Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

TABLE OF CONTENTS 

 Page # 

I. Final Work Plan (FWP) 3 

II. Revised Ecological Risk Assessment Problem Formulation 8 

2
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

I. FINAL WORK PLAN 

Introduction:

This is EPA’s Final Work Plan for the registration review of fenoxycarb. The work plan 

includes the expected registration review time line. The work plan also addresses public 

comments on the Preliminary Work Plan in the Summary Document posted in the initial 

registration review docket, or any other comments on the initial docket. The Summary 

Document provided information on what EPA knows about the pesticide and what additional 

risk analyses and data or information the Agency believes are needed to make a registration 

review decision. 

The Agency is implementing the new registration review program, and plans to review each 

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

standard for registration. Changes in science, public policy, and pesticide use practices will 

occur over time. 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 that statutory standard. The public phase of registration review begins when the initial 

docket is opened for each case. Information on this program is provided at: 

http://www.epa.gov/oppsrrd1/registration_review. 

Based on public comments, the Fenoxycarb Final Work Plan has been modified slightly from 

the Fenoxycarb Preliminary Work Plan. First, the ecological Problem Formulation has been 

revised so that all fenoxycarb labels are included in its Table 1. Second, justifications for the 

required ecological studies have been included in the ecological Problem Formulation. 

In addition, the Final Work Plan has been revised to clarify that two studies will be required to 

conduct the human health assessment: a developmental toxicity test and a multi-generation 

reproductive toxicity test in rats. In lieu of conducting these two separate studies, the study 

requirements can be satisfied by an extended 1-generation toxicity test in rats. If this approach 

is chosen, registrants should consult the Agency on the study design, including seeking 

protocol approval, prior to the conduct of the study. The HED Registration Review Problem 

Formulation document has not been revised and is the same as was presented in the 

Fenoxycarb Preliminary Work Plan. 

Risk Assessment and Data Needs:

Ecological Risk: 

• The Agency anticipates conducting a comprehensive ecological risk assessment, 

including an endangered species assessment, for all fenoxycarb uses. 

• The planned ecological risk assessment will allow the Agency to determine whether 

fenoxycarb’s use has "no effect" or "may affect" federally listed threatened or 

endangered species (listed species) or their designated critical habitat. If the assessment 

indicates that fenoxycarb "may affect" a listed species or its designated critical habitat, 

the assessment will be refined. The refined assessment will allow the Agency to 

determine whether use of fenoxycarb is “likely to adversely affect” the species or 

critical habitat or "not likely to adversely affect" the species or critical habitat. When 

an assessment concludes that a pesticide's use "may affect" a listed species or its 

3
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

designated critical habitat, the Agency will consult with the U.S. Fish and Wildlife 

Service and/or National Marine Fisheries Service (the Services), as appropriate. 

• The Agency needs the following data in order to complete these assessments: 

o 850.2300 Avian Reproduction Test 

o 870.3800 Chronic Mammalian Toxicity Test (could be satisfied by an extended 

one-generation reproduction study) 

o 850.4250, 850.4225 Terrestrial Plant Toxicity Tests 

o 850.4400 Aquatic Plant Toxicity Tests 

• Please refer to the Section II of this document, Problem Formulation for the Ecological 

Risk Assessment of Fenoxycarb,” for a detailed discussion of the anticipated risk 

assessment needs (p. 8). This revision replaces the ecological Problem Formulation 

that was presented in the Preliminary Work Plan for Fenoxycarb. 

Human Health Risk: 

• Fenoxycarb’s registered uses are all non food uses. Fenoxycarb has turf and other 

outdoor uses which could lead to exposure through drinking water. The Agency plans 

to complete a drinking water assessment for fenoxycarb. 

• A review of the toxicity database will be undertaken to determine whether there is an 

appropriate incidental oral endpoint for residential risk assessment. No residential 

handler or post application risk assessments have been conducted on fenoxycarb. The 

Agency plans to assess residential handler and post application exposure and risk as 

part of the Registration Review process. If products intended for use by residential 

handlers are cancelled, then a residential handler risk assessment would not be 

conducted. 

• The Agency may conduct an aggregate assessment for drinking water exposure and 

residential uses. 

• The Agency plans to conduct an occupational handler exposure and risk assessment to 

address dermal exposure from the agricultural use of fenoxycarb. An occupational 

handler assessment for inhalation exposure has been previously conducted for the 

agricultural fenoxycarb uses. The Agency plans to conduct an occupational handler 

dermal and inhalation exposure and risk assessment for the turf and greenhouse uses of 

fenoxycarb. 

• The Agency plans to conduct an occupational post application exposure and risk 

assessment for all existing uses of fenoxycarb. 

• The Agency needs the following data in order to complete these assessments: 

o 870.3800 Chronic Mammalian Toxicity Test 

o 870.6300 Developmental Neurotoxicity Test 

o In lieu of conducting these two separate studies, the registrant may consider 

conducting an extended 1-generation toxicity study in rats as described by 

Cooper et.al. (2006)1

. If this approach is chosen, EPA strongly encourages the 

registrant to consult the Agency on the study design, including seeking protocol 

approval from EPA, prior to the conduct of the study. Should the extended 1-

 

1

 Cooper, et.al. (2006) “A Tiered Approach to Life-Stages Testing for Agricultural Chemical Safety Asessment” 

Crit. Rev. Toxicol. 36(1): 69-98

4
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

generation reproduction study find other effects that require further 

investigation, EPA would consider the need for additional studies. 

• Please refer to the “Fenoxycarb Summary Document – Registration Review: Initial 

Docket (August 1, 2007), Section IV – Human Health Effects Scoping Document” for a 

detailed discussion of previous human health assessments (Document ID: EPA-HQOPP-2006-0111-0007).

 

Timeline:

EPA has created the following estimated timeline for the completion of the fenoxycarb 

registration review. 

Activities Estimated 

Month/Year 

Opening Docket 

Open Public Comment Period for Fenoxycarb Docket July 2007 

Close Public Comment Period September 2007 

Case Development 

Develop Final Work Plan (FWP) 2007 – Oct.-Dec. 

