% bait 

for 5 days Ad libitum 5 20 11 nr

Ahmed et al. 1996

MRID# 44631401

European 

ferret

Prairie dogs fed 25 g 

of 0.0025% bait daily 

for 6 daysc

4 (1 every other 

day) 8 6 5 nr

Fisher and Timm 

1987

European 

ferret

Voles/mice fed 

0.0075% baitc 5 total 4 2 1

d

(ct) Bachhuber and 

Beck 1988f

Red fox Mice fed 0.0075% 

baitc 20 total 4 1 1

e no survivors

European 

ferret

Muskrats fed 0.0075% 

baitc Ad libitum 48

2

1

0

1

1 (bl)

no survivors Jobsen 1798f

European 

ferret

Voles fed 0.0075% 

baitc Ad libitum 3 4 0 (ct) Anonymous 1983f

Weasel Mice fed 0.005% bait Ad libitum 90 4 3 0 Anonymous 1981f

a

eb = external bleeding; ih = internal hematoma; bl = bleeding (unspecified); ct = increased blood coagulation time; nr = not reported

b ground squirrels were fed no-choice for 3 days followed by 3 days in which they had a choice of bait or untreated laboratory chow

c baits registered in the U.S. are either 0.005% or 0.01% a.i.

d

individual recovered from moribund state after administration of antidote, but assumed ‘dead’ without antidote treatment

e

individual was sacrificed but considered ‘dead’ based on coagulation index

f Cited in US EPA (2004) Potential Risks of Nine Rodenticides to Birds and Nontarget Mammals: a Comparative Approach and Joermann 1998
Page 20 of 65

6.3 Incident Database Review

A thorough review and analysis of available incident reports for all registered anticoagulant 

rodenticides was completed in 2013, and a summary of the 18 chlorophacinone wildlife incidents 

reported with a certainty of possible, probable, or highly probable is included in Appendix C.

This means that, at a minimum, there was supporting evidence (e.g., hemorrhaging) and/or 

residue data to indicate that the wildlife involved in the incident was adversely affected by 

exposure to an anticoagulant rodenticide and/or an independent wildlife specialist, based on 

findings of a necropsy examination and toxicological analysis, identified an anticoagulant 

rodenticide as the cause of death in the incident report.

The reported avian species include herbivorous geese, granivorous/insectivorous quail and 

turkeys, as well as carnivore/scavenger birds that include the barn owl, turkey vulture, bald 

eagle, and red-tailed hawk. The reported mammalian species include herbivorous and 

granivorous squirrels. Omnivorous mammals such as a raccoon and carnivores including the 

badger, coyote, and bobcat, were also cited in the reported incidents.

Although most of the reported wildlife incidents involve animals found dead, there are several 

rodenticide incidents that involve incapacitated animals (most of which died after being found). 

They demonstrate that animals exposed to rodenticides may be incapacitated in ways that would 

almost certainly make them more vulnerable to predators and accidental deaths (e.g., car or 

window strikes). If an animal dies due to predation or an accident, their death may not 

necessarily be attributed to a pesticide, even if it is a contributing factor.

7 Exposure Pathways of Concern

The environmental fate properties and use patterns of chlorophacinone indicate that non-target 

consumption of bait, consumption of individuals that have consumed bait, and runoff represent 

potential transport mechanisms of chlorophacinone to aquatic and terrestrial organisms. 

Drinking water and inhalation exposure pathways were screened using the SIP (Screening 

Imbibition Program) and STIR (Screening Tool for Inhalation Risk) screening methods SIP and 

STIR are described in detail at: http://www2.epa.gov/pesticide-science-and-assessing-pesticiderisks/models-pesticide-risk-assessment#terrestrial. The drinking water pathway was found to be 

an exposure pathway of potential concern for acute and chronic risks to mammals as well as 

chronic risks to birds due to high solubility and high toxicity of chlorophacinone. The inhalation 

exposure pathway was found not to be an exposure pathway of concern for birds due to the low 

volatility of chlorophacinone. SIP and STIR results are presented in Appendix B.
Page 21 of 65

8 Analysis Plan

8.1 Stressors of Concern

8.1.1 Ecological Risk 

For this registration review, the stressor of ecological concern for terrestrial and aquatic 

organisms is parent chlorophacinone. 

Chlorophacinone has two identified minor degradates: o-phthalic acid and p-chlorophenylphenyl 

acetic acid (Table 4). Both degradates were found in the hydrolysis study at pH 5 and the aerobic 

soil metabolism study. A comparison of the structures of these two degradates with those of the 

parent and other anticoagulant rodenticides suggest that the toxic moiety is no longer present in 

these degradates. 

There were three major degradates, CO2 and two that were not identified (Table 4). The first 

unidentified degradate was observed at 11.7% in the pH 5 hydrolysis study, and 0.9% from 

aerobic soil metabolism study. The second unidentified degradate was material at the origin of 

the thin-layer chromatograms at 10.5%. Occurrence at the origin of the chromatogram suggests 

that material was either very polar, or very immobile. Often this material is composed of a 

mixture of compounds, so that it may not, in fact be, a single major degradate. For the outdoor 

uses of chlorophacinone, it is formulated in pelleted bait or weather-resistant rodenticide products, 

it is probable that contact of this degradate with soil and water will be minimal. Furthermore, 

because risk is expected to result from direct consumption of bait products or from consumption 

of prey which directly consumed the bait, the formation of degradation products in the soil and 

water is not a major concern in this assessment. Risk from the unidentified degradates was, 

therefore, not quantified.

8.1.2 Drinking Water 

The previous assessments concluded that due to the application amounts and application methods 

of chlorophacinone, surface water or ground water contamination with chlorophacinone is 

unlikely. No drinking water assessment will be needed.

8.2 Measures of Exposure 

In this assessment, transport of parent chlorophacinone through runoff to water bodies is 

considered in deriving quantitative estimates of chlorophacinone. With a vapor pressure of 3.58 

x 10-6torr and a calculated Henry’s Law constant 5.12 x 10-7atm∙m3∙mol-1, volatilization and 

atmospheric transport are very unlikely

For this registration review, it will be assumed that terrestrial animals could be exposed in two 

different pathways. Animals may directly consume bait (primary consumption), or animals may 

consume contaminated carcasses either killed or scavenged by the consumer (secondary 

consumption). Both approaches and the expected exposure levels are detailed below. It is 
Page 22 of 65

important to note that these methods are not typically used in EFED risk assessments.

8.2.1 Estimating Aquatic Exposure

Given that aquatic risks have not been exceeded in previous risk assessments, the exposure 

assessment will be conducted at the first tier using the GENEEC model, version 2.0, dated 

August 1, 2001 and input parameters outlined in Table 8. GENEEC is a metamodel of the Tier 2 

models PRZM and EXAMS and as such mimics the output of these models. However, GENEEC 

is hard-wired to a single, high exposure scenario which is intended to be protective of aquatic 

environments for all crops on a national basis. If risks are above levels of concern at Tier 1 using 

GENEEC, more refined modeling at Tier 2 can be conducted which considers crop specific 

location information and additional fate data such as vapor pressure. 

Table 8. Chlorophacinone Input Values (GENEEC) for Aquatic Exposures

Property Value Comment

Solubility 3.4 ppm MRID 42237401

Photolysis in Water 0 Assume that chlorophacinone is stable to 

photolysis. An unacceptable study was used 

previously.

Aerobic Soil Degradation 78 d Upper 90% confidence bound on 2 values 

Aerobic aquatic metabolism 156 d 2 x aerobic soil metabolism used in absence of 

data

Koc 20,299 l∙kg-1 Slope of line regression on Kd on OC%

Incorporation depth 0 in All labels for broadcast application do not allow 

for incorporation.

Application rate 0.001 lbs a.i./acre Highest labeled application rate appears on the 

SLN, CA 890024, with a broadcast application 

rate of 10 lbs product/acre (0.001 lbs a.i./acre) and 

a single reapplication 4 days later. 

Number of applications 2

Application interval 4 d

The GENEEC results based on the input values of Table 8 are presented below:

 RUN No. 1 FOR chlorophacinone ON rodent * INPUT VALUES * 

 --------------------------------------------------------------------

 RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE NO-SPRAY INCORP

 ONE(MULT) INTERVAL Koc (PPM ) (%DRIFT) (FT) (IN)

 --------------------------------------------------------------------

 0.010( 0.020) 2 4 20299.0 3.4 GRANUL( 0.0) 0.0 0.0

 FIELD AND STANDARD POND HALFLIFE VALUES (DAYS) 

 --------------------------------------------------------------------

 METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED

 (FIELD) RAIN/RUNOFF (POND) (POND-EFF) (POND) (POND) 

 --------------------------------------------------------------------

 78.00 2 0.00 0.00- 0.00 156.00 156.00

 GENERIC EECs (IN NANOGRAMS/LITER (PPTr)) Version 2.0 Aug 1, 2001

 --------------------------------------------------------------------

 PEAK MAX 4 DAY MAX 21 DAY MAX 60 DAY MAX 90 DAY

 GEEC AVG GEEC AVG GEEC AVG GEEC AVG GEEC

 --------------------------------------------------------------------

 86.31 80.56 56.32 29.97 21.24
Page 23 of 65

The estimated environmental concentrations (EECs) are 0.086 μg/L, 0.056 μg/L, and 0.030 μg/L, 

respectively for the peak concentration, 21-day average concentration, and 60-day average 

concentration. These EECs are in the range of about 0.0025% of solubility and are orders of 

magnitude lower than the available aquatic toxicity endpoints; therefore, the likelihood of 

aquatic impacts from the exposure viewpoint is insignificant.

8.2.2 Estimating Primary Terrestrial Exposure

EFED’s exposure assessment for the rodenticides differs from that for most other pesticides. For

a rodenticide, the bait itself is the potential food item of concern. Thus, the amount of active 

ingredient in the formulated bait is used as an estimated environmental concentration (EEC). 

This information is used to estimate the amount of grain bait that birds and mammals of various 

sizes need to consume to obtain a dose expected to be lethal to 50% of the individuals in the 

population (i.e., LD50 dose). Estimates of food-ingestion rates (g dry matter per day) are 

determined from established allometric equations presented in the Wildlife Exposure Factors 

Handbook (USEPA 1993). The concentration of chlorophacinone in grain bait is also used to 

estimate dietary exposure (mg a.i. per kg in bait). 

8.2.2.1 Expected Chlorophacinone Accumulation through a Single Feeding on 

Bait 

Exposure through bait consumption will be calculated using two methodologies. For the first 

method, chlorophacinone exposure is calculated as mg a.i./kg-bwt, where kg-bwt is the 

kilograms of the consuming individual for three standard weight classes of passeriforms and 

rodents. Exposure (food dry weight consumption) estimates were derived using allometric 

equations from USEPA (1993). The allometric equations for passeriform birds and rodent 

mammals were used as these would best approximate those individuals with high potential for 

consuming grain and they would give the most conservative exposure estimates. Food dry weight 

was converted to wet weight assuming the bait contained 10% water, similar to the assumption 

that seeds for wildlife consumption contain 10% water (USEPA 1993). Formulas for calculation 

of dose estimates are provided in Table 9, and chlorophacinone exposure estimates (on a dose 

basis) are provided in Table 10. 

Table 9. Formulas for Calculation of Daily Chlorophacinone Intake based on Consumption of 

Bait.

Passeriform bird food intake (g, dry weight): FI (g dry-wt/day) = 0.398 * Wt(g)0.850

Rodent mammal food intake (g, dry weight): FI (g dry-wt/day) = 0.621 * Wt(g)0.564

Food intake (g, wet weight): FI (g wet-wt/day) = FI (g dry-wt/day) / 0.90

Chlorophacinone intake (mg a.i./kg-bwt/day) = FI (g wet-wt/day) * mg a.i./kg-bait / Wt(g)
Page 24 of 65

Where: Wt(g) = weight (in grams) of the bird or mammal consumer

mg a.i./kg-bait = 50 or 100 depending on chlorophacinone concentration in bait

Table 10. Expected Daily Chlorophacinone Intake for Default Bird and Mammal 

Weights based on Consumption of Bait.

Weight 

(g)

Food intake 

(g drywt/day)

Food intake 

(g wetwt/day)

Chlorophacinone intake (mg a.i./kg-bwt/day)

Bait concentration = 

50 mg a.i./kg-bait

Bait concentration = 

100 mg a.i./kg-bait

Passeriform 

Birds*

20 5.1 5.6 14.1 28.2

100 19.9 22.2 11.1 22.2

1000 141.2 156.9 7.8 15.6

Rodent 

Mammals

15 2.9 3.2 10.6 21.2

35 4.6 5.1 7.3 14.6

1000 30.6 34.0 1.7 3.4

*surrogate for reptiles and terrestrial-phase amphibians

8.2.2.2 Expected Chlorophacinone Accumulation through Multiple Feedings 

on Bait 

Available data on the retention times for chlorophacinone are provided in Table 11. Data on 

elimination from blood are available from two studies (half-life ranges from 0.4 to 11.7 days). 

