UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

MEMORANDUM 

DATE: December 15, 2015 

SUBJECT: Diphacinone and Diphacinone Sodium Salt. Human Health Assessment 

Scoping Document in Support of Registration Review. 

PC Code: 06770 I, 067705 

Decision No.: 502489 

Petition No.: NA 

DP Barcode: 0426292 

Registration No.: NA 

Regula tory Action: Registration Review Scoping 

Risk Assessment Type: Single Chemical/Aggregate Case No.: NA 

TXR No.: NA CAS No.: 82-66-6 

MRID No.: A 40 CFR: NA 

FROM: Bridgen 

Christopher 

Bobowiec

Schlosser, 

, Biologist 

Toxicologist 

~ 

'-#./5-~c>-: 

Sumitra Bose Biswas, Chemist 

Risk Assessment Branch Vl (RAB6) 

Health Effects Division (7509P) ,, 

THROUGH: 

Risk 

Austin 

Assessment 

Wray, Ph.D.

Branch 

, Toxicologist 

IV (RAB fV) 

/4. ~ W ~ 

Health Effects Division (HED, 75,Q?~ _ ~ ~ 

Margarita Collantes, Biologist, ~K 1 ~ 

Risk Assessment Branch (RAB) II / 

Health Effects Division (7509P) 