Issue DCI 2008 – Jul.-Sept. 

Data Submission 2011 – Jul.-Sept. 

Open Public Comment Period for Preliminary Risk Assessments 2012 – Oct.-Dec. 

Close Public Comment Period 2012 – Oct.-Dec. 

Registration Review Decision 

Open Public Comment Period for Proposed Reg. Review Decision 2013 

Close Public Comment Period 2013 

Final Decision and Begin Post-Decision Follow-up 2013 

Total (years) 6 

Summary of Comments Received During Docket Opening:

The fenoxycarb registration review docket was open for a 60-day comment period beginning 

on August 1, 2007. During that time, several comments were received. They are summarized 

below. These comments, which are addressed in this document, did not change the work plan 

or timeline set out in the preliminary work plan. Further, this document makes final the work 

plan for the fenoxycarb registration review process. 

Summary of Comments from FIFRA Endangered Species Task Force (FESTF)

1. Comment: The FIFRA Endangered Species Task Force (FESTF) submitted a 

comment that the Agency should ensure any company who is a registrant for 

fenoxycarb, but not a member of the FESTF (or a company having met its data 

compensation obligations) provide a formal offer-to-pay to FESTF in conjunction with 

their support of the active ingredient. The primary registrant of fenoxycarb products, 

Syngenta, is a FESTF member and is entitled to rely on FESTF data. 

5
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

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. 

Summary of Comments from Syngenta Crop Protection 

2. Comment: Syngenta submitted a voluntary cancellation request for several of their 

fenoxycarb products. Syngenta intends to maintain the following registrations: 100-722 

and 100-723. Syngenta has requested voluntary cancellation of the following 

registrations: 100-725, 100-746, 100-750, 100-753, and the outstanding experimental 

use permits that remain active in EPA databases. 

Response: These requests for voluntary cancellation will be published in the Federal 

Register. As long as registrants do not withdraw their requests for voluntary 

cancellation, and no other group notifies EPA that they would like to support the 

product, the products will be cancelled at the end of the comment period. 

3. Comment: Syngenta is only supporting product 100-722, Award Fire Ant Bait, and 

product 100-723, Fenoxycarb Technical. Syngenta notes that cancellation of the 

residential-use fire ant products will eliminate the need to conduct a consumer handler 

risk assessment for the fire ant use of fenoxycarb. Syngenta has also requested 

voluntary cancellation of its only fenoxycarb wettable powder product (100-750). If 

other registrants with similar products request voluntary cancellation for their products, 

EPA will not need to assess the risk associated with this type of product. 

Response: The Agency thanks Syngenta for its comment, and will consider the affect 

that those product cancellations will have on the risk assessment scenarios. 

4. Comment: The only end-use fenoxycarb registration that Syngenta intends to maintain 

is 100-722, a granular product for use by commercial workers for fire ant infestations. 

Fire ants are limited to areas of the Southern U.S., so the extent of fenoxycarb use is 

limited. 

Response: The Agency thanks Syngenta for its comment and will consider this 

information as it conducts the registration review and makes its registration review 

decisions. 

Summary of Comments from SC Johnson, United Industries Corp., and Whitmire MicroGen 

5. Comment: EPA has received voluntary cancellation requests from SC Johnson for 

products 4822-292 and 4822-442. Both products are indoor residential use products 

that had not been marketed by the company for several years. 

Response: These requests for voluntary cancellation will be published in the Federal 

Register. As long as registrants do not withdraw their requests for voluntary 

cancellation, and no other group notifies EPA that they would like to support the 

product, the products will be cancelled at the end of the comment period. 

6. Comment: United Industries Corp. indicated to EPA that it plans to cancel product 

8660-156, a granular for application to golf courses and sod farms, via non-payment of 

maintenance fees. 

6
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

Comment: Whitmire Micro-Gen indicated to EPA that it plans to cancel product 499-

375, a total release fogger for use in greenhouses, via non-payment of maintenance 

fees. 

Response: If the companies cancel their products as indicated, EPA will publish a 

Federal Register Notice cancelling the products through non-payment of maintenance 

fees. 

Next Steps:

Ecological and human health risk assessments will be conducted, as detailed in the Risk 

Assessment and Data Needs Section above. As noted previously, the Agency will require four 

studies through the data call-in process in order to conduct complete human health and 

ecological risk assessments, including an endangered species assessment for all uses 

7
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C., 20460 

PC Code: 125301 

DP Barcode: D337398 

December 12, 2007 

MEMORANDUM

Subject: Registration Review – Problem Formulation for the Ecological Risk Assessment of 

Fenoxycarb (revised from July 24, 2007 version due to addition of labels in Table 1) 

To: Katie Weyrauch, Chemical Review Manager 

 Re-registration Branch 7508 P 

 Special Review and Re-registration Division 

 Office of Pesticide Programs 

From: Marie Janson, Environmental Scientist 

 James Lin, Ph. D., Environmental Engineer 

Environmental Risk Branch 1 

 Environmental Fate and Effects Division 7507 P 

 Office of Pesticide Programs 

Through: Nancy Andrews, Ph.D., Branch Chief 

 Thuy Nguyen, RAPL 

 Environmental Risk Branch 1 

 Environmental Fate and Effects Division 7507 P 

 Office of Pesticide Programs 

Attached is the problem formulation for the ecological risk assessment to be conducted as part of the 

Registration Review of the insect growth regulator, fenoxycarb. This problem formulation was revised 

from the July 24, 2007 version to add additional labels to Table 1. 

 

8
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

REGISTRATION REVIEW

ECOLOGICAL RISK ASSESSMENT

PROBLEM FORMULATION FOR:

FENOXYCARB

Ethyl (2-[4-phenoxyphenoxy]ethyl) carbamate

PREPARED BY: 

Marie Janson, Environmental Scientist 

James Lin, Environmental Engineer 

Environmental Risk Branch 1 

Environmental Fate and Effects Division 

Office of Pesticide Programs 

APPROVED BY: 

Nancy Andrews, Ph.D., Chief 

Environmental Risk Branch 1 

Environmental Fate and Effects Division 

Office of Pesticide Program 

December 12, 2007

9
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

STRESSOR SOURCE AND DISTRIBUTION

Fenoxycarb is an insecticide (or growth regulator) that disrupts the development of the pest. 

