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Fenpropimorph Registration Review Team

Human Health & Environmental Effects

David Bays

James Breithaupt

Patricia Jennings

Nathan Mottl

Michelle Centra

Risk Management

Donna Kamarei

Rose Kyprianou

Lorena Rivas

Office of General Counsel

Philip Ross 
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TERMS, ABBREVIATIONS AND SYMBOLS

A.I. or a.i. active ingredient

atm-m3/mole atmospheric pressure-cubic meter per mole

°C degrees Celsius

CAS Chemical Abstracts Service 

CFR Code of Federal Regulations 

DCI data call-in

EC50 median (or 50 percent) effect concentration

ECOTOX ECOTOXicology

EDSP Endocrine Disruptor Screening Program 

EPA Environmental Protection Agency 

FFDCA Federal Food, Drug, and Cosmetic Act

FIFRA Federal Insecticide, Fungicide, and Rodenticide Act

FQPA Food Quality Protection Act 

FWP Final Work Plan

GLN guideline number

IDS Incident Data System 

Koc organic carbon normalized soil-water partition coefficient

Kd soil-water partition coefficient

Kow octanol-water partition coefficient

LC50 median (or 50 percent) lethal concentration

LD50 median (or 50 percent) lethal dose

LOAEL lowest-observed-adverse-effect-level

Log Kow logarithm of the octanol-water partition coefficient

μg microgram

mg/kg milligram per kilogram

mg/kg/day milligram per kilogram per day 

mg/L milligram per liter

mm Hg millimeter of mercury

MOE margin of exposure 

MRID Master Record Identification Number

MRL maximum residue limit 

N/A not applicable 

nm nanometers

NOAEC no-observed-adverse-effect-concentration

NOAEL no-observed-adverse-effect-level

OCSPP Office of Chemical Safety and Pollution Prevention

OECD Organization for Economic Co-operation and Development

OPP Office of Pesticide Programs

PAD population adjusted dose

% percent

PC Code Pesticide Chemical Code

PCF pounds per cubic foot

pH power of hydrogen or power of the concentration of the hydrogen ion

pKa power of the acid dissociation constant or negative base-10 logarithm of the acid 

dissociation constant of a solution

ppm parts per million

PWP Preliminary Work Plan

QSAR quantitative structure-activity relationship

RED Reregistration Eligibility Decision
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SAR structure activity relationship

SF safety factor

TEP typical end-use product

TGAI technical grade active ingredient

TMDL total maximum daily loads

UF uncertainty factor

UV/VIS ultraviolet/visible light absorption

WWTPs wastewater treatment plants
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Table of Contents

1 Introduction............................................................................................................................. 7

1.1 Statutory and Regulatory Authority ................................................................................. 7

1.2 Updates to the Work plan................................................................................................. 7

1.3 Case Overview ................................................................................................................. 8

1.4 Chemical Identification and Properties............................................................................ 9

1.5 Use/Usage Description................................................................................................... 11

1.5.1 Registrations ........................................................................................................... 11

1.5.2 Summary of Registered Uses.................................................................................. 11

1.6 Regulatory History ......................................................................................................... 11

1.6.1 Tolerance Information ............................................................................................ 12

1.7 Incidents......................................................................................................................... 12

1.7.1 Human Health ......................................................................................................... 12

1.7.2 Ecological ............................................................................................................... 12

2 Anticipated Data Needs ........................................................................................................ 12

3 Human Health Risk Assessment........................................................................................... 14

3.1 Existing Toxicological Endpoints.................................................................................. 14

3.2 Dietary Exposure............................................................................................................ 16

3.2.1 Food ........................................................................................................................ 16

3.2.2 Drinking Water ....................................................................................................... 16

3.3 Occupational and Residential Exposures....................................................................... 16

3.3.1 Occupational Handler Exposure ............................................................................. 17

3.3.2 Residential Handler Exposures............................................................................... 17

3.3.3 Residential Post-Application Exposures................................................................. 17

3.4 Aggregate and Cumulative Exposure............................................................................. 18

3.4.1 Aggregate Exposures.............................................................................................. 18

4 Environmental Risk Assessment........................................................................................... 18

4.1 Environmental Fate Assessment .................................................................................... 20

4.1.1 Leaching from Wood .............................................................................................. 20

4.1.2 Water, Sediment, and Soil ...................................................................................... 20

4.1.3 Waste Water Treatment Plants (WWTPs).............................................................. 21

4.1.4 Water Quality.......................................................................................................... 21

4.2 Environmental Exposure Pathways................................................................................ 21

4.3 Ecological Effects Assessment....................................................................................... 22

4.3.1 Mechanism of Action.............................................................................................. 22

4.3.2 Measures of Effect (Ecotoxicology Endpoints)...................................................... 22

4.4 Exposure Analysis Plan.................................................................................................. 23

4.4.1 Aquatic and Terrestrial Wildlife Exposure Estimates ............................................ 23

4.4.2 Screening Level Down-the-Drain Analysis............................................................ 24

4.5 Effects Analysis Plan ..................................................................................................... 24

5 Endocrine Disruptor Screening Program (EDSP)................................................................. 24

6 Optional Label Changes........................................................................................................ 25

7 Next Steps............................................................................................................................. 25

8 References............................................................................................................................. 26

Appendix A Toxicology Profile............................................................................................... 27
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Appendix B Environmental Fate ............................................................................................. 34

Appendix C Ecotoxicology Profile.......................................................................................... 40

Appendix D Screening Level Down-the-Drain Analysis ........................................................ 46

Appendix E Product Chemistry............................................................................................... 47

Appendix F Comments Received Concerning the Preliminary Work Plan............................ 50

List of Tables

Table 1 – Summary of Anticipated Risk Assessments and Data Needs for the Registration 

Review of Fenpropimorph....................................................................................8

Table 2 – Anticipated Registration Review Schedule .................................................................... 9

Table 3 – Chemical Identification of Fenpropimorph .................................................................... 9

Table 4 – Physical-Chemical and Environmental Fate Properties for Fenpropimorph................ 10

Table 5 – Summary of Fenpropimorph Registered Uses.............................................................. 11

Table 6 – Studies Anticipated as Needed for the Registration Review of Fenpropimorph.......... 13

Table 7 – Existing Toxicological Endpoints................................................................................. 15

Table 8 – Occupational Handler Exposure Scenarios for Fenpropimorph ................................... 17

Table 9 – Aquatic Toxicity Values for Parent Fenpropimorph and Fenpropimorph Acid........... 19

Table 10 – Ecological Effects Endpoints Selected for Assessing Risks from Fenpropimorph Use

....................................................................................................................................................... 22
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1 Introduction

This document is the United States Environmental Protection Agency’s (USEPA, EPA or “the 

agency”) Final Work Plan (FWP) for fenpropimorph. The FWP document explains what EPA's 

Office of Pesticide Programs (OPP) knows about fenpropimorph, highlighting anticipated data 

and assessment needs, identifying the types of information that would be especially useful to the 

agency in conducting the review, and providing an anticipated timeline for completing 

fenpropimorph’s review.

The registration review process was designed to include a public participation component to 

solicit input from interested stakeholders. The agency intends, by sharing this information in the 

docket, to inform the public of what it knows about fenpropimorph and what types of new data 

or other information would be helpful for the agency to receive as it moves toward a decision on 

fenpropimorph. 

1.1 Statutory and Regulatory Authority

The Food Quality Protection Act (FQPA) of 1996 mandated a registration review program. All 

pesticides distributed or sold in the United States generally must be registered by the USEPA 

based on scientific data showing that they will not cause unreasonable risks to human health or 

the environment when used as directed on product labeling. The registration review program is 

intended to make sure that, as the ability to assess risk evolves and as policies and practices 

change, all registered pesticides continue to meet the statutory standard of no unreasonable 

adverse effects to human health or the environment. Changes in science, public policy, and 

pesticide use practices will occur over time. Through the registration review program, the agency

periodically reevaluates pesticides to make sure that as change occurs, products in the 

marketplace can be used safely. Information on this program is provided at 

http://www2.epa.gov/pesticide-reevaluation.

The agency is implementing the registration review program pursuant to Section 3(g) of the 

Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and will review each registered 

pesticide every 15 years to determine whether it continues to meet the FIFRA standard for 

registration. The regulations governing registration review begin at 40 CFR 155.40. The agency

will consider benefits information and data as required by FIFRA. The public phase of 

registration review begins when the initial docket is opened for each case. The docket is the 

agency’s opportunity to state what it knows about the pesticide and what additional risk analyses 

and data or information it believes are needed to make a registration review decision.

1.2 Updates to the Work plan

Since the publication of the PWP, the agency has made the following updates: 

 Corrected the timeline in Table 2, the “Anticipated Registration Review Table.”

 Deleted “Guidance for Commenters” section.

 Updated Table 1, the “Summary of Anticipated Risk Assessments and Data Needs for the 

Registration Review of Fenpropimorph.”Edited a study title, and removed the honey bee 
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acute contact study from Table 6 “Studies Anticipated as Needed for the Registration 

Review of Fenpropimorph.”

 Updated Section 7, “Next Steps.”

 Added Appendix F, which includes the agency’s response to comments submitted about 

the PWP.

 Corrected formatting and typographical errors.

The agency received two submissions during the public comment period on the initial docket. 

See Appendix F for the agency’s responses to these comments.

Comments received did result in a modification to the anticipated data needs in the 

fenpropimorph PWP. This document makes final the work plan for the fenpropimorph

registration review process.

1.3 Case Overview

The Preliminary Work Plan (PWP) for fenpropimorph was published on September 24, 2014,

and the 60-day comment period ended on November 24, 2014. The agency received two 

submissions during the public comment period on the initial docket. Documents associated with 

this registration review can be viewed at http://www.regulations.gov in docket EPA-HQ-OPP2014-0404. Tables 1 and 2 below summarize the issues relevant to this registration review case

and the anticipated registration review schedule.

Table 1 – Summary of Anticipated Risk Assessments and Data Needs for the Registration 

Review of Fenpropimorph

Risk Assessment 

Assessment 

Necessary to 

Support 

Registration 

Review

Date of Most 

Recent 

Assessment

Type of Assessment 

Required

(New/Updated)

Data Anticipated as Needed

(See Table 6 for details)

Dietary (food) No 10-19-2005 None None 

Dietary (drinking water) No N/A None None

Occupational Handler Yes 8-2-07 Updated 875.1700 Product Use Information 

870.7800 Immunotoxicity 

Residential Handler No N/A None None

Residental Post 

Application - Incidental 

Oral and Dermal 

No N/A None None

Residental Post 

Application - Inhalation No N/A None None

Aggregate No N/A None None

Cumulative No N/A None None

Tolerance Review No 10-19-2005 None None
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Risk Assessment 

Assessment 

Necessary to 

Support 

Registration 

Review

Date of Most 

Recent 

Assessment

Type of Assessment 

Required

(New/Updated)

Data Anticipated as Needed

(See Table 6 for details)

Ecological Yes

7-12-2007 

(original)1

2-10-2009 

(updated)

Updated None

N/A = Not applicable

Table 2 – Anticipated Registration Review Schedule

Anticipated Activity Target Date* Completion Date

Phase 1: Opening the Docket 

Open Docket and 60-Day Comment Period for Preliminary Work Plan 2014-09 2014-09-24

Close Public Comment Period 2014-11 2014-11-24

Phase 2: Case Development 

Issue Final Work Plan 2015-03 2015-03

Issue Data Call-In (DCI) 2016-03

Receive Data to be Considered in Risk Assessment 2017-03

Open 30-Day Public Comment Period for Preliminary Risk Assessment(s) 2018-09

Close Public Comment Period 2018-10

Phase 3: Registration Review Decision and Implementation 

Open 60-Day Public Comment Period for Proposed Decision 2019-03

Close Public Comment Period 2019-05

Issue Final Decision 2019-09

Begin Post-Decision Follow-up 2019

Total (years) 5

*The anticipated schedule will be revised as necessary (e.g., need arising under the Endocrine Disruptor Screening Program with 

respect to the active ingredient in this case).

1.4 Chemical Identification and Properties

Table 3 presents the active ingredient to be assessed in case 5112: parent fenpropimorph (PC 

Code 121402) and the degradate fenpropimorph acid (PC Code 621402, 621602). Product 

chemistry data for fenpropimorph acid were not submitted to the agency, and as a result, the 

agency accessed other sources of information.

Table 3 – Chemical Identification of Fenpropimorph

Chemical 

Name Fenpropimorph Fenpropimorph acid (degradate)2,3

Chemical 

Classification Morpholine Morpholine

 

1 Petrie et al., July 12, 2007 and Petrie, Rick, February 10, 2009

2 Chemical Book, http://www.chemicalbook.com/ChemicalProductProperty_EN_CB72545117.htm

3 Pesticide Action Network, http://www.pesticideinfo.org/Detail_Chemical.jsp?Rec_Id=PC41987
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PC Code 121402 621402, 621602

CAS Number 67564-91-4 121098-45-1

Molecular 

Formula C20H33NO C20H31NO3

Molecular 

Weight 

(grams/mole)

303.48 333.47

Smiles code CC1CN(CC(O1)C)CC(C)Cc2ccc(cc2)C(

C)(C)C CC1CN(CC(O1)C)CC(C)Cc2ccc(cc2)C(C)(C)C(=O)(O)

Molecular 

Structure

The fenpropimorph product chemistry information relevant to risk assessment is summarized in 

Table 4, and the details of the product chemistry (Source: MRIDS 44323904, 44323906, 

44835201, 45857201, 45857202, 45857203, 45857219, 46097501, and 46097502) are discussed 

in Appendix E. 

