UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C., 20460 

OFFICE OF 

PREVENTION, PESTICIDES AND 

TOXIC SUBSTANCES

MEMORANDUM

 PC Code: 129013 

 DP Barcode: D365379 

 December 15, 2009 

SUBJECT: Registration Review –Preliminary Problem Formulation for Ecological 

Risk and Environmental Fate, Endangered Species, and Drinking Water 

Assessments for Cyphenothrin 

TO: Joy Schnackenbeck, Chemical Review Manager 

 Robert McNally, Risk Manager 

 Special Review and Reregistration Division (7509P) 

FROM: Brian Kiernan, Biologist 

Cheryl Sutton, Ph.D., Environmental Scientist 

 Environmental Risk Branch 4 

 Environmental Fate and Effects Division (7507P) 

 

REVIEWED 

BY: Marietta Echeverria, Risk Assessment Process Leader 

 Thomas Steeger, Ph.D., Senior Biologist 

Environmental Risk Branch 4 

 Environmental Fate and Effects Division (7507P) 

 

THROUGH: Elizabeth Behl, Chief 

 Environmental Risk Branch 4 

 Environmental Fate and Effects Division (7507P) 

 

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

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

species, and drinking water assessments to be conducted as part of the Registration 

Review of the pyrethroid ether insecticide, cyphenothrin (PC Code 129013; DP Barcode 

D365379). The problem formulation draws on information from both open literature and 

studies submitted by the technical registrants in response to data requirements. This 

document is intended to provide an overview of what is currently known regarding the 

environmental fate and ecological effects associated with cyphenothrin (CAS 39515-40-

7) and its degradates and outlines uncertainties regarding attributes of the parent 

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

hypothesis and the processes that will be used during the completion of the ecological 

risk assessment in support of Registration Review. This document also recommends 

Page 1 of 41 
studies that should be included in a generic data call-in (DCI) to address uncertainties 

surrounding the environmental fate and potential ecological effects of cyphenothrin. 

Page 2 of 41 
 

Problem Formulation for the 

Environmental Fate and Ecological Risk 

and Endangered Species Assessments in Support 

of the Registration Review of Cyphenothrin 

Cyphenothrin (CAS 39515-40-7)

Prepared by:

Brian Kiernan, Biologist 

Cheryl Sutton, Ph.D., Environmental Scientist 

U. S. Environmental Protection Agency 

Office of Pesticide Programs 

Environmental Fate and Effects Division 

Environmental Risk Branch IV 

1200 Pennsylvania Ave., NW 

Mail Code 7507P 

Washington, DC 20460

Reviewed by: 

Marietta Echeverria, Risk Assessment Process Leader 

Thomas Steeger, Ph.D., Senior Biologist 

Elizabeth Behl, Branch Chief

Page 3 of 41 
I. Purpose 

The purpose of this problem formulation is to provide an understanding of the 

environmental fate and ecological effects of the registered uses of cyphenothrin (PC Code 

129013). Cyphenothrin is a pyrethroid ester insecticide used indoors (household/ 

domestic dwellings, storage areas, pet living/sleeping quarters, ships and boats, 

processing plants). An environmental fate and ecological risk assessment would not be 

required for the indoor uses. Because there is a squeeze-on spot treatment for dogs and 

horses, the possibility of surface water contamination will be evaluated to account for the 

possibility of a treated animal entering into a surface water body or being washed 

following treatment. There is a single outdoor use (Reg. No. 1021-1765) for aerosol spray 

application to external doorways, window cracks and corners under porches and patios, for 

which an environmental risk assessment is necessary. This document will provide a plan 

for analyzing data relevant to cyphenothrin and for conducting environmental fate and 

ecological risk and endangered species assessments for its registered outdoor uses. 

Drinking water exposure will not be assessed since a dietary risk assessment is not going 

to be conducted. Additionally, this problem formulation is intended to identify data gaps, 

uncertainties, and potential assumptions used to address those uncertainties, relative to 

characterizing the ecological risk associated with the registered uses of cyphenothrin. 

II. Problem Formulation 

A. Nature of Regulatory Action 

The Food Quality Protection Act of 1996 mandated the EPA to implement a new 

program for assessing the risks of pesticides, i.e., Registration Review 

(http://www.epa.gov/oppsrrd1/registration_review/). All pesticides distributed or sold in 

the United States generally must be registered by EPA. The decision to register a 

pesticide is based on the consideration of scientific data and other factors showing that it 

will not cause unreasonable risks to human health, workers, or the environment when 

used as directed on product labeling. The Registration Review program is intended to 

ensure that, as the capability 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 and the environment. Because changes in science, public 

policy and pesticide use practices will occur over time, the Agency will periodically 

reevaluate pesticides to ensure that as change occurs, products in the marketplace can 

continue to be used without unreasonable risk. 

As part of the implementation of the Registration Review program, pursuant to Section 

3(g) of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), the Agency is 

conducting an environmental fate and ecological risk assessment to determine whether 

cyphenothrin continues to meet the FIFRA standard for registration. This problem 

Page 4 of 41 
formulation for the environmental fate and ecological risk assessment chapter in support 

of Registration Review is intended for the initial docket opening the public phase of the 

review process. 

B. Conclusions from Previous Risk Assessments 

The Agency has not previously conducted an ecological risk assessment or a drinking 

water assessment for cyphenothrin since the chemical's use was considered limited to 

indoors. The registrant, Sumitomo Chemical America, Inc, submitted an application for a 

manufacturing use registration for cyphenothrin in 1985 and an application for the first 

end-use product in 1987. Registration was granted in 1991 (Reg. No. 10308-10). The 

first squeeze on spot treatment was registered for use on horses in 2005 (Reg. No. 

002517-0084) and dogs in 2006 (Reg. No. 002517-0080).

Page 5 of 41 
III. Stressor Source and Distribution 

A. Mechanism of Action 

Cyphenothrin, (RS)-α-cyano-3-phenoxybenzyl (1RS)-cis-trans-2,2-dimethyl-3-(2-

methylprop-1-enyl)cyclopropanecarboxylate, belongs to the pyrethroid ester class of 

insecticides. Its mode of action involves inhibition of nerve impulse transmission by 

affecting sodium channels. It is a non-systemic insecticide which has contact and 

stomach action, with rapid knockdown (causes rapid paralysis that may be reversible and 

that may or may not lead to death), and some repellent properties. 

Like many pyrethroids, cyphenothrin is formulated with a synergist. While not present in 

the squeeze-on spot treatments, the spray and indoor fogger formulations contain the 

synergist N-octyl bicycloheptene dicarboximide, also known as MKG-264 

(http://www.epa.gov/pesticides/reregistration/REDs/mgk_red.pdf). Cyphenothrin is also 

often formulated with other pyrethroid insecticides. 

B. Overview of Pesticide Usage 

Currently, cyphenothrin is registered for spray and indoor fogger for insect control, and 

squeeze-on spot treatment for dogs and horses. The outdoor use is for spray coverage 

(aerosol spray cans) of cracks around doors and windows, and localized resting areas 

(e.g., under eaves), dark corners under porches and patios. Products labels indicate 

control of spiders, ticks, fleas, beetles, ants, flies, midges, yellow jackets (adult), small 

flying insects, cockroaches and other pests in domestic, public health and industrial 

situations. Available cyphenothrin use information was obtained from the active labels in 

the Pesticide Product Label System (PPLS; http://www.epa.gov/pesticides/pestlabels/). 

Active registration numbers were obtained from the Label Usage Information System 

(LUIS) report. 

C. Environmental Fate and Transport 

Cyphenothrin, a Type II pyrethroid, is a chrysanthemate ester "first-generation" 

photolabile pyrethroid, according to an analysis conducted by the California Department 

of Pesticide Regulation CDPR; Spurlock & Lee, 2008). In general, it is recognized that 

this class (i.e., first-generation pyrethroids) of synthetic pyrethroid compounds may 

photodegrade rapidly in sunlight (photolysis), with half-lives generally on the order of 

hours (Spurlock & Lee, 2008). Low water solubility (hydrophobicity) is one of the 

distinguishing characteristics of pyrethroid pesticides, which influences partitioning to 

sediment and dissolved organic matter, and the bioavailability of these compounds. 

No environmental fate guideline studies have been submitted to EPA to support the 

registration of cyphenothrin. However, available nonguideline data defining the physical, 

Page 6 of 41 
chemical, fate and transport characteristics associated with cyphenothrin are summarized 

in Table 1. These data were obtained from the product chemistry data (USEPA, 1986) 

submitted by the registrant, and have been supplemented by with information from the 

Pesticide Properties DataBase (PPDB) and the Material Safety Data Sheet (MSDS; 

7/6/09 update) for cyphenothrin. 

Table 1. General physico-chemical and environmental fate properties of cyphenothrin (no 

environmental fate guideline data submitted in support of registration). 

Chemical/Fate Parameter Value(s) Source Comments 

Molecular weight (MW) (g/mol) 375.47 Pesticide Properties 

DataBase (PPDB) 

PPDB 6 July 2009 

update 

Vapor pressure (VP) (20°C) 1.16 x 10-4 Pa 

8.7 x 10-7 mmHg Product Chemistry 2/19/86 EPA memo 

Water solubility (mg/L; at 25°C) 1.0 Product Chemistry 

Prod. Chem. data 

reported a range of 

0.1-1.0 ppm. 

2/19/86 EPA memo 

Henry’s Law Constant (20°C) 1.85 X 10-03 (dimensionless) -- -- 

Octanol-to-water partition coefficient (log 

KOW; 20°C) 6.29 Product Chemistry 2/19/86 EPA memo 

Hydrolysis half-lives (25°C) (days) stable PPDB PPDB 6 July 2009 

update 

Soil photolysis half-life 

(days) No data -- -- 

Aqueous photolysis half-life (days) No data -- -- 

Aerobic soil metabolism half-life (days) No data -- -- 

Aerobic aquatic metabolism half-life (days) No data -- -- 

Anaerobic aquatic metabolism half-life (days) No data -- -- 

Soil partition coefficients (Kd) No data -- -- 

Organic-carbon normalized partition 

coefficients (Koc)(mL/goc) 9,224 PPDB PPDB 6 July 2009 

update 

Fish bioconcentration factors (BCF) No data -- -- 

Page 7 of 41 
There are no data available on the bioconcentration/bioaccumulation potential of 

cyphenothrin. The reported logarithm of the octanol-water partition coefficient (Log 

Kow) for cyphenothrin is 6.29, which typically suggests a high potential for 

bioaccumulation. A preliminary analysis was conducted using the Agency’s PBT 

Profiler (http://www.epa.gov/pbt/tools/toolbox.htm). This model, based on structuralactivity relationships, indicates that cyphenothrin has properties consistent with persistent 

bioaccumulative and toxic compounds. Additionally, the Agency’s ASTER model 

(Assessment Tools for the Evaluation of Risk; 

http://www.epa.gov/med/Prods_Pubs/aster.htm) provides an estimated BCF for 

cyphenothrin of 73,128X. Given the lack of environmental fate data specific to 

cyphenothrin, this estimate is based primarily on the compound's log Kow. The 

chrysanthemate moiety of first-generation pyrethroids is known to be sensitive to 

photodegradation (Spurlock and Lee 2008), and pyrethroids in general are known to 

partition to organic matter rapidly. Further, the degree to which currently registered uses 

may result in long-term exposure is not clear. The potential for cyphenothrin to persist in 

the environment and bioaccumulate in the food chain will be explored further in the risk 

assessment. 