Fenoxycarb has an insect-specific mode of action exhibiting strong juvenile hormone activity. 

It inhibits metamorphosis to the adult stage, induces interference with the molting of early 

instar larvae, and produces certain ovicide and delayed larvicide adulticide effects in various 

insect species. Fenoxycarb is used as an insecticide, miticide, insect growth regulator, sex 

attractant or feeding stimulant to control fire ants, big-headed ants, white flies, soft scales, 

fungus gnats, thrips, shore flies and lepidopterous leaf miners. 

 

INTEGRATION OF AVAILABLE INFORMATION

The risk assessments available in the docket, and which serve as the basis for this problem 

formulation, include the following: 

 

• (1996) DP Barcode D223481 Memorandum: Review of proposed new use of 

fenoxycarb (Logic Fire Ant Bait) on forage hay and grasses. 

• (1996) Comprehensive environmental fate and ecological review for re-registration of 

new uses of fenoxycarb as a 40% WP on pome fruits and tree nuts, and as a fire ant bait 

for use on forage hay, grass and citrus. 

• Section 18 (1996) specific exemptions for use of fenoxycarb to control 

 pear psylla on pears in Oregon and Washington 25% WP 

• July 9, 1997 review of the Novartis letter, dated 3/24/1997, which responds to the 

EFED review of the proposed use of Logic Fire ant bait on citrus, dated 12/12/1996. 

ECOLOGICAL EFFECTS

TOXICITY STUDIES

The available acute toxicity data on the active ingredient indicate that fenoxycarb is practically 

non-toxic to birds (LD50 >3000 mg/kg; LC50 =11,574 ppm), practically non-toxic to small 

mammals (LD50 >16,800 rat), moderately toxic to freshwater fish (LC50 = 1.6- 1.86 ppm), 

highly toxic to freshwater invertebrates (LC50 = 0.4 ppm), highly toxic to estuarine/marine fish 

(LC50 = 1.07 ppm), and highly to moderately toxic to estuarine/marine invertebrates (LC50 or 

EC50 = 0.15 – 2.2 ppm). 

No toxicity studies were submitted for aquatic plants, terrestrial plants, chronic birds, chronic 

estuarine marine fish and chronic estuarine marine invertebrates. For chronic mammal study, a 

10
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

two generation rat reproduction study was submitted to the Agency; however in the absence of 

liver toxicity information on parental animals and the presence of decreased pup weight in all 

dose groups, the parental and offspring NOAEL could not be established, and the study was 

deemed unacceptable by the HIARC committee on 12/22/1997. Since the decreased pup 

weight occurred at the lowest dose group of 200 mg/kg-diet, EFED used an LOAEL of 200 

mg/kg-diet to assess chronic risks to mammals. Furthermore, based on a developmental 

(teratology) rabbit study, a NOAEL of 100 mg/kg-bw based on decreased body weight gain 

and NOAEL of 200 mg/kg-bw for incidence of fetal malformation (spina bifida) along with 

hypoplastic tail were established. The NOAEL values from the developmental (teratology) 

rabbit study were not selected for toxicity endpoints because the above rat reproduction study 

values were more sensitive for exposure of fenoxycarb in dietary administration. Uncertainty 

exists with this value, however because a NOAEL was not established therefore exceedences 

are underestimated. 

 

INCIDENT REPORTS

The Agency has reviewed incident reports in the Ecological Incident Information System 

(EIIS) for adverse effects to fish or wildlife that were attributed to fenoxycarb use. The 

Agency has received one report of adverse field effects to non-target animals that was linked to 

use of fenoxycarb. In 2000, mortality of approximately 100 catfish occurred in a pond in 

Texas following application of fenoxycarb and abamectin adjacent to the pond. Although the 

incident was likely related to runoff of these pesticides during a rain event, the Agency does 

not know if the mortality was caused by exposure to fenoxycarb or abamectin, or a 

combination of the two. This is the only major incident reported to the Agency linking 

fenoxycarb use to any adverse effects to non-target animals or plants. Aggregate reports from 

the registrants, however, have identified six minor incidents of adverse effects to plants and 

one minor incident of adverse effects to a non-target invertebrate. The Agency has received no 

incident report from pesticide registrants concerning fenoxycarb contamination of ground or 

surface water. 

A lack of reported incidents does not necessarily mean that such incidents have not occurred. 

In addition, incident reports for non-target plants and animals typically provide information on 

mortality events only. Reports for other adverse effects, such as reduced growth or impaired 

reproduction, are rarely received. 

 

EXPOSURE CHARACTERISTICS

The guideline laboratory data indicate that fenoxycarb is moderately persistent in soil. In 

sandy loam soil, aerobic and anaerobic degradation of fenoxycarb was found to follow biphasic 

kinetics. The primary half-life for aerobic degradation was determined to be 6.7 hours and the 

secondary half-life value was calculated to be 8.2 months. The primary anaerobic half-life was 

calculated to be 16 days and the secondary half-life value was calculated to be 8.5 months. 

Based on batch equi1ibrium, column leaching and terrestria1 field dissipation data, fenoxycarb 

11
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

appears to have a little potential for movement into groundwater, except on soils with low 

organic matter and high sand content. 

Fenoxycarb has a potential to reach surface water through runoff, erosion and spray drift, when 

applied to the treated fields. In aquatic environment, fenoxycarb is stable to hydrolysis and 

moderately photolytic persistent with aqueous photolysis half-lives of 18 – 23 days. Based on 

the aerobic aquatic metabolism half-lives of 3.9 days in the water system alone and 18.8 days 

in the combined sediment and water system, fenoxycarb is not expected to be persistent. 