Table 4 – Physical-Chemical and Environmental Fate Properties for Fenpropimorph

Guideline 

No. Parameter Fenpropimorph Fenpropimorph Acid (degradate)4

Physical/Chemical Properties

830.7000 pH 8.6 at 1% in CIPAC water 

8.2 at 1% in de-ionized water

Not available

830.7050 UV/Visible 

Absorption 

Photolytically stable in artificial sunlight 

(≥290 nm) for up to 30 days at pH 5 and 

25oC.

Expected to be photolytically stable in 

artificial sunlight (≥290 nm) based on 

chemical structure

830.7200 Melting point 

(

oC) Liquid at STP 308.11

830.7220 Boiling point 

(

oC) > 300oC

507.95

830.7300 Density 0.933 g/cm3 Not available

830.7370 Dissociation 

constant

pKa: 6.98 (20oC); 

pKb 7.02 @ 20oC and 7.19 at 25oC

Not available

830.7550

Octanol-water 

partition 

coefficient at 

25 oC (Log 

Kow)

2.6 (22oC, pH 5)

4.1 (22oC, pH 7)

4.4 (22oC, pH 9)

0.7

830.7840 Solubility in 

water (mg/L)

pH 7: 4.32 mg/L at 20oC;

pH 9-11: 3.53 mg/L at 20oC 

16.7

830.7950 Vapor pressure 

(mmHg)

3.5 x 10-5at 20oC;

6.5 x 10-5at 25oC

1.16 x 10-11

 

4 EPI-WEB 4.11, http://www.epa.gov/oppt/exposure/pubs/episuitedl.htm
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Guideline 

No. Parameter Fenpropimorph Fenpropimorph Acid (degradate)4

None 

(calculated)

Henry’s Law 

(atm m3 mol-1)

(assumes pH 7 

and 25 oC)

6 x 10-6

3.05 x 10-13

atm-m3/mol = atmosphere cubic meter per mole; oC = degrees Celsius; mg/L = milligrams per liter; mmHg = 

millimeters of mercury;

1.5 Use/Usage Description

1.5.1 Registrations

There are two EPA registered products containing fenpropimorph as an active ingredient (a.i.) 

which are limited to antisapstain use on freshly cut wood products during storage and transit 

only. One product is registered as a manufacturing use product (MUP, 96 % a.i.) and the other 

product is registered as an end-use product (EUP, 5.4 % a.i.). Both products are liquid 

formulations (emulsifiable concentrates). 

1.5.2 Summary of Registered Uses

Table 5 presents a summary of the registered uses of fenpropimorph that will be assessed in this 

registration review. Fenpropimorph can be applied by the following application methods: nonpressure wood treatment through dip or spray to control sapstain, prevent mold and decay on 

green or freshly cut lumber and wood products like logs, poles, posts, composites, veneers and 

wood chips and saw dust. 

The sole active end-use label states that treated lumber must be stored under cover, indoors, or at 

least 100 feet from any pond, lake, stream, wetland, or river to prevent possible runoff of the 

product into the waterway. As per the labels, treated lumber stored within 100 feet of a pond, 

lake, stream, wetland, or river must be either covered with plastic or surrounded by a berm to 

prevent surface water runoff into the nearby waterway. The label also notes that “the product is 

intended to provide sapstain, mold and decay control during storage and transit which is not 

intended to extend to the end-use site.” The product is not intended to be efficacious in the enduse site. 

Table 5 – Summary of Fenpropimorph Registered Uses

Use Application Method Application Rate

(ppm)

Wood Treatment

Non-pressure treatment (Antisapstain)

Dip Tank 18.9 ppm

Spray System 54 ppm

1.6 Regulatory History

The first pesticide product containing fenpropimorph was registered on September 29, 1998 for 

the use of wood treatment. A Reregistration Eligibility Decision (RED) was not completed for 
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fenpropimorph because the first pesticide product containing it was registered after November 1, 

1984. 

1.6.1 Tolerance Information

Fenpropimorph has a tolerance in 40 CFR 180.616 for imported bananas at a rate not to exceed a 

limit of 2.0 ppm. Import tolerances will not be assessed as part of registration review of 

fenpropimorph. 

1.7 Incidents

1.7.1 Human Health 

No fenpropimorph human poisoning incidents have been reported in OPP’s Incident Data 

System (IDS) for the time period from 2005 to 2012, based on a search conducted on July 17, 

2014. 

1.7.2 Ecological 

No fenpropimorph ecological incidents have been reported in OPP’s IDS for the time period 

from 2005 to present, based on a search conducted on July 17, 2014.

2 Anticipated Data Needs

Table 6 presents a summary of the data anticipated as being needed to support this registration 

review.
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Table 6 – Studies Anticipated as Needed for the Registration Review of Fenpropimorph

GLN Study Name Test Substance

Time Frame 

(Measured in months 

from DCI Receipt)

Risk Assessment(s) Data 

Will Support

Use Site(s) Triggering 

Anticipated Data 

Requirement

Applicable 

Exposure Scenario

Studies Anticipated to be Required through the Registration Review DCI

870.7800 Immunotoxicity TGAI 12 months Occupational Assessment Antisapstain Worker exposure

875.1700 Product Use Information TEP 12 months Occupational handler Antisapstain Worker exposure
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3 Human Health Risk Assessment

The existing toxicology database for fenpropimorph is considered substantial and of high 

scientific quality. Toxicological endpoints have been selected from this database to conduct risk 

assessment(s) for initial pesticide registration as well as maintaining registration of products 

incorporating fenpropimorph as an active ingredient. However, there remains one data gap; an 

immunotoxicity study (OCSPP 870.7800) conducted with the TGAI fenpropimorph. This special 

test is an anticipated data requirement for all antimicrobial non-food, pesticide products (Federal 

Register, Vol. 78, No. 89, May 8, 2013/Rules and Regulations).

The agency anticipates the need to revise the human health risk assessment for fenpropimorph, 

specifically, the original occupational assessment that was recently conducted for registration in 

2007. The agency expects to require additional data (see Table 6) for use in conducting the 

registration review.

For this registration review case, there are no intended food/food contact uses for registered 

products containing fenpropimorph when used as an antimicrobial agent for the control of 

sapstain, mold and decay of freshly cut lumber and wood products during storage and transit 

only. Although there is an established import tolerance for fenpropimorph on bananas, the import 

tolerance will not be reassessed during registration review (see Section 1.6.1).

3.1 Existing Toxicological Endpoints

In the most recent antimicrobial risk assessment for fenpropimorph (D342435), the agency 

selected doses and endpoints, and established uncertainty factors and Margin of Exposures

(MOEs) from the existing toxicology database to conduct human health risk assessments (Table 

7). Short- and intermediate-term incidental oral exposure doses/endpoints as well as short- and 

intermediate-term dermal and inhalation exposure doses/endpoints were used for risk assessment 

purposes. In addition, the target MOE of 100 was used for all dermal exposure scenarios 

assessed. A target MOE of 100 was also used for the inhalation exposure scenarios with an 

additional 10x uncertainty factor (total uncertainty factor of 1000) applied to the NOAEL to 

account for the lack of a route-specific inhalation toxicity study (i.e. inhalation endpoint 

established from an oral toxicity study requiring route-to-route extrapolation) to determine if a 

route-specific inhalation toxicity study is warranted.

However, the agency anticipates requiring an immunotoxicity study and will revisit the 

endpoints to determine if any revisions are necessary. 
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Table 7 – Existing Toxicological Endpoints

Exposure 

Scenario

Dose Used in Risk 

Assessment 

(mg/kg/day)

Target Margin of Exposure 

(MOE), Uncertainty Factor 

(UF), 

FQPA Safety Factor (SF)

Study and 

Toxicological Effects

Incidental Oral

Residential

Short-Term 

(1-30 days) and 

Intermediate-Term 

(1- 6 months)

NOAEL(dev.) =

15 mg/kg/day

UF = 100 

(10x inter-species extrapolation, 

10x intra-species variation)

Target MOE res. = 100 

Prenatal Developmental Toxicity in 

Rabbits

(MRID 44323914)

LOAEL (dev.) = 30 mg/kg/day 

based on cleft palate, 4/116 fetuses 

(2/20 litters), 0 in control; anomalies

Dermal Irritation

Occupational, 

Residential

Short-Term

(1-30 days) 

A dermal irritation risk assessment is not needed because occupational uses are mitigated via PPE and

no residential dermal exposure is expected.

Dermal a

Occupational, 

Residential

Short-Term 

(1-6 months)

NOAEL (mat.) = 

10 mg/kg/day

UF = 100

(10x inter-species extrapolation, 

10x intra-species variation)

Target MOE occ./res. = 100

Prenatal Developmental Toxicity in 

Rats (MRID 44323912)

LOAEL (mat.) = 40 mg/kg/day based 

on decreased body weight gain

Dermal a

Occupational, 

Residential

Intermediate-Term 

(1- 6 months)

NOAEL = 

0.7 mg/kg/day (males)

0.8 mg/kg/day (females)

UF = 100

(10x inter-species extrapolation, 

10x intra-species variation)

Target MOE occ./res. = 100

90-Day Oral Toxicity and 

Neurotoxicity in Rats 

(MRID 44380105)

LOAEL (sys.) = 7.1 mg/kg/day (m.)

 8.5 mg/kg/day (f.)

based on decreased body weight and 

body weight gain in both sexes

Inhalation b

Occupational, 

Residential

Short-Term 

(1-30 days) 

NOAEL (mat.) = 

10 mg/kg/day

UF = 100

(10x inter-species extrapolation, 

10x intra-species variation)

Target MOE occ./res. = 100

Prenatal Developmental Toxicity in 

Rats (MRID 44323912)

LOAEL (mat.) = 40 mg/kg/day based 

on decreased body weight gain

Inhalation b

Occupational, 

Residential

Intermediate-Term 

(1- 6 months)

NOAEL =

1.7 mg/kg/day (males)

2.1 mg/kg/day (females)

UF = 100

(10x inter-species extrapolation, 

10x intra-species variation, 10x 

for route-to-route extrapolation 

from an oral toxicity study) 

Target MOE occ./res. = 1000

Chronic Toxicity/Carcinogenicity in 

Rats (MRID 44380106)

LOAEL (sys.) = 8.8 mg/kg/day (m.) 

 11.2 mg/kg/day (f.)

based on histopathological liver 

findings 

Cancer

(oral, dermal, 

inhalation)

Classification: “Not likely to be carcinogenic to humans”. No increased incidences in tumors in a 

chronic toxicity/carcinogenicity study in the rat or a carcinogenicity study in the mouse

UF = uncertainty factor, NOAEL = no observed adverse effect level, LOAEL = lowest observed adverse effect level, Target 

MOE = target margin of exposure, PPE = personal protective equipment.

a 12% dermal absorption factor (at a dose of 0.04 to 0.4 mg/cm2

) was established from an in vivo dermal penetration study in 

rats (MRID 47154901). In lieu of a route-specific dermal toxicity study, this dermal absorption factor can be applied to an oral 

NOAEL for dermal risk assessments.
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b

In lieu of a route-specific inhalation toxicity study, an additional 10x uncertainty factor for route-to-route extrapolation can be 

applied to an oral NOAEL for inhalation risk assessments.

3.2 Dietary Exposure

There is dietary exposure from the use of fenpropimorph on imported bananas. This exposure 

was assessed in the 2005 dietary risk assessment (D321866) and the risks are not of concern. In 

addition there was no significant drinking water exposure from the antisapstain use of 

fenpropimorph. As a result, the agency does not anticipate requiring a new dietary (food and 

water) risk assessment.

3.2.1 Food

A risk assessment was previously done for the banana import tolerances during registration and 

the agency concluded the risks were not of concern (D324756). There is no direct or indirect 

food contact for fenpropimorph as a result of the antisapstain use. Therefore, no dietary risk 

assessment from food containing fenpropimorph is anticipated as being required for the

antimicrobial uses. 

3.2.2 Drinking Water

The potential for drinking water exposure to fenpropimorph from ingestion of surface and 

ground water in the vicinity of end-use products is expected to be negligible. The leaching rate of 

parent fenpropimorph from a rainfall study (MRID 46074205) was low, which is consistent with 

the limited water solubility of 3.5-4.3 mg/l (Table 4). Because of the widespread geographical 

distribution of the treated wood, the low use rate and the low total pounds used per year, residues 

are expected to be low and dispersed. 

The potential for drinking water exposure to fenpropimorph from ingestion of surface and 

ground water in the vicinity of industrial use sites is also not expected. The sole end-use label 

states that wastes must be treated as hazardous waste and disposal must be conducted according 

to label instructions, a state pesticide or environmental control agency, or by guidance from a 

hazardous waste representative. Consequently, down-the-drain releases from industrial use of 

fenpropimorph are not expected to occur, and no drinking water exposure is expected to occur.