Risk 

~~~a Assessment Davis, Branch 

Branch 

Chief 

VI (RAB6) 

J~~ 

Health Effects Division (7509P) 

TO: Christina Motilall, Chemical Review Manager 

Risk Management and Implementation Branch I (RMIB I) 

Pesticide Reevaluation Division (PRO) (7508P) 

As part of Registration Review, the Pesticide Reevaluation Division (PRO) has requested that the 

Health Effects Division (HED) provide a human health risk assessment scoping document for the 

rodenticide agent diphacinone and diphacinone sodium salt. The most recent risk assessment for 

diphacinone was conducted in April 9, 1997 (Memo, J. Redden, HED Chapter of the 

Reregistration Eligibility Decision Document (RED) for Diphacinone). 

Page 1 of32 
Executive Summary 

HED has prepared a scoping document to support Registration Review for diphacinone or (2-

diphenylacetyl-1 ,3-indandione) and diphacinone sodium salt. Diphacinone is a first generation 

anticoagulant rodenticide that acts by inhibiting the enzyme vitamin K epoxide reductase which 

is a crucial component in a number of normal clotting factors. Diphacinone is registered to 

control house mice, a variety of rats, squirrels. and voles inside and within 100 feet of man-made 

structures, in agricultural fields, orchards and the subterranean control of moles and gophers 

around lawns, golf courses, and other turf areas. There are over 50 diphacinone end-use products 

comprised of 0.005 % - 0.2 % active ingredient (ai) formulated as cakes, liquid concentrate, meal 

bait, paraffinized pellets, paraffin blocks, ready-to-use place packs, slabs, and tracking powder. 

Products that are intended primarily for occupational use are packaged in 4 pounds or more. 

Diphacinone toxicity is manifested as an increase in prothrombin and partial thromboplastin 

time. Signs of toxicity include dyspnea, lethargy, hemorrhage from the nose, and uterine 

bleeding. Death follows excessive external and/or internal bleeding. Technical grade 

diphacinone has high acute toxicity via oral, dermaL and inhalation routes of exposure (Toxicity 

Category 1). It is a non-irritant to the skin (Category IV) and moderate irritant to the eye 

(Category lIJ). Diphacinone is not a dermal sensiti zer. There is no cancer c lassification for 

di phaci none. 

To evaluate the scope of work necessary to support Registration Review, HED has considered 

recent risk assessments for diphacinone and its sodium salt, updates to its toxicity, exposure, and 

usage databases, and the latest Agency science policy and risk assessment methodologies. 

The toxicology database for diphacinone is adequate for risk assessment of registered uses. The 

toxicology studies available include: a 21-day dermal in rabbits, 2 1-day oral in mice, acute 

toxicity in rats, 14-day repeat dose in rats. developmental toxic ity in rats, mutagenicity battery. 

and a metabolism study in rats. There are no chronic and/or carcinogenicity studies on 

diphacinone. Given the exclusively non-food uses chronic and/or carcinogenicity studies are not 

required. Additionally, the available mutagenicity studies showed that there is no mutagenicity 

concern. Based on a weight of evidence approach considering all the available hazard and 

exposure inforn1ation, HED's HASPOC determined that the subchronic inhalation toxic ity study, 

developmental toxicity study in rabbits reproduction, neurotoxicity and immunotoxicity studies 

are not required (U. Habiba, TXR0057326, 12/15/20 15). At the time of Registration Review the 

Agency may update points of departures (PODs) and toxicological endpoints based on updated 

policies for occupational and residential exposure assessments as well as the potential for 

drinking water exposure. Additionall y, the uncertainty fac tors will be reassessed in the context of 

the updated PODs and endpoints. 

In the previous 1997 assessment dietary food and drinking water exposures were not quantified 

because of the limited non-food use pattern and the Food Quality Protection Act (FQPA) 

considerations did not apply. Therefore an aggregate risk assessment was not conducted in 1997. 

While the dietary food remains not a concern for HED, the registered aerial agricultural 

broadcast applications to post-harvest orchards and nurser1es may induce consideration of 

drinking water estimates during the Registration Review process. I lowever it is noted that the 

Page 2 of 32 
Page 3 of 32

application rate is considerably low (maximum single aerial application rate is 20 pounds of 

product per acre or 1.03 E-03 pounds of active ingredient per acre).

A short term dermal and inhalation occupational and residential handler exposure assessment 

will be required during Registration Review based on the potential exposure to handlers (mixers, 

loaders, applicator, etc.) during the use of pelleted, liquid concentrate, and dust formulations of 

diphacinone. Exposure to products formulated as bait cakes, blocks, sachets, and disposable bait 

stations is considered to be negligible. Occupational post-application exposure is not expected 

due unlikely hood of reentry to the use sites (residential structures, post-harvest agricultural 

fields, etc.). Residential post-application exposure is not anticipated as products must be tamper 

resistant packaging if used above ground. The one exception of this is product formulated as a 

tracking powder (EPA Reg #12455-56) which is applied indoors in residential settings. Postapplication incidental ingestion exposure for the tracking powder formulation should be assessed 

during Registration Review. There have been recent changes in assessment assumptions, 

including body weight, amount treated, and transfer coefficients that will need to be incorporated 

into exposure assessments during Registration Review along with any changes to reevaluate the 

points of departure, toxicity endpoints, and uncertainty factors used for risk assessment purposes.

Spray drift exposure is not anticipated for the current diphacinone use pattern, however the 

Agency will examine the need for spray drift and volatilization assessments during Registration 

based on the potential for exposure to bystanders from agricultural applications.

Introduction

Diphacinone (2-diphenylacetyl-1,3-indandione) is a rodent control agent registered for the 

control of rodents in and around farm structures, households, and domestic dwellings, 

uncultivated agricultural and nonagricultural areas, commercial transportation facilities, 

industrial areas, in sewage systems, aircraft, ships, boats, railway cars, and food processing, 

handling, and storage areas and facilities. The anticoagulant is formulated as meal baits, tracking 

powder, concentrates, paraffinized pellets, ready-to-use place packs, paraffin blocks, cakes, and 

slabs. All products are 0.005 percent active ingredient, with the exception of three formulations: 

(1) Ditrac Tracking Powder, which is 0.2% active ingredient, (2) Contrax-P Cakes, which are 

0.025% active ingredient, and (3) Diphacinone concentrate, which is 0.1% active ingredient. 

The most recent human health risk assessment was finalized in April 2007 (Memo, J. Redden to 

L. Rossi, and “HED Chapter of the Reregistration Eligibility Decision Document (RED) for 

Diphacinone”).

In 2008, the Agency issued a risk mitigation decision for ten rodenticides, of which diphacinone 

was included. The mitigation decision set restrictions in order to minimize exposure to children, 

wildlife and domestic animals. The risk mitigation decision is summarized below and does not 

apply to rodenticide field (non-commensal rodents) uses or tracking powder products.

 Consumer-based products (≤ 1 pounds),

o Second-generation anticoagulants are prohibited as well as loose 

baits/pellets/meal as a form for above ground outdoor uses.
Page 4 of 32

o When applied outdoors above ground and in areas accessible to children, 

non-target wildlife or domestic animals, baits must be contained in bait 

stations. 

o Products for use outdoors and above-ground must be placed within 50 feet 

of a building.

 Professional-based products,

o Must be sold in quantities of ≥ 4 pounds (first-generation 

anticoagulants/non-anticoagulants), ≥ 8 pounds (second-generation 

anticoagulants; agricultural building use) and ≥ 16 pounds (second 

generation anticoagulants; above ground outdoor use).

o May not be offered for sale in consumer stores (hardware, grocery, etc.).

o Must also be placed within 100 feet of a structure (fence and perimeter 

baiting beyond 100’ of a man-made structure are prohibited) when used 

outdoors and above ground, see 50 foot Document Clarification Letter to 

Bell (03.20.12) (signed) in docket number EPA-HQ-OPP-2006-0955-0820 

found at www.regulations.gov.

o For uses of first-generation or non-anticoagulants, product labels require 

bait stations if children, wildlife or domestic animals may be exposed.

o For uses of second-generation anticoagulants, labels require bait stations 

for all outdoors above grounds placements and/or indoor placements 

where children, wildlife or domestic animals may be exposed.

Several of the diphacinone products are currently registered as restricted use pesticides (RUPs). 

Products intended for occupational use are packaged as 4 pounds (lbs.) or more. The majority of 

diphacinone products are applied using tamper resistant bait stations, which are required for all 

rodenticides where children and pets may be present per 2008 anticoagulant rodenticide 

mitigation. There are, however, some diphacinone end use products that are applied with aerial, 

and ground broadcast equipment at a maximum rate of 20 lbs. of product per acre or 1.03 E-03 

lbs. active ingredient per acre in post-harvest fruit tree orchards and commercial nurseries. In 

addition, tamper resistant bait stations are not required for burrow, canopy, and tracking powder

applications. See preliminary use profile table in the appendix (Attachment 3) for more 

information on application rate and application methods of diphacinone products.

Hazard Identification/Toxicology

Diphacinone is an anticoagulant rodenticide with terrestrial and residential non-food uses. 