In the terrestrial environment, fenoxycarb has a potential to reach non-target organisms through 

runoff, erosion and spray drift, following application to the treated fields. Fenoxycarb appears 

to dissipate in terrestrial ecosystems through a microbially-mediated process including 

chemical transformations with subsequent mineralization. However, under an anaerobic 

terrestrial environment, fenoxycarb is more persistent. In addition parent fenoxycarb binds to 

soi1, so its mobility should be 1imited. Due to the low Henry’s Law constant with solubility of 

5.66 ppm and vapor pressure of 6.5 x 10-9 mm Hg, the volatilization effects are expected to be 

minimal. With a BCF of 95, the bioaccumulation is not expected to be a problem. 

CHARACTERISTICS OF ECOSYSTEMS POTENTIALLY AT RISK

For fenoxycarb, the ecosystems at greatest risk are those in close proximity to the use areas. 

These would include new fields (surrounding non-agricultural terrestrial habitats) and water 

bodies directly adjacent to treated fields that may receive chemical residues via drift and/or 

runoff. Within water bodies, the water column, sediments, and pore water are all 

compartments of concern. The use sites that fenoxycarb are used on are; home lawns, 

ornamentals, nurseries, sod farms, horse farms, turf, certain non-bearing citrus crops, and other 

non-agricultural land. A single application (dust, granular, pressurized liquid, wettable powder) 

is made at rates ranging from 0.015 – 0.174 lbs. a.i./acre, depending on the use site. 

Application methods used are single mound treatment, broadcast and aerial application. 

Organisms of concern include birds, mammals, reptiles, fish, and terrestrial and aquatic 

invertebrates, plants, and amphibians. The assessment endpoints are intended to reflect 

population sustainability and community structure within ecosystems and hence relate back to 

ecosystems at risk. If risks are expected for given species/taxa based on the screening-level 

assessment, then risks might be expected to translate to higher levels of biological 

organization. 

12
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

ASSESSMENT ENDPOINTS

Assessment endpoints are defined as “explicit expressions of the actual environmental value 

that is to be protected.” Defining an assessment endpoint involves two steps: 1) identifying the 

valued attributes of the environment that are considered to be at risk; and 2) operationally 

defining the assessment endpoint in terms of an ecological entity (i.e., a community of fish and 

aquatic invertebrates) and its attributes (i.e., survival and reproduction). Therefore, selection of 

the assessment endpoints is based on valued entities (i.e., ecological receptors), the ecosystems 

potentially at risk, the migration pathways of pesticides, and the routes by which ecological 

receptors are exposed to pesticide-related contamination. The selection of clearly defined 

assessment endpoints is important because they provide direction and boundaries in the risk 

assessment for addressing risk management issues of concern. Changes to assessment 

endpoints are typically estimated from the available toxicity studies, which are used as the 

measures of effects to characterize potential ecological risks associated with exposure to a 

pesticide, such as fenoxycarb. 

To estimate exposure concentrations, the ecological risk assessment considers a single 

application at the maximum application rate to fields that have vulnerable soils. The most 

sensitive toxicity endpoints are used from surrogate test species to estimate treatment-related 

direct effects on acute mortality and chronic reproductive, growth and survival assessment 

endpoints. Toxicity tests are intended to determine effects of pesticide exposure on birds, 

mammals, fish, terrestrial and aquatic invertebrates, and plants. These tests include short-term 

acute, sub-acute, and reproduction studies and are typically arranged in a hierarchical or tiered 

system that progresses from basic laboratory tests to applied field studies. The toxicity studies 

are used to evaluate the potential of a pesticide to cause adverse effects, to determine whether 

further testing is required, and to determine the need for precautionary label statements to 

minimize the potential adverse effects to non-target animals and plants. However, the previous 

assessments did not evaluate toxicity to aquatic plants, terrestrial plants, chronic toxicity to 

birds and chronic toxicity to mammals due to lack of available data. 

 

13
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

CONCEPTUAL MODEL

In order for a chemical to pose an ecological risk, it must reach ecological receptors in 

biologically significant concentrations. An exposure pathway is the means by which a 

pesticide moves in the environment from a source to an ecological receptor. For an ecological 

exposure pathway to be complete, it must have a source, a release mechanism, an 

environmental transport medium, a point of exposure for ecological receptors, and a feasible 

route of exposure. 

The conceptual model (Figure 1) depicts the potential pathways for ecological risk associated 

with fenoxycarb use. The conceptual model provides an overview of the expected exposure 

routes for organisms within the fenoxycarb action area. For terrestrial organisms, one route of 

exposure considered is the dietary route; consumption of food items such as plant leaves that 

have fenoxycarb residues as a result of spraying and drift. An additional route of exposure for 

terrestrial organisms is the direct uptake of granules from granular applications of fenoxycarb. 

For aquatic animal species, the major routes of exposure are considered to be via the 

respiratory surface (gills) or the integument. Direct contact and/or root uptake is the major 

route of exposure for terrestrial and wetland (riparian) plants, while aquatic plants may be 

exposed via direct uptake and adsorption. Estimated exposure concentrations for all organisms 

are obtained through the use of several Agency exposure models. 

 

RISK HYPOTHESIS

Based on an examination of the physical/chemical properties of fenoxycarb, the fate and 

disposition in the environment, and mode of application, a conceptual model was developed 

that represents the possible relationships between the stressor, ecological receptors, and the 

assessment endpoints. Major routes of dissipation for fenoxycarb are soil (aerobic and 

anaerobic) binding and aerobic aquatic metabolism to CO2 which results in exposure to various 

terrestrial and aquatic receptors. 

14
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

FIGURE 1. ECOLOGICAL CONCEPTUAL DIAGRAM FOR FENOXYCARB

15
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

ANALYSIS PLAN OPTIONS

In Registration Review, pesticide ecological risk assessments will follow the Agency’s 

Guidelines for Ecological Risk Assessment, will be in compliance with the paper titled 

“Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs, 

U.S. Environmental Protection Agency” (“Overview Document”) (January 2004), and will be 

done in accordance with Section 7 of the Endangered Species Act. 