IV. Receptors

Consistent with the process described in the Overview Document (USEPA 2004), the risk 

assessment for cyphenothrin will rely on a surrogate species approach. Toxicological 

data generated from surrogate test species, which are intended to be representative of 

broad taxonomic groups, are used to extrapolate to potential effects on a variety of 

species (receptors) included under these taxonomic groupings. 

Acute and chronic toxicity data from studies submitted by pesticide registrants along with 

the available open literature will be used to evaluate the potential direct and indirect 

effects of cyphenothrin on aquatic and terrestrial receptors. This includes toxicity data on 

the technical grade active ingredient, degradates, and when available, formulated 

products (e.g. “Six-Pack” studies). Open literature studies are identified using EPA’s 

ECOTOXicology database (ECOTOX) (USEPA 2007b), which employs a literature 

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

wildlife. The evaluation of these sources of data may also provide insight into the direct 

and indirect effects of cyphenothrin on biotic communities from loss of species that are 

sensitive to the chemical and from changes in structure and functional characteristics of 

the affected communities. 

Table 2 provides a summary of the taxonomic groups and the surrogate species tested to 

characterize the potential acute and chronic ecological effects of cyphenothrin. In 

addition, the table provides a preliminary overview of the potential acute toxicity of 

cyphenothrin by providing the acute toxicity classifications. 

Page 8 of 41 
A. Effects to Aquatic Organisms 

Technical grade cyphenothrin is classified as very highly toxic to freshwater fish, 

aquatic-phase amphibians and freshwater aquatic invertebrates on an acute exposure basis 

(Table 2). No guideline studies on acute exposure to estuarine/marine organisms have 

been submitted. Effects of chronic exposure to cyphenothrin on fish or aquatic 

invertebrates have not been submitted to support risk assessment. No data on the effect 

of cyphenothrin on aquatic plants are available. In the absence of guideline toxicity 

studies or ECOTOX data for cyphenothrin, the Agency will consider the potential for 

bridging data from similar pyrethroids if such data is available. 

Some aquatic invertebrate species have been found to have greater sensitivity to 

pyrethroids than Daphnia magna, the species typically used in guideline toxicity studies 

submitted to EPA (Werner and Moran 2008). To support their evaluation of pyrethroids, 

CDPR has requested acute and chronic sediment toxicity data for the amphipod Hyallela 

azteca and the benthic invertebrate midge, Chironomus spp., to address potential aquatic 

risks 

(http://www.cdpr.ca.gov/docs/registration/reevaluation/chemicals/summary_ai_data_req.

pdf ). The Agency will make use of all available reliable data in evaluating the potential 

risks associated with registered uses of cyphenothrin. 

B. Effects to Terrestrial Organisms 

Cyphenothrin is categorized as practically nontoxic to birds, terrestrial-phase amphibians, 

and reptiles on a subacute dietary exposure basis (Table 2); however, no effects data 

from acute oral exposure are available. Also, no data are available to evaluate the effect 

of chronic exposure on avian species or their surrogates. Data reviewed by the Health 

Effects Division (HED) show cyphenothrin to be moderately toxic to mammals on an 

acute oral exposure basis. Limited information is available regarding the effects of 

chronic exposure to mammals. No data are available on the potential effect of 

cyphenothrin exposure on honeybees although as an insecticide adverse effects should be 

expected on beneficial as well as target insects. No data are available with which to 

evaluate the toxicity of cyphenothrin to terrestrial plants. However, there several 

incidents of phytotoxicity associated with permethrin (PC Code 109701), a similarlystructured pyrethroid, reported in the Environmental Incident Information System (EIIS) 

database. 

Page 9 of 41 
Table 2. Test Species Evaluated for Assessing Potential Ecological Effects of 

Cyphenothrin and the Associated Acute Toxicity Classification. NA=data not 

available. 

Taxonomic 

Group 

Surrogate 

Species 

Acute Toxicity 

Citation 

MRID 

Acute Toxicity 

Classification* 

Chronic Toxicity 

Birds1

Bobwhite quail 

(Colinus 

virginianus) 

LD50 = NA 

LC50>5,600 mg/kg diet 

-- 

40983601 

Practically 

nontoxic 

NOAEC = NA 

LOAEC = NA 

--- 

--- * 

Mammals 

Laboratory rat 

(Rattus 

norvegicus) 

LD50 =318 mg/kg 42436212 

Moderately 

toxic 

NOAEC =NA 

LOAEC =NA 

-- 

-- * 

Insects Honey bee (Apis 

mellifera L.) NA -- -- 

Terrestrial 

plants3 NA NA NA 

Freshwater fish2

Rainbow trout 

(Oncorhynchus 

mykiss) 

96-hour LC50 = 0.34 μg/L 41087502 Very highly 

toxic 

NOAEC = NA 

LOAEC = NA 

-- 

-- * 

Freshwater 

invertebrates 

Water flea 

(Daphnia magna) 

48-hour EC50 = 0.43 μg/L 41087501 Very highly 

toxic 

NOAEC = NA 

LOAEC =NA 

-- 

-- * 

Estuarine/marine 

fish NA NA NA 

Estuarine/marine 

invertebrates NA NA NA 

Aquatic plants NA NA NA 

* Chronic Toxicity is not classified 

1

 Birds represent surrogates for terrestrial-phase amphibians and reptiles. 

2

 Freshwater fish may be surrogates for aquatic-phase amphibians. 

3

 Four species of two families of monocots (one is corn); six species of at least four dicot families (one is 

soybeans). 

C. Degradate toxicity 

There are currently no available data on the degradation of cyphenothrin. 

Page 10 of 41 
D. Ecological Incidents 

A preliminary review of the Ecological Incident Information System (EIIS; 2007a)) 

maintained by the Agency’s Office of Pesticide Programs (OPP) indicates no incidents 

have been reported as of 07/22/2009. However, there are several incidents of 

phytotoxicity associated with permethrin (PC Code 109701), a similarly-structured 

pyrethroid. Additionally, the lack of reported incidents cannot be construed as the lack of 

incidents. Since 1998, registrants are only required to submit detailed information to 

EPA on 'major' incidents (for example, affecting >200 flocking birds). Minor incidents 

are aggregated and are not included in EIIS due to the lack of detail provided. In 

addition, there have been changes in state monitoring efforts due to lack of resources. 

A search on 8/15/09 of the Avian Incident Monitoring System (AIMS; 

http://www.abcbirds.org/abcprograms/policy/pesticides/aims/aims/index.cfm) maintained 

by the American Bird Conservancy, did not reveal any incidents involving cyphenothrin 

and birds. 

Reported pet incidents involving the use of cyphenothrin, from 10/2007-8/2009, include 

71 mortalities, 73 major incidents, 2674 moderate incidents and 13,373 minor incidents. 

These numbers represent incidents from all pet pesticide products, including shampoos. 

Cyphenothrin products account for 10% of the total reported pet mortalities, 13% of all 

major incidents, 54% of all moderate incidents and 65% of minor incidents. These data 

are for cyphenothrin co-formulated with pyriproxifen (CAS 95737-68-1), and it is unclear 

whether one active or the other, or an emergent effect from the formulation is responsible 

for these incidents. 

E. Ecosystems Potentially at Risk 

The ecosystems potentially at risk are often extensive in scope; therefore, it may not be 

possible to identify specific ecosystems during the development of a nation-wide 

ecological risk assessment. Outdoor uses of cyphenothrin are labeled for outside surfaces 

of window and door frames, as well as dark corners and localized resting areas such as 

under eaves), porches, patios and garages. However, in general terms, terrestrial 

ecosystems potentially at risk could include areas immediately adjacent to treated 

structures and areas that may receive drift or runoff. Areas adjacent to the aerosol can 

spray treated areas could include lawns, ornamental plantings, stream and pond edges. 

Aquatic ecosystems potentially at risk include water bodies adjacent to, or downstream 

from, the aerosol can spray treated areas and might include impounded bodies such as 

ponds, lakes and reservoirs, or flowing waterways such as streams or rivers. In coastal 

areas, aquatic habitat also includes estuarine areas. Wash-off from treated dogs and 

horses may result in surface water contamination, either through the animal’s immersion 

in the waterbody or as a result of washing pets that have been treated. 

Page 11 of 41 
V. Assessment Endpoints 

Assessment endpoints represent the actual environmental value that is to be protected, 

defined by an ecological entity (species, community, or other entity) and its attribute or 

characteristics (USEPA 1998). For cyphenothrin, the ecological entities include the 

following: birds, reptiles, terrestrial-phase amphibians, mammals, freshwater fish, 

freshwater aquatic-phase amphibians and invertebrates, estuarine/marine fish and 

invertebrates, terrestrial plants, insects and aquatic plants. The attributes for each of these 

entities include growth, reproduction, and survival. 

Assessment endpoints for cyphenothrin, as well as all pesticides evaluated for ecological 

risk, include potential direct toxic effects on the survival, reproduction, and growth of the 

receptors, as well as indirect effects, such as reduction of the prey base or modification of 

habitat. Each assessment endpoint requires one or more “measures of ecological effect,” 

defined as changes in the attributes of an assessment endpoint or changes in a surrogate 

entity or attribute in response to exposure to a pesticide. Specific measures of ecological 

effect are generally evaluated based on acute and chronic toxicity information from 

registrant-submitted guideline tests that are performed on a limited number of organisms. 

Additional ecological effects data from the open literature will also be considered. 

Currently available ECOTOX references are presented in Appendix 1. 