One available liver elimination half-life is available (35.4 days).

Table 11. Retention of Chlorophacinone in Blood and Liver

Rodenticide Species Dose (mg 

a.i./kg) # doses

Blood t1/2

(days)

Liver 

retention

(days)

Reference

(MRID)

Chlorophacinone Mouse 336 

μg/mouse 1 11.7 35.4 (t1/2)

Vandenbroucke et 

al. 2008

Chlorophacinone Rat 4-5 1 0.4 NA Belleville 1981 

(00155540)

As indicated previously, chlorophacinone typically causes mortality several days after ingestion, 

which may allow target animals to consume bait for several days before dying. This can lead to 

doses that far exceed the lethal dose. A compound that accumulates in body tissues may pose 

greater risk to primary and secondary consumers, especially if repeated sublethal exposure 

results in the accumulation of a lethal dose or if additional exposures occur before the lethal dose 

has taken its effect (i.e., leading to a dose that is beyond what is sufficient to cause mortality). 

Cumulative rodenticide doses for animals consuming bait for six consecutive days were also 

calculated using formulae in Table 12. This analysis assumed that 100% of the daily diet of the 

animals is represented by the rodenticide bait and that they eliminate the chlorophacinone with a 

half-life of 35.4 days based on the single liver half-life value (Table 11). In the formula, the 

variable “C” represents the concentration of the pesticide in the bait. The elimination rate 
Page 25 of 65

constant (k) was calculated using the estimated chlorophacinone half-life (t1/2 = 35.4 days), and 

food intake (FI) was calculated according to the allometric equation for each taxonomic group 

(Table 9). The resulting cumulative body burden concentrations of chlorophacinone are 

presented in Table 13. 

Table 12. Formulas for Calculation of Chlorophacinone Body Burden based on 

Consumption of Bait for Six Consecutive Days.

D D e FI C

k

t t

* *  ( 1) 





  1/ 2

k  ln 2 t

Table 13. Calculated chlorophacinone body burden in avian and mammalian consumers 

of bait after six days of exposure 

Body weight 

(g)

Bait concentration = 50 mg a.i./kg-bait Bait concentration = 100 mg a.i./kg-bait

Passerine Generic Bird Passerine Generic Bird

20 80.6 72.3 161.2 144.6

100 63.3 41.2 126.6 82.4

1000 44.8 18.5 89.6 37.0

Rodent Generic Mammal Rodent Generic Mammal

15 60.5 46.1 121.0 92.2

35 41.8 39.6 83.6 79.2

1000 9.7 21.8 19.4 43.6

8.2.2.3 Expected Chlorophacinone Exposure based on Bait Concentration

The second exposure method for primary consumption of bait results in a diet concentration of 

50 or 100 mg a.i./kg-bait (concentrations of chlorophacinone as packaged in bait). 

8.2.3 Estimating Secondary Terrestrial Exposure

Secondary exposure analysis (from consumption of contaminated individuals) requires

consideration of residues in tissues of target and non-target organisms that are commonly 

consumed by predators and scavengers. Moreover, it is important to know how long the residue 

persists in body tissues. Residue concentrations for non-target animals fed chlorophacinone were 

submitted by the registrant and are available in open literature. Design and methodology vary 

among studies, adding unknown variability to the results and analysis. Pending development of 

additional methods and testing requirements for such studies, these tests provide the best data 

available. 

The determination of chlorophacinone intake for individuals consuming chlorophacinone 

poisoned animals or carcasses is calculated in a manner similar to the approach for individuals 

consuming bait (Section 3.3.1). Empirical residue data was used instead of bait concentration of 

chlorophacinone (Table 14). Chlorophacinone body burdens in deceased field and laboratory 

studies were determined in mammals, after exposure to chlorophacinone bait. Data from several

studies were available in which deceased mammals were collected from treated fields and 

analyzed for residues or in which deceased laboratory animals dosed with chlorophacinone were
Page 26 of 65

analyzed for chlorophacinone residues. For all studies, it was assumed the concentrations were 

reported using wet weights of the mammals. Mean concentrations ranged from 0.122 to 1.58 mg 

a.i./kg-bw, with reported individual values ranging from <LOD to 4.1 mg a.i./kg-bw. Field 

collected data are subject to a number of uncertainties including, but not limited to: 

 possible partial decomposition of bodies in field, 

 collection may miss carcasses with highest body burdens, and

 collection may miss individuals that were rapidly predated, died off site, or died 

underground.

Because of the lack of data on chlorophacinone residues in birds, amphibians and reptiles, it was 

assumed the mammal body burden data would be relevant for all the evaluated taxonomic 

groups. Due to the uncertainties regarding adequate sampling to capture the full distribution of 

carcass residue values, the maximum reported individual value, 4.1 mg a.i./kg-carcass, will be 

used for this assessment. 
Page 27 of 65

Table 14. Chlorophacinone Residue Levels in Mammalian Primary Consumers

Exposure information

Carcass species Sample

size

mg ai/kg bait Mean whole-carcass

residue (mg a.i./kg-bw) Reference

Field, spot bait; active burrows treated 2 day 

interval for 4 applications. Daily carcass

searches, first 10 carcasses collected after trt 

began

California ground 

squirrel

10 100 1.27 + 0.56 (sd)

range (0.237 – 2.24)

MRID 43922201

Baroch 1996 

(Supplemental)

Field, spot bait; active burrows treated 2 day 

interval for 4 applications. Daily carcass 

searches, first 10 carcasses collected after trt 

began

California ground 

squirrel

10 50 0.52 + 0.31(sd)

range (0.244 – 1.29)

Field, bait stations. Daily carcass searches, first 

10 carcasses collected after trt began

California ground 

squirrel

10 50 0.57 + 0.27 (sd)

range (0.123 – 0.896)

MRID 43922202

Baroch 1996 

(Supplemental)

Field, spot bait. Daily carcass searches for 15 

days after trt began

Belding’s ground 

squirrel

38 100 6 carcasses<LOD=0.025

32 carcasses:

0.159+0.141(sd)

range (0.025 – 0.546)

Ramey et al. 2007

Primus et al. 2001

(Quantitative)

Field, bait station. Daily carcass searches for 15 

days after trt began

Belding’s ground 

squirrel

16 50 0.122

range (<LOD, 0.265)

Primus et al. 2001

(E0165)

Matschke, 1999 

Microtus (Quantitative) sp. vole 3 50 1.58 

range(0.26-4.1)

Field, bait applied in burrow systems. Radiocollared animals followed for 13 days after 

application. Collared animals with no movement 

for 3 days were excavated.

Valley pocket gopher 8 50 and 100 0.357 

range (<LOD, 1.21)

Primus et al. 2001

(E0165)

Stewart et al 2000

Quantitative

Field, spot bait; Collected daily 2-15 days after 

first application

California ground 

squirrel

21 50 0.28

range (0.02 – 0.71)

MRIDs 45855101 

and 46117303

Salmon et al 2002

Field, spot bait; Collected daily 2-15 days after Goodall et al. 2002

first application

California ground 

squirrel

16 100 1.41

range (0.30 – 2.72)
Page 28 of 65

Table 14. Chlorophacinone Residue Levels in Mammalian Primary Consumers

Exposure information

Carcass species Sample

size

mg ai/kg bait Mean whole-carcass

residue (mg a.i./kg-bw) Reference

Field, broadcast; Collected daily 2-15 days after 

first application

California ground 

squirrel

16 50 0.26 

range (<LOD, 1.01) 

(supplemental)

Field, broadcast; Collected daily 2-15 days after 

first application

California ground 

squirrel

20 100 0.51

range (<LOD – 1.31)

Field, in-burrow; Collected daily 2-15 days after 

first application

Black tailed prairie 

dogs (8) and one 

cottontail rabbit

9 50 0.58 

range (0.01, 1.25)

MRIDs 47333602, 

47333603 and 

48294401 

(supplemental)

Field, bait application and collection methods 

unknown

Black-tailed prairie 

dog

8 NA 1.48 

range(0.85, 2.24)

Laboratory, 5 days bait consumption Laboratory rat 5 50 0.47 

range(0.21-0.93)

MRID 44631402

Baroch 1997

(supplemental)

Laboratory, 5 days bait consumption Laboratory rat 4 50 0.45 

range(0.18-0.81)

MRID 44631401

Ahmed et al. 1996 

(supplemental)
Page 29 of 65

Chlorophacinone exposure through carcass consumption is calculated as mg a.i./kg-bwt, where 

kg-bwt is the kilograms of the consuming individual for three weight classes of birds and 

mammals. For this analysis, bird weight classes of 100, 1000, and 5000 g individuals and 

mammal weight classes of 50, 1000, and 3000 g individuals were used to better represent the 

larger size of carnivores and scavengers relative to the full range of bird and mammal weights. 

The measured maximum body burden in the prey was then used to estimate rodenticide exposure 

in the secondary consumer using the general food intake allometric equations described in 

Section 3.1 above. Secondary consumers were assumed to be mammals weighing 50g, 1000g, or 

3000g, or birds weighing 100g, 1000g, or 5000g. For example, American kestrels range from 

100-150g, red-tailed hawks range from 900-1000g and bald eagles range from 4000-5000g 

(Dunning 1984). Exposure (food dry weight consumption) estimates were derived using generic 

bird and mammal allometric equations (EPA 1993). Food dry weight was converted to wet 

weight assuming the consumed prey/carcass contained 68% water (USEPA 1993). Formulas for 

calculation of dose estimates are provided in Table 15, and chlorophacinone exposure estimates 

(on a dose basis) are provided in Table 16. 

Table 15. Formulas for Calculation of Daily Chlorophacinone Intake for Birds and Mammals

based on Consumption of Carcasses.

Bird food intake (g, dry weight): FI (g dry-wt/day) = 0.648 * Wt(g)0.651

Mammal food intake (g, dry weight): FI (g dry-wt/day) = 0.235 * Wt(g)0.822

Food intake (g, wet weight): FI (g wet-wt/day) = FI (g dry-wt/day) / 0.32

Chlorophacinone intake (mg a.i./kg-bwt/day) = FI (g wet-wt/day) * 4.1 mg a.i./kg-carcass / Wt(g)

Where: Wt(g) = weight (in grams) of the bird or mammal consumer

Table 16. Expected Daily Chlorophacinone Intakes for Carnivorous Birds and Mammals

based on Consumption of Contaminated Carcasses

Weight (g) Food intake 

(g dry-wt/day)

Food intake 

(g wet-wt/day)

Chlorophacinone intake 

(mg a.i./kg-bwt/day)

Birds* 100 13.0 40.6 1.66

1000 58.2 181.7 0.75

5000 165.8 518.1 0.43

Mammals 50 5.9 18.3 0.51

1000 68.7 214.7 0.88

3000 169.5 529.8 0.72

*surrogate for reptiles and terrestrial-phase amphibians

The second exposure method for consumption of contaminated carcasses results in a carcass 

concentration of 4.1 mg a.i./kg-carcass (maximum measured concentration of chlorophacinone in 

carcasses).
Page 30 of 65

8.2.4 Estimating Additional Environmental Exposures

Screening level calculations suggest that the drinking water pathway may be significant in 

causing acute and chronic effects to terrestrial organisms. However, screening level calculations 

indicate risks due to inhalation of chlorophacinone in vapor phase are low. The drinking water

exposure pathway may be further considered at the time of the risk assessment (Appendix C). 

No monitoring data in surface water, in groundwater or in air were found from the USGS NAWQA 

program (http://water.usgs.gov/nawqa), the California Department of Pesticide Regulation CDPR 

(http://www.cdpr.ca.gov/docs/emon/surfwtr/surfcont.htm) or from the USEPA STORET program. 

Water monitoring programs such as these generally monitor for agricultural pesticides and typically 

do not include analysis for rodenticides such as chlorophacinone. If water monitoring data are 

identified at the time the risk assessment is conducted, these data will be used for additional 

exposure characterization.

8.3 Measures of Effect 

Toxicity data presented in Section 6 of this problem formulation will be used to calculate risk 

quotients. Any additional information submitted by the registrant or found in the open literature 

prior to conduct of the risk assessment will also be considered. The open literature studies are 

identified using EPA’s ECOTOXicology database (ECOTOX) (USEPA, 2007c), which employs 

a literature search engine for locating chemical toxicity data for aquatic life, terrestrial plants, 

and wildlife. The evaluation of both sources of data can also provide insight into the direct and 

indirect effects of pesticides on biotic communities from loss of species that are sensitive to the 

chemicals and from changes in structure and functional characteristics of the affected 

communities.

9 Endangered Species Assessment

Consistent with the Agency’s responsibility under the Endangered Species Act (ESA), the 

Agency will evaluate risks to federally threatened and/or endangered (listed) species from 

registered uses of pesticides in registration review. The process for evaluating potential risks to 

listed species is further described at 

http://www.epa.gov/oppfead1/endanger/litstatus/riskasses.htm.