Previously completed screening level risk assessments and exceedences of Agency levels of 

concern indicate a need to further examine and refine acute risk to terrestrial and aquatic nonvascular plants. Potential chronic risks to small medium and large-sized birds will be assessed 

when additional toxicity data is submitted. Potential chronic risks to small medium and largesized mammals are uncertain with current toxicity data submitted. Finally, analysis of 

potential indirect effects on listed species is required. 

The Agency wishes to better understand 1) which environmental and product specific factors 

contribute most to the off-site movement and phytotoxicity of fenoxycarb, 2) risks to 

terrestrial and aquatic plants 3) the effectiveness of buffer restrictions, and 4) options for 

additional mitigation, where required 4) chronic risks to birds and mammals 5) Incident 

information would be extremely helpful in understanding the current situation with regards to 

potential risk to non-target species. 

Table 1 shows the current status of risk assessments for registered uses of fenoxycarb. In 

addition to refining the ecological risk assessment, other uncertainties and potential paths 

forward are described below. 

• No assessment of risks to terrestrial and aquatic risks to plants was done in previous 

assessments due to lack of submitted toxicity studies. Therefore, these studies 

would be of value to assess risks to terrestrial and aquatic plants. 

• Previous assessments did not evaluate chronic reproductive risks to mammals. A 

two generation rat reproduction study was submitted to the Agency, however a 

parental and offspring NOAEL could not be established. Decreased pup weight 

occurred at the lowest dose group of 200 mg/kg-diet. EFED will use the LOAEL of 

200 mg/kg-diet based on decreased pup weight to assess chronic risks to mammals 

due to lack of available chronic reproductive toxicity data. Uncertainty exists with 

this value, however because a NOAEL was not established therefore exceedences 

are underestimated. In addition, no chronic reproductive toxicity studies for birds 

were submitted to the Agency. However, based on previous assessments 

unreviewed toxicity data regarding possible chronic reproductive effects of 

fenoxycarb to avian life reported the NOEL values to be 160 ppm for mallard duck 

and 400 ppm for bobwhite quail. When these NOEL values are modeled in the 

TREX terrestrial model with application rates of 0.015 lb ai/A and 0.136 lb ai/A, 2 

applications, 14 day intervals, and a 35 day half-life, no chronic exceedences 

occurred with chronic RQs values ranging from 0.001 to 0.40. However, the 

unreviewed toxicity study in which the above NOEL values were derived was not 

16
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

identified in the previous assessments. Therefore, these values can not be verified. 

Also, no analogs for fenoxycarb were identified by EFED to estimate chronic 

reproductive toxicity values for birds or mammals. Also, based on the exposure 

and risk characterization (MRID 438295-03), fenoxycarb is an insect growth 

regulator which is a “hormone analog that interferes with the normal juvenile 

hormone titre and therefore molting, maturation and reproduction. In fire ants it has 

been shown to suppress the growth of follicular epithelium, nurse cells and 

cytoplasm/yolkplasm and cause resorption of eggs.” In addition to target organisms 

it has been shown to impact the reproductive capability of the early life stage of 

fish. It is not known how this mode of action will express itself in higher organisms 

which produce eggs such as fish, reptiles, amphibians, birds and mammals. Since 

the freshwater aquatic invertebrate shows significant impacts on reproductive 

effects (RQ=112.5 for 0.015 lb ai/A application rate) and modeling shows that 

exposure will occur for terrestrial organisms. Therefore, chronic bird and mammal 

studies would be useful in evaluating risks to these organisms. 

• A screening level assessment of acute and chronic risks to terrestrial and aquatic 

organisms has not been completed for all uses. Therefore, risks to these organisms 

require further evaluation. 

• The tier I screening level assessment showed acute risk quotients for some 

fenoxycarb uses to be above levels of concern for freshwater and estuarine/marine 

fish and invertebrates. Since these assessments were conducted using tier 1 

exposure models on 0.015 lb ai/A, 0.125 lb ai/A and 0.31 lb ai/A, the Agency will 

refine the risk assessment by first estimating EECs using tier II models. It is 

expected that the refinement will result in lower or no LOC exceedences based on 

0.015 lb ai/A and 0.136 lb ai/A application rates for freshwater and 

estuarine/marine fish and invertebrates. 

• An assessment of chronic risk to estuarine/marine invertebrates has been completed 

based on acute to chronic ratios. Based on the acute and chronic data for 

freshwater invertebrates, and the acute data for estuarine/marine invertebrates, an 

acute to chronic ratio can be calculated and applied in order to estimate the NOAEC 

value for estuarine/marine invertebrates. Doing so results in a grass shrimp 

NOAEC of 0.006 ppb. There is some uncertainty surrounding this estimated value, 

however the acute to chronic ratio method is commonly used in these types of 

circumstances and is a reasonable approach using the best available data. For 

fenoxycarb, a NOAEC of 0.006 ppb for estuarine/marine invertebrates will be used 

in the risk assessment. The Agency does not believe a new study for estuarine 

marine invertebrates would change the overall risk conclusions because the toxicity 

values (daphnid LC50 400 ppb, daphnid NOEC 0.0016 ppb and grass shrimp LC50

220 ppb) used to derive the acute to chronic ratio method provide adequate 

information. 

• An assessment of chronic risk to estuarine/marine fish has been completed based on 

acute to chronic ratios. Based on the acute and chronic data for freshwater fish, and 

17
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

the acute data for estuarine/marine fish, an acute to chronic ratio can be calculated 

and applied in order to estimate the NOAEC value for estuarine/marine fish. Doing 

so results in a silverside minnow NOAEC of 32.1 ppb. There is some uncertainty 

surrounding this estimated value, however the acute to chronic ratio method is 

commonly used in these types of circumstances and is a reasonable approach using 

the best available data. For fenoxycarb, a NOAEC of 32.1 ppb for estuarine/marine 

fish will be used in the risk assessment. The Agency does not believe a new study 

for estuarine marine fish would change the overall risk conclusions because the 

toxicity values (rainbow trout LC50 1600 ppb, rainbow trout NOEC 48 ppb and 

silverside minnow LC50 1070 ppb) used to derive the acute to chronic ratio method 

provide adequate information 

Data already collected in laboratory studies on fenoxycarb will be used as inputs to the tier I 

AGDRIFT model. Should this approach prove to be workable, the results of this modeling 

exercise may be used to evaluate the buffer distances when LOC exceedences occur from spray 

applications of fenoxycarb. 