3.3 Occupational and Residential Exposures

The agency anticipates the need to revise the occupational assessment based on new exposure 

assumptions for the scenarios presented in the 2007 occupational exposure assessment 

(D342435) for the new use of fenpropimorph for wood preservation. Although MOEs did not 

exceed the agency’s level of concern for this assessment, the agency has a new sapstain worker 

exposure study (MRID 47618301) for calculating the worker exposures for these scenarios. 
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3.3.1 Occupational Handler Exposure

EPA does not anticipate the need for additional exposure data. However, EPA does anticipate the 

need to revise the latest occupational handler assessment that was conducted during registration 

in August of 2007. The occupational handler dermal and inhalation exposures to fenpropimorph 

were initially assessed during registration using surrogate unit exposure data from workers 

exposed from an antisapstain worker exposure study for another antimicrobial pesticide (MRID 

45524304). EPA will use the new sapstain study to revise the assessment. However, the 

approach to calculate the occupational handler exposures for diptank operations, maintenance 

operations, dry wood operations, and wet wood operations will be revised. In all cases, the 

MOEs for the previous assessment were either not of concern (greater than the target MOE of 

100) or mitigated by engineering controls in the previous assessment. During registration review, 

EPA will conduct a revised assessment with new exposure assumptions that will incorporate 

scenarios identified in Table 8.

Table 8 – Occupational Handler Exposure Scenarios for Fenpropimorph

Scenario Exposure Route(s) Duration

Occupational Exposures

Diptank Operations

Diptank Tank Operator (gloves) Dermal Inhalation Short and Intermediate-Term

Diptank Tank Operator (no gloves) Dermal Inhalation Short and Intermediate-Term

Maintenance Operations

Millwright Dermal Inhalation Short and Intermediate Term 

Chemical Operator Dermal Inhalation Short and Intermediate-Term 

Maintenance (Cleanup Crew) Dermal Inhalation Short and Intermediate-Term 

Dry Wood Operations

All Dermal Inhalation Short and Intermediate- Term

Wet Wood Operations

All Dermal Inhalation Short and Intermediate- Term

3.3.2 Residential Handler Exposures

No residential handler exposures are anticipated for the antisapstain wood use.

3.3.3 Residential Post-Application Exposures

A risk assessment will not be conducted for residential post-application exposures, since minimal 

exposures are anticipated for the antisapstain wood use. Antisapstain use is for lumber of interior 

building materials and millwork. People are not exposed to this lumber because it is typically 

covered by drywall when used for framing and millwork such as window frames are typically 

painted. 
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3.4 Aggregate and Cumulative Exposure

3.4.1 Aggregate Exposures 

An aggregate assessment is not necessary since there is no residential or drinking water exposure

from the pesticidal use of fenpropimorph. 

3.4.2 Cumulative Exposures 

With respect to cumulative exposure, 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 fenpropimorph and any other substances; 

fenpropimorph does not appear to produce a toxic metabolite produced by other substances.

Therefore, for the purposes of this registration review, EPA has not assumed that fenpropimorph

has a common mechanism of toxicity with 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 http://www.epa.gov/pesticides/cumulative/.

4 Environmental Risk Assessment

A risk assessment for fenpropimorph was completed in 2007 and identified a potential for level 

of concern (LOC) exceedance under a low dilution runoff scenario.5 Fenpropimorph converts to 

fenpropimorph acid in the environment and was detected in laboratory sediment studies at up to 

approximately 10% of initial fenpropimorph concentration. At that time, the agency concluded 

that a number of plant toxicity, marine organism, and sediment toxicity studies were outstanding 

for fenpropimorph.

A second risk assessment was completed in 2009.6 It used data submitted by the registrant that 

was required in the 2007 risk assessment and was based on fenpropimorph being used as an 

antisapstain treatment only, with the restriction that wood must be treated within 24 hours of 

sawing or cutting. The product label includes the following EPA precautionary statement: 

“Treated lumber must be stored under cover, indoors, or at least 100 feet from any pond, lake, 

stream, wetland, or river to prevent possible runoff of the product into the waterway. Treated 

lumber stored within 100 feet of a pond, lake, stream, wetland, or river must be either covered 

with plastic or surrounded by a berm to prevent surface water runoff into the nearby waterway. 

If a berm or curb is used around the site, it must consist of impermeable material (clay, asphalt, 

concrete) and be of sufficient height to prevent runoff during heavy rainfall events.”

The end-use labels have statements prohibiting the use of treated wood in beehive construction.

However, the agency has determined that this prohibition is not practical. Therefore, during 

registration review, EPA will work with the registrants to remove these statements. The 

honeybee acute contact study 850.3020 has been satisfied (MRID 47125501). Although the 

toxicity of residues to honeybees 850.3030 is also usually required, the agency has determined 

 

5 Petrie et al., 2007

6 Petrie et al., 2009
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that for compounds such as fenpropimorph which leach slowly, results of this study are not 

expected to be pertinent for risk assessment, therefore, this study is not expected to be required. 

The honey/beeswax residue study 860.1500 – Magnitude of the residues in honey and beeswax is

waived for the proposed antisapstain use.

For the degradate fenpropimorph acid, the registrant submitted three acute toxicity studies on

freshwater aquatic organisms. The results of these studies are included in Table 9. 

MRID 47425202 – Rainbow trout acute static toxicity test using 99.8% fenpropimorph acid. 

This study is supplemental and does not meet guideline requirements but may be useful for risk 

assessment purposes. The 96 hour LC50 was ≥ 100 mg ai/L.

MRID 47425203 – Green algae acute toxicity test using 99.8% fenpropimorph acid. This study 

is supplemental and does not meet guideline requirements but may be useful for risk assessment 

purposes. The 72 hour EC50 was ≥ 100 mg ai/L.

MRID 47425204 – Aquatic invertebrate acute toxicity test using 99.8% fenpropimorph acid. 

This study is supplemental and does not meet guideline requirements but may be useful for risk 

assessment purposes. The 48 hour EC50 was ≥ 100 mg ai/L.

These studies were submitted to demonstrate that fenpropimorph acid is of lesser toxicity to 

aquatic organisms than fenpropimorph.

Table 9 – Aquatic Toxicity Values for Parent Fenpropimorph and Fenpropimorph Acid 

 Species Fenpropimorph

(mg ai/L)

Fenpropimorph acid

(mg ai/L)

Rainbow trout LC50 ≥ 0.74 – 5.15 LC50 ≥ 100

Green algae EC50 = 0.327 EC50 ≥ 100

Daphnia magna EC50 = 0.30-12.24 EC50 ≥ 100

The higher acute LC50 and EC50 values for fenpropimorph acid relative to parent fenpropimorph 

in Table 9 indicate that fenpropimorph acid is less toxic to aquatic plants and animals than 

fenpropimorph. It could be assumed that fenpropimorph acid is less toxic on a chronic basis as 

well, however, no comparative studies are available to confirm this assumption. 

The agency has not previously conducted a risk assessment that supports a complete endangered 

species determination for fenpropimorph. The ecological risk assessment planned during 

registration review will allow the agency to determine potential acute and chronic risks to aquatic 

organisms exposed to fenpropimorph that are transported from treated wood into the aquatic 

environment. The risk assessment also will allow the agency to determine whether the 

antisapstain use of fenpropimorph has 'no effect' or 'may affect' federally listed threatened or 

endangered species (listed species) or their designated critical habitats. When an assessment

concludes that a pesticide’s use 'may affect' a listed species or its designated critical habitat, the 
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agency will consult with the U.S. Fish and Wildlife Service and/or National Marine Fisheries 

Services (the Services), as appropriate.

4.1 Environmental Fate Assessment

Based on a wood leaching study using rainfall (MRID 46074205), fenpropimorph used as an 

antisapstain product can leach to the environment at low concentrations for an extended period of 

time. In the environment, fenpropimorph is relatively water-insoluble (Table 4), and will largely 

partition to sediment based on aerobic aquatic metabolism data (MRID 45857318). Based on its 

low vapor pressure and Henry’s law constants, it is unlikely to move from soil or water into air 

(Table 4). Fenpropimorph is persistent in aerobic soil (MRID 45857217) but is not mobile 

(MRID 45857318).

7 As a result, transport of parent fenpropimorph by runoff to surface water 

and by leaching to ground water from treated wood is expected to be limited.

The degradate fenpropimorph acid forms from metabolism of parent fenpropimorph in aerobic 

soil (MRID 45857217) and in two aerobic aquatic systems containing both water and sediment 

(MRID 45868904). Fenpropimorph acid was not formed at significant quantities (>10 % of 

applied parent compound) in aerobic soil but was formed at significant quantities in the sediment 

phase from degradation of fenpropimorph and repartitioned to the water phase. Fenpropimorph 

acid was mobile to highly mobile in two soils (MRID 45857318). As a result, transport of 

fenpropimorph acid to aquatic systems from runoff is expected to be limited, but any parent 

fenpropimorph in aquatic systems will partition to the water phase as fenpropimorph acid.

4.1.1 Leaching from Wood

Pine wood was treated and leached using rainfall. The maximum and average leaching rates were 

0.85 and 0.18 μg/cm2/day and the cumulative leaching was 17.9 μg/cm2over a 237 day period 

(MRID 46074205). Additional data on leaching are not required because the submitted leaching 

study satisfies the data requirement. 

4.1.2 Water, Sediment, and Soil

Fenpropimorph is stable to hydrolysis (MRID 45857216) and photodegradation in water 

(46074201). For aerobic aquatic metabolism, the half-lives of parent fenpropimorph in two 

loamy sand systems containing water and sediment were 54 and 18 days, respectively. The 

aerobic aquatic half-lives for the degradate fenpropimorph acid were 121 and 29 days in these 

aquatic systems, respectively. Residues of parent fenpropimorph were generally higher in 

sediment than water but water residues were higher for fenpropimorph acid (MRID 45868904). 

In two soils, parent fenpropimorph was slightly mobile with Freundlich Kads values of 46 and 79 

L/kg and Koc values of 3,833 and 8,778 L/kg in loamy sand and sandy loam soils. On the other 

hand, the degradate fenpropimorph acid was mobile to highly mobile with Freundlich Kads 

 

7 Log Koc values of 0-2 are mobile to highly mobile and Log Koc values of 3-4 are considered to be slightly mobile 

(http://www.fao.org/docrep/003/x2570e/x2570e06.htm ) 
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values of 0.5 and 1 L/kg and Koc values of 42 and 111 L/kg in loamy sand and sandy loam soils 

(MRID 45857318).

8

4.1.3 Waste Water Treatment Plants (WWTPs)

Data for routes of dissipation and toxicity in WWTPs were not submitted, but are not anticipated 

to be required because fenpropimorph is not expected to be transported to WWTPs. The sole

end-use label states that wastes must be treated as hazardous waste and disposal must be 

conducted according to label instructions, a state pesticide or environmental control agency, or 

by guidance from a hazardous waste representative.

4.1.4 Water Quality

Fenpropimorph is not identified as a cause of impairment for any water bodies listed as impaired 

under section 303(d) of the Clean Water Act.

9

In addition, no Total Maximum Daily Loads 

(TMDL) have been developed for fenpropimorph.

10 More information on impaired water bodies 

and TMDLs can be found at EPA’s website.

11

4.2 Environmental Exposure Pathways

Based on the antisapstain use of fenpropimorph in Table 5, the agency has created conceptual 

models for potential routes of environmental exposure which are included in “Conceptual 

Models for Environmental Exposure Pathways of Antimicrobial Pesticides,” found in the docket 

at www.regulations.gov (EPA-HQ-OPP-2014-0638-001). For the antisapstain use, the relevant 

page number is 29. All relevant routes of environmental exposure will be considered in the risk 

assessment.

There is no significant anticipated environmental exposure to fenpropimorph from the wood 

treatment process because the sole end-use label states that wastes must be treated as hazardous 

waste and disposal must be conducted according to label instructions, a state pesticide or 

environmental control agency, or by guidance from a hazardous waste representative.

The treated lumber must be stored under cover, indoors, or at least 100 feet from any pond, lake, 

stream, wetland, or river to prevent possible runoff of the product into the waterway. Treated 

lumber stored within 100 feet of a pond, lake, stream, wetland, or river must be either covered 

with plastic or surrounded by a berm to prevent surface water runoff into the nearby waterway. If 

a berm or curb is used around the site, it must consist of impermeable material (clay, asphalt, 

concrete) and be of sufficient height to prevent runoff during heavy rainfall events.

 

8 Log Koc values of 0-2 are mobile to highly mobile and Log Koc values of 3-4 are considered to be slightly mobile 

(http://www.fao.org/docrep/003/x2570e/x2570e06.htm ) 

9 http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885

10http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=885&p_pollutant

_group_name=PESTICIDES

11 http://www.epa.gov/owow/tmdl/
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4.3 Ecological Effects Assessment

The agency has determined that adverse effects to terrestrial animals, aquatic freshwater animals, 

and green algae are expected to be minimal for the antisapstain use of fenpropimorph. The labeling 

restrictions listed above are expected to protect non-target species from antisapstain treated and 

stored wood. This restricted use pattern would cause minimal exposure to these non-target 

organisms. The primary degradate, fenpropimorph acid, would not be a risk concern to non-target 

organisms based on a lack of toxicity and a lack of exposure (MRIDs 47425202, 47425203 and 

47425204). 

4.3.1 Mechanism of Action

Fenpropimorph acts by inhibiting egosterol biosynthesis leading to the arresting of cell 

proliferation in fungi.

4.3.2 Measures of Effect (Ecotoxicology Endpoints)

Ecotoxicity endpoint data are used as measures of effects to aquatic and terrestrial organisms. 

All available ecotoxicity endpoints in the agency’s files from studies submitted by registrants or 

other interested parties, federal laboratory data, or from the public literature are tabulated in 

Appendix C along with the data requirements and data gaps. The most sensitive values for each

receptor group are used for the risk assessment (Table 10). These selected endpoints will be 

updated during the risk assessment phase based on any additional submitted data or data found in 

the public literature. 