VI. Conceptual Model 

For a pesticide 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 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 for cyphenothrin provides a written description and visual 

representation of the predicted relationships between cyphenothrin, potential routes of 

exposure, and the predicted effects for the assessment endpoint. The conceptual model 

consists of two major components: risk hypothesis and a conceptual diagram (USEPA 

1998). 

Page 12 of 41 
A. Risk Hypothesis 

A risk hypothesis describes the predicted relationship among the stressor, receptor 

exposure, and assessment endpoint response along with the rationale for their selection. 

For cyphenothrin, the following ecological risk hypothesis will be employed for the 

national-level ecological risk assessment: 

Cyphenothrin, when used as a squeeze-on spot treatment for dogs or horses, or 

used on outdoor surfaces, in accordance with current labels, may result in off-site 

movement of the compound via wash-off (from pets), runoff, erosion of sedimentbound residues or spray drift leading to exposure of nontarget plants and 

animals. These potential exposure pathways may result in adverse effects upon 

the survival, growth, and/or reproduction of non-target terrestrial and aquatic 

organisms. These nontarget organisms may include Federally-listed threatened 

and endangered species.

B. Conceptual Diagram 

The known and/or estimated environmental fate properties of cyphenothrin indicate that 

pet wash-off, runoff, erosion of sediment-bound residues and spray drift represent 

possible transport mechanisms of cyphenothrin to aquatic and terrestrial environments. 

Given the labeled outdoor uses of cyphenothrin (which generally limit application to 

outside treatment of structures), and the directions for squeeze-on spot treatments (which 

state treated animals should not be washed immediately after treatment unless adverse 

reaction is observed), the likelihood and magnitude of residue transport and receptor 

exposure is likely limited but remains uncertain. Still, because there is an outdoor 

residential use and a pet spot treatment use, exposure remains possible. The transport 

mechanisms (e.g. sources) are depicted in the conceptual models below (Figures 1, 2 and 

3) and result in the movement of cyphenothrin into aquatic (water and sediment) and 

terrestrial (soil and foliage) habitats. The movement away from the site of application in 

turn represents exposure pathways for a broad range of biological receptors of concern 

and the potential attribute changes, i.e., effects such as reduced survival, growth and 

reproduction, in the receptors due to cyphenothrin exposure. 

Page 13 of 41 
Figure 1. Conceptual model for potential risks of cyphenothrin to aquatic 

organisms. Dotted lines indicate exposure pathways that have a low likelihood of 

contributing to ecological risk.

Cyphenothrin applied to external home surfaces 

Spray drift 

Fish/aquatic-phase 

amphibians 

Eggs 

Larvae 

Juveniles / Adults 

Individual organisms 

Reduced survival 

Reduced growth 

Reduced reproduction 

Food chain 

Reduction in algae 

Reduction in prey 

Habitat integrity 

Reduction in primary productivity

Reduced cover 

Community change 

Surface water/ 

Sediment 

Runoff 

Aquatic Animals 

Invertebrates 

Vertebrates 

Uptake/gills 

or integument 

Ingestion Ingestion

Soil 

Uptake/gills 

or integument 

Aquatic Plants 

Non-vascular 

Vascular 

Uptake/cell, 

roots, leaves Riparian plant

terrestrial 

exposure 

pathways see 

Figure 2 

Groundwater 

Stressor 

Source

Exposure 

Media 

Receptors 

Attribute 

Change 

Page 14 of 41 
Stressor 

Source

Receptors 

Attribute 

Change 

Cyphenothrin applied to external home surfaces 

Spray drift 

Birds / Terrestrialphase amphibians 

/ reptiles / 

mammals 

Terrestrial 

insects 

Individual organisms 

Reduced survival 

Reduced growth 

Reduced reproduction 

Food chain 

Reduction in prey 

Habitat integrity 

Reduction in primary productivity

Reduced cover 

Community change 

Terrestrial/riparian plants 

grasses/forbs, fruit, seeds 

(trees, shrubs) 

Runoff 

Mammals 

Exposure 

Media 

Soil 

Ingestion 

Ingestion

Ingestion

Ingestion

Dermal uptake/Ingestion 

Root uptake 

Birds / 

Amphibians 

Ingestion 

Figure 2. Conceptual model for potential risks of cyphenothrin to terrestrial 

organisms. Given the limited outdoor uses, no effort has been made to identify a 

single predominant route of terrestrial exposure in this diagram.

Page 15 of 41 
Stressor Cyphenothrin Used as Spot Treatment (Washing or Immersion in Surface Water Body) 

or “Down-the-drain’ 

Source/ 

Transport 

Pathways 

Wastewater 

flow/surface waters 

Source/ 

Exposure 

Media 

Riparian/ 

Wetland 

Foliage/Soil 

Receiving Water 

Body/Treatment Facility/ 

Sediment 

Exposure 

Route 

Direct Contact/ 

Root Uptake Gill/ 

 Integument 

Uptake 

Receptors 

Attribute 

Changes 

Aquatic 

Invertebrates, 

Vertebrates 

Wetland/ 

Riparian 

Plants 

Individual Plants

Reduced survival, 

growth, or reproduction 

Individual 

Vertebrates and 

Invertebrates

Reduced survival 

or reproduction 

Aquatic 

Plants 

Uptake/ 

Adsorption

Plant Population

Reduced 

population 

growth 

Figure 3. Conceptual model for potential risks of cyphenothrin to aquatic 

organisms a result of the spot treatment for pets. 

VII. Analysis Plan 

In order to address the risk hypothesis, the potential for adverse effects on the 

environment will be estimated. The use, environmental fate, and ecological effects of 

cyphenothrin will be characterized and integrated to estimate risk. For screening-level 

assessments, this is accomplished using a risk quotient (ratio of exposure concentration to 

effects concentration) approach. Although risk is often defined as the likelihood and 

magnitude of adverse ecological effects, the risk quotient approach does not provide a 

quantitative estimate of likelihood and/or magnitude of an adverse effect. However, as 

outlined in the Overview Document (USEPA 2004), the likelihood of effects to 

individual organisms from particular uses of cyphenothrin may be estimated using a 

probit dose-response slope and either the level of concern (discussed below) or actual 

calculated risk quotient value. 

Page 16 of 41 
This analysis plan will be revisited and may be revised depending upon the information 

submitted by the public in response to the opening of the Registration Review docket for 

cyphenothrin. 

A. Stressors of Concern 

The stressor of concern in the assessment will be the parent compound (cyphenothrin). 

There are no available guideline data on the environmental fate of cyphenothrin or 

degradates that may form; fate data are being requested. If degradates of concern are 

identified, they will be considered in the risk assessment. Potentially toxic contaminants 

resulting from the manufacturing process and present in the formulated pesticide will also 

be considered. 

The cyphenothrin aerosol spray, which is registered for residential outdoor use, is 

formulated with the synergist N-octyl bicycloheptene dicarboximide, also known as 

MKG-264. According to the Registration Eligibility Decision (RED) for MKG-264 

(http://www.epa.gov/pesticides/reregistration/REDs/mgk_red.pdf), MKG-264 is 

moderately toxic to aquatic animals from acute exposure. However, the RED modeled 

exposure from agricultural uses of MKG-264, at higher concentrations than are expected 

from the labeled outdoor use of the cyphenothrin aerosol spray. However, the presence 

of a synergist may result in greater sensitivity to the formulated product than is indicated 

by guideline studies on the technical product. 

Evaluation of pesticide active ingredient mixtures is beyond the scope of this assessment 

because of the myriad factors that cannot be quantified based on the available data. 

Those factors include identification of other possible co-formulations and their 

concentrations, differences in the pattern and duration of exposure among contaminants, 

and the differential effects of other physical/chemical characteristics of the receiving 

waters (e.g. organic matter present in sediment and suspended water). Evaluation of 

factors that could influence additive/synergistic effects is beyond the scope of the 

assessment. However, the Agency acknowledges that not considering mixtures could 

over- or under-estimate risks depending on the type of interaction and factors discussed 

above. The assessment will, however, consider the toxicity of formulated products 

(including formulations involving more than one active ingredient) and will determine 

whether formulated products are more toxic than the technical grade active ingredient 

data used for assessing both direct and indirect risks. 

B. Measures of Exposure 

Agency measures of exposure are typically based on terrestrial and aquatic models that 

estimate environmental concentrations of the chemical being assessed using labeled 

application rates and methods for large-scale uses (e.g., agricultural and public health 

uses). These models require environmental fate data as input. However, because the 

outdoor uses assessed here are limited to small-scale, residential uses, exposure will be 

estimated to the best degree possible based on potential cyphenothrin use patterns, known 

Page 17 of 41 
or estimated chemical properties (e.g., rapid photodegradation and hydrolytic stability), 

and toxicity. There are no monitoring data for cyphenothrin. 

For outdoor urban uses in general, it is assumed that runoff water from rain and/or lawn 

watering may move pesticide directly to surface water or to storm sewers and then to 

surface water. In general, outdoor urban uses are comprised of multiple, relatively small, 

temporally and spatially variable applications, and urban scenarios relevant to this use 

pattern have not been fully developed for models used by OPP. Runoff in urban areas 

may be impacted by pesticides in runoff (water or sediment) or application to 

impermeable surfaces. Aquatic exposure modeling will be conducted for the outdoor use 

of cyphenothrin (application to outdoor premises, patios by aerosol can/general surface 

spray) based on conservative assumptions. The potential for cyphenothrin to reach 

surface water from the outdoor spray use may be minimal based on the label language, 

but the potential exists and will be evaluated. 

A second possible route of aquatic exposure results from wash-off from spot-treatment of 

dogs or horses. Label language states that treated animals should be washed or rinsed if 

sensitivity is indicated after treatment. Therefore, the assessment will consider the 

potential of wash-off from treated pets reaching surface waters, both from washing 

treated pets and from pets immersing in streams, ponds or lakes. Possible evaluation of 

this type of exposure is laid out in detail in the publically available Registration Review 

problem formulation for the pyrethroid etofenprox (PC Code 128965; 

http://www.epa.gov/oppsrrd1/registration_review/etofenprox/index.htm), where 

Estimated Environmental Concentrations (EEC) are estimated using conservative 

assumptions and the USEPA OPPT Down-the-Drain component of the E-FAST model 

(see Appendix 2). 

For ponds and other water bodies, 100% of the cyphenothrin mass from a conservative 

estimate of a number of treated animals could be considered as potentially entering the 

waterbody. The EPA standard pond (2,000,000 L) may be used determine exposure. 

This might be a conservative assumption considering that many spot treatments are 

designed to be absorbed by the pet, thereby providing extended protection. Furthermore, 

the assessment could assume that 100% of the mass washed from a pet will remain in the 

water column. Given the low solubility of cyphenothrin, this would also be a 

conservative assumption. 