Technical grade diphacinone has high acute toxicity via oral, dermal, and inhalation routes of 

exposure (Toxicity Category I). It is a non-irritant to the skin (Category IV) and moderate irritant 

to the eye (Category III). Diphacinone is not a dermal sensitizer. At present, the available 

toxicological database for diphacinone is adequate and will support a reregistration eligibility 

determination.

The toxicology studies available include: a 21-day dermal in rabbits, 21-day oral in mice, acute 

toxicity in rats, 14-day repeat dose in rats, developmental toxicity in rats, mutagenicity battery, 

and a metabolism study in rats. A 2-generation reproduction toxicity study is not required for 

diphacinone. Chronic and/or carcinogenicity studies are not required given the exclusively non-
Page 5 of 32

food use pattern. The available mutagenicity studies show no mutagenicity concern. There was 

no susceptibility seen in the developmental study. Based on a weight of evidence approach 

considering all the available hazard and exposure information, HED determined that the 

following studies were not required: subchronic inhalation toxicity study, developmental toxicity 

study in rabbits, reproduction, acute and subchronic neurotoxicity, and immunotoxicity (U. 

Habiba, TXR0057326, 12/15/2015).

Diphacinone toxicity is manifested as an increase in prothrombin and partial thromboplastin 

time. Signs of toxicity include dyspnea, lethargy, hemorrhage from the nose, and uterine 

bleeding. Death follows excessive external and/or internal bleeding. A 14-day repeated dose 

toxicity study in Sprague Dawley rats was conducted specifically to identify effects on clotting 

factors and overt signs of toxicity or lethality associated with anticoagulant effects following 

single and repeated dosage with technical diphacinone. In this study, a no observed adverse 

effect level (NOAEL) of 0.085 mg/kg/day was reported based on decreased prothrombin and 

activated partial thromboplastin times at the lowest observed adverse effect level (LOAEL) of 

0.175 mg/kg/day following repeated exposure. The NOAEL of 0.085 mg/kg/day was selected 

for assessment of risk via inhalation exposure as no route-specific study was available. For 

dermal exposures, a NOAEL of 0.10 mg/kg/day was selected from the 21-day dermal study in 

rabbits based on clinical signs consistent with anti-coagulant effects at the LOAEL of 1 

mg/kg/day. 

At the time of Registration Review the Agency may update PODs and toxicological endpoints 

since they are considered conservative based on updated policies for endpoint selection. 

Additionally, the uncertainty factors will be reassessed in the context of the updated PODs and 

endpoints. Please refer to Attachment 4 for a summary of the toxicity endpoints and points of 

PODs and Attachment 6 for the complete toxicity profile table.

Conclusions: The toxicology database for diphacinone is adequate for risk assessment of the 

current uses. At the time of Registration Review, the Agency may update PODs and 

toxicological endpoints since they are considered conservative based on updated policies for 

endpoint selection. Additionally, the uncertainty factors and the need for a dietary endpoint 

based on water only will be reassessed in the context of the updated PODs and policies.

Residue Chemistry and Dietary Exposure

All uses of diphacinone are non-food uses; therefore, no tolerances are established or needed. In 

addition, a dietary exposure assessment from food is not needed. However, the broadcast 

applications to orchards may result in the need for a drinking water assessment in Registration 

Review.

Conclusions: A new dietary exposure assessment is not anticipated to be needed during 

Registration Review unless there are drinking water exposure estimates.
Page 6 of 32

Residential Exposure

Residential Handler Exposure

Diphacinone is currently registered for use to control rats, mice, and squirrels in residential 

settings including in and around homes as well subterranean control of gophers and moles in 

gardens and turf. Residential handler exposure from handling tamper resistant bait stations 

loaded with non-dusty formulations such as sachets, bait cakes, and paraffinized pellets is 

considered to be negligible. There is however anticipated handler dermal and inhalation 

exposure from hand dispersal (including cup and spoon) of non-paraffinized products such as 

meal or grain-based baits for the subterranean control of moles and gophers. 

Residential Post-Application Exposure

Post-application exposure to products placed in tamper resistant bait stations or below ground are 

not anticipated. Tamper resistant bait stations are mandatory for any bait placed above ground 

where children and/or pets may be present with the exception of tracking powder products. 

Therefore an episodic ingestion assessment may be necessary during Registration Review 

Non Occupational Spray Drift or Volatilization

Residential bystander exposures resulting from off-site transport (i.e., spray drift or 

volatilization) is unlikely due to how diphacinone is formulated and used except for the granular 

broadcast applications of diphacinone in commercial orchards and nurseries [(and others as 

appropriate)]. The approach is outlined in the revised (2012) Standard Operating Procedures for 

Residential Risk Assessment (SOPs) – Residential Exposure Assessment Standard Operating 

Procedures Addenda 1: Consideration of Spray Drift. This guidance indicates that drift is not a 

concern when solid materials are applied (e.g., by aerial equipment). Therefore, only the 

potential for volatilization will be evaluated for each pesticide during the Registration Review 

process which ensures that all uses for that pesticide will be considered concurrently. In terms of 

volatilization, the agency has developed a Volatilization Screening Tool and a subsequent 

Volatilization Screening Analysis (http://www.regulations.gov/#!docketDetail;D=EPA-HQOPP-2014-0219). During Registration Review, the Agency will utilize this analysis to determine 

if data (e.g. flux studies, route-specific inhalation toxicological studies) or further analysis is 

required for diphacinone.

Conclusions: A residential handler assessment is required during Registration Review. An 

episodic incidental oral post-application assessment for tracking powder formulated products 

may be needed during Registration Review. The Agency will examine the need for a 

volatilization assessment, as well as evaluate the potential diphacinone exposure from spray drift 

during Registration Review.

Aggregate Risk Assessment

In accordance with the Food Quality Protection Act, HED must consider and aggregate pesticide 

exposures and risks from three major sources: food, drinking water, and residential exposures. 

Diphacinone is registered for non-food uses, however water exposure may be a possibility due to 

the aerial and ground applications in agricultural settings. For adults, the pathways leading to 

exposure remain residential handler dermal and inhalation exposure from handling non-
Page 7 of 32

paraffinized products for subterranean control. Residential handler exposure and quantitative 

drinking water estimates for diphacinone may be aggregated if deemed appropriate at the time of 

Registration Review. An aggregate risk assessment of any duration is not anticipated for 

children unless it is determined that an episodic incidental oral post-application assessment is 

needed for tracking powder formulations. 

Conclusions: If computing drinking water estimates is deemed appropriate from the aerial 

agricultural uses of diphacinone then a short term adult aggregate assessment is expected during 

the Registration Review, unless changes in use pattern or updated procedures occur.

Occupational Exposure

In the previous 1997 assessment HED had concerns about the risks to handlers of diphacinone 

products, particularly commercial handlers with the (1) handling large quantities of product, (2) 

handling dusty, non-paraffinized products and (3) applying products by hand. However 

exposure and risk estimates were not identified due to lack of unit exposure data available at the 

time. In 2007, the ready to use (RTU) pelleted product, Kaput Field Rodent Bait B Registration 

# 72500-11 was assessed for ST and IT occupational handler dermal exposure (M. Dow, 

D338351, 04/09/2007). Based on this assessment HED recommended requiring commercial 

handlers to wear waterproof gloves while handling all diphacinone formulations that are not 

contained in a tamper-resistant bait stations or in placed packs. Diphacinone labels reflect this 

mitigation requirement.

Occupational Handler Exposure

Occupational handlers are anticipated to have short- and intermediate-term dermal and inhalation 

exposures from mixing, loading, and applying the liquid concentrates on grain bait, loading and 

applying pelleted and impregnated grain bait products by aerial, ground, and handheld 

equipment, and applying the tracking powder formulation. Occupational dermal and inhalation 

exposure to reloading bait cakes, bait sachets, and disposable bait stations is considered to be 

negligible. Long-term occupational exposure is not expected. The registered end use 

diphacinone products require occupational handlers to wear long sleeved shirts, long pants, 

shoes, socks, and water proof gloves with the exception of pre-filled bait stations. Diphacin 110 

concentrate (REG # 61282-43) requires mixers and loaders to wear a dust mist filtering respirator 

protection. Updated occupational exposure assessment policies and body weight assumptions 

will be incorporated into diphacinone exposure assessments for Registration Review. In addition 

inhalation margins of exposure will be included in the Registration Review of diphacinone and 

its sodium salt. 

Occupational Post-Application Exposure

There is no anticipated occupational post-application exposure to the current use pattern of 

diphacinone and diphacinone salt. If new policies or procedures are put into place, the Agency 

may revisit the need for a quantitative occupational post-application inhalation exposure 