Table 10 – Ecological Effects Endpoints Selected for Assessing Risks from Fenpropimorph 

Use

Receptor 

Group Surrogate Species Risk Scenario Toxicity Endpoint Reference(MRID #)

Freshwater fish

Bluegill Sunfish Acute 96-h LC50 = 3.25 mg/L 45857205

Rainbow Trout Chronic NOAEC = 0.00016 mg/L 46074303

Freshwater 

invertebrates Daphnia magna

Acute 48-h EC50 = 12.24 mg/L 45847207

Chronic NOAEC = 0.082 mg/L 46074305

Freshwater benthic 

invertebrates Freshwater midge

Subchronic/

Chronic

 10-day LC50 = 13 mg/kg

 NOAEC = 4.9 mg/kg

47425201

Estuarine/marine fish Sheepshead minnow

Acute Waived --

Chronic Not requiredA --

Estuarine/marine 

invertebrates

Mollusk Acute WaivedB--

Shrimp Acute Waived --
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Receptor 

Group Surrogate Species Risk Scenario Toxicity Endpoint Reference(MRID #)

Chronic Not requiredA --

Estuarine/marine 

benthic invertebrates Marine amphipod

Subchronic/

Chronic

Waived --

Algae Green alga

Non-listed 96-hr EC50 = 0.327 mg/L 45868903

Listed --

Aquatic vascular 

plants Duckweed

Non-listed Waived --

Listed --

Seedling Emergence Red clover

Non-listed Waived --

Listed --

Vegetative vigor Canola

Non-listed Waived --

Listed --

Birds

Northern bobwhite 

quail Acute LD50 ≥2000 mg/kg 45868901

Mallard duck

Subacute 

dietary

LC50 = 5000 mg/kg

45857204

Chronic Not requiredA --

Mammals

Acute NOAEL = 30 mg/kg/day 43471604

Chronic NOAEL = 16 mg/kg/day 45756501

Non-target insects Honey bee Acute

Oral LC50 ≥95.6 ug ai/bee

Contact LC50 ≥100 ug ai/bee

 47125501

A Not required for this use pattern.

B Waived for this chemical based on its use as an antisapstain wood preservative. This limited use pattern would lead 

to little if any exposure to non-target organisms.

4.4 Exposure Analysis Plan

4.4.1 Aquatic and Terrestrial Wildlife Exposure Estimates

The agency intends to conduct a risk assessment for fenpropimorph from the in-service use of 

treated wood. This in-service risk assessment may be qualitative based on: (1) widespread 

geographical use of treated wood, (2) low application rate, (3) the treatment is intended for 
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protection in transit, and (4) in structures, most wood is painted or stained which would reduce 

leaching. Further, as a practical matter, antisapstain treated wood is not intended to protect wood 

in aquatic environments. Docks and piers would be constructed from pressure treated wood. 

Typically, wood treatment uses can result in down the drain releases from treatment and storage 

of wood. However, for fenpropimorph, the agency does not intend to conduct a risk assessment 

from treatment and storage of wood at industrial use sites because the sole end-use label states 

that wastes must be treated as hazardous waste and disposal must be conducted according to 

label instructions, a state pesticide or environmental control agency, or by guidance from a

hazardous waste representative. Consequently, down-the-drain releases from industrial use of 

fenpropimorph are not expected to occur. 

4.4.2 Screening Level Down-the-Drain Analysis

The agency does not anticipate the need for a Down-the-Drain (DtD) assessment because the 

sole end-use label states that wastes must be treated as hazardous waste and disposal must be 

conducted according to label instructions, a state pesticide or environmental control agency, or 

by guidance from a hazardous waste representative. 

4.5 Effects Analysis Plan

Open literature studies will be identified through EPA’s ECOTOXicology (ECOTOX) database. 

The ECOTOX database will be searched when the risk assessment is prepared. Any acute or 

chronic endpoints that are more sensitive than what is currently available will be used in the risk 

assessment.

5 Endocrine Disruptor Screening Program (EDSP)

As required by FIFRA and FFDCA, EPA reviews numerous studies to assess potential adverse 

outcomes from exposure to chemicals. Collectively, these studies include acute, subchronic and 

chronic toxicity, including assessments of carcinogenicity, neurotoxicity, developmental, 

reproductive, and general or systemic toxicity. These studies include endpoints which may be 

susceptible to endocrine influence, including effects on endocrine target organ histopathology, 

organ weights, estrus cyclicity, sexual maturation, fertility, pregnancy rates, reproductive loss, 

and sex ratios in offspring. For ecological hazard assessments, EPA evaluates acute tests and 

chronic studies that assess growth, developmental and reproductive effects in different 

taxonomic groups. As part of the 1998 registration action, for fenpropimorph, EPA reviewed 

these data and selected the most sensitive endpoints for relevant risk assessment scenarios from 

the existing hazard database. However, as required by FFDCA section 408(p), fenpropimorph is 

subject to the endocrine screening part of the Endocrine Disruptor Screening Program (EDSP). 

EPA has developed the EDSP to determine whether certain substances (including pesticide 

active and other ingredients) may have an effect in humans or wildlife similar to an effect 

produced by a “naturally occurring estrogen, or other such endocrine effects as the Administrator 

may designate.” The EDSP employs a two-tiered approach to making the statutorily required 

determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a 
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chemical substance to interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal 

systems. Chemicals that go through Tier 1 screening and are found to have the potential to 

interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP where EPA 

will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 

testing is designed to identify any adverse endocrine-related effects caused by the substance, and 

establish a dose-response relationship between the dose and the E, A, or T effect. 

Under FFDCA section 408(p), the agency must screen all pesticide chemicals. Between October 

2009 and February 2010, EPA issued test orders/data call-ins for the first group of 67 chemicals, 

which contains 58 pesticide active ingredients and 9 inert ingredients. A second list of chemicals 

identified for EDSP screening was published on June 14, 201312 and includes some pesticides 

scheduled for registration review and chemicals found in water. Neither of these lists should be 

construed as a list of known or likely endocrine disruptors.

For further information on the status of the EDSP, the policies and procedures, the lists of 

chemicals, future lists, the test guidelines and the Tier 1 screening battery, please visit our 

website.13

6 Optional Label Changes

The agency invites any label amendments that could be considered to eliminate the anticipated 

need for EPA to require certain data, reduce the possibility that EPA’s planned risk assessments 

overestimate risk due to reliance on conservative assumptions, and/or improve label clarity.

During registration review, EPA intends to work with registrants to modify labels to remove 

unenforceable statements regarding how treated wood is to be used as discussed in Section 4. 

7 Next Steps

A DCI will be developed regarding the data needs listed under the “Anticipated Data Needs” 

section of this document. The agency expects to issue the DCI by March 2016.

 

12 See http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0477-0074 for the final second list of 

chemicals.

13 http://www.epa.gov/endo/
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8 References 

Chemical Book. 2010. Fenpropimorph Acid. , 

http://www.chemicalbook.com/ChemicalProductProperty_EN_CB72545117.htm

EPI-WEB 4.11. 2012. U.S. EPA. 

http://www.epa.gov/oppt/exposure/pubs/episuitedl.htm

Pesticide Action Network. 2014. Fenpropimorphic Acid. 

http://www.pesticideinfo.org/Detail_Chemical.jsp?Rec_Id=PC41987

Collantes, M. and Drew, W. February 10, 2006. REVISION: Clarification of Data 

Requirements for Fenpropimorph. Human Health Risk Assessment to Support Tolerance 

on Imported Bananas. DP Barcode 326756.

Lindheimer, T. August 2, 2007. Revised Occupational Exposure Assessment of Proposed 

New Use of Fenpropimorph (121402) Formulation for Wood Preservation. DP Barcode 

342435.

Petrie, R., Mostaghimi, S., and Gowda, S. July 12, 2007. Ecological Risk and Fate 

Assessment for fenpropimorph (Wolsin® FL 35) New Chemical Wood Preservative 

Antisapstain Use. DP Barcodes D333166, D333168, D333170, D333171

Petrie, R. February 10, 2009. Review of Studies and Ecotoxicity Data Waiver Requests 

for the Conditional Registration of the Antisapstain Use of fenpropimorph (Wolsin® FL 

35). DP Barcodes D350203, D353064

U.S. Environmental Protection Agency (EPA). 2002. ECOTOX User Guide: 

ECOTOXicology Database System. Version 3.0. Available: http://www.epa.gov/ecotox/

U.S. Environmental Protection Agency (EPA). March 2006. Pesticide Fact Sheet, 

Fenpropimorph New Chemical Tolerance Established.

 
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Appendix A Toxicology Profile

Acute Toxicity for Product Labeling 

Acute toxicity profile for technical fenpropimorph is presented in Table A1. Fenpropimorph has 

low acute toxicity via the oral, dermal and inhalation routes of exposure (Toxicity Category III

and IV). Acute eye irritation testing resulted in classification of this active ingredient as Toxicity 

Category II. The acute dermal irritation study in rabbits showed severe irritation after one hour 

exposure (Toxicity Category I). Fenpropimorph is a skin sensitizer in the Beuhler Guinea pig 

assay. There is no evidence of delayed neurotoxicity in hens following exposure to 

fenpropimorph.

Table A1 – Acute Toxicity Studies for Fenpropimorph 

Guideline 

Number Study Type MRID Number Results Toxicity Category

870.1100 Acute Oral – Rat 45857208 LD50 = 2,830 mg/kg (males)

 1,670 mg/kg (females)

 2,230 mg/kg (combined)

III

870.1100 Acute Oral – Rat 45857209 LD50 = 3,650 mg/kg (males)

 3,425 mg/kg (females)

 3,515 mg/kg (combined)

III

870.1200 Acute Dermal – Rat 45857210 LD50 > 4,000 mg/kg (males, females)

 > 4,000 mg/kg (combined)

III

870.1300 Acute Inhalation - Rat 45857211 LC50 = 3.7 mg/L (males)

LC50 = >2.2, <2.4mg/L (females)

LC50 = 2.9 mg/L (combined)

IV

870.2400 Acute Eye Irritation - Rabbit 45857212 Redness (no observation between 72 hours 

and day 8)

I

a

870.2500 Acute Dermal Irritation - Rabbit 45857213 Severely irritating after 1 hour exposure I

a 

870.2600 Skin Sensitization –

Guinea pigs (Buehler Method) 45857214 Skin sensitizer N/A

N/A = Not applicable

a Also classified as “No worse than Toxicity Category II”

Subchronic Toxicity 

The liver was affected by the administration of fenpropimorph in subchronic toxicity studies. In 

one 90-day rat study (MRID 44380105), the LOAELs were 7.1 and 8.5 mg/kg/day for males and 

females, respectively, based upon decreases in body weights and body weight gains in both sexes 

as well as an increase in absolute and relative liver weights in males and increases in only 

relative liver weights in females. In this study, the NOAELs were 0.7 and 0.8 mg/kg/day for 

males and females, respectively. A second 90-day rat toxicity study (MRID 44380103) reported 

an increase in liver weights at doses of 1.54 mg/kg/day in males and 1.80 mg/kg/day in females 

(HDT); however, no other effects in the liver of these animals were noted.

Although a dermal toxicity range-finding study in rats (MRID 44380104) was conducted with 

fenpropimorph, this study was not appropriate for risk assessment purposes because neither an 
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irritation nor a systemic toxicity LOAEL could be established. The highest dose tested (2 

mg/kg/day) represented the maximum dose of test material that would not produce severe 

irritation, making the dose selection inadequate for a dermal toxicity study. For registration 

review, a repeat dermal absorption study in not anticipated to be needed; the dermal absorption 

factor of 12% can be applied to an oral NOAEL for dermal risk assessments. 

An inhalation toxicity study was not conducted for fenpropimorph. However, an additional 10x 

uncertainty factor for route-to-route extrapolation can be applied to an oral NOAEL for 

inhalation risk assessments in lieu of a route-specific inhalation toxicity study.

Developmental Toxicity 

In a rat developmental toxicity study (MRID 44380108), the maternal NOAEL was 40 

mg/kg/day with a LOAEL of 160 mg/kg/day based upon vaginal bleeding and decreased body 

weight and body weight gain. The same numerical NOAEL and LOAEL were reported for 

developmental toxicity in this study with the following being observed at the LOAEL dose of 

160 mg/kg/day: decreased number of live fetuses/dam, increased resorptions, increased % postimplantation loss and increased incidence of cleft palate. In a second rat development toxicity 

study (MRID 44323912) in which dosing began during gestation and continued through lactation 

(GD 15 through PND 21), the maternal NOAEL was 10 mg/kg/day with a maternal LOAEL of 

40 mg/kg/day based upon decreased body weight gain. For the developmental portion of the 

study, the NOAEL was also 10 mg/kg/day with a LOAEL of 40 mg/kg/day based upon a 

decrease in the number of live fetuses/dam, an increase in post-implantation loss. Decreased 

mean litter size, decreased number of live pups and decreased survival indices. In addition, 

decreases in grip strength were observed in female fetuses as part of the protocol for this 

developmental/neurotoxicity toxicity in rats. However, there was no visceral or skeletal 

examination of fetuses/pups conducted in this combined study. 