Given that cyphenothrin is a pyrethroid, it is possible that cyphenothrin will sorb to 

benthic aquatic sediments or other solids thereby reducing water column availability but 

increasing exposure to benthic invertebrates. In addition, there is the potential for 

microbial degradation within treatment facilities (from the Down-the-Drain assessment) 

that could further reduce cyphenothrin concentrations prior to discharge. Environmental 

fate data for cyphenothrin are needed to better address these assumptions and 

uncertainties. 

For exposure to terrestrial organisms, spray drift from outdoor applications may be 

intercepted by plant surfaces and forage items. The mass of cyphenothrin from a 

Page 18 of 41 
conservative drift assumption could be used as an application rate in the EFED terrestrial 

exposure T-REX (v.1.4.1) model. Exposure to terrestrial animals through consumption 

of treated feed items is estimated from the application rate using a nomogram derived 

from the work of Hoerger and Kenaga (1972) and Fletcher et al. (1994). Potential for 

risk to plants may be estimated by using the TerrPlant model (v.1.2.2). Environmental 

fate data for cyphenothrin are needed to better address assumptions and uncertainties 

related to persistence and mobility in terrestrial environments.. 

C. Measures of Effect 

Ecological effects data are used as measures of direct and indirect effects to biological 

receptors. Data may be obtained from registrant-submitted guideline studies or from 

literature studies identified by ECOTOX. The ECOTOX database will be searched in 

order to provide more ecological effects data to better characterize potential biological 

receptor reaction to cyphenothrin exposure. ECOTOX is a source for locating single 

chemical toxicity data and potential chemical mixture toxicity data for aquatic life, 

terrestrial plants, and wildlife. ECOTOX was created and is maintained by the USEPA, 

Office of Research and Development, and the National Health and Environmental Effects 

Research Laboratory's Mid-Continent Ecology Division (USEPA 2007b). 

Where available, sublethal effects observed in both registrant-submitted and open 

literature studies will be evaluated qualitatively. Such effects may include behavioral 

changes, lethargy, changes in coloration, etc. Quantitative assessments of risks, though, 

will be limited to those endpoints that can be directly linked to the Agency’s assessment 

endpoints of impaired survival, growth and reproduction. 

The assessment of risk for direct effects to non-target organisms makes the assumption 

that toxicity of cyphenothrin to birds is similar of that to terrestrial-phase amphibians and 

reptiles. The same assumption is made for fish and aquatic-phase amphibians. 

The acute measures of effect used for animals in this screening-level assessment are the 

LD50, LC50 and EC50. LD stands for "Lethal Dose", and LD50 is the amount of a material, 

given all at once, that is estimated to cause the death of 50% of the test organisms. LC 

stands for “Lethal Concentration” and LC50 is the concentration of a chemical that is 

estimated to kill 50% of the test organisms. EC stands for “Effective Concentration” and 

the EC50 is the concentration of a chemical that is estimated to produce a specific effect in 

50% of the test organisms. Endpoints for chronic measures of exposure for listed and 

non-listed animals are the NOAEL/NOAEC. NOAEL stands for “No Observed-AdverseEffect-Level” and refers to the highest tested dose of a substance that has been reported 

to have no harmful (adverse) effects on test organisms. The NOAEC (i.e., “NoObserved-Adverse-Effect-Concentration”) is the highest test concentration at which none 

of the observed effects were statistically different from the control. For non-listed plants, 

only acute exposures are assessed (i.e., EC25 for terrestrial plants and EC50 for aquatic 

plants); for listed plants, either the NOAEC or EC05 is used. 

Page 19 of 41 
In the absence of data for either acute or chronic effects, cyphenothrin toxicity will be 

presumed. The absence of appropriate data will be especially problematic for the 

endangered species effects determinations and means of identifying mitigation that could 

potentially obviate such determinations. 

D. Integration of Exposure and Effects 

Risk characterization is the integration of exposure and ecological effects characterization 

to determine the potential ecological risk from the use of cyphenothrin on porches, 

external home surfaces, and pets and the likelihood of direct and indirect effects to nontarget organisms in aquatic and terrestrial habitats. The exposure and toxicity effects data 

are integrated in order to evaluate the risks of adverse ecological effects on non-target 

species. For the assessment of cyphenothrin risks, the risk quotient (RQ) method will be 

used to compare exposure and measured toxicity values. In this approach, EECs are 

divided by acute and chronic toxicity values. The resulting RQs are then compared to the 

Agency’s levels of concern (LOCs) (USEPA 2004). These criteria are used to indicate 

when cyphenothrin use, as directed on the label, have the potential to cause adverse direct 

or indirect effects to non-target organisms. As noted previously, where data are lacking 

on the toxicity of cyphenothrin, risk will be presumed. 

The quantitative assessment of risk will primarily depend on the deterministic pointestimate based approach described in the risk assessment. An effort will be made to 

further qualitatively describe risk using probabilistic tools that the Agency has developed. 

These tools have been reviewed by FIFRA Scientific Advisory Panels and have been 

deemed as appropriate means of refining assessments where deterministic approaches 

have identified risks. 

E. Endangered Species Assessments 

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

EPA will evaluate risks to Federally-listed threatened and/or endangered (listed) species 

from registered uses of cyphenothrin. This assessment will be conducted in accordance 

with the Overview Document (USEPA 2004), provisions of the ESA, and the Services’ 

Endangered Species Consultation Handbook (USFWS/NMFS 1998). 

The assessment of effects associated with registrations of cyphenothrin is based on an 

action area. The action area is considered to be the area directly or indirectly affected by 

the federal action, as indicated by the exceedance of Agency Levels of Concern (LOCs) 

used to evaluate direct or indirect effects. The Agency’s approach to defining the action 

area under the provisions of the Overview Document (USEPA 2004) considers the results 

of the risk assessment process to establish boundaries for that action area with the 

understanding that exposures below the Agency’s defined LOCs constitute a no-effect 

threshold. For the purposes of this assessment, attention will be focused on the footprint 

of the action (i.e., the area where cyphenothrin application occurs), plus all areas where 

offsite transport (i.e., wash-off, spray drift, runoff of sediment-bound residues (erosion), 

Page 20 of 41 
etc.) may result in potential exposure that exceeds the Agency’s LOCs. Specific 

measures of ecological effect that define the action area for listed species include any 

direct and indirect effects and/or potential modification of its critical habitat, including 

reduction in survival, growth, and reproduction as well as the full suite of sublethal 

effects available in the effects literature. Therefore, the action area extends to a point 

where environmental exposures are below any measured lethal or sublethal effect 

threshold for any biological entity at the whole organism, organ, tissue, and cellular level 

of organization. In situations where it is not possible to determine the threshold for an 

observed effect, the action area is not spatially limited and is assumed to be the entire 

United States. 

F. Drinking Water Assessment 

A drinking water assessment will not be conducted to support future human health 

dietary risk assessments of cyphenothrin. Based upon the limited nature of the registered 

outdoor uses of cyphenothrin, and the fact that there are no tolerances on food 

commodities, EFED does not expect this compound to adversely impact groundwater or 

surface water for human dietary exposure. The Health Effects Division (HED) is not 

going to conduct a dietary risk assessment for cyphenothrin. 

G. Preliminary Identification of Data Gaps 

1. Fate 

The environmental fate database for cyphenothrin is essentially nonexistent. To date, no 

environmental fate studies have been submitted for this compound. Based on 40 CFR 

Part 158, Subpart N (revised July 1, 2008) for labeling that includes residential outdoor 

uses, the following studies are required but have not been submitted: hydrolysis, aerobic 

soil metabolism and leaching and adsorption/desorption. Because cyphenothrin is a first 

generation pyrethroid, and those compounds may be sensitive to photodegradation, 

additional data are required for aqueous photolysis and are requested for soil 

photodegradation. Additionally, anaerobic soil metabolism data are recommended to 

more fully characterize the environmental fate of cyphenothrin. Although required under 

Part 158, EFED does not believe terrestrial field dissipation studies would be useful for 

the risk assessment based on the current use patterns of cyphenothrin. The environmental 

fate data gaps are listed in Table 3. 

Page 21 of 41 
Table 3. Available environmental data for cyphenothrin and remaining data gaps. 

158 

Guideline 

(OPPTS) 

Description MRID/ 

Accession Classification Data Gap? Comments 

161-1 

(835.2120) Hydrolysis No data -- Yes 

Required under CFR 40 Part 

158. 

162-1 

(835.4100) 

Aerobic Soil 

Metabolism No data -- Yes 

163-1 

(835.1230 

835.1240) 

Leaching and 

Adsorption/ 

Desorption 

No data -- Yes 

164-1 

(835.6100) 

Terrestrial Field 

Dissipation No data -- No 

Required under CFR 40 Part 

158, but not believed 

necessary for currently 

registered uses 

161-2 

(835.2240) 

Photodegradation 

in Water No data -- Yes 

Required to characterize 

exposure, including 

identification of potentially 

toxic photoproducts. 

161-3 

(835.2410) 

Photodegradation 

on Soil No data -- Yes* Recommended to characterize exposure. 

162-2 

(835.4100) 

Anaerobic Soil 

Metabolism No data -- Yes* Recommended to characterize exposure. 

*No data have been submitted for these guidelines. While not required for outdoor residential uses, these 

data are recommended because they would be expected to have a significant impact on the exposure 

assessment, particularly with regard to aquatic exposure from treated animals entering ponds. 

2. Effects 

The cyphenothrin ecological effects data for aquatic and terrestrial organisms are very 

limited. These data gaps are highlighted below (Tables 4-6). Additionally, no data have 

been provided on the toxicity of cyphenothrin degradates; as discussed previously, in the 

absence of data to the contrary, any identified major degradates will be presumed to be as 

toxic as the parent. More thorough rationales regarding the need for data is included in 

Appendix 3. Effects, and potential risks, are assumed by the Agency unless data indicate 

otherwise. 

Because of the outdoor uses (use on structures that could be located near water and use 

on pets), data are needed regarding the potential toxicity of fish and aquatic invertebrates 

from chronic exposure to cyphenothrin. Since cyphenothrin may be expected to partition 

to sediments in aquatic systems, toxicity to sediment-dwelling invertebrates is being 

requested. 

Page 22 of 41 
Data should also be submitted for acute effects to estuarine and marine animals. These 

data are conditionally required for residential outdoor pesticide uses. Because 

cyphenothrin is very highly toxic to aquatic animals on an acute exposure basis, and 

because some pyrethroids exhibit greater toxicity in saltwater (Werner and Moran 2008), 

these data should be submitted in order to conduct a thorough risk assessment. 