10 Endocrine Disruptor Screening Program

Chlorophacinone was not included in the first group or the second group of chemicals issued an 

order to conduct Tier 1 EDSP testing. For additional information the EDSP program, visit 

http://www2.epa.gov/endocrine-disruption .
Page 31 of 65

11 Preliminary Identification of Data Gaps 

11.1 Fate

The environmental fate database for chlorophacinone is not complete (Table 17). However, data 

gaps were not identified as these data are not necessary for risk assessment at this time.

Additional fate data would be unlikely to change the risk conclusions for the aquatic risk 

assessment for chlorophacinone.

Table 17. Available environmental fate data for chlorophacinone and remaining data 

gaps.

158

Guideline

(OPPTS)

Description MRID Classification

Are data 

needed for risk 

assessment?

Comments

835.1240

(163-1)

Adsorption/Desorption MRID 42666001

MRID 42205503

Acceptable no

Data have not been 

submitted to fulfill some 

guidelines. Data gaps were

not identified as these data 

are not necessary for risk 

assessment at this time.

835.2120

(161-1)

Hydrolysis MRID 42205501 Acceptable no

835.2240

(161-2)

Photodegradation in 

water

MRID 42205502 Unacceptable no

835.2410

(161-3)

Photodegradation on 

soil

MRID 42452301 Unacceptable no

835.4100

(162-1)

Aerobic soil 

metabolism

MRID 43159801 Acceptable no

835.4200

(162-2)

Anaerobic soil 

metabolism

None NA no

835.4300

(162-4)

Aerobic Aquatic 

Metabolism

None NA no

835.4400

(162-3)

Anaerobic Aquatic 

Metabolism

None NA no 

835.6100

(164-1)

Terrestrial Field 

Dissipation

None NA no

850.1730

(165-4)

Fish Bioconcentration 

Factor

None NA no

11.2 Effects

Tables 18 and 19 identify ecological effects studies by MRID that offer data for each guideline 

requirement, as well as study classifications and whether or not further data are needed in order 

to support risk assessment. 

Inadequate data are available to characterize the differential toxicity among bird species. Data 

have been submitted to the Agency for the bobwhite quail acute oral gavage study (most 

sensitive LD50 = 258 mg a.i./kg-bwt). However, for diphacinone (also an indandione 

anticoagulant rodenticide), large species differences have been documented (LD50 = 1630 mg 

a.i./kg-bw for bobwhite quail (MRID 42245201) and LD50 = 98.6 mg a.i./kg-bw for American 
Page 32 of 65

kestrel (Rattner et al., 2011)). Therefore, EFED requests acute oral toxicity data be submitted for 

a passerine species and for a carnivorous species. Toxicity of chlorophacinone to the American 

kestrel was evaluated by Rattner et al. (2015); however, the study was only carried out for 7 days 

and no mortality occurred and an LD50 could not be estimated. Rattner et al. (2015) concluded 

that histological evidence of hemorrhage was present at all chlorophacinone dose levels and 

overt signs of intoxication, liver chlorophacinone residues, and changes in prothrombin time, 

Russell’s viper venom time and hematocrit, were generally dose-dependent. Additional toxicity 

data on a wider range of species would be beneficial to better understand the natural variation 

and to improve confidence in the assessment of risk to non-target species. 

Chlorophacinone exposure to terrestrial invertebrates may occur if individuals feed on the bait, 

feed on live animals contaminated with chlorophacinone residues, or feed on carcasses with 

chlorophacinone residues. EFED has reviewed one terrestrial invertebrate study (Burying beetle,

Nicrophorus orbicollis, MRID 47383001) and has an earthworm study currently under review 

(MRID 47383002). If the study is classified as Acceptable, the data need will be considered met. 

However, EFED would appreciate submission of any additional available terrestrial invertebrate 

toxicity and/or bioaccumulation data for the risk assessment. EFED does not have concerns for 

chlorophacinone exposure to insect pollinators such as bees and butterflies, as expected 

exposures would be low. Chlorophacinone is not applied as a spray; therefore, expected exposure 

on plants, including flowers, would be low. Pollinators would not be expected to feed on live 

animals or carcasses that may have been contaminated with chlorophacinone. No terrestrial 

invertebrate incidents have been reported for chlorophacinone. 

EFED does not recommend requesting terrestrial plant, aquatic plant, chronic fish, or chronic 

aquatic invertebrate toxicity data at this time as these data would not be expected to change the 

conclusions of this risk assessment. There remains uncertainty in the level of risk for each of 

these taxonomic groups given the missing data; however, the expected exposures for the 

proposed change in use pattern will be relatively low:

 Terrestrial plants - No data are available to assess of the toxicity of chlorophacinone to 

terrestrial plants; however, exposure to plants is also expected to be low since there is no 

spray application and the material is applied as a formulated bait or a treated grain. 

Chlorophacinone binds strongly to organic material (i.e., the formulated bait or grain) and 

little is expected to be available for runoff or leaching. No plant incidents have been 

reported for chlorophacinone.

 Aquatic plants – No data are available to assess the toxicity of chlorophacinone to aquatic 

plants; however, aquatic exposure is also expected to be low since there is no spray 

application and the material is applied as a formulated bait or a treated grain. 

Chlorophacinone binds strongly to organic material (i.e., the formulated bait or grain) and 

little is expected to be available for runoff or leaching. No aquatic incidents have been 

reported for chlorophacinone.

 Chronic fish and aquatic invertebrates – No data are available to assess the chronic 

toxicity of chlorophacinone to fish and aquatic invertebrates; however, aquatic exposure 

is expected to be low since there is no spray application and the material is applied as a 

formulated bait or a treated grain. Chlorophacinone is highly acutely toxic to fish and 

invertebrates, and chronic effects would not be unexpected. However, chlorophacinone 

binds strongly to organic material (i.e., the formulated bait or grain) and little is expected 
Page 33 of 65

to be available for runoff or leaching for this proposed use. No aquatic incidents have 

been reported for chlorophacinone.

Table 18. Available ecological effects data for terrestrial organisms exposed to cycloate 

and remaining data gaps. 

OCSPP 

Guideline Data Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are data 

needed for 

risk 

assessment?

Current Additional Data 

Need

850.2100 Avian oral toxicity 41513101 acceptable Yes Data are requested for avian 

acute oral with passerine and 

39233 Review pending acute oral with carnivore

850.2200 Avian dietary 

toxicity 

41513102 Acceptable No --

41513103 Acceptable

29144 Review pending

29143 Review pending

47323201 Supplemental

850.2300 Avian reproduction 489904001 supplemental No --

489904002 acceptable

Non-guideline Avian inhalation (None) (N/A) No Data have not been 

submitted to fulfill this 

guideline. A data gap was 

not identified as these data 

are not necessary for risk 

assessment at this time.

850.3020 Honey bee acute 

contact toxicity

(None) (N/A) No Data have not been 

submitted to fulfill this 

guideline. A data gap was 

not identified as these data 

are not necessary for risk 

assessment at this time.

850.3030 Honey bee residue 

on foliage

(None) (N/A) No

Non-guideline, 

OECD TG 213

Acute oral toxicity 

to adult honey bees

(None) (N/A) No

Non-guideline, 

OECD TG 237

Acute oral toxicity 

to larval honey 

bees

(None) (N/A) No

Non-guideline Chronic oral 

toxicity to adult 

honey bees

(None) (N/A) No

Non-guideline Chronic oral 

toxicity to larval 

honey bees

(None) (N/A) No

Non-guideline Field trial of 

residues in pollen 

and nectar

(None) (N/A) No

Non-guideline, 

OECD Guidance 

75

Semi-field testing 

for pollinator

(None) (N/A) No

850.3040 Field testing for 

pollinator

(None) (N/A) No
Page 34 of 65

Table 18. Available ecological effects data for terrestrial organisms exposed to cycloate 

and remaining data gaps. 

OCSPP 

Guideline Data Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are data 

needed for 

risk 

assessment?

Current Additional Data 

Need

850.3100 Earthworm 

Subchronic 

Toxicity Test 

47383002 Review pending No Data need may be met 

pending outcome of review.

850.4100 Seedling 

Emergence and 

Seedling Growth

(None) (N/A) No Data have not been 

submitted to fulfill this 

guideline. A data gap was

not identified as these data 

are not necessary for risk 

assessment at this time.

850.4150 Vegetative Vigor (None) (N/A) No

Table 19. Available ecological effects data for aquatic organisms exposed to 

chlorophacinone and remaining data gaps. 

OCSPP

Guideline Data Requirement

Submitted 

Studies 

(MRID)

Study 

Classification

Are data 

needed to 

conduct risk 

assessment?

Current Additional Data Need

850.1010 Freshwater invertebrate 

acute toxicity

42356101 Acceptable No --

850.1025

850.1035

850.1045

850.1055 

Saltwater invertebrate 

acute toxicity 

(None) (N/A) No Data have not been submitted to 

fulfill this guideline. A data gap 

was not identified as these data are 

not necessary for risk assessment at 

this time.

850.1075 Freshwater fish acute 

toxicity 

42356102 Acceptable No --

42356103 Acceptable

850.1075 Saltwater fish acute 

toxicity 

(None) (N/A) No Data have not been submitted to 

fulfill this guideline. A data gap 

was not identified as these data are 

not necessary for risk assessment at 

this time.

850.1300 Freshwater invertebrate 

life cycle 

(None) (N/A) No

850.1350 Saltwater invertebrates 

life cycle 

(None) (N/A) No

850.1400 Freshwater fish 

early-life stage

(None) (N/A) No

850.1400 Saltwater fish 

early-life stage 

(None) (N/A) No

850.1500 Fish life cycle (None) (N/A) No

850.4400 Aquatic plant Toxicity 

Test using Lemna spp.

(None) (N/A) No

850.4500 Algal toxicity 47323204 Unacceptable No

850.4550 Cyanobacteria (None) (N/A) No
Page 35 of 65

12 References 

Open Literature

Cox , P. and R.H. Smith. 1992. Rodenticide ecotoxicology: pre-lethal effects of anticoagulants on rat behavior. Proc. 

Vertebr. Pest Conf. 15:165-170.

Crowell, M, C Eason, S Hix, K Broome, A Fairweather, E Moltchanova, J Ross and E Murphy. 2013. First 

generation anticoagulant rodenticide persistence in large mammals and implications for wildlife management. New 

Zealand Journal of Zoology, http://dx.doi.org/10.1080/03014223.2012.746234

Dunning, J. B., Jr. 1984. Body weights of 686 species of North American birds. Monograph Number 1. Western 

Bird Banding Association, Cave Creek, Arizona, USA

King, R.B. 2002. Predicted and observed maximum prey size – snake size allometry. Functional Ecology 16: 766–

772.

Mendenhall, V.M. and L.F. Pank. 1980. Secondary poisoning of owls by anticoagulant rodenticides. Wildl. Soc. 

Bull. 8:311-315. MRID#s 46750931, 40077202, 00094694

Rattner, BA, KE Horak, SE Warner, DD Day, CU Meteyer, SF Volker, JD Eisemann, JJ Johnson. 2011. Acute 

toxicity, histopathology, and coagulopathy in American kestrels (Falco sparverius) following administration of the 

rodenticide diphacinone. Environmental Toxicology and Chemistry, Vol. 30, No. 5, pp. 1213–1222.

Rattner, B. A., K. E. Horak, R. S. Lazarus , S. L. Schultz, S. Knowles, B. G. Abbo, and S. F. Volker. 2015. Toxicity 

reference values for chlorophacinone and their application for assessing anticoagulant rodenticide risk to raptors. 

Ecotoxicology. 24:720–734

Savarie, P.J. and R.K. LaVoie. 1979. Secondary toxicity hazards of the anticoagulant brodifacoum to American 

kestrels (Falco sparverius). Unpubl. report, Denver Wildlife Research Center. 24 pp. MRID# 80244, 00079312

U.S. Environmental Protection Agency. 1993. Wildlife Exposure Factors Handbook. Office of Research and 

Development. December. EPA/600/R-93/187

U.S. Environmental Protection Agency. 1998a. Guidelines for Ecological Risk Assessment. United States 

Environmental Protection Agency (USEPA). Risk Assessment Forum. Office of Research and Development. 

Available at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=12460 (Accessed June 19, 2009).

U.S. Environmental Protection Agency.1998b. Reregistration Eligibility Decision (RED): Rodenticide Cluster. 

July 1998. EPA 738-R-98-007.

U.S. Environmental Protection Agency. 2004a. Overview of the Ecological Risk Assessment Process in the Office of 

Pesticide Programs. US EPA Office of Pesticide Programs, Environmental Fate and Effects Division.

U.S. Environmental Protection Agency. 2004b. Potential Risks of Nine Rodenticides to Birds and Nontarget 

Mammals: a Comparative Approach. July 2004. US EPA Office of Pesticide Programs, Environmental Fate and 

Effects Division.