There were two developmental rabbit studies conducted with fenpropimorph. In the study 

conducted in 1993 (MRID 44323914), the maternal NOAEL was 15 mg/kg/day with a LOAEL 

of 30 mg/kg/day based upon 9/20 dams showing swelling of the anus on GD 15-29. The 

developmental NOAEL was also 15 mg/kg/day with a LOAEL of 30 mg/kg/day based upon 

increased incidence of cleft palate (4/116 fetuses; 2/20 litters; 0 in concurrent controls). In the 

earlier study (MRID 44323913), the maternal NOAEL was 12 mg/kg/day and the LOAEL was 

36 mg/kg/day based upon increased mortality, abortions and clinical signs of toxicity. The 

developmental NOAEL was 12 mg/kg/day and the LOAEL was 36 mg/kg/day based upon 

increased incidence of resorptions, external anomalies and skeletal variations/retardation.

Reproductive Toxicity

In the 2-generation reproduction study in rats (MRID 44323915), the NOAELs for parental, 

reproductive and offspring toxicity were the highest dose tested (2.04 and 2.79 mg/kg/day for 

males and female, respectively). Thus, LOAELS were not established in this study. Animals 

were not dosed high enough as the dose selection was based upon increased relative liver 

weights in a 90-day oral toxicity study in rats. Although a maternal, reproductive and offspring 

LOAEL could not be established, this study was classified as Acceptable/Non-guideline.
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Chronic Toxicity 

In the chronic toxicity rat study (MRID 44380106), the LOAELs for liver findings were 1.7 and 

2.1 mg/kg/day for males and females, respectively. No liver effects were noted in the 90-day dog 

study at doses up to 11.63 mg/kg/day for males and 14.64 mg/kg/day for females. However, in 

the 12-month dog study (MRID 44323911) , the NOAEL was 3.2 mg/kg/day (both sexes) with 

the LOAELs being 12.3 and 13.2 mg/kg/day for males and females, respectively, based upon ≥ 

200% increase in alanine aminotransferase (ALT). No liver changes were reported for any of the 

other toxicity studies in the fenpropimorph database.

Carcinogenicity 

In accordance with the EPA Draft Guidelines for Carcinogen Risk Assessment (July, 1999), 

fenpropimorph was classified as, “not likely to be carcinogenic to humans.” There were no 

increased incidences of benign or malignant tumors in the rat chronic toxicity/carcinogenicity 

study (MRID 44380106) or the mouse carcinogenicity study (MRID 44380107) conducted with 

fenpropimorph.

Mutagenicity 

A complete battery of mutagenicity studies was negative for fenpropimorph in a reverse gene 

mutation study in Salmonella typhimurium (MRID 44323917), an in vitro mammalian 

chromosome aberration study in Chinese hamster lung cells (MRID 44323919), an in vivo

mammalian cytogenetic micronucleus assay in mice (MRID 44323918) and an unscheduled 

DNA synthesis assay in primary rat hepatocytes/mammalian cell cultures (MRID 44323916).

Other Toxicological Effects 

Neurotoxicity Battery

Effects of administration of fenpropimorph were on a variety of measured nervous system 

parameters. In two 90-day rat studies (MRID 44380103, 44380105), there were decreases in 

serum/plasma cholinesterase levels. However, these serum/plasma values are not considered 

relative for risk assessment purposes. In addition, there were decreases in brain cholinesterase 

levels at 2.1 mg/kg/day in both sexes. Regarding a mouse carcinogenicity study (MRID 

44380107), in females only, the NOAEL for RBC cholinesterase was 0.5 mg/kg/day with a 

LOAEL of 3.5 mg/kg/day. These cholinesterase effects were not considered in choosing 

NOAELs or LOAELs because of the inconsistency of the results (i.e. no clear dose-response 

relationship) among studies, species and controls. No apparent effect on cholinesterase levels 

was noted in dogs (MRID 44323911). Additional nervous system effects were reported in the 

acute neurotoxicity study in rats (MRID 44323910) where the NOAELs for males and females 

were 500 mg/kg and the LOAELs were 1500 mg/kg based upon piloerection plus dilation of the 

ventricles of the brain observed in one male and piloerection plus dilation of the ventricles of the 

brain with overall decreased motor activity in one female.

Developmental Neurotoxicity
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A developmental neurotoxicity study is not anticipated to be required because neurotoxicity 

parameters were affected only at very high doses, considerably higher than the NOAELs and 

RfDs established for developmental effects (i.e. cleft palate) in the acute dietary endpoint and 

liver-related changes in the chronic dietary endpoint. Therefore, the acute and chronic dietary 

endpoints established for fenpropimorph will provide a margin of safety of 500 times lower for 

acute and 2000 times lower for chronic effects before any significant neurotoxic effects are 

observed. For registration review of the antimicrobial wood preservative uses of fenpropimorph 

only, acute and chronic dietary risk assessments are not needed.

Metabolism and Pharmacokinetics

In a rat metabolism and pharmacokinetic study (MRID 44323920), 96-110% of the radioactivity 

was recovered within 96 hours of dosing. High levels were found in feces of intravenous dosed 

rats (45-49%), indicating biliary excretion as a major route of elimination. In bile-duct 

cannulated rats, most of the dose was recovered in the bile. After oral dosing, high levels were 

recovered in the urine and bile, indication absorption from the gastrointestinal (GI) tract. No 

parent compound was found in the urine, feces or bile; fenpropimorph was completely 

metabolized. Fenpropimorph metabolism appears to involve oxidation of the tert-butyl group on 

the phenyl ring to form the acid metabolite BF 421-2, which is hydroxylated to yield the major 

metabolite BF 421-3. Most of the radioactivity in bile (56-69%) was made up of many unknown 

components. The presence of unknown components in bile, suggest that metabolites which are 

initially excreted, undergo further metabolism and reabsorption prior to final elimination in urine 

and feces. Several major metabolites (>5% of the administered dose) were detected in urine and 

feces.

Dermal Penetration

In an in vivo dermal penetration study (MRID 47154901) designed to approximate field 

conditions, an absorption factor of 12% was estimated in the rat based on an 8-hour exposure at a 

dose of 0.04 to 0.4 mg/cm2fenpropimorph. Although this study does not satisfy the guideline 

requirement for a dermal penetration study in rats, it is classified acceptable/non-guideline 

because it provides sufficient information for estimation of a dermal penetration factor that can 

be applied to an oral NOAEL for dermal risk assessments. No dermal toxicity study is 

anticipated to be required for fenpropimorph.

References

MRID 44323910. Mellert, W.; Kaufmann, W.; Hildebrand, B. (1997) Acute Oral Neurotoxicity 

of Fenpropimorph in Wistar Rats: Lab Project Number: 97/10592: 20C0047/93061. 

Unpublished study prepared by BASF Aktiengesellschaft. 420 p.

MRID 44323911. Hellwig (1990) Report on the Study of Fenpropimorph in Beagle Dogs. 

Administration via the Dier over 12 months: Lab Project Number: 90/0172: 33D0133/87021. 

Unpublished study prepared by BASF Aktiengesellschaft. 842 p.
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MRID 44323912. Hoffmann, T.; Merkle, J. (1979) Study of the Prenatal and Postnatal Toxicity 

of Fenpropimorph in Rats: Lab Project Number: 79/10164: T282R. Unpublished study prepared 

by BASF Aktiengesellschaft. 344 p. 

MRID 44323913. Zeller, H.; Merkle, J. (1980) Study to Determine the Prenatal Toxicity of 

Fenpropimorph in Rabbits: Lab Project Number: 80/0109: T316K. Unpublished study prepared 

by BASF Aktiengesellschaft. 258 p.

MRID 44323914. Marty, J. (1993) CGA 101 031 (Fenpropimorph) Technical: Rabbit Oral 

Teratogenicity: (Final Report): Lab Project Number: 93/11016: 923154. Unpublished study 

prepared by Ciba-Geigy. 263 p.

MRID 44323915. Merkle, J. (1982) Report on a Reproduction Study with Fenpropimorph in the 

Rats After Oral Administration (Feeding): 2-Generation Study: Lab Project Number: 82/079. 

Unpublished study prepared by BASF Aktiengesellschaft. 1152 p.

MRID 44323916. Cifone, M. (1988) Report on the Mutagenicity Test on Fenpropimorph in the 

Rat Primary Hepatocyte Unscheduled DNA Synthesis Assay: (Revised Final Report): (Includes 

Phase 3 Summary): Lab Project Number: 88/0210: 10001-0-447: 61M0133/879008. 

Unpublished study prepared by Hazleton Labs America, Inc. 37 p.

MRID 44323917. Engelhardt, G. (1994) Report on the Study of Fenpropimorph in the Ames 

Test (Salmonella/Mammalian-Microsome Mutagenicity Test-Standard Plate Test and 

Preincubation Test): Project Lab Number: 94/10180: 40M0047/934047: 934047. Unpublished 

study prepared by BASF Aktiengesellschaft. 40 p.

MRID 44323918. Engelhardt, G. (1994) Cytogenetic Study in vivo of Fenpropimorph in Mice 

Micronucleus Test: Single Intraperitoneal Administration: (Includes Phase 3 Summary): Lab 

Project Number: 94/10966: 26M0047/934049. Unpublished study prepared by BASF 

Aktiengesellschaft. 72 p.

MRID 44323920. van Dijk, A. (1989) (Carbon 14)-RO 14/3169: Absorption, Distribution, 

Excretion, and Metabolism after Single Oral Intravenous, Single Oral, and Repeated Oral 

Administration to the Rat: Lab Project Number: 89/0315: 063641. Unpublished study prepared 

by RCC Umweltchemie AG. 413 p.

MRID 44380103. Kirsch, P. (1979) Study of the Toxicity of Fenpropimorph (Reg. No. 108 406) 

on Rats in a 3-Month Feeding Experiment: Lab Project Number: 79/079. Unpublished study 

prepared by BASF Aktiengesellschaft. 738 p.

MRID 44380104. Kirsch, P. (1979) Study of the Toxicity of Fenpropimorph (Reg. No. 108 406) 

in Beagle Dogs in a 3-Month Feeding Experiment: Lab Project Number: 80/0171. Unpublished 

study prepared by BASF Aktiengesellschaft. 487 p.
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MRID 44380105. Mellert, W.; Deckardt, K.; Kaufmann, W. et al. (1997) Subchronic Oral 

Toxicity and Neurotoxicity of Fenpropimorph (Reg. No. 108 406) in Wistar Rats Administration 

in the Diet for 3 Months: Lab Project Number: 97/10591: 50C0047/93057. Unpublished study 

prepared by BASF Aktiengesellschaft. 720 p.

MRID 44380106. Hunter, B.; Barnard, A.; Hayman, R. et al. (1982) Fenpropimorph (Reg. No. 

108 406): Assessment of Potential Tumorigenic and Toxic Effects in Prolonged Dietary 

Administration to Rats: Lab Project Number: BAF/308/81138: 82/092. Unpublished study 

prepared by Huntingdon Research Centre. 1974 p.

MRID 44380107. Hunter, B.; Heywood, R.; Hayman, R. et al. (1982) Fenpropimorph (Reg. No. 

108 406): Assessment of Potential Tumorigenic Effects in Prolonged Dietary Administration to 

Mice: Lab Project Number: BAF/320/81746: 82/142: BSF/320. Unpublished study prepared by 

Huntingdon Research Centre. 1201 p.

MRID 44380108. Hofmann, H. (1978) Investigation to Determine the Prenatal Toxicity of 

Fenpropimorph (Reg. No. 108 406) in Rats: Lab Project Number: 78/043. Unpublished study 

prepared by BASF Aktiengesellschaft. 141 p.

MRID 45857208. Gelbke (1978) Report about the Acute Oral Toxicity of the Preparation Reg. 

No. 108 406 in Rats: Lab Project Number.: 78/0144: BASF/78/0144: 77/960 Unpublished study 

prepared by BASF Aktiengesellschaft, Gewerbehygiene und Toxikologie. 11 p.

MRID 45857209. Leuschner, F. (1978) The Acute Oral Toxicity of the Preparation Reg. No. 108 

406 in Rats: Lab Project Number: 78/042: BASF/78/042: 78/164-1. Unpublished study prepared 

by Laboratorium fur Pharmakologie und Toxikologie. 14 p.

MRID 45857210. Jackh, D. (1982) Report on the Study about the Acute Dermal Toxicity of 

"Reg. No. 108406" in the Rat: Lab Project Number: 82/026: BASF/82/026. Unpublished study 

prepared by BASF Ag. 6 p.

MRID 45857211. Klimisch, H.; Zeller, H. (1979) Determination of the Acute Inhalation Toxicity 

LC50 of Fenpropimorph (Reg. No. 108406) as a Liquid Aerosol after 4-Hour Exposure in 

Sprague-Dawley Rats: Lab Project Number: 79/072: BASF/79/072. Unpublished study prepared 

by BASF Ag, Gewerbehygiene und Toxikologie. 22 p.

MRID 45857212. Grundler, O. (1980) Report on the Study of the Primary Irritation of "Reg. No. 

108406" on the Eye of White Rabbits: Lab Project Number: 80/0170: BASF/80/0170: 79/356. 

Unpublished study prepared by BASF Aktiengesellschaft, Gewerbehygiene und Toxikologie. 9 

p.

MRID 45857213. Grundler, O.; Leuschner, F. (1980) Primary Dermal Irritation of 

Fenpropimorph Techn. on the Rabbit Skin: Lab Project Number: WOL/80/04/10: 79/356: BASF 
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80/0212. Unpublished study prepared by Laboratorium fur Pharmakolgie und Toxikologie and 

BASF Aktiengesellschaft. 18 p.

MRID 45857214. Gelbke, D. (1979) Dermal Sensitization Study on the Guinea Pig According to 

the Maximization Test: (Fenpropimorph): Lab Project Number: 79/0121: BASF/79/0121. 

