UNITED ST A TES ENVIRONMENT AL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

MEMORANDUM 

December I 5, 20 I 5 

OFFICE OF CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

SUBJECT: Rodenticides: Summary of Hazard and Science Policy Council (HASPOC) 

Meeting on October 1, 2015: Recommendations on Data Requirements for 

Rodenticides. 

PC Codes: See Table below 

Decision No.: NIA 

Petition No.: NI A 

Risk Assessment Type: NI A 

TXR No.: 0057326 

MRID No.: NIA 

FROM: Uma Habiba 

Executive Secretary, HASPOC 

Health Effects Division (7509P) 

THROUGH: Jeff Dawson, Co-Chair 

Jaime D' Agostino, PhD., C -

HASPOC 

Health Effects Division (7509P) 

TO: Matthew Crowley, Biologist 

Risk Assessment Branch II 

Chris Schlosser, Toxicologist 

Risk Assessment Branch VI 

Health Effects Division (7509P) 

MEETING ATTENDEES 

DP Barcode: NIA 

Registration No.: NIA 

Regulatory Action: NIA 

Case No.: NI A 

CAS No.: See below 

40 CFR: NIA 

HASPOC Members: Anna Lowit, Elissa Reaves, Elizabeth Mendez, Jaime D' Agostino, Jeff 

Dawson, John Kough, Jonathan Leshin, Matt Lloyd, Michael Metzger, P. V. Shah, Ray Kent, 

Sarah Gallagher, Uma Habiba 

Presenter: Barry O'Keefe, Christopher Schlosser, Matt Crowley, Vincent Chen 

Other Attendees: Anwar Dunbar, Bridget Bobowiec, Chris Olinger, Christina Swartz, Don 

Wilbur, Donna Davis, Laura Nollen, Monica Hawkins, Yung Yang 

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Page 2 of 10

I. PURPOSE OF MEETING 

Rodenticides are meant to kill or control mammalian species via their acute toxicity or other means 

such as a birth control agent. While they have differing chemistries (i.e., there are various active 

ingredients) their uses and the subsequent exposure patterns associated with these uses are similar 

such that data requirements can be evaluated in a consistent fashion across all rodenticide 

ingredients. This approach provides for workload efficiencies and ensures consistency for 

evaluating potential data requirements, which are summarized in the table at the end of the 

document. Therefore, the Hazard and Science Policy Council (HASPOC) met on October 1, 2015 

to determine a consistent framework for rodenticide data requirements. 

II. EXPOSURE FRAMEWORK 

This section outlines the process used for identifying the exposure scenarios required for the 

selection of endpoints for risk assessment. 

Dietary 

 All rodenticides are considered non-food uses. Therefore, no dietary exposure assessment 

will be conducted for residues on food. 

 If the rodenticide has broadcast uses (e.g., aerial applications over fields), a drinking 

water assessment might be applicable and a dietary exposure assessment for water only 

may be conducted. 

Non-dietary 

 Residential 

o Handler 

 If the rodenticide has loose formulations (e.g., granules, pellets, tracking 

powders) for consumer products, residential dermal and inhalation 

assessments will be conducted because exposure is anticipated during the 

application of such product (e.g., from generation of particulates resulting 

in dermal and inhalation exposure). Place packs, bait blocks, or sachets 

are examples of formulations for which a residential or occupational 

handler assessment would not be conducted because they prevent or 

significantly minimize exposures to those products. 

o Post-application 

 If bait stations are required in homes/residential areas, access to the 

product will be prevented and no residential post-application oral exposure 

assessment will be conducted. 

 No post-application dermal or inhalation exposure assessments will be 

conducted in situations where the types of formulations and use patterns 

prevent exposure and rodenticides are expected to be of low volatility. 

The following should also be considered: 

 If tracking powder formulations are available, a post-application 

oral assessment should be conducted because access to the product 

following its application might be possible. 
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 If the rodenticide is limited to underground uses only, access to the 

product will be prevented and no residential post-application oral 

exposure assessment will be conducted. 

 Occupational 

o Handler 

 If the rodenticide is formulated as a granule, pellet, tracking powder or 

other similar loose form (i.e., not in bait stations or other packaging which 

prevents exposure), occupational dermal and inhalation handler 

assessments will be conducted because exposure is anticipated during the 

application from generation of particulates. Place packs, bait blocks, or 

sachets in appropriate containers would be examples of formulations for 

which an occupational handler assessment would not be conducted. 

o Post-application 

 No post-application dermal or inhalation assessments will be conducted 

because the types of formulations are expected to be of low volatility and 

no significant contact with foliar or other surface residues are expected for 

workers to contact in areas previously treated with rodenticides. 