U.S. Environmental Protection Agency. 2011. Risks of Chlorophacinone Use to the Federally Threatened

Alameda Whipsnake (Masticophis lateralis euryxanthus), California Tiger Salamander (Ambystoma californiense),

Central California Distinct Population Segment, And the Federally Endangered California Tiger Salamander 

(Ambystoma californiense) Sonoma County Distinct Population Segment and Santa Barbara County Distinct 

Population Segment, Salt Marsh Harvest Mouse (Reithrodontomys raviventris), and San Joaquin Kit Fox (Vulpes 

macrotis mutica). US EPA Office of Pesticide Programs, Environmental Fate and Effects Division. June 29, 2011.
Page 36 of 65

Environmental Fate Data Submitted To Support Registration

Guideline: 161-1 Hydrolysis

-------------------------------------------------------------------------------------

MRID: 62177 Lyonnaise Industrielle Pharmaceutique (1978) Residue Studies of Chlorophacinone. (Unpublished 

study received Jul 25, 1978 under 40868-9; submitted by Interstate Sales, Edgewater, N.J.; CDL: 234579-AN) 

MRID: 129279 Lyonnaise Industrielle Pharmaceutique (1978) Residue Studies of Chlorophacinone. A translation 

of: Etude de la Remanence de Chlorophacinone. (Unpublished study received Jun 7, 1978 under 7173-140; 

submitted by Chempar Chemical Co., Inc., New York, NY; CDL:234130-A; 234129) 

MRID: 42205501 Spare, W. (1992) Hydrolysis of Chlorphacinone: Lab Project Number: 1415. Unpublished study 

prepared by Agrisearch Inc. 76 p. 

Guideline: 161-2 Photodegradation-water

-------------------------------------------------------------------------------------

MRID: 155544 Biospherics Inc. (1981) Environmental Fate Studies of Chlorophaci- none: [Aqueous 

Photodegradation of Chlorophacinone]: Lipha Re- port No. 86-005. Unpublished study. 16 p. 

MRID: 42205502 Spare, W. (1992) Aqueous Photolysis of Chlorphacinone: Lab Project Number: 1417. 

Unpublished study prepared by Agrisearch Inc. 77 p. 

Guideline: 161-3 Photodegradation-soil

-------------------------------------------------------------------------------------

MRID: 34510 Chempar Chemical Company, Incorporated (19??) Persistence Study of Chlorophacinone (CPN). A 

translation of: Etude la Remanence de Chlorophacinene. (Unpublished study including French text received Oct 6, 

1976 under 7173-140; CDL:234128-A) 

MRID: 74365 Lyonnaise Industrielle Pharmaceutique (1977) Residue Studies of Chlorophacinone. (Unpublished 

study received Apr 3, 1981 under unknown admin. no.; submitted by Chempar Chemical Co., Inc., New York, N.Y.; 

CDL:244794-A) 

MRID: 42452301 Spare, W. (1992) Soil Photolysis of Chlorophacinone: Lab Project Number: 1418. Unpublished 

study prepared by Agrisearch Inc. 98 p. 

Guideline: 161-4 Photodegradation-air

-------------------------------------------------------------------------------------

MRID: 155545 Lechevin, J. (1979) Stability in Nature of Chlorophacinone Baits: Lipha Report No. 86-006. 

Unpublished study prepared by Lipha. 3 p. 

MRID: 155546 Askham, L.; Singh, S.; Singh, U.; et al. (1984) Bioanalytical Evaluation of Chlorophacinone. 

Unpublished paper presented at the Sixth International Biodeterioration Symposium; Aug 5-10, 1984, Washington, 

DC. 19 p. 

Guideline: 162-1 Aerobic soil metabolism

-------------------------------------------------------------------------------------

MRID: 43159801 Spare, W. (1994) Aerobic Soil Metabolism of Chlorophacinone: Lab Project Number: 1419: 

1419R. Unpublished study prepared by Agrisearch Inc. 151 p. 

Guideline: 163-1 Leach/adsorp/desorption

-------------------------------------------------------------------------------------

MRID: 34510 Chempar Chemical Company, Incorporated (19??) Persistence Study of Chlorophacinone (CPN). A 

translation of: Etude la Remanence de Chlorophacinene. (Unpublished study including French text received Oct 6, 

1976 under 7173-140; CDL:234128-A) 
Page 37 of 65

MRID: 50807 Chempar Chemical Company, Incorporated (19??) Persistence Study of Chlorophacinone (CPN). 

Includes undated method entitled: Method of radiochemical determination. (Unpublished study received Dec 30, 

1976 under 7173-175; CDL:228612-AR) 

MRID: 62177 Lyonnaise Industrielle Pharmaceutique (1978) Residue Studies of Chlorophacinone. (Unpublished 

study received Jul 25, 1978 under 40868-9; submitted by Interstate Sales, Edgewater, N.J.; CDL: 234579-AN) 

MRID: 74365 Lyonnaise Industrielle Pharmaceutique (1977) Residue Studies of Chlorophacinone. (Unpublished 

study received Apr 3, 1981 under unknown admin. no.; submitted by Chempar Chemical Co., Inc., New York, N.Y.; 

CDL:244794-A) 

MRID: 42205503 Spare, W. (1992) Adsorption/Desorption of Chlorphacinone in Four Soil Types: Lab Project 

Number: 1416. Unpublished study prepared by Agrisearch Inc. 99 p. 

MRID: 42666001 Spare, W. (1993) Adsorption/Desorption of Chlorophacinone in Four Soil Types: Amended Final 

Report: Lab Project Number: 1416. Unpublished study prepared by Agrisearch Inc. 105 p. 

MRID: 92018021 Baron, R. (1993) Liphatech Phase 3 Summary of MRID 42666001 and Related MRIDs 

42205503. Chlorophacinone...: Adsorption/ Desorption of Chlorophacinone in Four Soil Types: Project No. 1416 

(Amended). Prepared by Agrisearch Inc. 7 p. 

Guideline: 164-1 Terrestrial field dissipation

-------------------------------------------------------------------------------------

MRID: 74365 Lyonnaise Industrielle Pharmaceutique (1977) Residue Studies of Chlorophacinone. (Unpublished 

study received Apr 3, 1981 under unknown admin. no.; submitted by Chempar Chemical Co., Inc., New York, N.Y.; 

CDL:244794-A) 

MRID: 128398 Chempar Chemical Co., Inc. (1972) ?Efficacy: Rozol|. (Compilation; unpublished study received 

Mar 20, 1974; Aug 31, 1972 under 7173-EX-1; CDL:127465-A) 

MRID: 128401 Horsfall, F. (1972) Letter sent to P. Ochs dated Aug 17, 1972: ?Chlorophacinone: Gas 

chromatograph charts obtained in analyses of sprayed apples|. (Unpublished study received Aug 22, 1972 under 

7173-EX-1; prepared by Virginia Polytechnic Institute and State Univ., Dept. of Horticulture, submitted by 

Chempar Chemical Co., Inc., New York, NY; CDL:127466-A) 

MRID: 129279 Lyonnaise Industrielle Pharmaceutique (1978) Residue Studies of Chlorophacinone. A translation 

of: Etude de la Remanence de Chlorophacinone. (Unpublished study received Jun 7, 1978 under 7173-140; 

submitted by Chempar Chemical Co., Inc., New York, NY; CDL:234130-A; 234129) 

Ecological Toxicity Data Submitted To Support Registration:

Guideline: 850.2100 Avian Single Dose Oral Toxicity

-------------------------------------------------------------------------------------

MRID: 29142 Chempar Chemical Company, Incorporated (1980) Fish and Wildlife Studies with Chlorophacinone. 

Summary of studies 241868-B through 241868-F. (Unpublished study received Feb 27, 1980 un- der 7173-180; 

CDL:241868-A) 

MRID: 39233 Beavers, J.B.; Fink, R.; Brown, R.; et al. (1979) Final Report: Acute Oral LD50--Bobwhite Quail: 

Project No. 154-109. (Unpublished study received Feb 27, 1980 under 7173-180; prepared by Wildlife 

International, Ltd. in cooperation with Washington Col- lege, submitted by Chempar Chemical Co., Inc., New York, 

N.Y.; CDL:241868-B) 

MRID: 50813 Chempar Chemical Company, Incorporated (1980) Fish and Wildlife Studies with Chlorophacinone: 

Summary. (Unpublished study re- ceived Mar 18, 1980 under 7173-185; CDL:242018-A) 
Page 38 of 65

MRID: 5005716 Grolleau, G.; Paris, G. (1975) Essais d'intoxication du canard col-vert~Anas platyrhynchos~L_ a 

l'aide du coumafene et du chlorophacinone_ ?Trials of intoxication of green collared duck,~Anas platyrhynchos~L_ 

with coumaphene and chlorophacinone_| Annales de Zoologie--Ecologie Animales 7(4):553-556. 

MRID: 41513101

Fletcher, D. ; Pedersen, C. (1989) Chlorophacinone: 30-Day Acute Oral LD50 Study in Bobwhite Quail: Lab Project 

No: 87 QD 106. Unpublished study prepared by Bio-Life Associates, Ltd. 42 p. 

MRID: 92018007 Baron, R. (1990) Chempar Phase 3 Summary of MRID 41513101. 30-Day Acute Oral LD50 in 

Bobwhite Quail: Chlorophacinone: Study No. BLAL 87 QD 106. Prepared by Bio-Life Associates. 12 p. 

Guideline: 850.2200 Avian Dietary Toxicity

-------------------------------------------------------------------------------------

MRID: 2370 Grolleau, G. (1969) Toxicity Tests with Chlorophacinone on Gray Partridge--?~Perdix perdix~(L). 

(Unpublished study received Jul 24, 1970 under 7173-62; prepared by ?French| National Institute for Agronomic 

Research, Laboratoire des Petis ?Sic| Vertebres, submitted by Chempar Chemical Co., Inc., New York, N.Y.; 

CDL:008006-P) 

MRID: 29142 Chempar Chemical Company, Incorporated (1980) Fish and Wildlife Studies with Chlorophacinone. 

Summary of studies 241868-B through 241868-F. (Unpublished study received Feb 27, 1980 un- der 7173-180; 

CDL:241868-A) 

MRID: 29143 Beavers, J.B.; Fink, R.; Brown, R.; et al. (1979) Final Report: 14- Day Dietary LCI50^--Mallard 

Duck: Project No. 154-102. (Unpub- lished study received Feb 27, 1980 under 7173-180; prepared by Wildlife 

International, Ltd. in cooperation with Washington College, submitted by Chempar Chemical Co., Inc., New York, 

N.Y.; CDL:241868-C) 

MRID: 29144 Beavers, J.B.; Fink, R.; Brown, R.; et al. (1979) Final Report: 14- Day Dietary LCI50^--Bobwhite 

Quail: Project No. 154-101. (Un- published study received Feb 27, 1980 under 7173-180; prepared by Wildlife 

International, Ltd. in cooperation with Washington College, submitted by Chempar Chemical Co., Inc., New York, 

N.Y.; CDL:241868-D) 

MRID: 47425 Grolleau, G.; Giban, J. (1969) Toxicity Tests with Chlorophacinone on Gray Partridge--Perdix perdix 

(L.). (France, Institut National de la Recherche Agronomique, Laboratoire des Petis Vertebres, unpublished study; 

CDL:210147-P) 

MRID: 50813 Chempar Chemical Company, Incorporated (1980) Fish and Wildlife Studies with Chlorophacinone: 

Summary. (Unpublished study re- ceived Mar 18, 1980 under 7173-185; CDL:242018-A) 

MRID: 41513102 Fletcher, D.; Pedersen, C. (1989) Chlorophacinone: 30-Day Acute Dietary LC50 Study in 

Bobwhite Quail: Lab Project No: 87 QC 105. Unpublished study prepared by Bio-Life Associates, Ltd. 41 p. 

MRID: 92018008 Baron, R. (1990) Chempar Phase 3 Summary of MRID 41513102. 30-Day Acute Dietary LC50 

Study in Bobwhite Quail: Chlorophacinone: Study No. BLAL 87 QC 105. Prepared by Bio-Life Associates. 14 p. 

MRID: 92018009 Baron, R. (1990) Chempar Phase 3 Summary of MRID 41513103. 30-Day Acute Dietary LC50 

Study in Mallard Ducklings: Chlorophacinone: Study No. BLAL 87DC103. Prepared by Bio-Life Associates. 13 p. 

Guideline: 850.2300 Avian reproduction test

-------------------------------------------------------------------------------------

MRID: 48994001 Stafford, J. (2012) Reproductive Toxicity Test with the Northern Bobwhite (Colinus virginianus): 

Chlorophacinone. Project Number: 14007/4101. Unpublished study prepared by Smithers Viscient. 388p.