Data are necessary regarding the acute toxicity of cyphenothrin to wildfowl, upland game 

species and to passerines due to the outdoor use. Additionally, data are needed regarding 

the reproductive effects of chronic exposure of birds to cyphenothrin. Data on the 

subacute dietary toxicity of cyphenothrin to birds are available. 

Data are needed for assessment of potential cyphenothrin toxicity to terrestrial plants. 

Although phytotoxicity data on insecticides was not previously required for insecticides, 

CFR 40 Part 158, October 2007 requires at least a Tier I phytotoxicity study for all 

pesticides with outdoor uses. Given the reported incidents of phytotoxicity for the 

similarly-structured pyrethroid permethrin, at least the vegetative vigor terrestrial plant 

data should be submitted for cyphenothrin. 

There are no data available on the toxicity of cyphenothrin to honey bees, although as an 

insecticide, adverse effects could be expected to occur. Although currently risk 

assessments are not conducted for terrestrial invertebrates, the data would be used to 

examine relative impacts to adult bees as well as brood and inform label precautions, if 

effects are demonstrated. There are data in the open literature identified by ECOTOX 

that could provide information regarding the toxicity of cyphenothrin to the aquatic-phase 

of insects. These data are generally from aggregate studies on pyrethroids in general and 

conducted on target species. Therefore, the submission of guideline data for honey bees 

is recommended. 

Additionally, CFR 40 Part 158 states that if ’an ingredient other than the active ingredient 

is expected to enhance the toxicity of the active ingredient’, toxicity data are required on 

the end-use product for aquatic organisms. Since cyphenothrin is formulated with a 

synergist, aquatic toxicity data should be submitted for the formulated product. 

Page 23 of 41 
Table 4. Available ecological effects data for terrestrial animals exposed to 

technical cyphenothrin and remaining data gaps. 

158 

Guideline 

(OPPTS) 

Description MRID/ 

Accession Classification Data Gap? Comments 

71-1 

(850.2100) Avian oral toxicity -- NA Yes 

Required under CFR 40 Part 

158 

71-2 

(850.2200) 

Avian dietary 

toxicity 40983601 Acceptable No 

71-4 

(850.2300) Avian reproduction -- NA Yes 

141-1 

(850.3020) 

Honeybee acute 

contact toxicity -- NA Yes 

Page 24 of 41 
Table 5. Available ecological effects data for aquatic animals exposed to technical 

cyphenothrin and remaining data gaps. (NA=not applicable) 

Guideline Description MRID/ 

Accession Classification Data Gap? Comments 

72-1 

(850.1075) 

Freshwater fish – 

Acute toxicity 

42436240 Acceptable 

No1

Required under CFR 40 Part 

158 

1

However, data on the 

formulated product should be 

submitted 

2

An acute to chronic ratio may 

be used 

3

Cyphenothrin from spottreatment wash-off is expected 

to partition to sediment in 

aquatic systems where it is 

assumed to remain stable 

42436239 Acceptable 

72-3 

(850.1075) 

Saltwater fish – 

Acute toxicity No data NA Yes 

72-2 

(850.1010) 

Freshwater 

invertebrates – 

Acute toxicity 

43977313 Supplemental 

No1

41087502 Supplemental 

72-3 

(850.1025) 

(850.1035) 

Saltwater 

invertebrates – 

Acute toxicity 

No data NA Yes 

72-4 

(850.1300) 

Freshwater 

invertebrate – 

 life cycle test 

No data NA Yes 

72-4 

(850.1350) 

Saltwater 

invertebrates – 

life cycle test 

No data* NA No2

72-4 

(850.1400) 

Freshwater fish – 

early life stage test No Data NA Yes 

72-4 

(850.1400) 

Saltwater fish – 

early life stage test No data* NA No2

850.1735 

Whole sediment: 

acute freshwater 

invertebrates 

No data* NA Yes3

*Conditionally required for cyphenothrin 

Table 6. Available ecological effects data for plants exposed to cyphenothrin and 

remaining data gaps. 

Guideline Description MRID Classificatio

n 

Data Gap? Comments 

122-1 

(850.4100) 

Terrestrial Plant 

toxicity: Tier I 

seedling emergence 

No data NA No 

While all these studies 

are required under CFR 

40 Part 158, for the 

current label use pattern 

only the vegetative vigor 

data are deemed 

necessary for risk 

assessment 

122-1 

(850.4150) 

Terrestrial Plant 

toxicity: Tier I 

vegetative vigor 

No data NA Yes 

123-2 

(850.4400, 

4500, 

4550) 

Aquatic Plant Growth: 

algae No data NA No 

123-2 

(850.4400) 

Aquatic Plant Growth: 

vascular plants No data NA No 

Page 25 of 41 
VIII. References 

Fletcher, J.S., J.E. Nellessen, and T.G. Pfleeger. 1994. Literature review and evaluation 

of the EPA food-chain (Kenaga) nomogram, an instrument for estimating 

pesticide residues on plants. Environ. Tox. Chem. 13:1383-1391. 

Hoerger, F. and E. E. Kenaga, 1972. Pesticide Residues on Plants: Correlation of 

Representative Data as a Basis for Estimation of their Magnitude in the 

Environment. In F. Coulston and F. Korte, eds., Environmental Quality and 

Safety: Chemistry, Toxicology, and Technology, Georg Thieme Publ., Stuttgart, 

West Germany, pp. 9-28. 

Spurlock F. and Marshall Lee. 2008. Synthetic pyrethroid use patterns, properties and 

environmental effects. In: Synthetic Pyrethroids, Occurrence and Behavior in 

Aquatic Environments. J. Gan, F. Spurlock, P. Hendley, D. Weston, editors ACS 

Symposium Series 991. pp 3-25. 

U.S. Environmental Protection Agency. 1998. Guidelines for Ecological Risk 

Assessment. Risk Assessment Forum, Office of Research and Development, 

Washington, D.C. EPA/630/R-95/002F. April 1998. 

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=30759 

U.S. Environmental Protection Agency. 2000. Risk Characterization Handbook. 

Science Policy Council, U.S. Environmental Protection Agency, Washington, 

D.C. 20460. EPA 100-B-00-002. December 2000. 

U.S. Environmental Protection Agency. 2004. Overview of the Ecological Risk 

Assessment Process in the Office of Pesticide Programs, U.S. Environmental 

Protection Agency. Endangered and Threatened Species Effects Determinations. 

Office of Prevention, Pesticides and Toxic Substances, Office of Pesticide 

Programs, Washington, D.C. January 23, 2004. 

http://www.epa.gov/espp/consultation/ecorisk-overview.pdf 

U.S. Environmental Protection Agency. 2005. Generic Format and Guidance for the 

Level I Screening Ecological Risk Assessments Conducted in the Environmental 

Fate and Effects Division. Office of Pesticide Programs, Washington, D.C. 

January 24, 2005. http://www.epa.gov/oppefed1/ecorisk_ders/index.htm#framework 

U. S. Environmental Protection Agency. 2007a. Ecological Incident Information 

System. http://www.epa.gov/espp/consultation/ecorisk-overview.pdf 

U. S. Environmental Protection Agency 2007b. ECOTOXicology Database. Office of 

Research and Development National Health and Environmental Effects Research 

Laboratory’s (NHEERL’s) Mid-Continent Ecology Division (MED). 

http://cfpub.epa.gov/ecotox/ 

Page 26 of 41 
U.S. Fish and Wildlife Service (USFWS) and National Marine Fisheries Service 

(NMFS). 1998. Endangered Species Consultation Handbook: Procedures for 

Conducting Consultation and Conference Activities Under Section 7 of the 

Endangered Species Act. Final Draft. March 1998. 

U.S. Geological Survey. 2008. National Water Quality Assessment (NAWQA) program. 

Accessed 8 January 2008. http://water.usgs.gov/nawqa/. 

Werner, I. and K. Moran. 2008. Effects of Pyrethroid Insecticides on Aquatic 

Organisms. In: Synthetic Pyrethroids, Occurrence and Behavior in Aquatic 

Environments. J. Gan, F. Spurlock, P. Hendley, D. Weston, editors ACS 

Symposium Series 991. pp 310-334. 

Page 27 of 41 
Appendix 1 Accepted ECOTOX Papers 

Cyphenothrin 

Papers that Were Accepted for ECOTOX 

Acceptable to EcoTox and OPP

Brempong-Yeboah, C. Y., Saito, T., and Miyata, T. (1983). Injection Toxicity of Some Pyrethroids in the 

Armyworm. J.Pestic.Sci. 8 : 95-98. 

EcoReference No.: 112413 

Chemical of Concern: HCCH,PYN,PTR,FNT,FPP,FNV,CYP,PMR,CHT; Habitat: T; Effect 

Codes: MOR; Rejection Code: LITE EVAL 

CODED(CHT,PMR),TARGET(CYP,FNV,FPP,FNT). 

Brempong-Yeboah, C. Y., Saito, T., and Miyata, T. (1985). Topical and Injection Toxicities of Some 

Pyrethroids in the Housefly, Musca domestica L. Jpn.J.Sanit.Zool. 36: 31-38. 

EcoReference No.: 112648 

Chemical of Concern: FNT,FNV,CYP,PMR,CHT,SMT,HCCH; Habitat: T; Effect Codes: 

MOR,PHY; Rejection Code: LITE EVAL CODED(CHT),TARGET(FNT,FNV,CYP,PMR,SMT). 

Erkmen, B., Caliskan, M., and Yerli, S. V. (2000). Histopathological Effects of Cyphenothrin on the Gills 

of Lebistes reticulatus. Vet.Hum.Toxicol. 42: 5-7. 

EcoReference No.: 110977 

Chemical of Concern: CHT; Habitat: A; Effect Codes: MOR,CEL; Rejection Code: LITE 

EVAL CODED(CHT). 

Halliday, W. R., Morgan, N. O., and Kirkpatrick, R. L. (1987). Evaluation of Insecticides for Control of 

Stored-Product Pests in Transport Vehicles. J.Entomol.Sci. 22: 224-236. 

EcoReference No.: 70501 

Chemical of Concern: 

SMT,TMT,MOM,BDC,BFT,ACP,CHT,FPP,CYP,PMR,FNV,DDT,CBL,RSM,PPB; Habitat: T; 

Effect Codes: MOR; Rejection Code: LITE EVAL CODED(CHT),OK(PMR),NO 

MIXTURE(PPB,CBL),NO 

ENDPOINT(TMT),TARGET(SMT,FNV,CYP,FVL,CYF,FPP,BFT,RSM,ACP,MOM). 