If the planned ecological risk assessment continues to indicate that fenoxycarb may potentially 

impact, either directly or indirectly, listed species or critical habitat, and therefore does not 

support a “not likely to adversely affect” determination, further refinements will be made. This 

will involve determining whether use of fenoxycarb “may affect” a particular listed species, 

and if so, whether it is “likely to adversely affect” the species, or in the case of critical habitat, 

whether use of the pesticide may destroy or adversely modify any principle constituent 

elements for the critical habitat, and if so, whether the expected impacts are “likely to 

adversely affect” the critical habitat. The first step in the process is to improve the exposure 

estimates based on refining the geographic proximity of fenoxycarb’s use and the listed species 

and/or critical habitat. If there is no geographic proximity, this information would support a 

determination that fenoxycarb use will have no effect on the species or critical habitat. If after 

conducting the first step of this analysis the Agency determines that geographic proximity 

exists, both potential direct effects and any potential indirect effects of the pesticide use will be 

examined. This process is consistent with the Agency's Overview Document. The Agency 

will consult as necessary with the U.S. Fish and Wildlife Service and National Marine 

Fisheries Service (Services), consistent with the Services' regulations. 

If the screening level risk assessment identifies potential concerns for indirect effects on listed 

species for those organisms dependent upon birds, fish and aquatic invertebrates and possibly 

terrestrial or aquatic plants depending on new toxicity data submitted, the next step for EPA 

and the Services would be to identify which listed species and critical habitat are potentially 

implicated. Analytically, the identification of such species and critical habitat can occur in 

either of two ways. First, the agencies could determine whether the action area overlaps 

critical habitat or the occupied range of any listed species. If so, EPA would examine whether 

fenoxycarb’s potential impacts on non-endangered species would affect the listed species 

indirectly or directly affect a constituent element of the critical habitat. Alternatively, the 

agencies could determine which listed species depend on biological resources, or have 

constituent elements that fall into, the taxa that may be directly or indirectly impacted by 

18
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

fenoxycarb. Then EPA would determine whether the use of fenoxycarb overlaps the critical 

habitat or the occupied range of those listed species. 

 

ANTICIPATED DATA NEEDS

The Agency foresees requiring the following additional ecological effects data: terrestrial and 

aquatic plants, chronic mammal, and chronic bird. 

The Agency will however conduct a search of the open literature to ensure that all best 

available science is utilized. The Agency uses the ECOTOX database as its mechanism for 

searching the open literature for ecological effects information. ECOTOX integrates three 

previously independent databases - AQUIRE, PHYTOTOX, and TERRETOX - into a system 

which includes toxicity data derived predominately from the peer-reviewed literature, for 

aquatic life, terrestrial plants, and terrestrial wildlife, respectively. 

OTHER INFORMATION NEEDS

There is specific information that will assist the Agency in refining the ecological risk 

assessment, including any species-specific effects determinations. The Agency is very much 

interested in obtaining the following information: 

1. confirmation on the following label information 

a. sites of application 

b. formulations 

c. application methods and equipment 

d. maximum application rates 

e. frequency of application, application intervals, and maximum number of 

applications per season 

f. geographic limitations on use 

2. use or potential use distribution (e.g., acreage and geographical distribution of relevant 

crops) 

3. use history 

4. median and 90th percentile reported use rates (lbs. a.i./acre) from usage data – national, 

state, and county 

5. application timing (date of first application and application intervals) by crop – 

national, state, and county 

6. sub-county crop location data 

7. usage/use information for non-agricultural uses (e.g., forestry, residential, rights-ofway) 

8. directly acquired county-level usage data (not derived from state level data) 

a. maximum reported use rate (lbs. a.i./acre) from usage data – county 

b. percent crop treated – county 

c. median and 90th percentile number of applications – county 

d. total pounds per year – county 

e. the year the pesticide was last used in the county/sub-county area 

f. the years in which the pesticide was applied in the county/sub-county area 

9. typical interval (days) 

10. state or local use restrictions 

19
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

11. ecological incidents (non-target plant damage and avian, fish, reptilian, amphibian and 

mammalian mortalities) not already reported to the Agency 

12. monitoring data 

The analysis plan will be revisited and may be revised depending upon the data available in the 

open literature and the information submitted by the public in response to the opening of the 

Registration Review docket. 

20
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

 

TABLE 1 

CURRENT STATUS OF ECOLOGICAL RISK ASSESSMENT

FOR REGISTERED USES OF FENOXYCARB

(USE INFORMATION BASED ON LABLES)

Use Reg. 

number 

Product 

Name 

Application rate 

(lbs. a.i./A) 

Method of 

application 

Included in 

Previous EFED 

Screening Risk 

Assessment? 

LOC’s Exceeded in Tier I 

Screening Risk Assessment 

(?: not determined) 

RQ is in parenthesis

Fire Ant and Big 

Headed Ants in 

ornamentals, home 

lawns and landscaped 

areas around home, 

non-crop areas, horse 

farms, sod farms, 

non-grazed areas on 

farm, nurseries and 

fire ants in certain 

nonbearing crops 

100-722 Award ® Fire 

Ant Bait, 

Logic® Fire 

Ant Killer (CA 

only) 

0.015 

(retreatment may 

be desirable after 

3 – 4 months) 

granular 

(single mound, 

broadcast and 

aerial) 

Yes Birds: ? chronic 

Mammals: ? chronic 

Terrestrial Plants: ? 

Freshwater Fish: none 

Freshwater Invertebrates: 

chronic(112.5) 

Estuarine/Marine Fish: none 

E-M Invertebrates: chronic(30) 

Aquatic Plants: ? 