assessment for diphacinone.

Conclusions: There is sufficient information available to assess occupational handler exposures

however more information on use pattern and maximum application rate for products that are not 
Page 8 of 32

placed in a tamper resistant packaging would refine the assessment. Updated occupational 

handler exposure assessments will be conducted during Registration Review. Occupational postapplication exposure is not anticipated for Registration Review.

Public Health and Pesticide Epidemiology Data

As part of the Rodenticide Risk Mitigation Decision (RMD), and the subsequent Notice of Intent 

to Cancel (NOIC), the Environmental Protection Agency’s Office of Pesticide Programs’ 

Pesticide Re-evaluation Division requested an analysis of human incidents involving exposure to 

rodenticides in 2011 (S. Recore, D395567, 10/28/2011) and then updated in 2015 (S. Recore, 

D426573, 11/24/2015). Summary report listing incidents for diphacinone and diphacinone 

sodium salt are reported to the OPP Incident Data System (IDS), the National Pesticide

Information Center (NPIC), the Centers for Disease Control and Prevention/National Institute for 

Occupational Safety and Health (CDC/NIOSH), Sentinel Event Notification System for 

Occupational Risk-Pesticides (SENSOR), and Agricultural Health Study (AHS) databases. 

In order to minimize children and wildlife exposure to rodenticide products the 2008 RMD 

included risk mitigation measures requiring rodenticide products used in homes and marketed to 

general residential consumers be sold only with bait stations. Most rodenticide products 

complied with the mitigation measures required in the RMD as of June 4, 2011. The phase out 

production of the final 12 non-compliant products began in June 2014 and production of these 

products stopped on December 31, 2014. Distribution to retailers ended March 31, 2015. 

Due to the fact that these safety measures were only recently fully implemented, there is 

insufficient information available, at the time of this report, to determine if the mitigations have 

impacted the frequency of incidents occurring. However; AAPCC data is reviewed annually for 

reduction in reported rodenticide incidents as a Strategic Measure. For FY 2014 (using the 2013 

AAPCC annual report data), there was a reduction of 17% incidents reported to the AAPCC 

annual reports compared to the number of rodenticide exposures to children ages 1 to 6 years old 

in 2011. The reductions in child exposures are expected to become more prominent beginning in 

the 2016 AAPCC annual report; which will be reflected in the FY 2018 Strategic Measure. The 

target reduction for FY 2018 is to reduce rodenticide exposure incidents by 75% compared to a 

baseline measure of 11,674 reported incidents in 2008 in children ages 1 to 6 years old.

The Agency will continue to monitor the incident information and provide an updated review of 

incident, considering pre- and post-mitigation incidents separately, when the information 

becomes available. 

Tolerance Assessment and International Harmonization

There are no tolerances for diphacinone and diphacinone sodium salt as it is a non-food use.

Environmental Justice

Potential areas of environmental justice concerns, to the extent possible, were considered in this 

human health risk assessment, in accordance with U.S. Executive Order 12898, "Federal Actions 
Page 9 of 32

to Address Environmental Justice in Minority Populations and Low-Income Populations," 

http://www.epa.gov/compliance/environmentaljustice/resources/policy/exec_order_12898.pdf. 

As a part of every pesticide risk assessment, OPP considers a large variety of consumer 

subgroups according to well-established procedures. In line with OPP policy, HED estimates 

risks to pesticide exposures that are based on activities in and around the home that involve 

pesticide use in a residential setting. Whenever appropriate, these non-dietary exposures are 

calculated based on home use of pesticide products and associated risks for adult applicators and 

for toddlers, youths, and adults entering or playing on treated areas post-application are 

evaluated.

Cumulative

Unlike other pesticides for which EPA has followed a cumulative risk approach based on a 

common mechanism of toxicity, EPA has not made a common mechanism of toxicity finding as 

to diphacinone and any other substances and diphacinone does not appear to produce a toxic 

metabolite produced by other substances. For information regarding EPA’s efforts to determine 

which chemicals have a common mechanism of toxicity and to evaluate the cumulative effects of 

such chemicals, see the policy statements released by EPA’s Office of Pesticide Programs 

concerning common mechanism determinations and procedures for cumulating effects from 

substances found to have a common mechanism on EPA’s website at 

http://www.epa.gov/pesticides/cumulative/.

Human Studies

The risk assessments which have been previously conducted for diphacinone relied in part on 

data from studies in which adult human subjects were intentionally exposed to a pesticide to 

determine their dermal and inhalation exposure. Many such studies, involving exposure to many 

different pesticides, comprise generic pesticide exposure databases such as the Pesticide 

Handlers Exposure Database (PHED), the Agricultural Handler Exposure Task Force (AHETF) 

database, and the Outdoor Residential Exposure Task Force (ORETF). EPA has reviewed all the 

studies supporting these multi-pesticide generic exposure databases, and has found no clear and 

convincing evidence that the conduct of any of them was either fundamentally unethical or 

significantly deficient relative to the ethical standards prevailing at the time the research was 

conducted. All applicable requirements of EPA’s Rule for the Protection of Human Subjects of 

Research (40 CFR Part 26) have been satisfied, and there is no regulatory barrier to continued 

reliance on these studies.

Data Deficiencies

No toxicological, residue chemistry, or occupational and residential exposure data are needed to 

support the registered uses of diphacinone at this time, however more information on use pattern 

and maximum application rate for products that are not placed in a tamper resistant packaging 

including the tracking powder formulations would refine the assessment.
Page 10 of 32

References

Recent Memoranda Relevant to Registration Review of Diphacinone

Author DP/TXR # Date Title

Risk Assessment

J. Redden Not available April 9, 1997 HED Chapter of the Reregistration Eligibility 

Decision Document (RED) for Diphacinone.

Not available May 28, 2008

(revised June 24, 2008) Risk Mitigation Decision for Ten Rodenticides.

U. Habiba TXR0057326 December 15, 2015

Rodenticides: Summary of Hazard and Science 

Policy Council (HASPOC) Meeting on October 1, 

2015: Recommendations on Data Requirements for 

Rodenticides.

Occupational and Residential Exposure Assessment

M. Dow D338351 April 9, 2007

Diphacinone/Imidacloprid-Human, Non-dietary 

Exposure/Risk Assessment for the Proposed Use of 

Diphacinone and Imidacloprid as a “Rodent, Rabbit 

and Flea Control Bait”.

T. Campbell D231606 December 23, 1996

Occupational and residential exposure assessment 

and recommendations for the reregistration 

eligibility decision document for diphacinone. 

Incident Report

S. Recore

D395567 October 28, 2011 Rodenticides Tier II: Review of Human Incidents.

D426573, D42673 November 24, 2015

Rodenticide: Tier I (Scoping) Review of

Human Incidents and Epidemiology

Assessment.

Attachments

1. Chemical Identity Table

2. Physicochemical Properties of Technical Grade Diphacinone Table

3. Use Profile Table for Diphacinone.

4. Endpoint Selection Tables

5. Toxicology Data Requirements

6. Toxicity Profile Tables
Page 11 of 32

Attachment 1

Chemical Identity Table

Table A.1: Diphacinone Nomenclature

Chemical structure

C23H16O

Common name Diphacinone 

Company experimental name

IUPAC name (2-(diphenylacetyl)indan-1,3-dione

CAS name (2-(diphenylacetyl)-1H-indene-1,3(2H)-dione

CAS registry number 82-66-6

Chemical structure of diphacinone 

sodium salt

C23H15NaO3

IUPAC name of Sodium Salt sodium;2-(2,2-diphenylacetyl)inden-2-ide-1,3-dione
Page 12 of 32

Attachment 2

Physicochemical Properties of Technical Grade Triticonazole Table

Table A.2: Physicochemical Properties of the Technical Grade Diphacinone

Parameter Value Reference

Melting point (°C) 146 oC; PAI displays two crystalline 

forms melting at 137 and 141 oC

The Pesticide properties Database: 

http://sitem.herts.ac.uk/aeru/iupac/i

ndex.htm

pH Not available

Density at 20 °C (g ml-1)/ 1.28 (g ml-1)

Water solubility (at 20 °C) (mg l-1) 0.3 at 20oC (mg l-1)

Solvent solubility (at 20°C) (mg l1

)

Solvent Solubility (g/L)

C4 - Acetone 

C4 - Ethanol 

C4 - Heptane 

C4 - Xylene

22900 

16800 

1224 

43000

Vapor pressure at 25°C 1.37 X 10-05 at 25oC (mPa)

Dissociation constant (pKa) Not available Note: Acidic 

Octanol/water partition coefficient 4.85 pH 7, 20oC Log P

UV/visible absorption spectrum Not available
Page 13 of 32

Attachment 3. Preliminary Use Profile Table for Diphacinone

Table A.3. Preliminary Use Profile Table for Diphacinone (PC 067701) and Sodium Salt (PC 067705)

Company

Formulation 

[EPA Reg. 

No.]

Percent 

ai

Formulation 

Type

Net 

Contents

Packaging

Target 

and Area

Tamper 

Resistant 

Bait 

Stations 

Application Rate PPE RUP Use Directions and Limitations

BELL 

LABORATO

RIES, INC 

3699 

KINSMAN 

BLVD 

MADISON 

WI 53704 

608/241-

0202

LIQUA-TOX 

II 

EPA 

Registration 

Number: 1245

5-61

0.106% 

(Dipha

cinone 

Sodium 

Salt)

Concentrate 

in Pouch

8 -50 

pouches 

containing 

1.68 fl. Oz 

pouches

Norway 

Rat, roof 

rat and 

house 

mice.

Yes

1.11E-04 lb ai/stations

with 50 stations

Rats: 16 oz. of diluted 

product in each stations.

Mice: 8 oz. of diluted 

product in each station

SL/G No

Do Not Use in Homes or Other 

Residential Settings For indoor use only 

inside of industrial, commercial, 

agricultural, and public buildings, and 

similar man-made structures. Do Not 