MRID: 48994002 Stafford, J. (2012) Reproductive Toxicity Test with the Mallard (Anas platyrhynchos): 

Chlorophacinone. Project Number: 14007/4102. Unpublished study prepared by Smithers Viscient. 348p.
Page 39 of 65

Guideline: 850.2400 Wild mammal acute toxicity

-------------------------------------------------------------------------------------

MRID: 2467 Pank, L.F.; Hirata, D.N. (1976) Primary and Secondary Toxicity of Anticoagulant Rodenticides: Job 

Completion Report: Work Unit DF-103.7. (Unpublished study received on unknown date under unknown admin. 

no.; prepared by U.S. Fish and Wildlife Service, Denver Wildlife Research Center, Wildlife Damage Research 

Station, submitted by Velsicol Chemical Corp., Chicago, Ill.; CDL: 230307-B) 

MRID: 69557 Virginia Polytechnic Institute and State University (1971) (Effectiveness Data with Regard to 

Chlorophacinone). (Compilation; unpublished study received Jul 9, 1973 under 7173-140; submitted by Chempar 

Chemical Co., Inc., New York, N.Y.; CDL:008321-A) 

MRID: 100061 Chempar Chemical Co., Inc. (1974) (Efficacy of Various Rodenticides). (Compilation; unpublished 

study received Jan 22, 1975 under 7173-140; CDL:235182-A) 

MRID: 92018001 Baron, R. (1990) Chempar Phase 3 Summary of MRID 00162324. Ground Squirrel-Coyote 

Secondary Toxicity Studies with Chlorophacinone and Bromadiolone, Residue Levels in Ground Squirrel Tissues 

from Davis, CA, and Residue Method Validation, Chlorophacinone Tissues: LiphaTech Report Nos. 86-032, 1410, 

and 1400a. Prepared by Univ. of CA. 11 p. 

MRID: 47333601 Yoder, C. (2008) Acute Oral Toxicity (LD50) of Chlorophacinone in Black-Tailed Prairie Dogs 

(Cynomys ludovicianus): Final Report. Project Number: QA/1446. Unpublished study prepared by US Dept. of 

Agriculture, APHIS, WS. 86 p.

Guideline: 850.2500 Field testing for terrestrial wildlife

-------------------------------------------------------------------------------------

MRID: 50803 Horsfall, F., Jr.; Libke, K.G.; Osborne, J.C. (1972) Toxicity Studies under Simulated Orchard 

Conditions. (Unpublished study including letters dated Nov 15, 1972 and Nov 20, 1972 from K.G. Libke and J.C. 

Osborne to Frank Horsfall, Jr., received Dec 30, 1976 under 7173-175; prepared by Virginia Polytechnic Institute 

and State Univ., submitted by Chempar Chemical Co., Inc., New York, N.Y.; CDL:228612-AN) 

MRID: 69567 Virginia Polytechnic Institute and State University (1972) (Toxicity Data Regarding 

Chlorophacinone and Opossums). (Compilation; unpublished study received Jul 9, 1973 under 7173-140; prepared 

by Dept. of Veterinary Science, Research Div., submitted by Chempar Chemical Co., Inc., New York, N.Y.; 

CDL:008321-AF) 

MRID: 42124101 Baron, R. (1991) LiphaTech Phase 3 Summary of MRID 40751402: Secondary Hazard 

Evaluation of Chlorophacinone in Raptors and Chlorophacinone Residue Levels in Hawk, Owl, and Vole Tissues 

from Pullman, Washington: Study 1407: Field Study No. 88-1. Revised. Unpublished study prepared by 

Agrisearch, Inc. 7 p. 

MRID: 44631401 Ahmed, S.; Baroch, J.; Carlet, L. et al. (1996) Secondary Hazard Study Using ChlorophacinoneKilled Laboratory Rats Fed to Domestic Ferrets (Mustela putorius furo): Lab Project Number: 96004. Unpublished 

study prepared by Genesis labs., Inc. 84 p. 

MRID: 44631402 Baroch, J. (1997) Secondary Hazard Study Using Chlorophacinone-Killed Laboratory Rats Fed 

to Black-Billed Magpies (Pica pica): Lab Project Number: 96019. Unpublished study prepared by Genesis labs., 

Inc. 77 p. 

MRID: 45855101 Salmon, T.; Whisson, D.; Gorenzel, W. (2001) Field Efficacy Studies Comparing 0.005% and 

0.01% Diphacinone and Chlorophacinone Baits for Controlling California Ground Squirrels (Spermophilus 

beecheyi): Final Report: Lab Project Number: 00-0471: 29: 30. Unpublished study prepared by University of 

California, Davis. 131 p. 

MRID: 48373006 Ingenloff, K.; Soniat, M. (2011) Exposure of Rozol Prairie Dog Bait to Northern Bobwhite Quail. 

Project Number: 10009. Unpublished study prepared by Genesis Laboratories, Inc. 36 p.
Page 40 of 65

MRID: 92018010 Baron, R. (1990) Chempar Phase 3 Summary of MRID 40751402. Secondary Hazard Evaluation 

of Chlorophacinone in Raptors and Chlorophacinone Residue Levels in Hawk, Owl, and Vole Tissues from 

Pullman, Washington: Field Study No. 88-1. Prepared by Agrisearch Inc. 7 p. 

MRID: 45855101 Salmon, T.; Whisson, D.; Gorenzel, W. (2001) Field Efficacy Studies Comparing 0.005% and 

0.01% Diphacinone and Chlorophacinone Baits for Controlling California Ground Squirrels (Spermophilus 

beecheyi): Final Report: Lab Project Number: 00-0471: 29: 30. Unpublished study prepared by University of 

California, Davis. 131 p. 

MRID: 45855102 VerCauteren, K.; Pipas, M.; Bourassa, J. (2002) A Camera and Hook System for Viewing and 

Retrieving Rodent Carcasses From Burrows: (Diphacinone and Chlorophacinone Baits): Lab Project Number: QA879. Unpublished study prepared by National Wildlife Research Center. 29 p. (OPPTS 850.2500) 

MRID: 46117301 Salmon, T.; Whisson, D.; Gorenzel, W. (2001) Field Efficacy Studies Comparing 0.005% and 

0.01% Diphacinone and Chlorophacinone Baits for Controlling California Ground Squirrels (Spermophilus 

beecheyi). Unpublished study prepared by University of California, Davis. 61 p.

MRID: 46117302 VerCauteren, K.; Pipas, M.; Bourassa, J. (2002) A Camera and Hook System for Viewing and 

Retrieving Rodent Carcasses from Burrows. Unpublished study prepared by U.S. Dept. of Agriculture, APHIS, 

ADC. 22 p.

MRID: 46117303 Goodall, M.; Primus, T.; Johnston, J. (2002) Determination of Cholorphacinone (sic) and 

Diphacinone Residues in California Ground Squirrels and Non-Target Animals. Unpublished study prepared by 

U.S. Dept. of Agriculture, APHIS, ADC. 19 p.

Guideline: 72-1 Acute Toxicity to Freshwater Fish

-------------------------------------------------------------------------------------

MRID: 29142 Chempar Chemical Company, Incorporated (1980) Fish and Wildlife Studies with Chlorophacinone. 

Summary of studies 241868-B through 241868-F. (Unpublished study received Feb 27, 1980 un- der 7173-180; 

CDL:241868-A) 

MRID: 29146 Sleight, B.H., III (1973) Acute Toxicity of Rozol to Bluegill (Lepomis macrochirus) and Rainbow 

Trout (Salmo gairdneri). (Unpublished study received Feb 27, 1980 under 7173- 180; prepared by EG&G 

Bionomics, submitted by Chempar Chemical Co., Inc., New York, N.Y.; CDL:241868-F) 

MRID: 47427 Ludermann, ? (1971) Report on Toxicity of Chlorophacinone in Carp and Trout. (Unpublished 

study received Jul 26, 1972 under 7173- EX-43; prepared by Institut fur Wasser Boden Und Lufthygiene des 

Bundesgesundheitsamtes I, Germany, submitted by Chempar Chemical Co., Inc., New York, N.Y.; CDL:210147-R) 

MRID: 50802 Sleight, B.H., III (1973) Acute Toxicity of Rozol to Bluegill (?~Lepomis macrochirus~) and 

Rainbow Trout (~Salmo gaird~- ?~neri~). (Unpublished study received Dec 30, 1976 under 7173- 175; prepared by 

Bionomics, Inc., submitted by Chempar Chemical Co., Inc., New York, N.Y.; CDL:228612-AM) 

MRID: 50813 Chempar Chemical Company, Incorporated (1980) Fish and Wildlife Studies with Chlorophacinone: 

Summary. (Unpublished study re- ceived Mar 18, 1980 under 7173-185; CDL:242018-A) 

MRID: 78596 Ludermann, ? (19??) Report on Toxicity of Chlorophacinone in Carp and Trout. (Unpublished study 

received Jun 27, 1974 under 7173- EX-6; prepared by Institut fur Wasser, Boden und Lufthygiene des 

Bundesgesundheitsamtes I--Berlin, Germany, submitted by Chempar Chemical Co., Inc., New York, N.Y.; 

CDL:223685-U) 

MRID: 42356102 Machado, M. (1992) Chlorophacinone--Acute Toxicity to Bluegill Sunfish (Lepomis 

macrochirus) under Flow-through Conditions: Final Report: Lab Project Number: 92-1-4079: 11219.0891.6104. 

105. Unpublished study prepared by Springborn Labs, Inc. 60 p. 
Page 41 of 65

MRID: 42356103 Machado, M. (1992) Chlorophacinone--Acute Toxicity to Rainbow Trout (oncorhynchus mykiss) 

under Flow-through Conditions: Final Report: Lab Project Number: 91-12-4025: 11219.0891. 6103.108. 

Unpublished study prepared by Springborn Labs, Inc. 58 p. 

MRID: 92018002 Baron, R. (1990) Chempar Phase 3 Summary of MRID 00029146. Chlorophacinone (LM-91) (2-

((4-Chlorophenyl) Phenyl Acetyl) lH- indane-1,3(2H)-Dione) or (2-((p-Chlorophenyl) Phenyl Acetyl)-1,3-

indanedione)..(CAS#3691-35-8)..Acute Toxicity of Rozol to Bluegill (Lepomis macrochirus) and Rainbow Trout 

(Salmo gairdneri). Prepared by EG&G Bionomics. 10 p. 

MRID: 92018003 Baron, R. (1990) Chempar Phase 3 Summary of MRID 00029146. Chlorophenyl(LM-91) (2-((4-

Chlorophenyl) Phenyl Acetyl) 1H-indane- 1,3(2H)-dione) or (2-((p-Chlorophenyl) Phenyl Acetyl)-1,3-indandione)..(CAS #3691-35-8)..Acute Toxicity of Rozol to Bluegill (Lepomis macrochirus) and Rainbow Trout (Salmo 

gairdneri). Prepared by EG&G Bionomics. 10 p. 

MRID: 92018017 Baron, R. (1992) LiphaTech Phase 3 Summary of MRID 42356102: Chlorophacinone - Acute 

Toxicity to Bluegill Sunfish (Lepomis macrochirus) under Flow-through Conditions: Report # 92-1-4079; SLI # 

11219-0891-6104-105. Unpublished study prepared by Springborn Laboratories, Inc. 9 p. 

MRID: 92018018 Baron, R. (1992) LiphaTech Inc. Phase 3 Summary of MRID 42356103. Chlorophacinone- Acute 

Toxicity to Rainbow Trout (Oncorhynchus mykiss) under Flow-through Conditions: Report # 91-12-4025; SLI 

Study # 11219-0891-6103.108. Prepared by Springborn Laboratories, Inc. 9 p. 

Guideline: 72-2 Acute Toxicity to Freshwater Invertebrates

-------------------------------------------------------------------------------------

MRID: 42356101 Putt, A. (1992) Chlorophacinone--Acute Toxicity to Daphnids (Daphnia magna) under Flowthrough Conditions: Final Report: Lab Project Number: 91-11-3998: 11219.0891.6105.115: 010190/FIFRA 72-2 

DM. Unpublished study prepared by Springborn Labs, Inc. 64 p. 

MRID: 92018004 Baron, R. (1990) Chempar Phase 3 Summary of MRID 00019142. Chlorophacinone @-((4-

Chlorophenyl) Phenyl Acetyl)1H-indane-1,3(2H) -dione) or (2-((p-Chlorophenyl) Phenyl Acetyl)-1,3-

indanedione).... (CAS #3691-35-8)..Acute Toxicity of Chlorophacinone to the Water Flea (Daphnia magna). 

Prepared by EG&G Bionomics. 9 p. 

MRID: 92018019 Baron, R. (1992) LiphaTech Inc. Phase 3 Summary of MRID 42356101. Chlorophacinone -

Acute Toxicity to Daphnids (Daphnia magna) under Flow-through Conditions: Report #91-11-3998; SLI # 11219-

0891- 6105.115. Prepared by Springborn Laboratories, Inc. 8 p. 

Guideline: 96-11 Rodenticides in orchards

-------------------------------------------------------------------------------------

MRID: 46227401 Schmit, T. (2004) Field Efficacy of Rozol Pellets for Controlling Montane Voles (Microtus 

montanus) and Other Microtus spp. in Orchards of the Pacific Northwest: Final Report. Project Number: 02143. 

Unpublished study prepared by Qualls Agricultural Laboratories, Inc. and Liphatech, Inc. 321 p.

Guideline: 96-12 Rodenticides on farms and rangelands

-------------------------------------------------------------------------------------

MRID: 41649301 Poche, R. (1990) California Ground Squirrel Field Efficacy Study Using Wilco Ground Squirrel 

Bait: Lab Project Number: WD-90-1. Unpublished study prepared by Genesis Laboratories. 78 p. 