Itoh, T., Shinjo, G., and Kurihara, T. (1986). Studies on Wide Mesh Netting Impregnated with Insecticides 

Against Culex Mosquitoes. J.Am.Mosq.Control Assoc. 2: 503-506. 

EcoReference No.: 91567 

Chemical of Concern: FPP,FNT,SMT,FNV,PMR,PLL,CHT; Habitat: T; Effect Codes: MOR; 

Rejection Code: LIGHT EVAL CODED(CHT),TARGET(FPP,FNT,SMT,FNV,PMR,PLL). 

Mikhail, M. W., Al-Bursheed, K. M., and Allam, K. A. M. (2007). Susceptibility of Culex pipiens Complex 

to Some Insecticides in Qatar. J.Egypt.Soc.Parasitol. 37: 893-902. 

EcoReference No.: 110956 

Chemical of Concern: EFX,CPY,CHT,PTP,CYF; Habitat: A; Effect Codes: MOR; Rejection 

Code: LITE EVAL CODED(CPY,CHT),OK(EFX,PTP,CYF). 

Page 28 of 41 
Rani, P. U. and Osmani, Z. (1984). Studies on the Toxic, Repellent and Attractant Properties of Certain 

Insecticides Towards the Housefly, Musca domestica nebulo (L.). Int.Pest Control 26: 72-74. 

EcoReference No.: 112684 

Chemical of Concern: CHT,DM,FNV; Habitat: T; Effect Codes: BEH,MOR; Rejection Code: 

LITE EVAL CODED(CHT),TARGET(DM). 

Rani, P. U. and Osmani, Z. (1982). Toxicity and Repellency of Certain Synthetic Pyrethroids Against 

Musca domestica (L), and Dysdercus cingulatus (F). Pesticides 16: 7-9. 

EcoReference No.: 112687 

Chemical of Concern: CHT,FNV,ATN; Habitat: T; Effect Codes: MOR,BEH; Rejection Code: 

LITE EVAL CODED(CHT),TARGET(FNV,ATN). 

Segawa, T., Nomura, Y., Nishio, H., and Nakata, Y. (1983). Pharmacological Activities of (RS)-alphaCyano-3-phenoxybenzyl (1R)-cis,trans-chrysanthemate (S-2703 forte). Oyo Yakuri 26: 613-625. 

EcoReference No.: 112649 

Chemical of Concern: CHT; Habitat: T; Effect Codes: BEH,PHY; Rejection Code: LITE 

EVAL CODED(CHT). 

Shim, J. C., Lee, D. K., and Lee, K. W. (1997). Insecticide Susceptibility of German Cockroaches 

(Blattaria: Blattellidae) in Seoul. Korean J.Entomol. 27: 73-77. 

EcoReference No.: 112850 

Chemical of Concern: 

BFT,DCTP,CPY,DM,DZ,PFF,ATN,CYP,PMR,EFX,FNTH,LCYT,FNT,TMT,CHT,PTR; 

Habitat: T; Effect Codes: MOR; Rejection Code: LITE EVAL 

CODED(CHT),TARGET(EFX,PMR,TMT,CYP,ATN,PFF,DZ,DM,CPY,DCTP,BFT). 

Tsuji, R., Isobe, N., and Kawasaki, H. (1996). Effect of Pyrethroids on Pentobarbital-Induced Sleeping 

Time in Relation to the Chemical Structure. Toxicology 106: 131-137. 

EcoReference No.: 70397 

Chemical of Concern: PLL,ATN,FPP,SMT,FNV,CHT,PMR,CYP,RSM; Habitat: T; Effect 

Codes: BEH; Rejection Code: LITE EVAL 

CODED(CHT,ATN,FPP,PLL,CYP,RSM,FNV,SMT,PMR,CHT),NO COC(TMT). 

Weerasinghe, I. S., Kasai, S., and Shono, T. (2001). Correlation of Pyrethroid Structure and Resistance 

Level in Culex quinquefasciatus Say from Saudi Arabia. J.Pestic.Sci. 26: 158-161. 

EcoReference No.: 66182 

Chemical of Concern: TMT,RSM,SMT,PMR,FNV,CHT,CYP,CYF,ATN,EFX,BFT,DM; Habitat: 

A; Effect Codes: MOR; Rejection Code: LITE EVAL 

CODED(CHT,CYF,BFT,DM),OK(TMT,RSM,SMT,PMR,FNV,CYP,EFX),TARGET(ATN). 

Yameogo, L., Tapsoba, J. M., and Calamari, D. (1991). Laboratory Toxicity of Potential Blackfly 

Larvicides on Some African Fish Species in the Onchocerciasis Control Programme Area. 

Ecotoxicol.Environ.Saf. 21: 248-256. 

EcoReference No.: 3042 

Chemical of Concern: PMR,CHT; Habitat: A; Effect Codes: MOR; Rejection Code: LITE 

EVAL CODED(PMR,CHT). 

Page 29 of 41 
Acceptable to EcoTox but not OPP

Abe, Y., Senbo, S., Takada, Y., Kawada, H., and Ito, T. (1994). The Effectiveness of Prallethrin Against 

Public Health Pests. Brighton Crop Prot.Conf.-Pests Dis. 3: 1023-1030. 

EcoReference No.: 111802 

Chemical of Concern: DM,CYP,LCYT,EFV,PMR,TMT,PLL,SMT,CHT,PPX,DDVP,PYN; 

Habitat: T; Effect Codes: MOR; Rejection Code: LITE EVAL 

CODED(PLL),OK(SMT,TMT,PMR,DDVP,CYP,EFV),NO MIXTURE(CHT,PPX),NO 

DURATION(DM). 

Brempong-Yeboah, C. Y., Saito, T., and Miyata, T. (1984). The Selective Toxicity of Some Synthetic 

Pyrethroids in the Armyworm, Pseudaletia separata (Walker) III. Cuticle Permeabilities of Some 

Pyrethroids. Appl.Entomol.Zool. 19: 87-94. 

EcoReference No.: 112566 

Chemical of Concern: PMR,FNV,CHT; Habitat: T; Effect Codes: MOR,PHY; Rejection Code: 

NO ENDPOINT(PMR,CHT),TARGET(FNV). 

Brempong-Yeboah, C. Y., Saito, T., and Miyata, T. (1984). Topical and Injection Toxicities of Some 

Pyrethroids in the Tobacco Cutworm, Spodoptera litura Fabricius. J.Pestic.Sci.(Nippon Noyaku 

Gakkaishi) 9: 481-487. 

EcoReference No.: 112900 

Chemical of Concern: FPP,FNV,CYP,PMR,CHT,SMT,HCCH,FNT; Habitat: T; Effect Codes: 

MOR,PHY; Rejection Code: NO CONTROL(CHT,SMT,PMR,CYP,FNV,FPP). 

Brempong-Yeboah, C. Y., Saito, T., and Miyata, T. (1984). Topical and Injection Toxicities of Some 

Pyrethroids to the German Cockroach, Blattella germanica (Dictyoptera: Blattellidae). 

Appl.Entomol.Zool. 19: 348-355. 

EcoReference No.: 112414 

Chemical of Concern: HCCH,PYN,PTR,FNT,FPP,FNV,CYP,PMR,CHT; Habitat: T; Effect 

Codes: MOR; Rejection Code: NO CONTROL(CHT,PMR),TARGET(CYP,FNV,FPP,FNT). 

Brempong-Yeboah, C. Y., Saito, T., Miyata, T., and Tsubaki, Y. (1982). Topical Toxicity of Some 

Pyrethroids. J.Pestic.Sci. 7 : 47-51. 

EcoReference No.: 72072 

Chemical of Concern: CPY,PYN,HCCH,PMR,SMT,CHT,FPP,FNV,FNT; Habitat: T; Effect 

Codes: MOR,PHY,BEH; Rejection Code: NO 

CONTROL(CPY,PYN,HCCH,PMR,SMT,CHT,FPP,FNV,FNT). 

Clements, A. N. and May, T. E. (1977). The Actions of Pyrethroids Upon the Peripheral Nervous System 

and Associated Organs in the Locust. Pestic.Sci. 8: 661-680. 

EcoReference No.: 112851 

Chemical of Concern: FNV,ATN,TMT,CHT,PYN; Habitat: T; Effect Codes: MOR; Rejection 

Code: NO CONTROL(FNV,ATN,TMT,CHT). 

De Sousa, B., Schmid, W., Hefti, H., and Bellus, D. (1982). The Biological Evaluation of Pyrethroids as 

Potential Mothproofing Agents. I. Esters of 2-Substituted 3,3-Dimethylcyclopropane-1-

Carboxylic Acids. J.Soc.Dyers Colour. 98: 79-84. 

EcoReference No.: 112439 

Chemical of Concern: CHT,DM,CYP,PMR,SMT; Habitat: T; Effect Codes: MOR; Rejection 

Page 30 of 41 
Code: NO CONTROL,NO ENDPOINT(CHT,DM,CYP,PMR,SMT). 

Elliott, M., Farnham, A. W., Janes, N. F., and Khambay, B. P. S. (1982). Insecticidal Activity of the 

Pyrethrins and Related Compounds. Part XII. Alpha-Substituted-3-Phenoxybenzyl Esters. 

Pestic.Sci. 13: 407-414. 

EcoReference No.: 112686 

Chemical of Concern: CHT; Habitat: T; Effect Codes: MOR; Rejection Code: NO 

ENDPOINT(CHT). 

Elliott, M., Janes, N. F., Khambay, B. P. S., and Pulman, D. A. (1983). Insecticidal Activity of the 

Pyrethrins and Related Compounds. Part XIII: Comparison of the Effects of alpha-Substituents in 

Different Esters. Pestic.Sci. 14: 182-190 . 

EcoReference No.: 112685 

Chemical of Concern: CHT; Habitat: T; Effect Codes: MOR; Rejection Code: NO 

ENDPOINT(CHT). 

Fuchs, M. E. A. (1988). Flushing Effects of Pyrethrum and Pyrethroid Insecticides Against the German 

Cockroach (Blattella germanica L.). Pyrethrum Post 17: 3-7. 

EcoReference No.: 112852 

Chemical of Concern: CHT; Habitat: T; Effect Codes: BEH; Rejection Code: NO 

CONTROL,NO ENDPOINT(PPB,CYF,CYP,DM,CHT,TMT,PMR,RSM,SMT,TMT). 