Use Outdoors or in sewers. Do not sell 

this product in individual containers 

holding less than 13.44 fl. oz. of bait 

concentrate. Mix 1.68 fl. oz. pouch in 1 

quart (32 fluid ounces) of water.

J.T. EATON 

& CO., INC. 

1393 E. 

HIGHLAND 

ROAD 

TWINSBU

RG OH 440

87 

800/321-

3421

BAIT BLOCK 

RODENTICID

E WITH 

PEANUT 

BUTTER 

FLAVORIZE

R 

EPA 

Registration 

Number: 56-42

0.005 

%

Bait Block

4 to 50 lbs

32 X 2 oz. 

to 400 X 2 

oz. Bait 

Blocks

Rats: 2 to 8 (2 oz.

blocks) or 4 to 16 oz.

with 15 to 30 feet 

intervals. 5.00E-05lb 

ai/station or 0.0025 lb 

ai/50 lb bag.

Mice: Break one 2 oz.

block into 3 pieces and 

place 1 or 2 pieces at 8 

to 10 feet intervals.

Use within 100 feet of man-made 

structures. Do not sell less than 4 

pounds of bait. Burrow baiting is 

prohibited. Do not use in sewer. Do not 

broadcast. Fence and perimeter baiting 

beyond 100 feet from structure is 

prohibited. APPLE BAIT 

BLOCK 

RODENTICID

E EPA 

Registration 

Number: 56-74

EATON'S 

ANSWER 

FOR THE 

CONTROL 

OF POCKET 

GOPHERS 

EPA 

Registration 

Number: 56-57

10, 12, 50 

lb.

Commercia

l Use

Gophers

No 

(below 

ground 

applicati

on)

Gopher: Probe 12 to 18 

inches from surface to 

mound and place one 

bait block at two or three 

location in each main 

burrow (runway) system.

Subterranean control of gophers in 

rangeland, cropland, (grain fields, 

forage corps, hay and alfalfa crops and 

vegetable crops), forest and non-crop 

areas including park, nurseries, and 

around homes. Do not apply this 

product above ground. Do not 

mechanically apply. 

1 pound

Intended 

for 

residential 

use
Page 14 of 32

Table A.3. Preliminary Use Profile Table for Diphacinone (PC 067701) and Sodium Salt (PC 067705)

Company

Formulation 

[EPA Reg. 

No.]

Percent 

ai

Formulation 

Type

Net 

Contents

Packaging

Target 

and Area

Tamper 

Resistant 

Bait 

Stations 

Application Rate PPE RUP Use Directions and Limitations

RECKITT 

BENCKISER 

LLC 

D/B/A 

RECKITT 

BENCKISER 

399 

INTERPACE 

PARKWAY 

PARSIPPA

NY NJ 0705

4 

973/404-

2716

D-CON BAIT 

STATION X 

EPA 

Registration 

Number: 3282-

98

0.005 

%

Prefilled 

disposable 

bait block 

stations

Prefilled 

disposable 

bait 

stations.

Block 

formulatio

n

Indoor 

Mouse 

Control

Yes

Remove the bait station 

from carton and place 

along wall or in corners. 

Place bait stations 8 to 

12 foot intervals.

For use to control house mice for 

indoors only Do not use outdoors or in 

areas accessible to pets and children. 

This is a not a refillable container

D-CON BAIT 

STATION IX 

EPA 

Registration 

Number: 3282-

99

D-CON BAIT 

STATION 

XIV 

EPA 

Registration 

Number: 3282-

100

Bait blocks

1 -2 

disposable 

bait 

stations 

with one 

1.0 oz. 

block. (1-

2) oz. (28 

g) per bait

Indoor 

and 

Outdoor 

Mouse

For use to control mice within 50 feet 

of homes accessible to children and pets 

indoors and outdoors. Do not apply 

where possibility of contaminating food 

or food surfaces.

D-CON BAIT 

STATION 

XIII 

EPA 

Registration 

Number: 3282-

101

D-CON BAIT 

STATION XI 

KILLS MICE 

EPA 

Registration 

Number: 3282-

102

1-2 

refillable 

bait station 

and 1-2 

refills 

(blocks) 

each 1.0 

oz. Block

D-CON BAIT 

STATION XII 

EPA 

Registration 

Number: 3282-

103
Page 15 of 32

Table A.3. Preliminary Use Profile Table for Diphacinone (PC 067701) and Sodium Salt (PC 067705)

Company

Formulation 

[EPA Reg. 

No.]

Percent 

ai

Formulation 

Type

Net 

Contents

Packaging

Target 

and Area

Tamper 

Resistant 

Bait 

Stations 

Application Rate PPE RUP Use Directions and Limitations

RCO 

INTERNATI

ONAL INC. 

D/B/A 

RCO INTL. 

INC. 

PO BOX 

191 

HARRISB

URG OR 97

446 

800/214-

2248

RCO MOLE & 

GOPHER 

PATROL 

BAIT 

EPA 

Registration 

Number: 5042-

331

0.005 

% Pelleted

Commercia

l size: 4-25 

lb

Moles and 

pocket 

around 

lawns, 

golf 

course, 

and other 

turf areas

No 

(below 

ground 

applicati

ons)

Moles: Deposit a 

teaspoon quantity about 

4 grams of bait through 

the hole. Bait each 

active subsurface at 10 -

15 foot intervals.

Gopher: Apply 1⁄2 cup of 

bait down enlarged hole. 

Make 2-3 application per 

active burrow system. 

Also can use a buried 

bait station with 1 lb SL/G

No

Do not apply bait above ground. Bait 

must be applied directly into mole and 

pocket gopher burrow system. Store out 

of reach of children and pets. Do not 

apply directly to water. Do not 

contaminate food or food surfaces. 

Residential

:

8 oz. and 

1lb

RCO 

PATROL 

BURROW 

BUILDER 

BAIT FOR 

MOLES & 

GOPHERS 

EPA 

Registration 

Number: 5042-

35

10-50 lb 

Manual App. 

Moles: 4 grams bait in 

top of runway.

Mechanical App.

Construct artificial 

burrows treat at 6-8 lb/A. 

or 4.0E-4 lb ai/acre

Yes

On lawns, golf courses, and sod farms 

in and bordering crop, rangeland fruit 

orchard, and non- crop areas. Do not 

apply bait above ground. Do use within 

prairie dog and active dens of San 

Joaquin Fox. Do not contaminate food 

or surfaces that come into contact with 

food. 

BELL 

LABORATO

RIES, INC 

3699 

KINSMAN 

BLVD 

MADISON 

WI 53704 

608/241-

0202

DITRAC 

ALLWEATHER 

CAKE 

EPA 

Registration 

Number: 1245

5-5 

0.005 

% Cake

4-50 lbs. 

Cake 

consists of 

1 lb slab 

scored into 

16 one oz. 

pieces.

Rats, 

mice, and 

meadow 

voles

Yes

Rats: 4 to 16 pieces of 

bait at 15 to 30 feet 

interval. Mice/Voles: one 

1 oz. piece per bait 

placement at 8 to 12 foot 

interval.

SL/G No

This product May Only be Used Inside 

and Within 100 Feet of Man-made 

Structures. Burrow baiting prohibited. 

Not permitted for use against the 

following species in California: Cotton 

rat, Eastern harvest mouse, Golden 

mouse, Polynesian rat, Meadow vole, 

White-throated woodrat, Southern 

plains woodrat, and Mexican woodrat

DIPHACINO

NE 

CONCENTRA

TE 

EPA 

Registration 

0.1 % Concentrate 25 lbs Rats and 

Mice

Only use to make formulated products in and around structures and inside transport vehicles 

(ships, trains, and aircraft).
Page 16 of 32

Table A.3. Preliminary Use Profile Table for Diphacinone (PC 067701) and Sodium Salt (PC 067705)

Company

Formulation 

[EPA Reg. 

No.]

Percent 

ai

Formulation 

Type

Net 

Contents

Packaging

Target 

and Area

Tamper 

Resistant 

Bait 

Stations 

Application Rate PPE RUP Use Directions and Limitations

Number: 

12455-9

DITRAC 

SUPER-SIZE 

BLOX 

EPA 

Registration 

Number: 1245

5-14 

0.005 

%. Bait block 4 -50 lbs.

Norway 

Rats, 

Roof 

Rats,

Yes

Use one bait block per 

placement. Space 

placements 15 to 30 feet 

apart in infested areas.

SL/G No

This product May Only be Used Inside 

and Within 100 Feet of Man-made 

Structures and sewers. Burrow baiting 

prohibited.

TECHNICAL 

DIPHACINO

NE 

EPA 

Registration 

Number: 1245

5-25 

99.3% Concentrate 1 lb.

Only for formulation into registered products in and around homes, industrial and agricultural 

buildings, similar man-made structures; inside transport vehicles (ships, trains, aircraft), in 

and around related port or terminal buildings, and in alleys located in urban areas.

DITRAC 

TRACKING 

POWDER 

EPA 

Registration 

Number: 1245

5-56

0.2 % Powder 6 – 25 lb No

Sprinkle 1⁄2 oz. (3 

teaspoons) of powder in 

patches 12 inches long 

and 6 inches wide. 

6.25E-05 lb ai/patch

Burrows place 5 grams 

of tracking powder in 

each burrow with pump 

duster.

SL/G Yes

For use indoors and in burrows leading 

indoors. DITRAC TRACKING 

POWDER must be placed in locations 

inaccessible to children, pets, domestic 

animals, or wildlife.

DITRAC 

ALLWEATHER 

BLOX 

EPA 

Registration 

Number: 1245

5-80 

0.005 

% 

Bait Block

4 lb (64 x 1 

ox bait 

block) to 

50 lb (800 

x 1 oz. bait 

block)

Rats, 

Mice, and 

Meadow 

Voles.

Yes

Rats: Apply 3 to 16 

ounces. Place 15 to 30 

feet for 10 days.

Baiting sewers: Use 3 to 

16 blocks per manhole.

Mice and Meadow 

Voles: Apply 1 block per 

infested area at 8-12 foot 

intervals.

SL/G No

This Product May Only be Used Inside 

and Within 100 Feet of Man-Made 

Structures. Not permitted for use 

against the following species in 

California: Cotton rat, Eastern harvest 

mouse, Golden mouse, Polynesian rat, 

Meadow vole, White-throated woodrat, 

Southern plains woodrat, and Mexican 

woodrat. Burrow baiting with Ditrac. 

Do not broadcast. 

DITRAC 

RODENTICID

E 

Pelleted 4-50 lb

RATS: Apply 4 to 16 oz. 

of bait (usually at 

intervals of 15 to 30 feet) 
Page 17 of 32

Table A.3. Preliminary Use Profile Table for Diphacinone (PC 067701) and Sodium Salt (PC 067705)

Company

Formulation 

[EPA Reg. 

No.]

Percent 

ai

Formulation 

Type

Net 

Contents

Packaging

Target 

and Area

Tamper 

Resistant 

Bait 

Stations 

Application Rate PPE RUP Use Directions and Limitations

EPA 

Registration 

Number: 1245

5-81 

per placement in infested 

areas. 5.00E-05lb 

ai/station or 0.0025 lb 

ai/50 lb bag.

MICE: Apply 1/4 to 1/2 

oz. (1 to 2 level 

tablespoons) of bait at 8 

to 12 foot intervals in 

infested areas. (Up to 2 

oz.).

DITRAC 

RODENTICID

E PLACE 

PAC 

EPA 

Registration

Number: 1245

5-83

Sachet 

(packets)

4 lb (22 x 3 

oz. place 

pacs) to 50 

lb (267 X 3 

oz. place 

pacs)

Rats and 

Mice

Rats: Place 1 to 5 place 

packs (3 to 15 oz.) at 15 

to 30 foot intervals.

Mice: 1⁄4 to 1⁄2 oz. (1-3 

level tablespoons) of bait 

at 8 to 12 foot intervals.

SL/G No

This Product May Only be Used Inside 

and Within 100 Feet of Man-Made 

Structure. Burrow baiting prohibited. 

Do not broadcast bait. Do not sell this 

product holding less than 4 pounds of 

bait. 

TOMCAT 

MOUSE 

KILLER VI 

EPA 

Registration 

Number: 1245

5-119

0.005 

% Bait Block

4 oz.

(112g) 4 x 

1 block 

bait & 

refillable 

bait station

Mice

Yes

Mice: One block bait in 

one bait station. Place 

bait station s 8 to 12 foot 

interval and maintain for 

15 days.

SL/G No

For use indoors and outdoors. This bait 

station may be used in an around 

(within 50 feet of) manmade structures. 