MRID: 45377804 Mach, J. (2001) Field Efficacy of Rozol Pocket Gopher Bait (0.005% chlorophacinone) for the 

Plains Gopher (Geomys bursarius): Final Report: Lab Project Number: 00007. Unpublished study prepared by 

LiphaTech, Inc. 201 p. 

MRID: 45855101 Salmon, T.; Whisson, D.; Gorenzel, W. (2001) Field Efficacy Studies Comparing 0.005% and 

0.01% Diphacinone and Chlorophacinone Baits for Controlling California Ground Squirrels (Spermophilus 

beecheyi): Final Report: Lab Project Number: 00-0471: 29: 30. Unpublished study prepared by University of 

California, Davis. 131 p. 
Page 42 of 65

MRID: 45855102 VerCauteren, K.; Pipas, M.; Bourassa, J. (2002) A Camera and Hook System for Viewing and 

Retrieving Rodent Carcasses From Burrows: (Diphacinone and Chlorophacinone Baits): Lab Project Number: QA879. Unpublished study prepared by National Wildlife Research Center. 29 p. (OPPTS 850.2500) 

MRID: 46117301 Salmon, T.; Whisson, D.; Gorenzel, W. (2001) Field Efficacy Studies Comparing 0.005% and 

0.01% Diphacinone and Chlorophacinone Baits for Controlling California Ground Squirrels (Spermophilus 

beecheyi). Unpublished study prepared by University of California, Davis. 61 p.

MRID: 46117302 VerCauteren, K.; Pipas, M.; Bourassa, J. (2002) A Camera and Hook System for Viewing and 

Retrieving Rodent Carcasses from Burrows. Unpublished study prepared by U.S. Dept. of Agriculture, APHIS, 

ADC. 22 p.

MRID: 46117303 Goodall, M.; Primus, T.; Johnston, J. (2002) Determination of Cholorphacinone (sic) and 

Diphacinone Residues in California Ground Squirrels and Non-Target Animals. Unpublished study prepared by 

U.S. Dept. of Agriculture, APHIS, ADC. 19 p.

MRID: 46227401 Schmit, T. (2004) Field Efficacy of Rozol Pellets for Controlling Montane Voles (Microtus 

montanus) and Other Microtus spp. in Orchards of the Pacific Northwest: Final Report. Project Number: 02143. 

Unpublished study prepared by Qualls Agricultural Laboratories, Inc. and Liphatech, Inc. 321 p.

MRID: 46993801 Borchert, J. (2006) Field Efficacy of Kaput Pocket Gopher Bait (0.005% Diphacinone) for 

Controlling Black-Tailed prairie Dogs (Cynomys ludovicianus) in Colorado. Project Number: N05006. 

Unpublished study prepared by Genesis Laboratories, Inc. 16 p.

MRID: 47116901 Arjo, W.; Shwiff, S.; Kirkpatrick, K. (2007) Efficacy and Economics of an Integrated Pest 

Management Program for Mountain Beaver Control: Final Report. Project Number: QA/1313. Unpublished study 

prepared by USDA APHIS National Wildlife Research Center and Olympia Field Station. 91 p.

MRID: 47267701 Lee, C.; Hygnstrom, S. (2007) Field Efficacy and Hazards of Rozol Bait for Controlling BlackTailed Prairie Dogs (Cynomys ludovicianus). Project Number: 06076. Unpublished study prepared by Kansas State 

University - State Agr. Sta. and University of Nebraska. 300 p.

MRID: 47333602 Lee, C.; Hygnstrom, S. (2007) Field Efficacy and Hazards of Rozol Bait for Controlling BlackTailed Prairie Dogs (Cynomys ludovicianus). Project Number: 06076. Unpublished study prepared by Kansas State 

University and University of Nebraska. 300 p.

MRID: 48046801 Forgacs, T. (2009) Field Efficacy of Rozol Bait for Control of California Ground Squirrels 

(Spermophilus beechii). Project Number: 09038. Unpublished study prepared by Liphatech, Inc. 179 p.

MRID: 49668101 Brunlinger, M. (2014) Field Efficacy of Rozol Bait for Control of California Ground Squirrels 

(Spermophilus beecheyi). Project Number: 13003. Unpublished study prepared by Liphatech, Inc. 250p.

Guideline: 171-4A3 Nature of the Residue in Livestock

-------------------------------------------------------------------------------------

MRID: 42760903 Spare, W. (1986) Chlorophacinone Residue Levels in Ground Squirrels from Davis, California: 

Lab Project Number: 1413. Unpublished study prepared by Agrisearch Inc. 23 p. 

Guideline: 850.5400 Algal toxicity, Tiers 1 and II

-------------------------------------------------------------------------------------

MRID: 47323204

Peither, A. (2003) Toxicity of Chlorophacinone to Scenedesmus subspicatus in a 72-hour Algal Growth Inhibition 

Test. Project Number: 844814. Unpublished study prepared by RCC Ltd. 63 p.

Guideline: 860.1300 Nature of the residue - plants, livestock

-------------------------------------------------------------------------------------
Page 43 of 65

MRID: 47333603 Primus, T. (2007) Determination of Chlorophacinone Residues in Prairie Dog Whole Body and 

Liver Tissues: Final Report. Project Number: 70/C/SS, QA/1405. Unpublished study prepared by US Dept. of 

Agriculture, APHIS, WS. 58 p.
Page 44 of 65

Appendix A: Label Use Information for chlorophacinone 

based on BEADs summary report

Use

Single Max 

Application 

Rate

Max 

Application 

Rate per 

Year

Min 

Application 

Retreatment 

Interval 

(days)

Max # of 

Applications 

Per Year

(or Crop 

Cycle)

Application 

Methods

Agricultural Crops / Soils

(Unspecified)

0.0000252

lb / burrow

NS

4 2

GBT

Agricultural Fallow/ Idleland /

Conservation Reserve

0.001lb / ac AB, GB

0.0000252

lb / burrow

GBT

Agricultural /Farm Structures 

/ Buildings and Equipment

0.00000219 

lb/bait station

NS

NS

0.0001 lb/ 

placement

4.4 lb / ac

Agricultural Uncultivated

Areas

0.0005 lb / ac 0.001 lb / ac 1 AB

0.001 lb /ac 0.002 lb / ac 1 GB

0.0001 lb / 

placement

NS

NS

GBT

0.0005 lb / ac GST

Alfalfa

0.0000126 

lb/ burrow GBT

0.0004 lb / ac

0.0002 lb / 

bait station

GBT 

(granular)

0.00001688 

lb / burrow 3

GBT

(wettable 

0.0004 lb / ac powder)

NS Animal Burrows, Harborages 

or Dens Of Plague Reservoir 

Hosts

0.0001 lb / 

burrow or / 

placement

GBT

Artichoke

0.00000055 

lb / plant or

0.00000625 

lb / plant

3 21

Barley

0.0002 lb / 

bait station NS NS GBT(granular)

0.00000099 

lb / burrow 2 2

GST 

(granular)

Christmas Tree Plantations

0.0005 lb / ac 0.001 1

NS

AB

0.001 lb / ac 0.002 1 GB
Page 45 of 65

0.0005 lb / ac

NS NS

GST

Commercial/Institutional/

Industrial Premises/Equip.

(Indoor)

4.4 lb / ac, or

0.0001 lb / 

placement, or

0.00000219 

lb / bait 

station

GBT

Commercial/Institutional/

Industrial Premises/Equip.

(Outdoor)

0.0001 lb / 

placement

Commercial Transportation 

Facilities (All or Unspecified) 

Commercial Transportation 

Vehicles (All or Unspecified) Fencerows / Hedgerows

FoodProcessing Plant

Premises (Non-Food Contact)

ForestPlanting (Reforestation

Programs) (TreeFarms, Tree

Plantations, etc.)

0.0005 lb /ac 0.001 lb /ac1 AB

0.001 lb /ac 0.002 lb /ac1 GB

0.005 lb /ac NS NS GST

ForestTrees (All or

Unspecified)

0.001 lb / ac

42 AB

0.002 lb /ac1

NS

GB

0.005 lb / ac NS NS GST

GolfCourseTurf

0.005 lb / ac 0.001 lb /ac1

0.0004 lb / ac

NS

NS

GBT

0.00001688 

lb / burrow

3

GBT 

(wettable 

powder)

Household /Domestic

DwellingsIndoorPremises 4.4 lb / ac

NS GBT

Household /Domestic

Dwellings OutdoorPremises

0.0001 lb / 

placement

NonagriculturalRight-of-Way 

/Fencerows /Hedgerows

0.001 lb / ac

42

AB

0.0000252 lb 

/ burrow

GBT

0.001 lb /ac GB

NonagriculturalUncultivated

Areas /Soils

0.0004 lb / ac NS NS GBT

0.00000099 

lb / burrow

22

GST 

(granular)

0.00001688 

lb / burrow

3 NS

GBT 

(wettable 

powder)

NurseryStock

0.001 lb /ac

42 AB

0.002 lb /ac1

NS GB

0.0005 lb /ac

NS

NS GST

0.0000252 lb 

/ burrow

42

GBT 

(granular)

Oats 0.0002 lb / 

bait station NS NS
Page 46 of 65

0.00000099 

lb / burrow 2 2

GST

(granular)

Orchards (Unspecified)

0.001 lb / ac NS 4 2 AB

0.001 lb / ac 0.002 lb / ac 1

NS

GB

0.0005 lb / ac

NS NS

GST

0.0004 lb / ac

GBT

GBT 

(wettable 

powder)

Ornamental Herbaceous 

Plants 0.0005 lb / ac 0.001 lb / ac 1

GST

Ornamental Lawns and Turf 0.004 lb / ac NS NS

GBT

GBT 

(wettable 

powder)

Ornamental Woods Shrubs 

and Vines 0.0005 lb / ac 0.001 lb / ac 1GST

Pastures

0.00000099 

lb / burrow

NS

2 2

GST 

(granular)

0.0002 lb / 

bait station NS NS

GBT

(granular)

Public Buildings / Structures

(Vert. Pest Control)

0.0001 lb / 

placement

GBT

Rangeland

0.001 lb / ac 4

2

AB

GB

0.00000099 

lb / burrow 2

GST 

(granular)

0.0000252 lb 

/ burrow 4GBT

0.0004 lb /ac

NS NS 0.0004 lb /ac

GBT 

(wettable 

powder)

Recreational Areas

0.001 lb / ac

4 2

AB

GB

0.0000252 lb 

/ burrow

GBT

Refuse / Solid Waste Sites 

(Indoor)

0.0001 lb / 

placement NS NS

Refuse / Solid Waste Sites

(Outdoor)

Right-of-Way (Railroad)

Wheat

0.0002 lb / 

bait station(s)

GBT 

(granular)

0.00000099 

lb / burrow 2 2

GST 

(granular)

Note: AB=Aerial Broadcast, GB=Ground Broadcast, GBT=Ground Bait Treatment, GST=Ground Spot treatment, 

NS=Not Specified. When formulation type is not specified, it is Bait/Solid.

There are several use sites being identified as NDC (no dosage conversion). They are as follows: 

agricultural/farm structure/buildings and equipment, commercial/institution/industrial premises/equipment 
Page 47 of 65

(indoor or outdoor), commercial transportation vehicles (all or unspecified), food processing plant premises 

(nonfood contact), household/domestic dwelling (indoor or outdoor) premises, public buildings/structure (vert. 

pest control), refuse/solid waste site (indoor or outdoor)
Page 48 of 65

Appendix B: Summary of Ecotoxicity Data for 

Chlorophacinone

Table B-1. Freshwater Fish Acute Toxicity of Chlorophacinone 

Species1,2 % a.i. 96-hourLC50

(mg a.i./L) 

Toxicity 

Category

MRID No. Study Classification

Bluegill sunfish, 

(Lepomis macrochirus)

100 0.710 Highly toxic 43256102*

(Machado, 1992)

Acceptable (flowthrough, 10 fish/level)

Rainbow trout,

(Onchorhynchus 

mykiss)

100 0.450 Highly toxic 43256103**

(Machado, 1992)

Acceptable (flowthrough, 10 fish/level)

*In previous assessments this study was cited as MRID 43249501; the correct MRID is 43256102.

** In previous assessments this study was cited as MRID 43249502; the correct MRID is 43256103.

Table B-2. Freshwater Invertebrate Acute Toxicity of Chlorophacinone

Species % diquat 

cation

48-hourEC50

(mg/L) 

Toxicity 

Category

MRID No.

Author, Year

Study Classification

Water flea 

(Daphnia magna)

100 0.64 Highly toxic 42356101

(Putt, 1992)

Acceptable (flowthrough)
Page 49 of 65

Table B-3: Avian Acute Toxicity to Chlorophacinone 

Species % A.I. Toxicity 

Endpoint

Toxicity 

Classification

MRID Status

Acute Single Oral Dose

Bobwhite quail 

(Colinus 

virginianus)

100 LD50= 258 mg/kgbw 1

Moderately 

toxic

41513101 (Fletcher 

and Pederson, 1989) Acceptable

Bobwhite quail 

(Colinus 

virginianus)

Tech. LD50= 495 mg/kgbw2

Not classified, 

study not 

reviewed

39233 (Beavers et 

al., 1979)

Study not yet 

reviewed by EPA; 

endpoints as 

reported by study 

author.