III. Toxicity Framework

This section outlines the process used for determining whether the database for a chemical 

contains appropriate studies for selection of endpoints for risk assessment. The categories 

presented below are based on the exposure conditions which were described in Section I. 

Negligible Overall Exposure - No occupational, residential or dietary exposures are anticipated 

(qualitative assessment) 

If no exposures are expected from the use patterns of these chemicals, the HASPOC 

recommends that no further studies be submitted to support registration review. However, if the 

use pattern were to change such that exposure is expected, then the Agency may revisit this 

conclusion. 

Occupational Exposure Only 

Based on the use pattern, only occupational handler exposures are expected. In this scenario no 

residential handler or post-application exposures are expected, nor are any dietary exposures 

expected. Therefore, based on a weight-of-evidence approach, the HASPOC recommends that 

the following studies are not required for this group of rodenticides: 

 870.3100, 90-Day oral rodent (conditionally required for non-food) 

 870.3150, 90-Day oral non-rodent (conditionally required for non-food) 

 870.7485, Metabolism and pharmacokinetics (conditionally required for non-food) 

Additionally, the available toxicity databases were evaluated and the HASPOC determined that 

the following studies were not required if they were not expected to provide a lower point of 
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departure (POD) for risk assessment (i.e., rodenticides with a well-established toxicity profile 

such as the 1st and 2nd generation anti-coagulants). Rationale for each rodenticide is provided in 

the summary table. 

 

 870.3700a, Prenatal developmental study in rat 

 870.3700b, Prenatal developmental study in rabbit 

 870.3800, Reproduction and fertility effects 

 870.6200a, Acute neurotoxicity 

 870.6200b, Subchronic neurotoxicity 

 870.7800, Immunotoxicity 

Furthermore, inhalation and dermal toxicity studies were not required by the HASPOC if an 

acceptable oral study, which properly addresses a chemical’s toxicity profile (i.e., correct 

duration of exposure and endpoints measured) was available and use of the oral study did not 

result in Margins of Exposure (MOE) above the Level of Concern (LOC), including a 10x 

database uncertainty factor when an oral study was used to predict toxicity derived from the 

inhalation route. Rationale for each rodenticide is provided in the summary table. 

A mutagenicity battery was required for all chemicals unless sufficient literature or structure 

activity relationship (SAR) data were available to characterize potential mutagenicity. 

Occupational, Residential and/or Dietary (drinking water) exposure 

For rodenticide chemicals with occupational handler and residential handler and/or postapplication exposure or dietary exposure via drinking water, a critical evaluation of the toxicity 

database was conducted. 

1. If the current database provided sufficient information to characterize the oral toxicity of 

the chemical, the HASPOC determined that the following studies were not required: 

o 870.3100, 90-Day oral rodent (conditionally required for non-food) 

o 870.3150, 90-Day oral non-rodent (conditionally required for non-food) 

o 870.7485, Metabolism and pharmacokinetics (conditionally required for nonfood) 

2. Additionally, the HASPOC determined that the following studies were not required if 

they were not expected to provide a lower POD for risk assessment (e.g., rodenticides 

that have a well-established toxicity profile such as the 1st and 2nd generation anticoagulants). Rationale for each rodenticide is provided in the summary table. 

 

o 870.3700a, Prenatal developmental study in rat 

o 870.3700b, Prenatal developmental study in rabbit 

o 870.3800, Reproduction and fertility effects 

o 870.6200a, Acute neurotoxicity 

o 870.6200b, Subchronic neurotoxicity 
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o 870.7800, Immunotoxicity 

Furthermore, inhalation and dermal toxicity studies were not required by the HASPOC if an 

acceptable oral study was available and use of the oral study did not result in MOEs above the 

LOC, including a 10x database uncertainty factor when an oral study was used to predict toxicity 

derived from the inhalation route. Rationale for each rodenticide is provided in the summary 

table. 

A mutagenicity battery was required for all chemicals unless sufficient literature or SAR data 

were available to characterize potential mutagenicity. 