For control of house mice only. This 

bait station can only be refilled with the 

block bait sold with this station. 

TOMCAT 

MOUSE 

KILLER V 

EPA 

Registration 

Number: 1245

5-126

1 

disposable 

bait station 

1 x 1 oz. 

(28 g) bait 

block. Up 

to 16 

disposable 

bait 

stations 

containing 

12 X 1 oz. 

(28 g ) bait 

blocks

TOMCAT 

MOUSE 

KILLER VII 

EPA 

Registration 

Number: 1245

5-127

House 

Mice For use indoors only.
Page 18 of 32

Table A.3. Preliminary Use Profile Table for Diphacinone (PC 067701) and Sodium Salt (PC 067705)

Company

Formulation 

[EPA Reg. 

No.]

Percent 

ai

Formulation 

Type

Net 

Contents

Packaging

Target 

and Area

Tamper 

Resistant 

Bait 

Stations 

Application Rate PPE RUP Use Directions and Limitations

TOMCAT 

MOUSE 

KILLER IX 

EPA 

Registration 

Number: 1245

5-128

No

TOMCAT 

MOUSE 

KILLER VIII 

EPA 

Registration 

Number: 1245

5-130

0.005 

%i

4 oz.

(112g) 4 x 

1 oz. block 

bait & bait 

station – 16 

oz. (454g) 

16 x 1 

block bait 

& refillable 

bait station.

Yes

PCQ Rodent 

Bait 

EPA 

Registration 

Number: 1245

5-136

Pelleted. 4 to 50 lbs.

Norway 

rats, roof 

rats, and 

house 

mice 

Yes

Rats: Place 4 to 16 oz. at

15 to 30 foot intervals 

and maintain for 10 

days. 4.0E-04 lb ai/patch

Mice: Open pac and 

apply 1⁄4 to 1⁄2 oz. (1-3 

level tablespoons) of bait 

at 8 to 12 foot intervals 

infested areas.1.56 E-06 

lb ai/patch

SL/G Yes

Use within 100 feet of man-made 

structures. Do not sell this product in 

individual containers holding less than 

4 pounds of bait. 

Commerc

ial 

Nurseries: 

Meadow 

and Pine 

Voles

No

Hand Baiting: l/2 oz. (2 

tablespoons) into each 

tree site (10 lb product 

per acre). 5.0E-04 lb 

ai/acre or 1.56E-05 lb 

ai/patch

BAIT STATIONS: Place 

2 Ib. bait station 

GROUND BROADCAST 

Hand and Spreader: 

Apply 10 Ib. per acre. 

For pine vole application 

For control of meadow and pine voles 

in commercial nurseries in the 

following states: Georgia, Michigan, 

Missouri, North Carolina, and South 

Carolina. Do not apply by aerial 

application. Do not apply this product 

in a way that will contact workers or 

other persons, either directly or through 

drift.
Page 19 of 32

Table A.3. Preliminary Use Profile Table for Diphacinone (PC 067701) and Sodium Salt (PC 067705)

Company

Formulation 

[EPA Reg. 

No.]

Percent 

ai

Formulation 

Type

Net 

Contents

Packaging

Target 

and Area

Tamper 

Resistant 

Bait 

Stations 

Application Rate PPE RUP Use Directions and Limitations

in states east of the 

Mississippi River, a rate 

of 20 Ib. per acre may be 

required.

1.0E-03 lb ai/acre

Commerc

ial Fruit 

Trees 

Orchards 

(Dormant

) Voles 

Yes/No

HAND BAITING: Place 

l/2 oz. (2 tablespoons) at 

each tree site (10 lb. per 

acre). 

BAIT STATIONS: Place 

2 Ib. of bait in a tamperresistant bait station in 

areas frequented by 

voles (near surface trails 

and burrows).

GROUND 

BROADCAST: Apply 10 

lb. per acre. 5.0E-04 lb 

ai/acre

Do not graze animals in treated areas. 

For use in Connecticut, Georgia, 

Idaho/aerial, Massachusetts, 

Michigan/aerial, Missouri, 

Montana/aerial, North

Carolina, New Hampshire, Ohio 

(aerial), Oregon/aerial, 

Pennsylvania/aerial, South Carolina, 

Utah/aerial, Virginia/aerial, 

Vermont/aerial, Washington/aerial, and 

West Virginia/aerial.

Tomcat 

Ground 

Squirrel Bait 

EPA 

Registration 

Number: 1245

5-145

0.005 

% Pelleted 4 to 50 lb

California 

ground 

Squirrel

Yes

2 to 4 lb of bait per 

station.

2.0E-04 lb ai/1 station or 

0.01 lb ai/50 lb bag

No

This Product May Only be Used Within 

100 Feet of Man-made Structures to

Control California Ground Squirrels

WILCO 

DISTRIBUT

ORS, INC. 

PO BOX 

291 

LOMPOC 

CA 93438 

805/735-

2476

GROUND 

SQUIRREL 

BAIT BY 

WILCO AG 

EPA 

Registration 

Number: 3602

9-17

0.005 

% Pelleted

20 lbs and 

40 lbs.

California 

Ground 

Squirrel

Yes

2 to 4 lbs of bait per 

station.

2.0E-04 lb ai/1 station

Yes

For use in building in non-crop areas, 

along fence lines. In rangeland and 

pasture land and in crop areas such as 

orchards.

GROUND 

SQUIRREL 

BAIT BY 

WILCO 

EPA 

4 lbs No For use around building including 

yards, and flower beds. 
Page 20 of 32

Table A.3. Preliminary Use Profile Table for Diphacinone (PC 067701) and Sodium Salt (PC 067705)

Company

Formulation 

[EPA Reg. 

No.]

Percent 

ai

Formulation 

Type

Net 

Contents

Packaging

Target 

and Area

Tamper 

Resistant 

Bait 

Stations 

Application Rate PPE RUP Use Directions and Limitations

Registration 

Number: 3602

9-20

GOPHER 

GETTER 

TYPE 2 AG 

BAIT BY 

WILCO 

EPA 

Registration 

Number:

36029-23

1-50 lb (1 

lb 

container) 

hand probe 

unit

Gophers

No 

(below 

ground 

applicati

on)

1 lb with 2-7 bait sets per 

burrow SL/G Yes

For control of pocket gophers in crop 

and non-crop areas. Subsoil application. 

GOPHER Do not broadcast.

GETTER 

TYPE 2 BAIT 

BY WILCO 

EPA 

Registration 

Number: 3602

9-24

25-50 lb

1⁄2 cup product/burrow. 

Make 2-3 applications 

per burrow system.

1.25E-05 lb ai/burrow or 

6.25 E-04 lb ai/50 bag

SL/G No

U.S. 

DEPARTME

NT OF 

AGRICULT

URE 

ANIMAL 

AND PLANT 

HEALTH 

INSPECTIO

N SERVI

4700 

RIVER 

ROAD, 

UNIT 149 

RIVERDA

LE MD 207

37 

DIPHACINO

NE-50: 

CONSERVAT

ION 

PELLETED 

RODENTICID

E BAIT FOR 

CONSERVAT

IO

EPA 

Registration 

Number: 5622

8-35

0.005 

%

Pelleted 20-50 lbs

Norway 

rats, roof 

rats, 

Polynesia

n rats, 

house 

mice

Yes

Rats: Apply 4 to 16 

ounces (113 to 454 

grams) of bail per 

placement at 5 to 50 

meters intervals.

Mice: Apply 7 to 14 

grams of bait per 

placement with 2 to 4 

meters intervals. 5.0E-05 

lb ai/station

SL/G Yes

For retail sale only to: USDA Animal 

and Plant Health Inspection Service 

Wildlife Services, U.S. Fish and 

Wildlife Service, and the U.S. National 

Park Service.

Burrow 

baiting

No 

(below 

ground 

applicati

on)

Rats: place 3 to 4 ounces 

(85 to 113 g) of bait 

inside each burrow 

entrance.

Mice: 0.25 ounces of 

bait in each active 

burrow.

Baits used in burrows may be applied in 

piles or in cloth or plastic bags.
Page 21 of 32

Table A.3. Preliminary Use Profile Table for Diphacinone (PC 067701) and Sodium Salt (PC 067705)

Company

Formulation 

[EPA Reg. 

No.]

Percent 

ai

Formulation 

Type

Net 

Contents

Packaging

Target 

and Area

Tamper 

Resistant 

Bait 

Stations 

Application Rate PPE RUP Use Directions and Limitations

301/851-

3885

Canopy 

Baiting No

4 to 7 ounces (113 g to 

200 g) of bait should be 

placed in a cloth or resealable plastic bag at 50 

meter intervals.

The bags should be knotted or 

otherwise sealed to avoid spillage and 

holes should be made in plastic bags to 

allow the bait odor to escape. Using 

long poles (or other devices) or by 

hand, bait filled bags should be placed 

in the canopy of trees or shrubs bait 

placement in the canopy of trees and 

shrubs):

Aerial and 

Ground 

broadcast

No

Broadcast bait pellets by 

helicopter or manually at 

a rate of 10 to 12.5 lbs. 

bait/acre. 6.25E-04 lb 

ai/acre. A single 

application may be, 

made at a rate no higher 

than 20.0 lbs bait 

per/acre. 1.03E-03 lb 

ai/acre

Broadcast applications are prohibited 

on vessels or in areas of human 

habitation. Aerial (helicopter) 

applications may not be made in winds 

higher than 35 mph (30 knots). Make a 

second broadcast application typically 5 

to 7 days after the first application, 

depending upon local weather 

conditions,

61282

HACCO, 

INC. 

110 

HOPKINS 

DRIVE 

RANDOLP

H WI 53956 

920/326-

5141

TECHNICAL 

DIPHACINO

NE EPA 

Registration 

Number: 6128

2-1

98.0% RODENTICIDE FOR FORMULATING USE ONLY. 110 pounds

DIPHACINO

NE 

TECHNICAL 

GRADE EPA 

Registration 

Number: 6128

2-5

98.6%

A Rodenticide only for Formulation into Registered Products. Mixers must wear coveralls worn over short-sleeved shirt and short 

pants, chemical-resistant footwear, socks, a dust/mist filtering respirator (MSHA/NIOSH approval number prefix TC-21C), protective 

eyewear, and waterproof gloves. 1 -50 pounds

PROMAR 

BAIT PACKS 

EPA 

Registration 

Number: 6128

2-6

0.005 

%

Pelleted 

readymade 

Bait Packs

4-60 lbs Rat and 

Mouse Yes

RATS: Apply 2-8 bait 

packs and at intervals of 

15 to 30 feet in infested 

areas.

MICE: Open bait pack 

and apply 1⁄4 to 1⁄2 ounces 

SL/G NO

This product may only be used inside 

and within 100 feet of buildings or 

inside of transport vehicles (ships, 

trains, or aircraft). This Product May 

Not Be Sold in Packaging that Holds 

Less Than 4 Pounds of Bait. Each bait 
Page 22 of 32

Table A.3. Preliminary Use Profile Table for Diphacinone (PC 067701) and Sodium Salt (PC 067705)

Company

Formulation 

[EPA Reg. 

No.]

Percent 

ai

Formulation 

Type

Net 

Contents

Packaging

Target 

and Area

Tamper 

Resistant 

Bait 

Stations 

Application Rate PPE RUP Use Directions and Limitations

RAT AND 

MOUSE 

KILLER BAIT 

PACK 

EPA 

Registration 

Number: 6128

2-9

0.005 

%

(1-2 level tablespoons) 

of bait at each at 8- to 

12-foot intervals.

pack is 2 ounces. Burrow baiting is 

prohibited

PROMAR 

BLOX ALLWEATHER 

RODENTICID

E 

EPA 

Registration 

Number: 6128

2-12

0.005 

% a.i.

12 oz. block 

scored or 16 

oz. block 

scored

4-36 lbs Yes

RATS: Apply 4 to 16 

one-ounce Promar® 

Blox at intervals of 15 to 

30 feet in infested areas. 

Or 5.0 E-05 lb ai/patch

MICE: Break Promar® 

Blox into discrete 1-

ounce pieces. Apply one 

1-2 ounce piece at 8- to 

12-foot intervals. 

This product may only be used inside

and within 100 feet of buildings or

inside of transport vehicles (ships,

trains, or aircraft). This Product May 

Not Be Sold in Packaging that Holds 

Less Than 4 Pounds of Bait. Burrow 

baiting is prohibited.

PROZAP 

MOUSE 

MAZE KILLS 

MICE 

EPA 

Registration 

Number: 6128

2-191

0.005 

% a.i.

1 ounce of 

bait per 

station

2 -4 bait 

preloaded 

bait 

stations

Indoor 

Mice

No (not 

tamper 

resistant)

MICE: Place a single 

unit at each placement 

location at 8 to 12 foot 

intervals