Unpublished study prepared by BASF Ag, Gewerbehygiene und Toxikologie. 13 p.

MRID 47154901. Schwartz, R. (2007) Studies of the Dermal Resorption of (Carbon 14)-

Fenpropimorph. Project Number: WOL/07/2905. Unpublished study prepared by Dr. Wolman 

GmbH. 125 p.
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Appendix B Environmental Fate

Environmental Fate and Transport Properties of Fenpropimorph 

and its Microbial Degradate Fenpropimorph Acid.

Past environmental fate assessments addressed the persistence and mobility of parent 

fenpropimorph, cis-4-[3-(p-tert-butylphenyl)-2-methylpropyl]-2,6-dimethylmorpholineone and 

the degradate fenpropimorph acid (fenpropimorph carboxylic acid). 

The sole end-use product (EPA Reg. No. 71406-4, 5.4 % fenpropimorph, CAS No. 121098-45-

1) is intended to preserve lumber that can be used in fresh water habitats but not marine or 

estuarine habitats. However, the label does not restrict uses that are or can be submersed in water 

or in structures that overlay water such as docks and piers. As a result, the agency assumes that 

aquatic exposure from treated wood can occur directly by leaching created by rainfall and 

submersion of exposed wood. The agency also assumes that aquatic exposure can occur from 

leaching of fenpropimorph from treated wood that is created by rainfall. Leached fenpropimorph 

from treated wood used in terrestrial areas can reach surface water by either runoff on the soil 

surface or by downward movement into the soil which reaches ground water that is in contact 

with surface water. 

Based on a wood leaching study (MRID 46074205), fenpropimorph used as an antisapstain 

product can leach at low concentration to the environment for an extended period of time. 

Fenpropimorph is relatively water-insoluble (Table 4), but will be present in both sediment and 

water based on aerobic aquatic metabolism data (MRID 45857318). Based on its low vapor 

pressure (6.5 x 10-6 mm Hg, Table 4), it is unlikely to vaporize from soil into air. Based on its 

low Henry’s Law constant (6 x 10-6atm m3 mol-1), fenpropimorph is unlikely to volatilize from 

water into air (Table 4). Parent fenpropimorph was slightly mobile in soil with Freundlich Kads 

values of 46 and 79 L/kg and Koc values of 3,833 and 8,778 L/kg in loamy sand and sandy loam 

soils (MRID 45857318). 

Fenpropimorph can dissociate to form fenpropimorph acid, and the disassociation constant (pKa) 

for fenpropimorph is 7 (Table 4). The pKa is the pH at which 50 % of a substance is non-ionized 

(non-dissociated) and 50 % is ionized (disassociated). At pH levels below the pKa, a compound 

will exist primarily as the non-ionized form and will exist primarily as the ionized form above 

the pKa. Consequently, at most pH values (pH 5-7), parent fenpropimorph will exist 

predominantly as the parent compound (non-ionized) and not as fenpropimorph acid (ionized). 

However, in areas that are calcareous (pH ~8.3) or sodic (pH ~9), fenpropimorph acid will 

eventually become the primary chemical specie. 

Fenpropimorph acid forms from metabolism of fenpropimorph in aerobic soil (MRID 45857217) 

and in two aerobic aquatic systems containing both water and sediment (MRID 45868904). 

Aerobic soil metabolism studies represent the degradation of a chemical in the oxygenated top 

layer of soil, and aerobic aquatic metabolism study represent degradation and partitioning of a 

chemical that occurs in an oxygenated surface water system that contains sediment. Based on 
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aerobic soil metabolism study results, fenpropimorph acid was not formed at significant 

quantities (>10 % of applied parent compound) in the soil environment. Based on aerobic aquatic 

metabolism study results, however, it was formed at significant quantities in the sediment phase 

from degradation of fenpropimorph and repartitioned to the water phase. Fenpropimorph acid 

was mobile to highly mobile with Freundlich Kads values of 0.5 and 1 L/kg and Koc values of 

42 and 111 L/kg in loamy sand and sandy loam soils (MRID 45857318).

Water and Sediment

Hydrolysis

Fenpropimorph is stable to hydrolysis at pH 3, 5, 7, and 9 (MRID 45857216).

Aqueous Photolysis

Data have not been submitted, but the limited sorption of UV/visible light by fenpropimorph 

above 290 nm of wavelength (MRID 46074201) is expected to prevent direct photodegradation 

in water.

Octanol-Water Partition Coefficient

The log Kow of fenpropimorph is 4.1 (>3), which indicates that sorption to soil and sediment 

and bioconcentration in fish and other aquatic organisms is likely. (MRID 45857203).

Aerobic Aquatic Metabolism

The half-lives of parent fenpropimorph in two loamy sand systems containing both water and 

sediment were 54 and 18 days, respectively. The half-lives for the degradate fenpropimorph acid 

were 121 and 29 days in these aquatic systems, respectively. Aqueous residues of parent 

fenpropimorph were higher for water than sediment for 2-7 days and sediment residues were 

higher for the remainder of the study (up to 100 days). On the other hand, aqueous residues of 

fenpropimorph acid were higher for water than in sediment throughout the study because it is 

more polar than the parent compound (MRID 45868904). 

Soil

Soil Leaching/Adsorption/Desorption Batch Equilibrium

Parent fenpropimorph was slightly mobile with Freundlich Kads values of 46 and 79 L/kg and 

Koc values of 3,833 and 8,778 L/kg in loamy sand and sandy loam soils. On the other hand, the 

degradate fenpropimorph acid was mobile to highly mobile with Freundlich Kads values of 0.5 

and 1 L/kg and Koc values of 42 and 111 L/kg in loamy sand and sandy loam soils (MRID 

45857318).

15

 

15 Log Koc values of 0-2 are mobile to highly mobile and Log Koc values of 3-4 are considered to be slightly mobile 

(http://www.fao.org/docrep/003/x2570e/x2570e06.htm ) 
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Aerobic Soil Metabolism

Fenpropimorph only slight degraded in aerobic soil with half-lives of 364-433 and 518-545 days 

in loamy sand and sandy loam soils, respectively. No significant degradation products were 

detected (MRID 45857217). 

Leaching from Treated Wood

Pine wood was treated and leached using rainfall. The maximum and average leaching rates were 

0.85 and 0.18 μg/cm2/day and the cumulative leaching was 17.9 μg/cm2over a 237 day period 

(MRID 46074205). Additional data on leaching are not anticipated to be required because the 

only use of fenpropimorph is an antisapstain, which is expected to create low concentrations over 

a long period of time based on the limited water solubility of 4.32 mg/l (Table 4). 

Fate and Transport in WWTP

Data for routes of dissipation and toxicity in WWTPs were not submitted. However, data on the 

environmental fate of fenpropimorph in WWTPs are not anticipated to be required because the 

sole end-use label states that wastes must be treated as hazardous waste and disposal must be 

conducted according to label instructions, a state pesticide or environmental control agency, or 

by guidance from a hazardous waste representative. 

Table B1. Status of Fenpropimorph Environmental Fate Studies

Test Guideline 

(parent 

compound unless 

stated)

OCSPP 

Guideline 

No. 

Study result Significant 

Degradation 

Products16

Study status Reference (MRID) 

and Comments

Hydrolysis 835.2120 Stable at pH 3, 

5, 7, and 9

None Acceptable 45857216

Rudel, 1988

25 oC

Gowda, Nov. 8, 

2006a review

Photodegradation 

in water by 

sunlight 

835.2210 No data Not applicable Not required Limited UV/Visible 

sorption above 290 

nm (MRID 

46074201)

Aerobic soil 

metabolism

835.4100 363-433 and 

518-545 days 

in loamy sand 

and sandy 

loam soil 1 

ppm, 

respectively17

213-284 and 

441-579 days 

in loamy sand 

None Acceptable 45857217

Rudel, 1989

25 oC

Gowda, Nov. 8, 

2006b review

5 ppm rate used for 

degradate 

identification only 

and not for 

persistence 

 

16 Significant degradates formed at >10 % of applied parent compound

17 Non-linear regression using days (x) and % applied parent (y) and all intervals
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and sandy 

loam soils at 5 

ppm, 

respectively.

estimates in risk 

assessment

Anaerobic 

aquatic 

metabolism

835.4400 No data Not applicable Not required None

Aerobic aquatic 

metabolism

835.4300 54 and 18 day 

half-lives in 

two loamy 

sand 

water:sediment 

systems18

121 and 39 day 

half-lives in two 

loamy sand 

water:sediment 

systems

Acceptable 45868904

Degradate was 

Fenpropimorph 

acid

Ebert, 2000

20 oC

Gowda, Nov. 8, 

2006c review

LeachingAdsorptionDesorption 

(unaged)

835.1230 Kd values of 

46 and 79 L/kg 

in 

loamy sand 

and sandy 

loam soils

Koc values of 

3,833 and 

8,778 L/kg

Kd values of 0.5 

and 1 L/kg in 

loamy sand and 

sandy loam soils 

(Fenpropimorph 

acid)

Koc values of 42 

and 111 L/kg

Supplemental 45857318

Stockmaier, 1996

Gowda, Nov. 8, 

2006d review

Aged leachingadsorptiondesorption of 

Fenpropimorph 

acid

835.1230 No further data 

required

No further data 

required

Supplemental 45867318

Stockmaier, 1996

Temp?

Gowda, Nov. 8, 

2006d review

Bioconcentration 

in Fish

850.1730 No data Not applicable 

for degradate 

fenpropimorph 

acid

Required for 

parent 

fenpropimorph19

None

Leaching from 

treated wood

OECD Draft 

CEN/TR 

15119

Data not used Not applicable Unacceptable 47010801

Hantzschel, 2006

Gowda, Nov. 8, 

2006e review

Study rejected 

because of incorrect 

protocol

AWPA E11-

06

Leaching rates 

(ug/cm2/day) 

0.85 (max)

0.18 (average)

0.00047 (min)

No data Supplemental 46074205

Maier, 2003

Gowda, Nov. 8, 

2006f review

 

18 Non-linear regression using days (x) and total of % applied parent compound (y) from water and sediment from 

all intervals 

19 Based on log Kow (Log P) of 4.1 (>3), 850.1730 data are required for parent fenpropimorph
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Cumulative 

leaching 

(ug/cm2)

17.9 (average)

References 

Ebert, D. 2000. Degradation of BAS 421 F in Water/Sediment Systems under Aerobic 

Conditions: (Final Report): Lab Project Number: 2000/1000146: BASF/2000/1000146: 58000. 

Unpublished study prepared by BASF Ag. 104 p. MRID 45868904

Food and Agriculture Organization of the United Nations. APPENDIX 2: Parameters of 

pesticides that influence processes in the soil. 

http://www.fao.org/docrep/003/x2570e/x2570e06.htm

Gowda, S. November 8, 2006a. Review of the study, Hydrolysis studies on BAS 421 F at pH 3, 

5, 7, and 9, to Support the Application for New Registration of End Use Product, Wolsin® FL 

35 Antisapstain containing the active ingredients, 5.4% Fenpropimorph, 2.7% Propiconazole and 

9% Boric acid, EPA File Symbol 71406-U. D333168

Gowda, S. November 8, 2006b. Review of the study, Aerobic Metabolism Studies of BAS 421 

F, to Support the Application for New Registration of End Use Product, Wolsin® FL 35 

Antisapstain containing the active ingredients, 5.4% Fenpropimorph, 2.7% Propiconazole and 

9% Boric acid , EPA File Symbol 71406-U. D333168

Gowda, S. November 8, 2006c. Review of the study, Degradation of BAS 421 F in 

Water/Sediment Systems under Aerobic Conditions to Support the Application for New 

Registration of End Use Product, Wolsin® FL 35 Antisapstain containing the active ingredients, 

5.4% Fenpropimorph, 2.7% Propiconazole and 9% Boric acid, EPA File Symbol 71406-U. 

D333168

Gowda, S. November 8, 2006d. Review of the study published in an article, Investigations on 

the Behaviour of Fenpropimorph and its Metabolite Fenpropimorph Acid in Soils, to Support the 

Application for New Registration of Wolsin® FL 35 Antisapstain containing the active 

ingredients, 5.4% Fenpropimorph, 2.7% Propiconazole and 9% Boric acid, EPA File Symbol 

71406-U. D333168

Gowda, S. November 8, 2006e. Review of the study, Leaching Behaviour of Wolsin FL-35 

Treated Wood in UC 3, to Support the Application for New Registration of End Use Product, 

Wolsin® FL 35 Antisapstain containing the active ingredients, 5.4% Fenpropimorph, 2.7% 

Propiconazole and 9% Boric acid, EPA File Symbol 71406-U. D333168

Gowda, S. November 8, 2006f. Review of the study, Leaching Behaviour of Wolsin FL-35 

Treated Timber, to Support the Application for New Registration of End Use Product, Wolsin® 

FL 35 Antisapstain containing the active ingredients, 5.4% Fenpropimorph, 2.7% Propiconazole 

and 9% Boric acid, EPA File Symbol 71406-U. D333168

Gowda, S. June 26, 2007. Environmental Fate Assessment of Fenpropimorph for New 

Chemical Registration. D333168
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Hantzschel, D. (2006) Leaching Behavior of Wolsin Fl-35 Treated Wood Exposed in UC 3: 

Fenpropimorph . Project Number: Wolman230606, P1032/G, 1032/4/G. Unpublished study 

prepared by Dr. Wolman Gmbh. 112 p. MRID 47010801

Maier, M. (2003) Leaching Behaviour of Wolsin FL-35 Treated Timber. Project Number: 

08/2003. Unpublished study prepared by Dr. Wolman GMBH. 10 p. MRID 46074205

Rudel, H. 1988. Hydrolysis Studies on BAS 421 F at pH 3, 5, 7, and 9: Lab Project Number: 

88/0443: BASF/88/0443: P86-C011. Unpublished study prepared by Fraunhofer-Institut fuer 

Umweltchemie und Oekotoxikologie. 48 p. MRID 45857216

Rudel, H. September, 1989. Aerobic Metabolism Studies of BAS 421F. Fraunhofer-Institut fur, 

Umweltchemie und Okotoxikogie, D-5948 Schmallenberg, Federal Republic of Germany. Study 

No.: P87-C023. Sponsor: BASF Corporation. BASF Registration Document No.: 89/10140. 