Acute Dietary

Bobwhite quail 100

LC50 = 56 mg/kgdiet 3 Highly toxic

41513102 (Fletcher 

and Pederson, 1989) Acceptable

Mallard duck 

(Anas 

platyrhynchos)

100

LC50 = 172 mg 

a.i./kg-diet 4 Highly toxic 41513103 (Fletcher 

and Pederson, 1989)

Acceptable

Bobwhite quail Tech.

LC50 = 242 mg 

a.i./kg-diet 5

Not classified, 

study not 

reviewed

29144 (Beavers et 

al., 1979)

Study not yet 

reviewed by EPA; 

endpoints as 

reported by study 

author.

Mallard duck Tech

LC50 = 426 mg 

a.i./kg-diet 5

Not classified, 

study not 

reviewed

29143 (Beavers et 

al., 1979)

Study not yet 

reviewed by EPA; 

endpoints as 

reported by study 

author.

Japanese quail 

(Coturnix c. 

japonica)

0.25% oil 

concentrate

LC50 = 60 mg 

a.i./kg-diet4 Highly toxic 47323201 (Reidel et 

al, 1990)

Supplemental (nonGLP study, raw data 

not submitted)

1 Birds were dosed on day 0 and followed for 30 days after dosing. All mortalities occurred within 5 days of the 

start of the test.

2 Birds were dosed on day 0 and followed for 14 days after dosing. All mortalities occurred within 10 days of the 

start of the test.

3 Birds were fed treated diet for 5 days and untreated diet for the following 25 days. All mortalities occurred within 

nine days of the start of the test.

4 Birds were fed treated diet for 5 days and untreated diet for the following 3 days. Total observation time was 8 

days after start of test.

5 Birds were fed treated diet for 5 days and untreated diet for the following nine days. Birds were observed for a 

total of 14 days.
Page 50 of 65

Table B-4: Avian Sub-Chronic Toxicity to Chlorophacinone 

Species % A.I. Toxicity 

Endpoints

Affected Endpoints MRID and Status

Japanese quail 0.25% oil 

concentrate

NOAEC = 1 mg 

a.i./kg-diet

LOAEC = 2 mg 

a.i./kg-diet

-Adult mortality at all test levels 

greater than 1 mg a.i./kg-diet.

-Increased relative liver mass and 

prothombin time at 4 mg a.i./kg-diet 

and greater for females.

-Increased liver mass, relative liver 

mass and prothombin time at 8 mg 

a.i./kg-diet and greater for males.

-Progeny appear unaffected.

47323201 (Reidel et 

al, 1990)

Supplemental (nonguideline, non-GLP 

study, raw data not 

submitted)

Table B-5: Avian Reproductive Toxicity to Chlorophacinone 

Species % A.I. Toxicity 

Endpoints

Affected Endpoints MRID and Status

Bobwhite quail 99.7%

NOAEC < 0.982 

mg a.i./kg-diet

LOAEC = 0.982 

mg a.i./kg-diet

Reduced eggshell thickness at 0.982 

and 2.9 mg a.i./kg-diet. Reduced 

number of eggs hatched as a 

percentage of live embryos at 2.9 and 

9.04 mg a.i./kg-diet. Reduced number 

of hatchling survivors as a percentage 

of eggs hatched at 9.04 mg a.i./kgdiet. One treatment-related adult 

mortality at 9.04 mg a.i./kg-diet.

489904001

Supplemental 

(definitive NOAEC 

not established)

Mallard duck 98.4%

NOAEC = 0.046 

mg a.i./kg-diet

LOAEC = 0.096 

mg a.i./kg-diet

Reduction in mean 14-day survivor 

weights at 0.096 and 0.96 mg a.i./kgdiet concentrations. Reductions in 

number of hatchlings of eggs set, 14-

day hatchling survival of eggs set, 

hatchling survival of number hatched, 

and hatchling weight at the 0.96 mg

a.i./kg-diet concentration.

Nine of 16 adult females died 

(treatment-related) at the 0.96 mg 

a.i./kg-diet concentration.

489904002

Acceptable
Page 51 of 65

Table B-6: Mammalian Acute Toxicity to Chlorophacinone

Test Type % A.I. Toxicity Endpoint Toxicity 

Classification MRID Status

Acute oral (gavage) single dose

Laboratory rat

Rattus 

norvegicus

100% LD50 = 3.15 mg a.i./kg-bw 

(male) 

LD50 = 10.95 mg a.i./kg-bw 

(female)

LD50 = 6.26 mg a.i./kg-bw 

(combined)

Very highly 

toxic

41875301

Acceptable a(Single 

dose, mortalities 

occurred 4 to 9 days 

after dosing)

Black-tailed 

Prairie Dogs 

(Cynomys 

ludovicianus)

99.4% LD50: 1.94 mg ai/kg bw

95% C.I.: (1.46, 5.77)

Slope = 3.45

Very highly 

toxic

47333601 Supplemental (Single 

dose, mortalities 

occurred 9 to 22 days 

after dosing) 

(sufficient raw data 

not included)

Pine vole 

(Microtus 

subterraneus)

NA

LD50: 14.2

95% C.I.: (11.4, 17.6)

Slope = 0.81

Highly toxic Byers (1978) Supplemental 

(qualitative)

Acute oral (gavage) multiple dose 

Norway Rat 

(wild type)

Rattus 

norvegicus

5-day cumulative dose 

LD50 = 0.8 mg a.i./kg-bw

Doses were administered daily 

for 5 days, the 5-day LD50 = 0.8 

mg a.i./kg-bw is equivalent to 5 

days of administration of 0.16 

mg a.i./kg-bw/day

Very highly 

toxic Ashton, et al. 

(1987)

Qualitative (no 

controls, length of 

observation not 

stated, time of 

mortalities and 

additional raw data 

not provided)

Laboratory 

Rat

5-day cumulative dose 

LD50 = 0.95 mg a.i./kg-bw

Doses were administered daily 

for 5 days, the 5-day LD50 = 

0.95 mg a.i./kg-bw is 

equivalent to 5 days of 

administration of 0.19 mg 

a.i./kg-bw/day

Very highly 

toxic Ashton, et al. 

(1987)

Qualitative (no 

controls, length of 

observation not 

stated, time of 

mortalities and 

additional raw data 

not provided)

Laboratory 

mouse (Mus 

musculus)

5-day cumulative dose 

LD50 = 5.95 mg a.i./kg-bw

Doses were administered daily 

for 5 days, the 5-day LD50 = 

5.95 mg a.i./kg-bw is 

equivalent to 5 days of 

administration of 1.19 mg 

a.i./kg-bw/day

Very highly 

toxic Ashton, et al. 

(1987)

Qualitative (no 

controls, length of 

observation not 

stated, time of 

mortalities and 

additional raw data 

not provided)

Acute Dietary

Laboratory 

Rat

Tech. LC50 = 1.14 (1.02-1.36) mg 

a.i./kg-diet

Slope = 13.2

Very highly 

toxic

Teeters 1981 

(TNM 66)*

Supplemental, 

Observed 14 days, 

mortalities 5-8 days
Page 52 of 65

Table B-6: Mammalian Acute Toxicity to Chlorophacinone

Laboratory 

Rat

Tech. LC50 = 1.14 (0.98-1.35) mg 

a.i./kg-diet

Slope = 7.2

Very highly 

toxic

Teeters 1981 

(TNM 117)*

Supplemental 

Observed 14 days, 

mortalities days 4-

12

Laboratory 

Rat

Tech. LC50 = 1.26 (1.11-1.47) mg 

a.i./kg-diet

Slope = 9.9

Very highly 

toxic

Teeters 1981 

(TNM 120)*

Supplemental 

Observed 14 days, 

mortalities days 4-8

Laboratory 

Rat

Tech. LC50 = 1.26 (0.97-1.64) mg 

a.i./kg-diet

Slope not estimated, binomial 

method

Very highly 

toxic

Teeters 1981 

(TNM 74)*

Supplemental 

Observed 14 days, 

mortalities days 5-

12

a As classified by OPP Health Effects Division (HED)

*Teeters, W.R.(1981) Chlorophacinone technical: Toxicity to Laboratory Rat. (U.S. Environmental Protection 

Agency, Pesticides Regulation Div., Agricultural Research Center, Animal Biology Laboratory, unpublished 

report.)
Page 53 of 65

Table B-7: Mammalian Developmental and Maternal Toxicity to Chlorophacinone 

Test Type % A.I.

NOAEL

(μg/kgbw/day)

LOAEL

(μg/kgbw/day)

Affected Endpoints MRID

(Status)

Developmental

(New Zealand 

white rabbit)

101 Maternal 

NOAEL = 5

Develop 

NOAEL = 10 

Maternal 

LOAEL = 10

Develop 

LOAEL = 25

Dose administered by oral gavage 

daily from gestation days 7 to 19, 

inclusive. 

Maternal NOAEL based on increased 

prothrombin and activated partial 

thromboplastin times in the 

preliminary range-finding study at 

gestation day 20.

Developmental NOAEL based on lack 

of sufficient fetuses/litters at the 

higher dose levels as high mortality 

was observed (13/16 rabbits at 25 

μg/kg/day and 16/16 rabbits at 75 

μg/kg/day) in definitive test. In 

addition external bleeding and internal 

hemorrhage were observed in the 25 

μg/kg/day and 75 μg/kg/day dose 

groups.

43570801 

(Acceptablea)

Developmental 

(Laboratory rat)

101 Maternal 

NOAEL = 50

Develop

NOAEL<12.5

Maternal 

LOAEL = 100

Develop 

LOAEL≤12.5

Dose administered by oral gavage 

daily from gestation days 6 to 15, 

inclusive. 

Maternal NOAEL based on dam 

mortality.

Developmental NOAEL based on 

increased incidences of hydroureter, 

distended ureter and total ureter 

anomaly in the fetuses.

43349501

(Acceptablea)

a As classified by OPP Health Effects Division (HED)
Page 54 of 65

Table B-8: Toxicity to Chlorophacinone to Non-target Terrestrial Invertebrates

Species % A.I. Toxicity Endpoints MRID Status

Burying 

beetle

Nicrophorus 

orbicollis

100 Number of beetle young emerging and 

total biomass of young was reduced in 

beetle trt group laying eggs in carcasses 

fed 50 mg a.i./kg-bait for 5-10 days 

compared when to control.

47383001 Supplemental 

(non-guideline)

Earthworm

(Eisenia 

foetida)

99.77

LC50 > 1000 mg ai/kg-soil

NOAEC (mortality) = 309 mg ai/kg-soil

NOAEC (weight change) < 95 mg 

ai/kg-soil

47383002

Study not yet 

reviewed by EPA; 

endpoints as 

reported by study 

author.
Page 55 of 65

Appendix C. Screening Level Models to Evaluate Potential 

Importance of Drinking Water and Inhalation Exposure 

Pathways
Page 56 of 65

SIP (Screening Imbibition Program, v1.0) Inputs and Conclusions

Table 1. Inputs

Parameter Value

Chemical name chlorophacinone

Solubility (in water at 25oC; mg/L) 3.4

Mammalian LD50 (mg/kg-bw) 6.26

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian species

Mammalian NOAEL (mg/kg-bw) 0.01

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian species

Avian LD50 (mg/kg-bw) 258

Avian test species northern bobwhite quail

Body weight (g) of "other" avian species

Mineau scaling factor 1.15

Mallard NOAEC (mg/kg-diet) 0.046

Bobwhite quail NOAEC (mg/kg-diet) 0

NOAEC (mg/kg-diet) for other bird species 0

Body weight (g) of other avian species

NOAEC (mg/kg-diet) for 2nd other bird species 0

Body weight (g) of 2nd other avian species

Table 2. Mammalian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 0.5848 0.5848

Adjusted toxicity value (mg/kg-bw) 4.8149 0.0077

Ratio of exposure to toxicity 0.1215 76.0309

Conclusion*

Exposure through drinking 

water alone is a potential 

concern for mammals

Exposure through drinking 

water alone is a potential 

concern for mammals

Table 3. Avian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 2.7540 2.7540

Adjusted toxicity value (mg/kg-bw) 185.8708 0.0023

Ratio of exposure to acute toxicity 0.0148 1206.7420

Conclusion*

Drinking water exposure 

alone is NOT a potential 

concern for birds

Exposure through drinking 

water alone is a potential 

concern for birds

*Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. Therefore, when 

aggregated with other routes (i.e., diet, inhalation, dermal), pesticide exposure through drinking water may contribute to 

a total exposure that has potential for effects to non-target animals.
Page 57 of 65

Welcome to the EFED Screening Tool for Inhalation Risk

This tool is designed to provide the risk assessor with a rapid method for determining the potential

significance of the inhalation exposure route to birds and mammals in a risk assessment.