SL/G No Use indoors only in areas inaccessible 

to children and pets.

RAMIK 

GREEN MINI 

BAIT PACKS 

EPA 

Registration 

Number: 6128

2-23

Bait packs

each with 

1.5 ounce of 

bait

4.2 – 37.5 

lbs

Mice and 

Rats 

Indoors 

and 

Outdoors

Yes

RATS: Place 2 to 8 bait 

packs per placement at 

intervals of 15 to 30 feet.

MICE: Open package 

and apply 1⁄4 to 1⁄2 ounces 

(1-2 level tablespoons) 

of bait at each placement 

at 8- to 12-foot intervals. 

Larger placements (up to 

2 ounces) may be needed 

at points of very high 

house mouse activity. 

6.25E-06 lb ai/patch

SL/G No

This product may only be used inside 

and within 100 feet of buildings or 

inside of transport vehicles (ships,

trains, or aircraft). Not be sold in 

packaging less than 4 lbs of bait. 

Burrow baiting is prohibited.
Page 23 of 32

Table A.3. Preliminary Use Profile Table for Diphacinone (PC 067701) and Sodium Salt (PC 067705)

Company

Formulation 

[EPA Reg. 

No.]

Percent 

ai

Formulation 

Type

Net 

Contents

Packaging

Target 

and Area

Tamper 

Resistant 

Bait 

Stations 

Application Rate PPE RUP Use Directions and Limitations

RAMIK 

OATS KILLS 

GROUND 

SQUIRRELS 

EPA 

Registration 

Number: 6128

2-24

0.005 

% a.i.

Grain bait 4-30 lbs

California 

Ground 

squirrels

Use 2 to 4 pounds of bait 

per station or 2.0E-04 lb 

ai/station

SL/G

.

Yes

This anticoagulant bait may only be 

used to control California ground 

squirrels in secured bait-station 

applications in or near levee or ditch 

banks, around farm buildings, along 

fence lines, in orchards, in or near 

crops, and in non-crop areas. Do not 

broadcast this bait, or apply it directly 

to food or feed crops.

RAMIK MINI 

BARS ALLWEATHER 

RAT AND 

MOUSE 

KILLER 

EPA 

Registration 

Number: 6128

2-26

Bait block

4-60 lbs

Rat and 

Mouse

Yes

Rats: Apply 4 to 16 oneounce Ramik Mini Bars 

per placement at 15 to 30 

feet

Mice: Place one 1-ounce 

Ramik Mini Bar at 8- to 

12-foot intervals.

SL/G No

This product may only be used inside 

and within 100 feet of buildings or 

inside of transport vehicles (ships, 

trains, or aircraft). Not to be sold in less 

than 4 lbs of bait.

RAT AND 

MOUSE 

KILLER 

WITH 

DIPHACINO

NE 

EPA 

Registration 

Number: 6128

2-41

0.005 

% 

Pellets 

Ready 

Mixed

Yes

Rats: Place 4 to 16 

ounces of bait per 

placement. Space 

placements at intervals 

of 15 to 30 feet in 

infested areas.

5.26E-05 lb ai/bait 

station

Mice: Apply 1⁄4 to 2 

ounces (1-2 level 

tablespoons) of bait at 

each placement location 

at 8- to 12-foot intervals. 

SL/G No

DIPHACIN 

110 

CONCENTRA

TE 

RODENTICID

E 

EPA 

Registration 

Number: 6128

2-431

0.1 % Concentrate 1-50 lbs Yes

SL/G 

+ 

PF5 

loade

rs

Appl

icato

rs 

SL/G

No 

For commercial use only be used inside 

and within 100 feet of buildings or 

inside of transport vehicles (ships, 

trains, or aircraft). Thoroughly mix one 

part of concentrate with 19 parts (by 

weight) of suitable bait material (e g 

cereal grains, oils, and sweeteners) For 

example, the formula in pellet form has 

been tested and found acceptable For 

commercial use only. May also be used 
Page 24 of 32

Table A.3. Preliminary Use Profile Table for Diphacinone (PC 067701) and Sodium Salt (PC 067705)

Company

Formulation 

[EPA Reg. 

No.]

Percent 

ai

Formulation 

Type

Net 

Contents

Packaging

Target 

and Area

Tamper 

Resistant 

Bait 

Stations 

Application Rate PPE RUP Use Directions and Limitations

for burrow baiting. Do not broadcast 

bait.

DIPHACIN 

110-A 

CONCENTRA

TE 

RODENTICID

E 

EPA 

Registration 

Number: 6128

2-44

2.0 % 

Rodenticide only for formulation into registered products. Mixers must wear coveralls worn over short-sleeved shirt 

and short pants, chemical-resistant footwear, socks, a dust/mist filtering respirator (MSHA/NIOSH approval number 

prefix TC-21C), protective eyewear, and waterproof gloves The following uses: in and around buildings, inside 

transport vehicles, in sewers (Norway rat, roof rat, and house mouse), orchards; rangeland (bait stations or spot baiting 

around burrow entrances); crop land (hand, underground application or around burrow entrances); forestry plantations, 

and non-crop 

RAMIK 

BROWN 

EPA 

Registration 

Number: 6128

2-45

0.005% Pelleted 10-50 lbs

Rats and 

Mice in 

Fruit Tree 

and Nut 

Orchards, 

Christmas 

Tree 

Farms, 

Tree 

plantation

s, and 

Commerc

ial 

nurseries 

for Voles

No

Inside burrows:

Rats: Place 4 to 16 oz. of 

bait per placement at 15-

to 30-foot intervals.

House Mice: Apply 1⁄4 to 

2 oz. (1-2 level 

tablespoons) of bait at 8-

to 12-foot intervals. 

SL/G Yes

For orchard aerial application only in 

those states specified in label. Apply 

after fall harvest and before new spring 

growth. Do not use hay cut after 

application and do not graze animals in 

treated areas. For ground applications 

use a commercially-made seed or 

fertilizer spreader. Uniformly apply 20 

lb of bait per acre for

Orchard: Hand spot 

baiting; 1 1⁄2 oz. of 

product in each vole hole 

or 4.7E-06 lb ai/patch.

Ground and Aerial 

Broadcasting: 20 lb 

product/A for Pine vole 

or 1.0E-03 lb ai/acre and 

10 lb product/acre for 

Meadow Vole or 5.0E04 lb ai/acre

RAMIK 

GREEN 

EPA 

Registration 

0.005 

% Pelleted. 4-60 lbs Rats and mouse

Yes

Rats: 4 to 16 ounces of 

bait per placement at 15 

to 30 feet in infested 

SL/G No

This product may only be used inside 

and within 100 feet of buildings or 

inside of transort vehicles (ships, trains, 

or aircraft). Not to be sold in packaging 
Page 25 of 32

Table A.3. Preliminary Use Profile Table for Diphacinone (PC 067701) and Sodium Salt (PC 067705)

Company

Formulation 

[EPA Reg. 

No.]

Percent 

ai

Formulation 

Type

Net 

Contents

Packaging

Target 

and Area

Tamper 

Resistant 

Bait 

Stations 

Application Rate PPE RUP Use Directions and Limitations

Number: 6128

2-46 

areas. 5.0E-05 lb 

ai/patch

Mice: apply 1⁄4 to 2 

ounces of bait at 8 to 12 

foot intervals. 6.25E-06 

lb ai/patch

that holds less than 4 pounds of bait. 

Burrow baiting prohibited. 

PROMAR 

RAT & 

MOUSE 

KILLER 

EPA 

Registration 

Number: 6128

2-47 

This product may only be used inside 

and within 50 feet of buildings or inside 

of transort vehicles (ships, trains, or 

aircraft). Not to be sold in packaging 

that holds less than 4 pounds of bait.

RAMIK 

GREEN BAIT 

PACKS 

EPA 

Registration 

Number: 6128

2-48 

Bait pack of 

pelleted 

material

Rats: Place 1 to 4 bait 

packs per placement at 

15 to 30 feet interval.

Mice: Open the one bait 

pack and apply 1⁄4 to 2 

ounces (1-2 level 

tablespoons) of bait at 8-

to 12-foot intervals. 

6.25E-06 lb ai/patch

This product may only be used inside 

and within 100 feet of buildings or 

inside of transort vehicles (ships, trains, 

or aircraft). Not to be sold in packaging

that holds less than 4 pounds of bait. 

Burrow baiting prohibited.

RAMIK 

MOUSER RF 

KILLS MICE 

EPA 

Registration 

Number: 6128

2-57 0.005 

%

Cake Bait in 

Refillable 

Bait Station 

2 to 16 

ounce. 

Mini bar 

weighs 

28.3 grams.

Mice Yes 

Mice: Place one Mini 

Bar in the bait station.at 

8 to 12 foot internals.

SL/G No Use indoors only. 

RAMIK 

GREEN AG 

EPA 

Registration 

Number: 6128

2-63 

Pellet 4-60 lbs Rats and 

Mice Yes

Rats: 4 to 16 ounces of 

bait per placement at 15 

to 30 feet.

5.0E-05 lb ai/patch

Mice: apply 1⁄4 to 2 oz. of 

bait at 8 to 12 foot 

intervals

6.25E-06 lb ai/patch

SL/G

. 

No

This product may only be used inside 

and within 100 feet of buildings or 

inside of transort vehicles (ships, trains, 

or aircraft). Not to be sold in packaging 

that holds less than 4 pounds of bait. 

Burrow baiting prohibited.
Page 26 of 32

Table A.3. Preliminary Use Profile Table for Diphacinone (PC 067701) and Sodium Salt (PC 067705)

Company

Formulation 

[EPA Reg. 

No.]

Percent 

ai

Formulation 

Type

Net 

Contents

Packaging

Target 

and Area

Tamper 

Resistant 

Bait 

Stations 

Application Rate PPE RUP Use Directions and Limitations

SCIMETRI

CS, LTD. 

CORP0RATI

ON 

PO BOX 

1045 

WELLING

TON CO 80

549 

970/482-

1330

KAPUT 

FIELD 

RODENT 

BAIT B 

EPA 

Registration 

Number: 7250

0-11

0.0025 

%

Pelleted 5-50 lbs

Ground 

squirrels 

and their 

fleas 

No

Manually scatter 1⁄2 cup 

per burrow in an area no 

larger than 50 ft2 or 8 

feet in diameter. 

6.25E-06 lb ai/burrow

SL/G Yes 

Used to control California ground 

squirrels in parks, golf courses, fruit 

tree orchards (dormant season only), 

non-crop rights-of-way and non-crop 

areas and aid in the reduction of fleas 

ground squirrels. 

KAPUT-D 

BURROW 

BUILDER 

POCKET 

GOPHER 

BAIT 

EPA 

Registration 

Number: 7250

0-12

0.005 

%

Pellet 25-50 lbs Pocket 

Gopher

No (only 

below 

ground 

applicati

ons)

Mechanical applicator: 

6-8 lb of bait per acre

4.0E-04 lb ai/acer

For control only of [Kills only] Pocket 

Gophers (Geomys sp. and Thomomys 

sp.) in and bordering

crops (alfalfa, forage, hay, vegetables 

and grains); rangeland; orchards; and 

non-crop areas (forestry plantations, 

golf

courses and other turf areas, levee/ditch 

banks, nurseries, parks and around 

agricultural buildings).

KAPUT-D 

COMBO 

BAIT 

BLOCKS 

EPA 

Registration 

Number: 7250

0-18

0.005% Bait Blocks 4-50 lbs

Norway 

Rats, 

Roof 

Rats, 

House 

Mice and 

Fleas

Yes 

Rats: Apply 3 to 15 

blocks per bait 

placement at 15 to 30 

feet House Mice: 1 bait 

block per placement at 8 

to 12 feet in infested 

area.

SL/G

No

This product may be used only inside 

and within 50 feet of buildings or inside 

transport vehicles (ships, trains or 

aircraft).

KAPUT D 

PRAIRIE 

DOG BAIT 

EPA 

Registration 

Number: 7250

0-22

0.005% Grain Bait 5 to 2000 

lbs

Prairie 

Dogs on 

rangeland 

and 

adjacent 

non-crop 

areas

No (only 

undergro

und 

applicati

ons)

Application by Hand and 

mechanical bait 

placement: Apply 1⁄4 cup 

of bait (approx. 2 ounces 

or 56 grams) at least 6 

inches down prairie dog 

burrows. 

6.25E-06 lb ai/station

Yes