A final summary outlining the HASPOC’s decisions for each rodenticide and data requirements 

are shown in the table below.
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Rodenticide Anticipated Quantitative Exposure Assessments Missing Studies Data Required? RaAlpha-chlorohydrin1

(PC code: 117101) None 

870.1100, Acute oral toxicity in rat 

No 

Nebaspatbaires

870.1200, Acute dermal toxicity 870.1300, Acute inhalation toxicity in rat 870.2400, Primary eye irritation in rabbit 870.2500, Primary dermal irritation 870.2600, Dermal sensitization 870.3100, 90-Day oral rodent 870.3150, 90-Day oral non-rodent 870.3200, 90-Day dermal 870.3465, 90-Day inhalation- rat 870.3700a, Prenatal developmental study in rat 870.3700b, Prenatal developmental study in rabbit 870.3800, Reproduction and fertility effects 870.5100, Bacterial reverse mutation assay 870.5300 and 870.5375, In vitromammalian cell assay 870.5385 and 870.5395, In vivocytogenetics 870.6200a, Acute neurotoxicity 870.6200b, Subchronic neurotoxicity 

1 Previously reviewed by HASPOC (U.Habiba 9/29/15; TXR #0057207) 
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870.7485, Metabolism and pharmacokinetics 870.7600, Dermal penetration 870.7800, Immunotoxicity 

Contrapest2

(PC Codes: 081700 and 081800) 

None 

870.1100, Acute oral toxicity in rat 

No 

Nebaspatbaires

870.1200, Acute dermal toxicity 870.1300, Acute inhalation toxicity in rat 870.2400, Primary eye irritation in rabbit 870.2500, Primary dermal irritation 870.2600, Dermal sensitization 870.3100, 90-Day oral in rodent 870.3150, 90-Day oral in non-rodent 870.3200, 28-Day dermal 870.3465, 90-Day inhalation 870.3700a, Prenatal developmental study in rat 870.3700b, Prenatal developmental study in rabbit 

2 Previously reviewed by HASPOC (U.Habiba 8/19/14; TXR #0056988) 
Page 8 of 10

870.3800, Reproduction and fertility effects 870.4200b, Carcinogenicity study in mouse 870.4300, Chronic toxicity/carcinogenicity in rat (or 870.4100 and 870.4200 in rat) 870.5100, Bacterial reverse mutation assay 870.5300 and 870.5375, In vitromammalian cell assay 870.5385 and 870.5395, In vivocytogenetics 870.6200a, Acute neurotoxicity 870.6200b, Subchronic neurotoxicity 870.7485, Metabolism and pharmacokinetics 870.7800, Immunotoxicity 

Chlorophacinone (PC code: 067707) 

870.3100, 90-Day oral in rodent 

No 

Avadetoxquaass

870.3800, Reproduction and fertility effects 870.6200a, Acute neurotoxicity 870.6200b, Subchronic neurotoxicity 870.7800, Immunotoxicity 
Page 9 of 10

870.3465, 90-Day inhalation Yes 

Dutrainfavaare chainh

Diphacinone (PC code: 067701) 

-Occupational handler 

-Residential postapplication oral 

870.3700b, Prenatal developmental study in rabbit 

No 

Avadmadetoxquaass

870.3800, Reproduction and fertility effects 870.6200a, Acute neurotoxicity 870.6200b, Subchronic neurotoxicity 870.7800, Immunotoxicity 870.3465, 90-Day inhalation No 

UstoxMOrelexp

Warfarin (PC code: 086002) None 

870.1100, Acute oral toxicity in rats 870.1200, Acute dermal toxicity 870.1300, Acute inhalation toxicity in rats 870.2400, Primary eye irritation in rabbits 870.2500, Primary dermal irritation 870.2600, Dermal sensitization 870.3100 90-Day oral rodent 870.3150 90-Day oral non-rodent 870.3200, 90-Day dermal 

No 

NebaspatstatamstaIn synvitof of 
Page 10 of 10

870.3465 90-Day inhalation in rats 870.3700a, Prenatal developmental study in rats 870.3700b, Prenatal developmental study in rabbits 870.3800, Reproduction and fertility effects 870.5100, Bacterial reverse mutation assay 870.5300 and 870.5375, In vitromammalian cell assay 870.5385 and 870.5395, In vivocytogenetics 870.6200a, Acute neurotoxicity 870.6200b, Subchronic neurotoxicity 870.7485 Metabolism and pharmacokinetics 870.7600 Dermal penetration 870.7800, Immunotoxicity 

and anttrewitpromeand ovewe