Hama, H. (1987). Development of Pyrethroid Resistance in the Diamondback Moth, Plutella xylostella 

LINNE (Lepidoptera: Yponomeutidae). Appl.Entomol.Zool. 22: 166-175. 

EcoReference No.: 112647 

Chemical of Concern: 

FNV,PMR,RSM,CYP,CHT,SMT,FPP,TMT,FVL,MLN,PFF,MOM,CBL,PPB,DDT,PYN; 

Habitat: T; Effect Codes: MOR; Rejection Code: NO MIXTURE(PPB),NO 

CONTROL(CHT,FNV,PMR,CYP,SMT,FPP,TMT,FVL,MLN,PFF,MOM,CBL),TARGET(EFV). 

Joy, R. M., Lister, T., Ray, D. E., and Seville, M. P. (1990). Characteristics of the Prolonged Inhibition 

Produced by a Range of Pyrethroids in the Rat Hippocampus. Toxicol.Appl.Pharmacol. 103: 528-

538. 

EcoReference No.: 92944 

Chemical of Concern: DM,FNV,CHT; Habitat: T; Effect Codes: BEH,BCM; Rejection Code: 

NO ENDPOINT(FNV,DM,CHT). 

Kaneko, H., Matsuo, M., and Miyamoto, J. (1984). Comparative Metabolism of Stereoisomers of 

Cyphenothrin and Phenothrin Isomers in Rats. J.Pestic.Sci. 9: 237-247. 

EcoReference No.: 91927 

Chemical of Concern: SMT,CHT; Habitat: T; Effect Codes: ACC; Rejection Code: NO 

ENDPOINT,NO CONTROL(SMT,CHT). 

Lee, C. Y., Yap, H. H., and Chong, N. L. (1996). Insecticide Toxicity on the Adult German Cockroach, 

Blattella germanica (L.) (Dictyoptera: Blattellidae). Malays.J.Sci. 17A: 1-9. 

EcoReference No.: 68667 

Chemical of Concern: BCY,BDC,BFT,CPY,CYP,CHT,DM,EFX,FNT,LCYT,PMR,PPX; 

Habitat: T; Effect Codes: MOR; Rejection Code: NO 

CONTROL(BCY,BDC,BFT,CPY,CYP,CHT,DM,EFX,FNT,LCYT,PMR,PPX). 

Page 31 of 41 
Lindsay, S. W., Hossain, M. I., Bennett, S., and Curtis, C. F. (1991). Preliminary Studies on the Insecticidal 

Activity and Wash-Fastness of Twelve Pyrethroid Treatments Impregnated into Bednetting 

Assayed Against Mosquitoes. Pestic.Sci. 32: 397-411 . 

EcoReference No.: 112688 

Chemical of Concern: LCYT,CHT,PMR,CYF,CYP,SMT,FPP,FNV,DM; Habitat: T; Effect 

Codes: MOR; Rejection Code: NO ENDPOINT(CHT,PMR,CYF,CYP,SMT,FPP,FNV,DM). 

Lucas, J. R., Ayzeren, C., Bowron, M., and Invest, J. F. (1996). Water Based Space Spray Technology the 

Fast Way to Control Flying Insects. Int.Pest Control 38: 111-113 . 

EcoReference No.: 112857 

Chemical of Concern: CHT,DM,TMT,LCYT,PPB; Habitat: T; Effect Codes: MOR,POP; 

Rejection Code: MIXTURE(TMT,PPB,CHT),NO ENDPOINT(DM). 

Matsunaga, T., Yoshida, K., Shinjo, G., Tsuda, S., Okuno, Y., and Yoshioka, H. (1983). New Pyrethroid 

Insecticides for Indoor Applications. In: J.Miyamoto and P.C.Kearney (Eds.), Proc.5th 

Int.Congr., Pestic.Chem.: Hum.Welfare Environ., Vol.2 Natural Products, Pergamon Press, New 

York 231-238. 

EcoReference No.: 112287 

Chemical of Concern: ATN,PPX,DDVP,FNT,PMR,DTATN,PYN; Habitat: T; Effect Codes: 

MOR; Rejection Code: NO CONTROL(DTATN,PMR,FNT,DDVP,PPX,ATN). 

Moustafa, M. and Metwally, M. M. (1992). New Rosin-Modified Varnish Compositions of Effective Pest 

Control. Pigm.Resin Technol. 21: 12-15. 

EcoReference No.: 112453 

Chemical of Concern: SMT,CHT,TMT; Habitat: T; Effect Codes: MOR; Rejection Code: NO 

MIXTURE(SMT,CHT,TMT). 

Mulla, M. S., Darwazeh, H. A., and Ede, L. (1982). Evaluation of New Pyrethroids Against Immature 

Mosquitoes and Their Effects on Nontarget Organisms. Mosq.News 42: 583-590. 

EcoReference No.: 10971 

Chemical of Concern: FPP,CYP,PYT,CHT; Habitat: A; Effect Codes: MOR,POP; Rejection 

Code: LITE EVAL CODED(CYP),OK(FPP,PYT),NO CONTROL(CHT). 

Nishimura, K., Kobayashi, T., and Fujita, T. (1986). Symptomatic and Neurophysiological Activities of 

New Synthetic Non-Ester Pyrethroids, Ethofenprox, MTI-800, and Related Compounds. 

Pestic.Biochem.Physiol. 25: 387-395. 

EcoReference No.: 110147 

Chemical of Concern: FNV,ATN,CHT; Habitat: AT; Effect Codes: PHY; Rejection Code: NO 

ENDPOINT,NO CONTROL(ATN,CHT,FNV). 

Roberts, R. H., Stark, P. M., and Meisch, M. V. (1984). Aerosol Evaluation of Selected Adulticides Against 

Colonized and Field Strains of Mosquitoes. Mosq.News 44: 528-533. 

EcoReference No.: 112415 

Chemical of Concern: HCCH,DDT,MLN,CHT; Habitat: T; Effect Codes: MOR; Rejection 

Code: NO CONTROL(MLN,CHT). 

Stejskal, V., Aulicky, R., and Pekar, S. (2008). Brief Exposure of Blattella germanica (Blattodea) to 

Insecticides Formulated in Various Microcapsule Sizes and Applied on Porous and Non-porous 

Surfaces. Pest Manag.Sci. 65: 93-98. 

Page 32 of 41 
EcoReference No.: 112517 

Chemical of Concern: FNT,DZ,CPY,CHT; Habitat: T; Effect Codes: MOR; Rejection Code: 

NO CONTROL,NO ENDPOINT(CHT,CPY). 

Tonkopii, V. (2006). Bioidentification of Xenobiotics in Water as a Part of Pollution Control. In: 

Proc.11th World Lakes Conf., Oct.31-Nov.4, Nairobi, Kenya 2: 371-373. 

EcoReference No.: 93004 

Chemical of Concern: 

CHT,RSM,ATN,DM,FNV,PCB,EN,DLD,AND,MLO,CBL,Cu,Co,Cd,Cr,As,Al,DDVP,DDT,HCC

H,HgCl2,PbN,CYP,PMR,SMT; Habitat: A; Effect Codes: MOR; Rejection Code: NO 

CONTROL(CHT,RSM,ATN,DM,FNV,PCB,EN,DLD,AND,MLO,CBL,Cu,Co,Cd,Cr,As,Al,DDV

P,DDT,HCCH,HgCl2,PbN,CYP,PMR,SMT),NO 

EFFECT(RSM,ATN,FNV,MLO,CBL,Cu,Cr,As). 

Wright, C. D. P., Forshaw, P. J., and Ray, D. E. (1988). Classification of the Actions of Ten Pyrethroid 

Insecticides in the Rat Using the Trigeminal Reflex and Skeletal Muscle as Test Systems. 

Pestic.Biochem.Physiol. 30: 79-86. 

EcoReference No.: 81428 

Chemical of Concern: PYT,CYF,DM,EFV,CHT,CYH,FPP,RSM,FSF; Habitat: T; Effect Codes: 

BEH,PHY; Rejection Code: NO CONTROL(PYT,CYF,DM,EFV,CHT,CYH,FPP,RSM,FSF). 

Yap, H. H., Lee, Y. W., Zairi, J., Jahangir, K., and Adanan, C. R. (2001). Indoor Thermal Fogging 

Application of Pesguard FG 161, a Mixture of d-Tetramethrin and Cyphenothrin, Using Portable 

Sprayer Against Vector Mosquitoes in the Tropical Environment. J.Am.Mosq.Control Assoc. 17: 

28-32. 

EcoReference No.: 80753 

Chemical of Concern: ATN,PPB,SMT,TMT,CHT; Habitat: A; Effect Codes: MOR,PHY; 

Rejection Code: NO CONTROL(ATN,PPB,SMT,TMT,CHT). 

Page 33 of 41 
Appendix 2 Down-the-Drain Scenario for Pet Spot Treatments from the 

Etofenprox Registration Review Problem Formulation 

Document available at 

(http://www.epa.gov/oppsrrd1/registration_review/etofenprox/index.htm)

• Preliminary Assessment: Based on Spot Treatment for Pets 

There is potential for discharge of etofenprox into surface water as a result of washing 

pets (cats only) that have been treated with etofenprox as a preventative spot treatment. 

EECs are estimated using multiple conservative assumptions and the USEPA OPPT 

Down-the-Drain component of the E-FAST model. 

It assumes that there is no degradation of etofenprox as a result of water flows 

through treatment works and that 100% of the applied etofenprox is washed off 

the cat and is dissolved in the waste water. 

Given a spot treatment containing 55% etofenprox, a specific gravity of 1.062, and a 

treatment volume of 2 ml, the amount of etofenprox in one treatment is about 1.17 g. 

Based on the Down-the-Drain component of the E-FAST model, the 50th percentile per 

capita daily indoor water usage is 388 L per person, or 1552 L per day for a family of 

four. The concentration of etofenprox in the waste stream given the above conditions 

would be 753 ppb (μg/L). However, this estimated concentration would be diluted by the 

wastewater flows from other households that do not have pets and/or are not using the 

etofenprox formulated treatment and/or are not washing their pets on a given day. The 

American Water Works Association estimates that total per capita wastewater production 

for municipalities is about 689 L/person/day. A recalculation of the estimated etofenprox 

calculation using this water usage estimate yields an EEC of 424 ppb. 