MRID 45857217).

Stockmaier, M.; Kreuzig, R.; Bahadir, M. (1996) Investigations on the Behaviour of 

Fenpropimorph and its Metabolite Fenpropimorph Acid in Soils. Pesticide Science 46:361-367. 

MRID 45857218
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Appendix C Ecotoxicology Profile

Toxicity to Terrestrial Receptors

Birds:

Two acute avian toxicity studies are available using technical fenpropimorph. 

Fenpropimorph is practically non-toxic when administered orally or as a sub-acute dietary 

treatment to avian test species. Both studies are acceptable, and fulfill the guideline 

requirement for avian acute toxicity (MRIDs 45868901, 45857204). 

Plants:

A Tier I vegetative vigor non-target plant toxicity test was conducted on 10 vascular plants 

to determine if the maximum recommended label dosage is phytotoxic to plants. If greater 

than 25% injury or growth reduction occurs, the pesticide is considered phytotoxic and Tier 

II studies are triggered. In this Tier I study (MRID 46074306), fenpropimorph was 

phytotoxic at greater than 25% to plants. The most sensitive monocot was corn, and the 

most sensitive dicot was cabbage). Fenpropimorph Tier II dose response studies for 

seedling emergence and vegetative vigor are outstanding for the rooted aquatic macrophyte 

rice (Oryza sativa). No other terrestrial plant species are required to be tested by the 

Antimicrobial Division at the Tier II level. The Tier I vegetative vigor study is acceptable 

and fulfills the guideline requirement for 850.4150 (MRID 46074306).

Toxicity to Aquatic Receptors

Freshwater Fish:

Three acute freshwater fish toxicity studies are available. Two studies, one using the 

Rainbow trout and one using the Bluegill sunfish, are technical grade tests. In both studies, 

the fenpropimorph was moderately toxic to freshwater fish. In the third test, the end-use

formulation was used. In this study, the fenpropimorph, propiconazole, boric acid mixture 

was highly toxic to freshwater fish on an acute toxicity basis (LC50 ≥ 0.74 mg/L, NOAEC 

= 0.10 mg/L). These studies are acceptable and fulfill the guideline requirement for 

freshwater fish acute toxicity tests (MRIDs 45857205, 45857206, 46070203).

Estuarine/Marine Fish:

No studies are available for the technical. However, the registrant has off-labeled the use 

of fenpropimorph in estuarine/marine habitats, and therefore these data are not required.

Freshwater Invertebrates:

Two acute freshwater invertebrate toxicity tests are available using the Daphnia magna. 

In the first, technical grade fenpropimorph was used. Fenpropimorph technical grade was 
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slightly toxic. In the second study, the end-use formulation was used. The fenpropimorph, 

propiconazole, boric acid mixture was highly toxic to freshwater aquatic invertebrates on 

an acute toxicity basis (LC50 = 0.30 mg/L, NOAEC = 0.10 mg/L, MRIDs 45857207, 

46074204). 

Estuarine/Marine Invertebrates:

No studies are available for fenpropimorph technical. However, the registrant has offlabeled the use of fenpropimorph in estuarine/marine habitats, and therefore these data are 

not required.

Chronic Aquatic Ecotoxicity Studies:

Freshwater Chronic Fish and Invertebrates:

Two chronic aquatic animal studies are available for technical grade fenpropimorph, a fish 

early life test using the Rainbow trout, and an invertebrate life cycle study using Daphnia 

magna. The most sensitive species is the freshwater fish having a NOAEC <0.00016 mg/L 

(body length). Both studies are acceptable and fulfill the guideline requirements for chronic 

freshwater fish and invertebrates (MRIDs 46074303, 46074305).

Estuarine/Marine Fish and Invertebrates:

No studies are available for fenpropimorph technical or end-use product. However, the 

registrant has off-labeled the use of fenpropimorph in estuarine/marine habitats, and 

therefore these data are not required.

Based on environmental fate data, fenpropimorph is either tightly bound to soil or 

converted to fenpropimorph acid. In laboratory studies, fenpropimorph acid (BF 421-2) 

was detected in sediment with a concentrations ranging from 6.2% to 9.1%. 

Fenpropimorph acid is not tightly bound to soil and has potential to move from the 

treatment (or storage) site. Aquatic invertebrate acute toxicity tests are 48 hours in duration, 

fish studies are 96 hours in duration, and algal toxicity studies are 96 to 120 days in 

duration. It is assumed that conversion from fenpropimorph parent to fenpropimorph acid 

will occur to some extent in aquatic toxicity tests.

Table C1. Summary of Antisapstain fenpropimorph Ecotoxicity Studies – 02/10/09

Study/Species MRID 

Number

Study Results Status of Study

Birds

Avian Acute Oral – 96.6%

850.2100/71-1

Bobwhite quail

45868901 LD50 ≥2000 mg/Kg

NOAEC = 1000 mg/kg

CORE - Practically 

non-toxic.

Avian Sub-Acute

Dietary – 94.7%

45857204 LC50 = 5000 mg/Kg CORE - Practically 

non-toxic.
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850.2200/71-2

Mallard duck

NOAEL = 1250 mg/Kg

Terrestrial Invertebrates

Acute Nontarget Insect -

Honey bee TGAI 95.7%

850.3020 acute oral

860.3030 acute contact

47125501 ORAL LC50 ≥95.6 ug ai/bee

 NOAEC = 6.25 ug ai/bee

CONTACT LC50≥100 ug ai/bee

 NOAEC = 6.25 ug ai/bee

Acceptable. 

Aquatic Animals

Acute Freshwater 

Invert. - 96.6%

850.1010/72-2 

Daphnia magna

45857207 EC50 = 12.24 mg/L

NOAEC = 1.0 mg/L

CORE – Slightly 

toxic.

Acute Freshwater

Invert.- Form. *

850.1010/72-2 

Daphnia magna

46074204 LC50 = 0.30 mg/L

NOAEC = 0.10 mg/L

CORE – Highly 

toxic.

Acute Freshwater

Invert.- Fenpropimorph. 

Acid – 99.8%

850.1010/72-2 

Daphnia magna

47425204 EC50 ≥ 100 mg/L

NOAEC ≥ 100 mg/L

Supplemental – Not 

repairable.

Acute Estuarine/Marine

Invert. TGAI

850.1035

Mysid shrimp

Waived.

Acute Estuarine/Marine

Invert. TGAI

850.1055

E. Oyster embryo larvae

Waived.

Acute Freshwater 

Fish- 96.6%

850.1075/72-1c

Rainbow trout

Oneorhynchus mykiss

45857206 LC50 = 5.15 mg/L

NOAEC = >1.0 mg/L

CORE – Moderately 

toxic.

Acute Freshwater 

Fish- Form.* 

850.1075/72-1c

Rainbow trout

Oneorhynchus mykiss

46074203 LC50 ≥ 0.74 mg/L

NOAEC = 0.10 mg/L

CORE – Highly 

toxic.

Acute Freshwater 

Fish- Fenpropimorph

Acid 99.8% 

850.1075/72-1c

Rainbow trout

Oneorhynchus mykiss

474252-02 LC50 ≥ 100 mg/L

NOAEC ≥ 100 mg/L

Supplemental – Not 

repairable.

Acute Freshwater

Fish - 96.6%

850.1075/72-1a

Bluegill sunfish

Lepomis macrochirus

45857205 LC50 = 3.25 mg/L

NOAEC = 0.63 mg/L

CORE – Moderately 

toxic.

Acute Estuarine/Marine

Fish TGAI

Waived.
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850.1075

Acute Sediment Freshwtr 

Inverts. Fen.Acid

850.1735

Waived.

Acute Sediment Marine 

Inverts. Fen.Acid

850.1740

Waived.

Acute Sediment Freshwtr 

Inverts. Fenpropimorph

Acid – 95.6%

Chironomous riparius

850.1790

47425201 EC50 ≥ 0.000125 mg/L

NOAEC ≥ 0.000125 mg/L

Supplemental – Not 

repairable.

Plants

Rooted Aquatic - Rice

850.4225/123-1

Oryza sativa

Waived.

Veg. Vigor – Cabbage

 Form.*

Most sensitive dicot

850.4150/122-1

Brassica oleracea

46074306 EC25 > 25% effect

Tier II data triggered.

Supplemental

Tier II data.

Waived.

Veg. Vigor – Corn

 Form*

Most sensitive monocot

850.4150/122-1

Zea mays

46074306 EC25> 25% effect

Tier II data triggered.

Supplemental

Tier II.

Waived.

Floating macrophyte

850.4400/123-2

Duckweed

Lemna gibba

Waived.

Blue-green cyanobacteria

850.5400/123-2

Anabaena flos-aquae

Waived.

Green algae - 96.6%

850.5400/123-2

Selenastrum 

capricornutum

45868903 EC50 = 0.327 mg/L

EC10 = 0.005 mg/L

Supplemental.

Green algae - 

Fenpropimorph Acid -

99.8%

850.5400/123-2

Selenastrum 

capricornutum

47425203 EC50 ≥ 100 mg/L

NOAEC= >25 mg/L

Supplemental.Not 

repairable.

Freshwater diatom

850.5400/123-2

Navicula pelliculosa

Waived.

Marine diatom

850.5400/123-2

Skeletonema costatum

Waived.
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Chronic Aquatic Tests

Fish Early Life -95.6%

850.1400/72-4a

Rainbow trout

Oneorhynchus mykiss

46074303 NOAEC ≤ 0.00016 mg/L 

 for body length

NOAEC = 0.00016 mg/L

 for body weight

CORE.

Aquatic Invertebrate Life 

Cycle - 95.4%

850.1300/72-4b

Daphnia magna

46074305 NOAEC = 0.082 mg/L

EC50 = 0.41 mg/L

CORE.

*Formulation – End-use product (fenpropimorph=5.4%, propiconazole=2.7%, boric acid = 9.0%).

References:

MRID 45857204: Avian Dietary LC50 Test Re. No. 108 406 (= Test Substance No. 87/133) in 

the Mallard Duck (Anas platyrhynchos L.) January 1988. BASF AG Department of Agricultural 

Research and Development D-6703 Limburgerhof, Germany.

MRID 45857205: Fenpropimorph: Acute toxicity study on the bluegill (Lepomis macrochirus 

RAF) in a static system (96 hours). December 22, 1999. Department of Toxicology BASF 

Aktiengesellschaft D-67056 Ludwigshafen/Rhein, Germany. ID: 14F0235/995028

MRID 45857206: Fenpropimorph: Acute toxicity study on the rainbow trout (Oncorhynchus 

mykiss Walbaum 1792) in a static system (96 hours). December 2, 1999. Department of 

Toxicology BASF Aktiengesellschaft D-67056 Ludwigshafen/Rhein, Germany. ID: 

121F0235/995026

MRID 45857207: Determination of the acute effect of BAS 421 F on the swimming ability of 

the water flea Daphnia magna STRAUS according to OECD 202 and GLP, EN 45001 and ISO 

9002. November, 1999. BASF Aktiengesellschaft Ecology and Environmental Analytics

Laboratory of Ecology 67056 Ludwigshafen, Germany. Document No.: 1999/11534

MRID 45868901: Fenpropimorph - Avian Single Dose Oral LD50 on the Bobwhite Quail 

(Colinus virginianus). February 3, 2000. Experimental Toxicology and Ecology BASF 

Aktiengesellschaft 67056 Ludwigshafen/Rhein, Germany. Report ID: 11W0235/99037

MRID 45868903: Effect of BAS 421 F on the Growth of the Green Alga Pseudokirchneriella 

subcapitata. February 29, 2000. BASF Aktiengesellschaft BASF Agricultural Center 

Limburgerhof Crop Protection Division Ecology and Environmental Analytics P.O. Box 

12067114 Limburgerhof, Germany. Study No. 58022

MRID 46074203: Acute Toxicity of Wolsin FL-35 to Rainbow Trout (Oncorhynchus mykiss) in 

a 96-hour Semi Static Test. April 2, 2003. Institut für Biologische Analytik und Consulting 

IBACON GmbH D-64380 Rossdorf, Germany. Report ID: 14643230

MRID 46074204: Acute Toxicity of Wolsin FL-35 to Daphnia magna in a 48-hour 

Immobilization Test April 4, 2003. Institut für Biologische Analytik und Consulting IBACON 

GmbH D-64380 Rossdorf, Germany. Report ID: 14642220
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MRID 46074303: Early Life-Stage Toxicity Test on the Rainbow Trout (Oncorhynchus mykiss

WALBAUM 1792) with Fenpropimorph. June, 1995. BASF Aktiengesellschaft Department of 