 Manufacturing 

use 

100-723 Fenoxycarb 

Technical 

N/A N/A N/A N/A 

Turf fertilizer and fire 

ant and Big Headed 

Ant bait to golf 

courses and sod 

farms 

8660-

156 

Polyon Turf 

Fertilizer 

award Fire Ant 

Bait 

0.0079 

(retreatment may 

be desirable after 

3 – 4 months) 

granular 

(broadcast ) 

N/A Ecological effects acute and 

chronic not assessed from 

previous risk assessments 

Greenhouses 499-375 Whitmire PT 

2100 

Preclude 

IGR Insect 

Growth 

Regulator 

N/A aerosol No This is for in-door greenhouse 

use only. 

Greenhouses 499-437 Whitmire PT® 

2120 TR 

Preclude® 

0.174 aerosol No This is for in-door greenhouse 

use only. 

Fire Ant Control , 

home lawns only and 

other non-crop land 

100-725 Logic Fire ant 

Killer* 

0.0067 l 

(retreatment 7 

days) 

Granular 

(broadcast and 

single mound) 

No Ecological effects acute and 

chronic not assessed from 

previous risk assessments 

 Manufacturing 

use 

100-746 Fenoxycarb 

1% Bait* 

N/A N/A N/A 

 For control of insects 

in container and 

landscape 

ornamentals, 

nurseries, greenhouse 

ornamental crops and 

interiorscapes 

100-750 Precision* 0.136 

(retreatment 14 

days outdoor 

applications) 

Wettable 

powder 

(chemigation, 

overhead 

irrigation, 

spray, drench) 

No Ecological effects acute and 

chronic not assessed from 

previous risk assessments 

 Manufacturing 100-375 Fenoxycarb N/A N/A N/A N/A 

21
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

Use Reg. 

number 

Product 

Name 

Application rate 

(lbs. a.i./A) 

Method of 

application 

Included in 

Previous EFED 

Screening Risk 

Assessment? 

LOC’s Exceeded in Tier I 

Screening Risk Assessment 

(?: not determined) 

RQ is in parenthesis

use 25 WP* 

Bug infestation in 

home, pet area and on 

dogs 

4822-

292 

Raid Flea 

killer IV Plus* 

N/A Aerosol spray N/A N/A 

Flea infestation 

occurs in home 

4822-

442 

Raid DOB* N/A dust N/A N/A 

* proposed for cancellation 

22
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

Guideline Number 850.2300 

Study Title: Avian Reproduction 

Rationale for Requiring the Data 

 No acceptable toxicity data was available for review for chronic risks to birds. Some 

assessments included data from unreviewed duck and quail reproductive studies which 

generated No-Observable-Effect-Levels (NOEL) of 160 ppm and 400 ppm, respectively 

however, these studies can not be verified. Also, no analogs for fenoxycarb were identified by 

EFED to estimate chronic reproductive toxicity values for birds. Based on the exposure and 

risk characterization, fenoxycarb is an insect growth regulator which is a “hormone analog that 

interferes with the normal juvenile hormone titre and therefore molting, maturation and 

reproduction. In fire ants it has been shown to suppress the growth of follicular epithelium, 

nurse cells and cytoplasm/yolkplasm and cause resorption of eggs.” It is not known how this 

mode of action will express itself in higher organisms which produce eggs such as fish, 

reptiles, amphibians, birds and mammals. 

 

In addition to target organisms it has been shown to impact the reproductive capability of the 

early life stage of fish and aquatic invertebrates. For the freshwater aquatic invertebrate chronic 

RQs exceeded the LOCs with RQs= 112.5 for the 0.015 lb ai/A application scenario. 

Mammals also showed reproductive effects in a developmental (teratology) rabbit study, a 

NOAEL of 100 mg/kg-bw based on decreased body weight gain and NOAEL of 200 mg/kgbw for incidence of fetal malformation (spina bifida) along with hypoplastic tail were 

established. 

The Agency has worked to finalize its update to the data requirements in 40 CFR part 158, 

which were promulgated in October 2007. Now two avian reproduction studies, one with a 

waterfowl and one with and upland game bird, are required to support all terrestrial use 

patterns. 

 

 Practical Utility of Data 

How did the agency make its registration decision without this data? 

To address potential risks previous assessments stated that avian reproduction studies using the 

TGAI were not required for fenoxycarb because the following conditions are not met: (1) birds 

may be subject to repeated or continuous exposure to the pesticide, especially preceding or 

during the breeding season, (2) the pesticide is stable in the environment to the extent that 

potentially toxic amounts may persist in animal feed, (3) the pesticide is stored or accumulated 

in plant or animal tissues, and or, (4) information derived from mammalian reproduction 

studies indicates reproduction in terrestrial vertebrates may be adversely affected by the 

anticipated use of the product. 

23
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

However, the above decisions do not include that short-term exposures to pesticides can lead to 

significant adverse reproductive effects. In addition previous assessments did not identify 

chronic effects in other taxa such as; the presence of chronic mammalian effects in rabbits and 

reproductive effects in aquatic organisms. 

Some assessments included data from unreviewed duck and quail reproductive studies which 

generated No-Observable-Effect-Levels (NOEL) of 160 ppm and 400 ppm, respectively 

however, these studies can not be verified. 

How will the data be used? 

The avian reproduction studies are needed for future regulatory decisions. The data would 

allow the Agency to quantify the potential for chronic risk, as measured by effects on 

reproduction and survival, from the use of fenoxycarb. 

How could the data impact the Agency’s future decision-making? 

If future risk assessments are performed without this data, the Agency would have to assume 

that fenoxycarb “may effect” birds directly (and endangered species from other taxa 

indirectly), and use of fenoxycarb might need to be restricted in areas where endangered 

species could be exposed. The lack of these data will limit the flexibility the Agency and 

registrants have in coming into compliance with the Endangered Species Act and could result 

in use restrictions for fenoxycarb which are unnecessarily severe. 

 

24
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

Guideline Number 870.3800 Reproduction and fertility effects 

Study Title: Mammalian Reproduction 

Rationale for Requiring the Data 

No acceptable toxicity data was available for review for chronic reproductive risks to 

mammals. Also, no analogs for fenoxycarb were identified by EFED to estimate chronic 

reproductive toxicity values for mammals. 