This product may only be used in 

underground applications. Do not apply 

bait at or above ground level. Treat only 

active burrows. Apply between October 

1 and March 15 of the following year, 

when animals will most readily take the 

grain bait. Do not allow livestock to 

graze in treated areas for 14 days after 

treatment and when no bait is found 

above ground.

DIPHACINO

NE 

TECHNICAL 

98.8% Concentrate 5 to 200 lbs 

Only for formulation into a rodenticide for use in and around buildings, inside transport vehicles, in 

sewers (Norway rat, roof rat and house mouse); in pome fruits, stone fruit, nurseries, forestry plantations, 

rangeland and selected non-crop sites.
Page 27 of 32

Table A.3. Preliminary Use Profile Table for Diphacinone (PC 067701) and Sodium Salt (PC 067705)

Company

Formulation 

[EPA Reg. 

No.]

Percent 

ai

Formulation 

Type

Net 

Contents

Packaging

Target 

and Area

Tamper 

Resistant 

Bait 

Stations 

Application Rate PPE RUP Use Directions and Limitations

EPA 

Registration 

Number: 7250

0-23

KAPUT 

GROUND 

SQUIRREL 

BAIT 

EPA 

Registration 

Number: 7250

0-24

0.0025

%

Grain Bait

4- 50 lbs

California 

Ground 

Squirrel

Yes 

2- 4 lbs of bait per 

station at 20 to 100 feet 

apart.

1.0E-04 lb ai/station

SL/G No

This product may be used only inside 

and within 100 feet of buildings or 

inside transport vehicles (ships, trains 

or aircraft). Do not broadcast. Do not 

sell this product in individual containers 

holding less than 4 lbs.

KAPUT-D 

POCKET 

GOPHER 

BAIT 

EPA 

Registration 

Number: 7250

0-9

0.005 

%

1-50 lbs Pocket 

gophers 

No (only 

below 

ground 

applicati

ons) 

1/2 cup of Kaput bait 

into the burrow. If using 

the Sub-Station place 1 

lb. of product

5.0E-05 lb ai/burrow

For use in and bordering crops (alfalfa, 

forage, hay, vegetable and grains0 

rangeland, orchards, and non-crop areas 

( forestry plantations, golf courses, 

lawns, parks). Make 2-3 manual 

applications per burrow system. Using a 

long-handled teaspoon, remove the plug 

from the mound
Page 28 of 32

Attachment 4. Endpoint Selection Table

Table A.4: Summary of Toxicological Doses & Endpoints for Diphacinone Occupational Human Health Risk 

Assessment

Exposure Scenario

Point of 

Departure 

(POD)

Uncertainty / 

FQPA Safety 

Factors

Level of Concern 

for Risk 

Assessment

Study and Toxicological Effects

Dermal Short Term 

(1-30 days)and 

Intermediate Term 

(1-6 months)

Maternal 

NOAEL = 0.10

mg/kg/day

UFA = 10x

UFH = 10x

Occupational LOC 

for MOE = 100

21-day Dermal Study in Rabbits

Maternal LOAEL = 50 

mg/kg/day

Based on clinical signs 

consistent with anti-coagulant 

effects at the LOAEL of 1 

mg/kg/da.

Inhalation Short 

Term (1-30 

days)and 

Intermediate Term 

(1-6 months)

NOAEL = 

0.085

mg/kg/day

UFA = 10x

UFH = 10x

FQPA SF = 

1X

Occupational LOC 

for MOE = 100

14-day Oral Study in SD rats

LOAEL = 0.175 mg/kg/day

Based on decreased prothrombin 

and activated partial 

thromboplastin times following 

repeated exposure. No routespecific study was available.

Cancer (dermal and 

inhalation)

N/A

Point of Departure (POD) = A data point or an estimated point that is derived from observed dose-response data and used to mark 

the beginning of extrapolation to determine risk associated with lower environmentally relevant human exposures. NOAEL = no 

observed adverse effect level. LOAEL = lowest observed adverse effect level. UF = uncertainty factor. UFA = extrapolation from 

animal to human (interspecies). UFH = potential variation in sensitivity among members of the human population (intraspecies).

FQPA SF = FQPA Safety Factor. MOE = margin of exposure. LOC = level of concern. N/A = not applicable.
Page 29 of 32

Attachment 5. Toxicology Data Requirements

The requirements (40 CFR 158.500) for non-food uses are in the table below. Use of the new 

guideline numbers does not imply that the new (1998) guideline protocols were used.

Table A.5: Toxicology Data Requirements for Diphacinone

Guideline Study Type Required Submitted Satisfied

870.1100 Acute Oral Toxicity Yes Yes Yes

870.1200 Acute Dermal Toxicity Yes Yes Yes

870.1300 Acute Inhalation Toxicity Yes Yes Yes

870.2400 Acute Eye Irritation Yes Yes Yes

870.2500 Acute Dermal Irritation Yes Yes Yes

870.2600 Skin Sensitization Yes Yes Yes

870.3100 90-Day Oral Toxicity in Rodents Yes Yes Yes

870.3150 90-Day Oral Toxicity in Non-Rodents CR No NA

870.3200 21/28-Day Dermal Toxicity NR No NA

870.3250 90-Day Dermal Toxicity Yes Yes Yes

870.3465 90-Day Inhalation Toxicity CR No Yesb

870.3700

Prenatal Developmental Toxicity Study (Rat) Yes Yes Yes

Prenatal Developmental Toxicity Study (Rabbit) Yes No Yesb

870.3800 Reproduction and Fertility Effects Yes No Yesb

870.4100 Chronic Toxicity (Rodent) CR No NA

870.4200

Carcinogenicity (Rat) CR No NA

Carcinogenicity (Mouse) CR No NA

870.5100 Bacterial Reverse Mutation Test Yes Yes Yes

870.5300

870.5375

in vitro Mammalian Cell Gene Mutation Test

in vitro Mammalian Chromosome Aberration Test Yesa YesYes Yes

870.5385

870.5395

Mammalian Bone Marrow Chromosomal Aberration Test

Mammalian Erythrocyte Micronucleus Test Yesa NoYes Yes

870.6100

Delayed Neurotoxicity of Organophosphorus Substances (Acute, Hen) CR No NA

Delayed Neurotoxicity of Organophosphorus Substances (28-Day, Hen) CR No NA

870.6200

Neurotoxicity Screening Battery (Acute, Rat) Yes No Yesb

Neurotoxicity Screening Battery (90-Day, Rat) Yes No Yesb

870.6300 Developmental Neurotoxicity Study CR No NA

870.7200 Companion Animal Safety CR No NA

870.7485 Metabolism and Pharmacokinetics Yes Yes Yes

870.7600 Dermal Penetration CR No NA

870.7800 Immunotoxicity Yes No Yesb

CR = Conditionally Required. NA = Not Applicable.

a Either guideline study type may be used to satisfy the data requirement (e.g. 870.5300 or 870.5375).

b Study not required (U. HabibaTXR0057326, 12/15/2015).
Page 30 of 32

Attachment 6. Toxicity Profile for Diphacinone

Table A.6.1: Acute Toxicity of Diphacinone Technical

Guideline 

No. Study Type MRID No. Species Results Toxicity Category

870.1100 Acute Oral 

Toxicity 00060605 Rat

LD50 (M) = 2.5 (1.32-3.44) mg/kg

LD50 (F) = 2.1 (1.55-2.86) mg/kg

combined = 2.3 (1.86-2.88) mg/kg

I

870.1100 Oral 42245202 Rat

LD50 (M) = 6.8 mg/kg

LD50 (F) = 8.0 mg/kg

combined = 7.0 (5.2-9.5)

mg/kg

I

870.1200 Acute Dermal 

Toxicity 42507001 Rabbit LD50 (M) = 3.6 (0.6-20.8) mg/kg

LD50 (F) = not done

I

870.1300

Acute 

Inhalation 

Toxicity

43000401 Rat LC50 (M) < 0.6 μg/L

LC50 (F) < 0.6 μg/L

I

870.2400 Acute Eye 

Irritation 42245203 Rabbit Moderate irritation clearing by day 4 III

870.2500 Acute Dermal 

Irritation Unknown Rabbit Slight erythema clearing within 48 hours, but 4/6 rabbits died between days 8 and 10. IV

870.2600 Dermal 

Sensitization 42132501 Guinea Pig

Neither a dermal irritant nor a sensitizer at a 

non-lethal dose level (2.5 mg/day) N/A
Page 31 of 32

Table A.6.2: Toxicity Profile of Diphacinone Technical

Guideline Study Type MRID (year) / Doses / Classification Results

870.3100

14-Day Oral 

Toxicity in 

Rodents 

(Rat)

43260701

Single Dose

0.13, 0.20, 1.00 and 2.50 mg/kg/day

Repeat Dose

0.025, 0.040, 0.085, and 0.175 

Acceptable/non-guideline

Single Dose

NOAEL = 0.13 mg/kg/day

LOAEL = 0.20 mg/kg/day based on increased 

PT and APTT.

Repeat Dose

NOAEL = 0.085 mg/kg/day

LOAEL = 0.175 mg/kg/day based on 

increased PT and APTT. 

870.3100

21-Day Oral 

Toxicity in 

Rodents

(Mouse)

00077319

0.1, 0.5, 1.0, 2.5, 5, 10 and 20 

mg/kg/day

Unacceptable/non-guideline

NOAEL = 0.5 mg/kg/day

LOAEL = 1 mg/kg/day based on 

hemorrhages & external bleeding

Clotting factors were not evaluated.

870.3200

21/28-Day

Dermal Toxicity

(Rabbit)

00074637

0, 0.1, 10 mg/kg/day

Acceptable/non-guideline

NOAEL = 0.1 mg/kg/day

LOAEL = 1 mg/kg/day based on hemorrhagic 

lesions in tissues/organs. 

Clotting factors were not evaluated.

870.3465

90-Day 

Inhalation 

Toxicity

Not required by HASPOC

870.3700

Prenatal 

Developmental 

Toxicity Study

(Rat)

42834801

0, 0.010, 0.025, 0.075 mg/kg/day

NOEL = 0.025

LOEL = 0.075 mg/kg/day

Based on clinical signs consistent with anticoagulant activity (reddish urogenital staining 

and reddish fluid in cage). Clotting factors 

were not evaluated. No effects were reported 

on body weights, food consumption or 

histopathology. 

Developmental NOEL = 0.075 mg/kg/day

Prenatal 

Developmental 

Toxicity Study

(Rabbit)

Not required by HASPOC

870.3800

Reproduction and 

Fertility Effects

(Rat)

Not required by HASPOC

870.5100

Bacterial 

Reverse 

Mutation Test

(Salmonella 

typhimurium)

42350901

TA98, 100, 1535, 1537 & 1538

5-500 μg/plate with and without S9

Negative 

870.5300

in vitro

Mammalian Cell 

Gene Mutation 

Test

42359901

CHO AS52

0.167 to 125 μg/ml

Negative
Page 32 of 32

Table A.6.2: Toxicity Profile of Diphacinone Technical

Guideline Study Type MRID (year) / Doses / Classification Results

870.5395

Mammalian 

Erythrocyte 

Micronucleus 

Test (Mouse)

42406801 Negative

870.6200

Acute 

Neurotoxicity 

Screening Battery

(Rat) Not Required by HASPOC 90-Day 

Neurotoxicity 

Screening Battery

(Rat)

870.7485

Metabolism and 

Pharmacokinetic

s (Rat)

92049009

SD Rats - 0.18, 0.4, 0.5, 1 mg/kg

Norwegian Rats – 3.5 mg/kg 

Swiss Albino Mice – 0.6 mg/kg

Absorption appeared reaching peak 

concentration at 4 hours after administration. 

Distribution data showed that the liver, 

muscle, blood, fat, and lung were the tissues 

demonstrating the greatest retention of the 

test chemical in the order liver (14 25% of the 

dose), muscle (0.18 4.4% of the dose), fat 

(0.55 1.16% of the dose), and lung (0.04 

0.5% of the dose). A half-life of 17 hours was 

estimated. Elimination of diphacinone 

derived radioactivity was primarily in feces, 

with between 47-77% of the dose in feces of 

rats, and 69-73% of the dose in mice. At 

least five metabolites of diphacinone were 

identified in urine, feces, and/or liver. These 

metabolites represent hydroxylated products 

of diphacinone occurring on the phenyl and 

indandionyl rings.

870.7800 Immunotoxicity

(Rat) Waived by HASPOC