Input

Application and Chemical Information

Enter Chemical Name chlorophacinone

Enter Chemical Use rodenticide

Is the Application a Spray? (enter y or n) n

If Spray What Type (enter ground or air) ground

Enter Chemical Molecular Weight (g/mole) 374.81

Enter Chemical Vapor Pressure (mmHg) 3.58E-06

Enter Application Rate (lb a.i./acre) 0.001

Toxicity Properties

Bird

Enter Lowest Bird Oral LD50 (mg/kg bw) 258

Enter Mineau Scaling Factor 1.15

Enter Tested Bird Weight (kg) 0.178

Mammal

Enter Lowest Rat Oral LD50 (mg/kg bw) 6.26

Enter Lowest Rat Inhalation LC50 (mg/L) 0.007

Duration of Rat Inhalation Study (hrs) 4

Enter Rat Weight (kg) 0.35

Output

Results Avian (0.020 kg )

Maximum Vapor Concentration in Air at Saturation 

(mg/m3) 7.22E-02

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 9.08E-03

Adjusted Inhalation LD50 1.61E+00

Ratio of Vapor Dose to Adjusted Inhalation LD50 5.64E-03

Exposure not Likely 

Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) not applicable

Ratio of Droplet Inhalation Dose to Adjusted Inhalation 

LD50 not applicablenot applicable

Results Mammalian (0.015 kg )

Maximum Vapor Concentration in Air at Saturation 

(mg/m3) 7.22E-02

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 1.14E-02

Adjusted Inhalation LD50 4.17E-01

Ratio of Vapor Dose to Adjusted Inhalation LD50 2.74E-02

Exposure not Likely 

Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) not applicable

Ratio of Droplet Inhalation Dose to Adjusted Inhalation 

LD50 not applicablenot applicable
Page 58 of 65

Appendix D. Wildlife Mortality Incidents Attributed to Use of 

Chlorophacinone

The table below is based on the Summary Table that was included in Docket ID EPA-HQ-OPP2011-0718 (“Risks of Non-Compliant Rodenticides to Nontarget Wildlife - Appendix D -

Wildlife Mortality Incidents”; Document ID EPA-HQ-OPP-2011-0718-0010). The table was 

updated to include additional incidents and additional information on previously reported 

incidents that was available to the Agency as of 2013. Any additional incidents reported to the 

Agency after 2013 for chlorophacinone have not been added to the table below. 
Page 59 of 65

INCIDENT 

NUMBER YEAR LEGALITY CERTAINTYA STATE LAND USE

GENERIC 

SPECIES 

(Number)

COMMENTS

B000179-001 1981 Registered 

use

Highly probable WA Field Quail (1)

This incident was reported in an article 

entitled, “Effects of Pelletized 

Anticoagulant Rodenticides on California 

Quail,” in the Journal of Wildlife 

Diseases, 1985, pp391 – 395. A 

moribund emaciated California quail was 

found in an orchard. The rodenticide 

chlorophacinone was found in the crop, 

and the gizzard contained a pink mass of 

paraffin that was selectively accumulated 

from the paraffinized pellets. [NOT IN 

EIIS]

I003351-033 1995 N/R Highly probable CA N/R Bobcat (1)

A bobcat was found dead the day after it 

was observed feeding on a barn owl in the 

Golden Gate National Recreation Area on 

February 14, 1995. The owl and bobcat 

carcasses were to the California Dept. of 

Fish and Game for analysis. A rodent 

carcass was found in the crop of the owl. 

Chlorophacinone was detected in the liver 

of the bobcat at 0.4 ppm.

I006306-005 1994 N/R Highly probable NY Residential Squirrel (1)

A gray squirrel was found dead in 

Albany County, NY in August, 1993. A 

subsequent necropsy showed both 

brodifacoum (0.53 ppm) and

chlorophacinone (0.62 ppm) to be present 

in the liver and brodifacoum in the 

stomach contents. There were inter- and 

intramuscular hemorrhages and free 

hemorrhage or bloody fluid in the body 

cavity.
Page 60 of 65

INCIDENT 

NUMBER YEAR LEGALITY CERTAINTYA STATE LAND USE

GENERIC 

SPECIES 

(Number)

COMMENTS

I006306-007 1993 N/R Highly probable NY Residential Squirrel (1)

A dead male gray squirrel was submitted 

on August 13, 1993, in Albany County, 

NY to the Wildlife Pathology Unit to

determine cause of death. Gross 

pathology findings indicated that the 

squirrel died from anticoagulant 

rodenticides. Brodifacoum 0.53 ppm and 

chlorophacinone 0.62 ppm were detected 

in the squirrel's liver.

I009111-001 1999 N/R Highly probable NY Urban Squirrel (1)

A grey squirrel was found dead in 

Manhattan and arrived at the Wildlife 

Pathology Unit the same day. A 

hemorrhage was present in the 

musculature overlying both scapulae. 

The right lung was hemorrhagic. The 

stomach contained ground nutmeats and 

analysis of the liver detected 

chlorophacinone residues at 0.47 ppm.

I009118-001 1999 N/R Probable NY Urban Squirrel (1)

An adult male gray squirrel was found 

dead, head-first in the split of a tree stump 

in Central Park, on February 14, 1999. A 

bacterial infection with pus was present 

over the skull, and several large tan 

necrotic areas were present in the liver. 

An analysis of the liver showed the 

presence of chlorophacinone at 0.29 ppm. 

In the opinion of the technical 

investigator, the squirrel may have died 

from the infection alone, but the pale 

musculature indicates blood loss had 

occurred from the anti-coagulant.
Page 61 of 65

INCIDENT 

NUMBER YEAR LEGALITY CERTAINTYA STATE LAND USE

GENERIC 

SPECIES 

(Number)

COMMENTS

I012972-001 2002 N/R Probable KS Field Turkey (2)

Two wild turkeys were found dead 

approximately 100 yards from a prairie 

dog town that has been baited with 

poisoned grain two and a half to three 

weeks prior to submission. The suspected 

poison was Rozol® pocket gopher 

poison. The landowner that found the 

turkeys contacted the Kansas Department 

of Wildlife and Parks. Necropsy showed 

dilated vessels in the crop area and 

diffuse hemorrhage around the crop. 

Pebbles and green feed material are 

present in the ventriculus. The 

gastrointestinal tract contains blue green 

grain in the crop. An analysis of the 

livers detected chlorophacinone residues 

of 0.69 and 0.40 ppm. 

I013810-013 1999 N/R Probable NY Urban Hawk (1)

This incident was part of the Contaminant 

Exposure and Effects – Terrestrial 

Vertebrates (CEE-TV) Database, Version 

3.3, October 2002 report. A red-tailed 

hawk was found in Manhattan. Necropsy 

results showed 0.18 ppm chlorophacinone 

residues in the liver. 

I019311-001 2008 N/R Highly probable KS N/R Badger (1)

Use of the product Rozol Pocket Bait 

Burrow Builder Formula with active 

ingredient chlorophacinone caused 

mortality of a badger in Kansas. A 

necropsy by the National Fish and 

Wildlife Forensics Lab determined that 

anticoagulant poisoning was the cause of 

death. Chlorophacinone was measured at 

320 ppb in the stomach and 2 ppm in the 

liver. Route of exposure was listed as 

"unknown" because no prairie dog 

remains were found inside the badger, but 

being a strict carnivore, it almost certainly 
Page 62 of 65

INCIDENT 

NUMBER YEAR LEGALITY CERTAINTYA STATE LAND USE

GENERIC 

SPECIES 

(Number)

COMMENTS

was affected through secondary 

poisoning.

I019968-001 2008 N/R Highly probable CA Field

Geese (70), 

vulture (2), 

Barn owl (1), 

bobcat (1)

In 2008, Department of Fish and Game 

Office of Spill Prevention and Response 

staff in Santa Cruz responded to an 

incident near a lettuce field near Morro 

Cojo Slough involving several dead 

Canada geese. Additional geese were 

found dead at the site for several weeks 

after the initial incident report. The total 

number of dead geese was estimated to be 

70. In addition, two turkey vultures, a 

red-tailed hawk, a barn owl, and a bobcat 

were found dead in the vicinity. The 

geese, predators and scavengers showed 

signs of anticoagulant toxicity. All but 

one of the animals tested positive for 

chlorophacinone.

I020607-001 2009 N/R Highly 

Probable KS Field Badger (1)

A dead badger was found on a private 

property. The liver was tested and 

chlorophacinone residues of 4.4 ppm 

(with a detectable limit of 0.25 ppm) were 

detected. It was determined the badger 

died from secondary poisoning, most 

likely resulting from use of 

chlorophacinone to control prairie dogs in 

the area.

I020996-001 2009 N/R Possible KS Field Wild Turkey 

(45)

Forty-five wild turkeys were found dead 

in and near the small town of Russell 

Springs, KS. Analyses of 6 of the turkey 

found phosphene gas in the crop contents, 

indicating poisoning by zinc phosphide. 

However, chlorophacinone was also 

detected in the crop contents of one of the 

turkeys, indicating that it may have also 

contributed to causing the mortality of 

some of the birds.
Page 63 of 65

INCIDENT 

NUMBER YEAR LEGALITY CERTAINTYA STATE LAND USE

GENERIC 

SPECIES 

(Number)

COMMENTS

I020996-003 2009 N/R Possible KS Park Raccoon (1)

The Department of Wildlife and Parks 

received numerous reports of dead 

raccoon at a city park. The raccoon was 

delivered to the Southeastern Cooperative 

Wildlife Disease Study College of 

Veterinary Medicine (SCWDS) for 

postmortem analysis. The intestines of 

the raccoon were distended with bloody 

contents. Several areas of hemorrhage 

were present under the skin and on the 

surface of many organs. Brodifacoum, 

chlorophacinone, and bromadiolone 

residues were detected in the liver 

although no residue amounts were 

provided in the report.

I022986-001 2011 N/R Possible NY Urban Red-tailed 

hawk (1)

A dead immature red-tailed hawk was 

found in Fort Tryon Park in Manhattan, 

NY. A clotted hemorrhage was observed 

in the left optical area of the left side of 

the head. There was 1-2 ml of clotted 

hemorrhage found in the ceolomec cavity. 

Toxicology analysis of liver tissue found 

brodifacoum at 0.149 ppm. Low 

concentrations of three other 

anticoagulant rodenticides were also 

detected 0.024 ppm difethialone, 0.018 

ppm bromadialone, and 0.004 ppm 

chlorophacinone.) 

I023324-002 2006 Registered 

use

Highly probable NE Field Bald eagle (1)

On December 6, 2006 a dead bald eagle 

was found in Red Willow County, NE by 

a Nebraska Conservation Officer (CFO). 

A pesticide applicator told the CFO that 

he had followed label instructions when 

applying Rozol to control prairie dogs. 

An internal examination noted 

hemorrhaging in muscle tissues and in the 

clavicular air sac. Chlorophacinone was 
Page 64 of 65

INCIDENT 

NUMBER YEAR LEGALITY CERTAINTYA STATE LAND USE

GENERIC 

SPECIES 

(Number)

COMMENTS

detected in the liver sample at 0.30 ppm.

I023352-001 2011 N/R Highly probable NE Field Bald eagle (1)

The carcass of a bald eagle from Buffalo 

County, NE was received by the USFWS 

on March 31, 2011. Chlorophacinone was 

detected at 0.4 ppm in the liver sample. 

Hemorrhaging was present in the 

subcutaneous tissue.

I024146-009 1997 N/R Highly probable CA N/R Coyote (1)

On September 12, 1997 a coyote was 

recovered from the Santa Monica 

Mountains National Recreation Area in 

Los Angeles County, CA. The carcass 

was sent to the Department of Fish and 

Game Pesticide Investigations Unit for 

necropsy and tissue analysis to try and 

determine the cause of death. Lab results 

detected residues of chlorophacinone in 

(blood sample 0.04 ppm), (intestinal 

sample 0.24 ppm), (liver sample 1.2 

ppm). Large hematomas involving most 

of the musculature were present on all 

four limbs. It is highly probable that the 

loss of this coyote was due to exposure to 

chlorophacinone, but unable to determine 

if exposure was primary or secondary.

I024152-004 2006 N/R Highly 

Probable CA N/R Coyote (1)

In 2006 in Santa Cruz County, CA a 

laboratory staff reported that a coyote 

liver was submitted to the Pesticide 

Investigations Unit in order to analyze for 

anticoagulant residues. The liver 

contained four anticoagulants; 

chlorophacinone (1.13 ppb), 

coumatetralyl (0.10 ppb), diphacinone 

(1.50 ppb) and warfarin (0.060 ppb). It is 

highly likely that mortality was caused by 

exposure to anticoagulants.
Page 65 of 65

INCIDENT 

NUMBER YEAR LEGALITY CERTAINTYA STATE LAND USE

GENERIC 

SPECIES 

(Number)

COMMENTS

A: Certainty describes the level of certainty that exposure to the given pesticide was the cause or a significant contributing factor of the effects 

observed in the incident.