For a chronic mammal study, a two generation rat reproduction study was submitted to the 

Agency, however a parental and offspring NOAEL could not be established. The HIARC 

committee in 12/22/1997 concluded that in absence of liver toxicity information on parental 

animals and the presence of decreased pup weight in all dose groups , the parental and 

offspring NOAEL could not be established therefore, the study is considered unacceptable by 

HED. Decreased pup weight occurred at the lowest dose group of 200 mg/kg-diet. EFED will 

used the LOAEL of 200 mg/kg-diet based on decreased pup weight to assess chronic risks to 

mammals due to lack of available chronic reproductive toxicity data. In a developmental 

(teratology) rabbit study, a NOAEL of 100 mg/kg-bw based on decreased body weight gain 

and NOAEL of 200 mg/kg-bw for incidence of fetal malformation (spina bifida) along with 

hypoplastic tail were established. The NOAEL values from the developmental (teratology) 

rabbit study were not selected for toxicity endpoints because the above rat reproduction study 

values were more sensitive for exposure of fenoxycarb in dietary administration. Uncertainty 

exists with this value, however because a NOAEL was not established therefore exceedences 

are underestimated. 

In addition to mammalian reproductive effects as described above fenoxcarb shows 

reproductive effects in other taxa as stated below: 

• Based on the exposure and risk characterization, fenoxycarb is an insect growth 

regulator which is a “hormone analog that interferes with the normal juvenile hormone 

titre and therefore molting, maturation and reproduction. In fire ants it has been shown 

to suppress the growth of follicular epithelium, nurse cells and cytoplasm/yolkplasm 

and cause resorption of eggs.” It is not known how this mode of action will express 

itself in higher organisms which produce eggs such as fish, reptiles, amphibians, birds 

and mammals. 

• In addition to the above target organisms it has been shown to impact the reproductive 

capability of the early life stage of fish and aquatic invertebrates. For the freshwater 

aquatic invertebrate chronic RQs exceeded the LOCs with RQs= 112.5 for the 0.015 lb 

ai/A application scenario. 

Therefore, based on the above reproductive effects seen in mammals and other taxa, EFED 

requests a chronic reproductive mammalian toxicity test to assess chronic risks to mammals. 

25
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

 

 Practical Utility of Data 

How did the agency make its registration decision without this data? 

For previous assessments that included wettable powders mammalian reproduction was not 

assessed and the mammalian reproduction study was listed as a data gap. 

How will the data be used? 

The mammalian reproduction studies are needed for future regulatory decisions. The data 

would allow the Agency to quantify the potential for chronic risk, as measured by effects on 

reproduction and survival, from the use of fenoxycarb. 

How could the data impact the Agency’s future decision-making? 

If future risk assessments are performed without this data, the Agency would have to assume 

that fenoxycarb “may effect” mammals directly (and endangered species from other taxa 

indirectly), and use of fenoxycarb might need to be restricted in areas where endangered 

species could be exposed. The lack of these data will limit the flexibility the Agency and 

registrants have in coming into compliance with the Endangered Species Act and could result 

in use restrictions for fenoxycarb which are unnecessarily severe. 

 

26
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

Guideline Numbers: 850.4250, 850.4225, 850.4400 

Study Title: Seedling Emergence, Vegetative Vigor and Aquatic Plant Toxicity Tests 

Rationale for Requiring the Data 

No toxicity data was available for review for terrestrial or aquatic plants. No open literature 

data or data from analogs were available to assess terrestrial or aquatic plant toxicity for 

fenoxycarb. Based on the exposure and risk characterization, fenoxycarb has a potential to 

reach surface water through runoff, erosion and drift when applied to the treated fields. 

Therefore, acute (listed and non-listed) potential risks to terrestrial and aquatic plants are 

uncertain from spray and granular applications of fenoxycarb. 

In aquatic environment, fenoxycarb is stable to hydrolysis and moderately photolytic persistent 

with aqueous photolysis half-lives of 18 – 23 days. Based on the aerobic aquatic metabolism 

half-lives of 3.9 days in the water system alone and 18.8 days in the combined sediment and 

water system, fenoxycarb is not expected to be persistent. 

Fenoxycarb appears to dissipate in terrestrial ecosystems through a microbially-mediated 

process including chemical transformations with subsequent mineralization. However, under 

an anaerobic terrestrial environment, fenoxycarb is more persistent. In addition parent 

fenoxycarb binds to soi1, so its mobility should be 1imited. 

The Agency has worked to finalize its update to the data requirements in 40 CFR part 158, 

which were promulgated in October 2007. Now, terrestrial and aquatic plant studies are 

required for insecticides due to possible phytotoxic effects and injury that insecticides may 

cause to non-target plants. 

 Practical Utility of Data 

How did the agency make its registration decision without this data? 

Terrestrial and aquatic plant toxicity data were not required for insecticides in previous 

assessments, however since new Agency guidelines were promulgated in October 2007 these 

studies are now required.

How will the data be used? 

The terrestrial and aquatic plant studies are needed for future regulatory decisions. The data 

would allow the Agency to quantify the potential for acute and acute endangered species risk, 

as measured by effects on reproduction and survival, from the use of fenoxycarb. Liquid and 

granular applications will be assessed by EFED in future assessments. Therefore, the seedling 

emergence, vegetative vigor and aquatic plant studies will be requested for exposure of 

fenoxycarb to endangered and non-endangered plants from runoff, erosion and drift. 

How could the data impact the Agency’s future decision-making? 

If future risk assessments are performed without this data, the Agency would have to assume 

that fenoxycarb “may effect” terrestrial and aquatic plants directly (and endangered species 

27
Docket Number: EPA-HQ-OPP-2007-0111

www.regulations.gov 

from other taxa indirectly), and use of fenoxycarb might need to be restricted in areas where 

endangered species could be exposed. The lack of these data will limit the flexibility the 

Agency and registrants have in coming into compliance with the Endangered Species Act and 

could result in use restrictions for fenoxycarb which are unnecessarily severe. 

 

28