Toxicology D-67056 Ludwigshafen/Rhein, Germany. Doc. No: 95/10517

MRID 46074304: Chronic Effects of BAS 492 01 F on Juvenile Fish- Leuciscus Idus L. “golden 

variety” – under more realistic exposure conditions in small field microcosms. October 31, 2002

BASF Aktiengesellschaft Crop Protection Division D-67114 Limburgerhof, Germany. Report 

ID: 2002/1011545

MRID 46074305: Reproduction test of the test material Ro 14-3169/000 on Daphnia magna acc 

to OECD-guideline 202 (Phase II). August 1989. NATEC-Institut Behringstrasse 154 D-2000 

Hamburg (FRG). Report ID:89/10174

MRID 47425201: Effect of Fenpropimorph on the Sediment-Dwelling Larvae of Chironomous 

riparius. September 1994. BASF Aktinogasellschaft, Ecology and Environmental Analytics, 

Postfatch 120 D-67114, Limburgerhof, FRG. Report ID: P94-E027

MRID 47425204: Effect of Reg. No. 231346 on Daphnia magna STRAUS in a Static Acute 

Toxicity Test. February 1997. BASF Aktiengesellschaft, Ecology and Environmental Analytics, 

Postfach 120, D-67114 Limburgerhof, FRG. Report ID: 35504

MRID 47425203: Effect of BF 421-2 on the Growth of the Green Alga Pseudokirchneriella 

subcapitata. November, 1997. BASF Aktiengesellschaft, Ecology and Environmental Analytics, 

Postfach 120, D-67114 Limbugergerhof, FRG. Report ID: 43890

MRID 47425202: Acute Toxicity Study on the Rainbow Trout (Oncorhynchus mykiss Walbaum 

1792) with Static System (96 hours). December 1997. BASF Aktiengesellschaft, Department of 

Toxicology, D-67056 Lutwigshafen/Rhein, FRG. Report No.: 12F0411/975072

MRID 47675201: Seedling Emergence, Tier II. September 18, 2008. Huntington Life Sciences

Limited, Huntington Research Centre. Report ID: DWM0002

MRID 47675201: Vegetative Vigour Tier II. June 17, 2008. Huntingdon Life Sciences 

Limited, Huntingdon Research Centre. Report ID: DWM0003

MRID 47675202: Wolsin Fl-35: Phytotoxicity test with the freshwater duckweed (Lemna 

gibba), under static conditions. 23 October 2008. Springborn Smithers Laboratories (Europe), 

Seestrasse 21,Postfach, CH-9326 Horn, Switzerland. Report ID: 1111.001.410

MRID 47675203: Assessment of the algal toxicity, Tiers I and II (96h EC50) of Wolsin FL-35 to 

The marine alga Skeletonema costatum, the freshwater algae Selenastrum capricornutum and 

Anabaena flos aquae. November 5, 2008. Opus Plus Limited, Flotta, United Kingdom

Report ID: 1051-27

USEPA. 2007. Ecological Risk and Fate Assessment for fenpropimorph (Wolsin® FL 35) New 

Chemical Wood Preservative Antisapstain Use. 

USEPA. 2009. Review of Studies and Ecotoxicity Data Waiver Requests for the Conditional 

Registration of the Antisapstain Use of fenpropimorph (Wolsin® FL 35).
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Appendix D Screening Level Down-theDrain Analysis

Data for routes of dissipation and toxicity in WWTPs were not submitted. However, data on the 

environmental fate of fenpropimorph in WWTPs are not anticipated to be required because

fenpropimorph is not expected to be transported to WWTPs. The sole end-use label states that 

wastes must be treated as hazardous waste and disposal must be conducted according to label 

instructions, a state pesticide or environmental control agency, or by guidance from a hazardous 

waste representative. As a result, the agency does not plan to conduct a down-the-drain analysis 

for fenpropimorph.
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Appendix E Product Chemistry

Fenpropimorph product chemistry information is summarized in Table E1 (Source: MRIDS 

44323904, 44323906, 44835201, 45857201, 45857202, 45857203, 45857219, 46097501, 

46097502)

Table E1 – Product Chemistry of Fenpropimorph

Guideline 

No.

Physical and Chemical 

Properties Fenpropimorph

830.1550 Product identity and 

composition Refer to Table 3. 

830.1600 Description of materials used 

to produce the product

Confidential Business Information (CBI).

830.1620 Description of production 

process

CBI.

830.1650 Description of Formulation 

Process

CBI.

830.1670 Discussion of Formation of 

Impurities

CBI.

830.1700 Preliminary analysis CBI.

830.1750 Certified limits CBI.

830.1800 Enforcement analytical 

method Capillary gas chromatography.

830.1900 Submittal of samples CBI.

830.6302 Color Colorless liquid.

830.6303 Physical State Liquid.

830.6304 Odor Faint aromatic odor.

830.6313 

Stability to normal and 

elevated temperature, 

metals/metal ions 

Stable to normal (25C) and elevated temperatures (54C) over the time 

interval of 14 days. Stable to metal and metal ions (aluminum, aluminum 

acetate, iron filings, and iron (II) acetate) at normal and elevated 

temperatures over the time interval of 14 days. Stable to light.

830.6314 Oxidation/Reduction Not oxidizing. No oxidizing properties.

830.6315 Flammability Not flammable.

Flash point: 157oC.

830.6316 Explodability Not explodable.

830.6320 Corrosion Characteristic Not reported.

830.7000 pH at 20C 8.6 at 1% in CIPAC water.

8.2 at 1% in de-ionized water.

830.7050 UV/Visible Absorption Photolytically stable in artificial sunlight (≥290 nm) for up to 30 days at 

pH 5 and 25oC.

830.7100 Viscosity at 20C 229 mPa·s.

830.7200 Melting point Liquid at STP.

830.7220 Boiling point >300oC.

830.7300 Density 0.933 g/cm3.

830.7370 Dissociation Constant pKa: 6.98 (20oC); 

pKb 7.02 @ 20oC and 7.19 at 25oC.
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Guideline 

No.

Physical and Chemical 

Properties Fenpropimorph

830.7550 Partition coefficient (noctanol/water) 

2.6 (22oC, pH 5)

4.1 (22oC. pH 7)

4.4 (22oC, pH 9)

830.7840 Solubility in water pH 7: 4.32 mg/L at 20oC;

pH 9-11: 3.53 mg/L at 20oC.

830.7860 Solubility in organic solvents

(g/100 ml)

Acetone 760.35

Ethyl Acetate 777.95

Toluene 764.60

Dichloromethane(DCM) 774.20

n-Heptane 725.35

CAN or ACN 772.70

Methanol 789.15

Iso-propanol 816.70

Octanol 770.50

Olive oil 778.90

830.7950 Vapor pressure (mm Hg) 3.5 x 10-5

at 20oC;

6.5 x 10-5at 25oC.

Product Chemistry References

MRID 44323904. Kastel, R. (1994) Physical and Chemical Properties Report for 

Fenpropimorph...TGAI: Lab Project Number: 94/10392: PCF 01296. Unpublished study 

prepared by BASF Aktiengesellschaft. 9 p. {OPPTS 830.6313, 830.7300, 830.7000, 830.7220, 

830.6315, 830.7100, 830.6302, 830.6303, 830.6304}.

MRID 44323906. Bross, M. (1992) Determination of Fenpropimorph in Technical 

Fenpropimorph by Capillary GC: Analytical Method CP No. 149/1: Lab Project Number: 

92/11989. Unpublished study prepared by BASF Aktiengesellschaft. 9 p. {OPPTS 830.1800}.

MRID 44835201. Cannan, T. (1998) BAS 421..F: Stability to Normal and Elevated 

Temperatures, Metals, and Metal Ions: Lab Project Number: 98118: FR9864: 98/5182. 

Unpublished study prepared by BASF Corporation. 13 p. {OPPTS 830.1630}.

MRID 45857201. Redeker, D. (1998) Water Solubility of Fenpropimorph in the Neutral Range 

and at pH 9-11: Lab Project Number: 88/11302: BASF/88/11302: BASF 88/10154. Unpublished 

study prepared by BASF Aktiengesellschaft. 32 p

MRID 46097501. Redeker (1992) Determination of the Solubility of Fenpropimorph in Organic 

Solvents at 20 Degrees C. Project Number: PCP01861, 3348, 92/11596. Unpublished study 

prepared by BASF Ag Research Station (Basf Aktiengesellschaft). 16 p.

MRID 46097502. Kastel, R. (1994) Physical and Chemical Properties Report for 

Fenpropimorph. Project Number: 94/10395, BASF/94/10395, PCF/01295. Unpublished study 

prepared by BASF Ag Research Station (Basf Aktiengesellscaft). 11 p.
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MRID 45857202. Redeker, D. (1998) Determination of the pKb Value of Fenpropimorph in 

Water: Lab Project Number: 88/11671: BASF/88/11671: 2541. Unpublished study prepared by 

BASF Aktiengesellschaft. 21 p.

MRID 45857203. Kastel, R. (1994) Physical and Chemical Properties Report for 

Fenpropimorph. Project Number: 94/10395, BASF/94/10395, PCF/01295. Unpublished study 

prepared by BASF Ag Research Station (Basf Aktiengesellscaft). 11 p. 
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Appendix F Comments Received 

Concerning the Preliminary Work Plan

On September 24, 2014, EPA opened a 60-day public comment period on the preliminary work 

plan (PWP) for the registration review of fenpropimorph. The comment period ended on 

November 24, 2014. During the public comment period the agency received two submissions 

related to the fenpropimorph PWP. Table F1 below lists the submitters. 

Table F1. Submitters of Comments on the “Fenpropimorph Preliminary Workplan”

BASF Corporation 

FIFRA Endangered Species Task Force (FESTF)

FESTF

Comment- The FIFRA Endangered Species Task Force (FESTF) submitted a comment 

noting that it has data that will assist the agency in conducting an endangered species risk 

assessment for fenpropimorph.

EPA Response- The agency thanks FESTF for its comment and will consider this 

information as it conducts the registration review and makes its registration review 

decisions. 

BASF 

850.3020- Honey bee acute contact toxicity, TGAI

Comment- BASF appreciates the importance of quantifying potential risks to beneficial 

insects, particularly pollinators. BASF has previously submitted a honey bee acute oral 

and contact toxicity study using fenpropimorph TGAI (MRID 47125501). The results 

from that study indicate that fenpropimorph is practically non-toxic to adult honey bees, 

with oral 48-hr LD50 value of ˃ 95 μg ai/bee and contact 48-hr LD50 value of ˃100 μg 

ai/bee. A dose of 100 μg ai/bee is typically used as a limit dose in such studies. The study 

submitted in 2007 was classified as Acceptable (Supplemental) by EPA due to minor test 

guideline deviations related to cage temperature and relative humidity. The study controls 

confirm that those minor deviations did not influence the study outcome and conducting a 

new study would likely yield similar results. Moreover, the current OCSPP 850.3020 

guideline says, “... it is unlikely a study will be rejected when there are slight variations 

from guideline environmental conditions and study design unless the control organisms 

are significantly affected...” The registered end use product containing fenpropimorph 

(5.4% ai) is an industrial wood preservative used to protect freshly cut lumber and wood 
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products during drying, storage and transport. It is applied to the surface of the exposed 

wood and provides temporary protection against sapstain, mold and decay. This surface 

treatment is physically removed during processing of the lumber, wood and wood 

products. Additionally, label directions specify, “Lumber treated with Sinesto® PFB 

must be stored under cover, indoors, or at least 100 feet from any pond, lake, stream, 

wetland or river ...Treated lumber stored within 100 feet of a pond, lake, stream, wetland 

or river must be either covered with plastic or surrounded by a berm...” Therefore, bee 

exposure to treated lumber (and wood products) is highly unlikely. Due to the low 

toxicity of fenpropimorph to honey bees and the limited exposure potential, BASF 

requests a waiver from additional honey bee testing.

EPA Response- The agency thanks BASF for their comment. The agency has reviewed 

the data, and agrees that the submitted study is acceptable. Thus, the agency has removed 

the honeybee acute contact study from the anticipated data needs for fenpropimorph’s 

registration review.

875.1700- Applicator Exposure Product Use Information, TEP

Comment- “BASF was unable to find guideline 875.1700 Applicator Exposure: Product 

Use Information among the OCSPP Harmonized Test Guidelines on the EPA’s website. 

Therefore, BASF requests that a copy of this guideline be provided for our review”.

EPA Response- The current product use guideline is not yet available as a final draft to 

the public. Draft guidelines on Product Use Information are available from the Science 

Advisory Panel (1998) on the web and can be found (under guideline 875.2700- this 

guideline is for Post Application Exposure) at 

http://www.epa.gov/scipoly/sap/meetings/1998/march/contents.htm. The agency has a 

more recent description of product use template available on the web which includes the 

general information to complete a product use study for handler and post application

exposures. This information can be found at: http://www2.epa.gov/pesticideregistration/study-profile-templates#toxicology under the 875 Use Pattern (Occupational 

and Residential Exposure Test Guidelines) under the Study Profile Template section, 

please refer to the Use Pattern/ Exposure Scenarios document. Since fenpropimorph is 

used as a wood preservative, the agency is interested in the non-pressure treatment of 

wood (spray/ dip tank application methods) and the American Wood Protection 

Association (AWPA) retention and description of the wood use (e.g., decks, play sets, 

fence posts, etc.). For handler activities, the agency anticipates needing a general

description of equipment, procedures, durations, and frequencies for worker tasks.