In a typical 50,000 person municipality, the number of cats that must be washed on a 

given day to equal the endangered species LOC for freshwater invertebrates (0.57 μg/L X 

0.05 = 0.0285 μg/L) and fish (2.7 μg/L X 0.05 = 0.135 μg/L) would be: 

Aquatic Invertebrates: 

 Number of cats = [(0.0285 g/L)(50,000 people)(689 L/person)]/1.2E+06 μg/dog) 

 Number of cats = 0.84 

Fish 

 Number of cats = [(0.135 g/L)(50,000 people)(689 L/person)]/1.2E+06 μg/dog) 

 Number of cats = 3.98 

This analysis indicates that in a municipality of 50,000 people, there would be sufficient 

etofenprox in the untreated municipal wastewater discharge from treatment facilities to 

exceed the listed species acute risk LOC for invertebrates if one cat was washed. For 

listed fish, four cats would need to be washed for concentrations of etofenprox in the 

Page 34 of 41 
untreated wastewater to exceed the listed species acute risk LOC. 

As stated above, this approach incorporates several conservative assumptions. The 

assessment method assumes that 100% of the etofenprox applied to cats is removed 

during pet washing. This is a conservative assumption considering that many spot 

treatments are designed to be absorbed by the pet thereby providing extended protection. 

Furthermore, this assessment assumes that 100% of the etofenprox washed from a pet 

remains in the water column. Given that etofenprox is similar to pyrethroids, it is 

possible that etofenprox will sorb to sediments or other solids thereby reducing 

availability. In addition, there is the potential for microbial degradation within treatment 

facilities that would further reduce etofenprox concentrations. Environmental fate data 

for etofenprox is needed to better address these assumptions and uncertainties. 

Page 35 of 41 
Appendix 3. Data Call-in Justification. 

Guideline Number: 850.1300 & 1400 

Study Title: Aquatic Invertebrate Life Cycle (freshwater) and Fish Early-Life-stage 

(freshwater) 

Rationale for Requiring the Data 

Chronic invertebrate life cycle and fish early life-stage data are required under 40 CFR Part 

158 (2008) data requirements for pesticides with residential outdoor uses. These data are 

necessary to determine if chronic exposure to cyphenothrin may adversely affect the 

survival, growth or reproduction of aquatic wildlife. 

Practical Utility of the Data 

How will the data be used? 

These data are necessary to characterize the potential risks from cyphenothrin to aquatic 

invertebrates, freshwater fish and aquatic-phase amphibians (for which the fish serve as 

surrogates). The available acute toxicity data indicate that cyphenothrin is very highly toxic 

to aquatic invertebrates and freshwater fish. Chronic exposure data will be used in the 

screening-level risk assessment to estimate the scope of sublethal effects and potential 

chronic risks to freshwater aquatic wildlife associated with the outdoor uses of 

cyphenothrin. In the absence of these data the Agency will presume effects to aquatic 

wildlife from chronic exposure to cyphenothrin. 

How could the data change the Agency’s decision or impact the Agency’s future 

decision-making? 

If future endangered species risk assessments are performed without these data, the Agency 

would have to assume that cyphenothrin “may affect” listed aquatic species directly (and 

listed species from other taxa indirectly), and use of cyphenothrin and its formulated 

products may need to be restricted in areas where listed 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 

cyphenothrin use that are unnecessarily severe. 

Guideline Number: 850.1735 

Study Title: Whole Sediment: Acute Freshwater Invertebrates 

Rationale for Requiring the Data 

Acute toxicity to sediment-dwelling invertebrates data are conditionally required under 40 

CFR Part 158 (2008) data requirements for pesticides with residential outdoor uses. Since 

cyphenothrin is expected to partition to sediments and may bioaccumulate in the aquatic 

food chain, these data are necessary to determine if cyphenothrin may adversely affect the 

survival, growth or reproduction of aquatic invertebrates and, indirectly, higher trophiclevel organisms. 

Practical Utility of the Data 

How will the data be used? 

These data are necessary to characterize the potential risks from cyphenothrin to aquatic 

Page 36 of 41 
invertebrates, freshwater fish and aquatic-phase amphibians (for which the fish serve as 

surrogates) and other higher trophic-level species. The available acute toxicity data indicate 

that cyphenothrin is very highly toxic to aquatic invertebrates and freshwater fish. In the 

absence of these data the Agency will presume effects to sediment-dwelling invertebrates. 

How could the data change the Agency’s decision or impact the Agency’s future 

decision-making? 

If future endangered species risk assessments are performed without these data, the Agency 

would have to assume that cyphenothrin “may affect” listed aquatic species directly (and 

listed species from other taxa indirectly), and use of cyphenothrin and its formulated 

products may need to be restricted in areas where listed 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 

cyphenothrin use that are unnecessarily severe. 

Guideline Number: 850.2100 

Study Title: Avian Acute Oral Toxicity 

Rationale for Requiring the Data 

Acceptable avian acute oral toxicity data have not been submitted for exposure of birds to 

cyphenothrin; these data are required under the 40 CFR Part 158 (2008) for pesticides with 

outdoor uses. The new Part 158 data requirements specify that avian acute oral toxicity data 

be submitted for either mallard duck or bobwhite quail and a passerine species. These data 

are necessary to determine the inherent toxicity of cyphenothrin to avian species independent 

of dietary exposure. 

Practical Utility of the Data 

How will the data be used? 

Avian acute oral toxicity data will be used in the screening-level assessment to determine 

whether there are differences in avian species’ sensitivity to cyphenothrin. If oral acute 

toxicity data are not submitted, risk will be assumed for all avian species. 

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

If future endangered species risk assessments are performed without these data, the Agency 

would have to assume that cyphenothrin “may affect” listed birds directly (and listed species 

from other taxa indirectly), and use of cyphenothrin and its formulated products may need to 

be restricted in areas where listed 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 cyphenothrin use that are 

unnecessarily severe. 

Guideline Number: 850.2300 

Study Title: Avian Reproduction 

Rationale for Requiring the Data 

Avian reproduction toxicity data have not been submitted for chronic exposure of birds to 

cyphenothrin; these data are required under the 40 CFR Part 158 (2008) for pesticides with 

Page 37 of 41 
outdoor uses. The Part 158 data requirements specify that avian reproduction toxicity data 

be submitted for both mallard duck and bobwhite quail. These data are necessary to 

determine the reproductive toxicity of cyphenothrin to avian species from chronic 

exposure. 

Practical Utility of the Data 

How will the data be used? 

Avian reproduction toxicity data for mallard ducks and bobwhite quail will be used in the 

screening-level assessment to determine whether there are effects on birds from chronic 

exposure to cyphenothrin. If reproductive toxicity data are not submitted, risk will be 

assumed for all avian species. 

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

If future endangered species risk assessments are performed without these data, the 

Agency would have to assume that cyphenothrin “may affect” listed birds directly (and 

listed species from other taxa indirectly), and use of cyphenothrin and its formulated 

products may need to be restricted in areas where listed 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 

cyphenothrin use that are unnecessarily severe. 

Guideline Number: 850.3020 

Study Title: Honeybee Acute Contact Toxicity 

Rationale for Requiring the Data 

Honeybee acute contact toxicity data have not been submitted for cyphenothrin; these data 

are required under the 40 CFR Part 158 (2008) for pesticides with outdoor uses. These 

data are necessary to determine the toxicity of cyphenothrin to honeybees. 

Practical Utility of the Data 

How will the data be used? 

Acute contact toxicity data for honeybees will be used in the screening-level assessment to 

determine whether there are potential adverse effects to honeybees from the use of 

cyphenothrin. 

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

Without these data, risk to honeybees and other beneficial insects will be presumed. If 

endangered species risk assessments are performed without these data, the Agency would 

have to assume that cyphenothrin “may affect” listed birds, and use of cyphenothrin and its 

formulated products may need to be restricted in areas where listed 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 cyphenothrin that are unnecessarily severe. 

Guideline Number: 850.4150 

Study Title: Terrestrial Plant Toxicity-Vegetative Vigor 

Rationale for Requiring the Data 

Page 38 of 41 
Data regarding the toxicity of cyphenothrin to terrestrial plants have not been submitted to 

the Agency. These data are required under the 40 CFR Part 158 (2008) data requirements 

for pesticides with outdoor uses. These data are necessary to determine whether the 

outdoor use of cyphenothrin could adversely affect terrestrial plants. 

Practical Utility of the Data 

How will the data be used? 

These data will be used to determine the potential for cyphenothrin to affect non-target 

plant species in the terrestrial environment. In the absence of data specific for these plants, 

risk to terrestrial plants will be assumed. Because plants are primary producers, providing 

the foundation of food sources for all animal species and habitat for most, the lack of these 

data may require the Agency to presume indirect affects to all species. 

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

If endangered species risk assessments are performed without these data, the Agency 

would have to presume direct risk to non-target plants and indirect risk to all animal 

species from use of cyphenothrin. Therefore, use of cyphenothrin and its formulated 

products may need to be restricted in areas where listed 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 

cyphenothrin that are unnecessarily severe. 

Guideline Number: 835.2120 

Study Title: Hydrolysis 

Rationale for Requiring the Data 

Acceptable data on the hydrolysis of cyphenothrin are required under 40 CFR Part 158, 

Subpart N (revised July 1, 2008) for labeling that includes residential outdoor uses. The 

Agency has a limited understanding of the environmental fate of cyphenothrin. Neither 

hydrolysis data nor a waiver request have been submitted to the Agency. 

Practical Utility of the Data 

How will the data be used? 

Currently there are no hydrolysis studies that provide information on the fate of 

cyphenothrin in water. The submitted data will be used to help characterize and quantify 

the environmental fate of cyphenothrin and any potential degradates in aquatic 

environments. For quantitative exposure estimation, these data will be used in modeling 

estimated environmental concentrations (EECs) of cyphenothrin for the aquatic exposure 

assessment. 

How could the data change the Agency’s decision, or impact the Agency’s future 

decision-making? 

In the absence of the requested data, cyphenothrin will be assumed to be stable to 

hydrolysis. This assumption will constitute an uncertainty in the risk assessment. 

Additionally, the identity of any potential degradates that could be of toxic concern would 

remain an unknown.

Page 39 of 41 
Guideline Number: 835.2240 

Study Title: Photodegradation in Water 

Rationale for Requiring the Data 

Acceptable data on the photodegradation of cyphenothrin in water are required under 40 

CFR Part 158, Subpart N (revised July 1, 2008) for labeling that includes aquatic uses. 

Although a direct aquatic use is not being assessed, there is a potential for direct aquatic 

exposure due to the entry of treated animals into ponds. The Agency has a limited 

understanding of the environmental fate of cyphenothrin. Because cyphenothrin is known 

to be photolabile, it is required that the photoproducts be identified to fully characterize the 

environmental fate of this compound. 

Practical Utility of the Data 

How will the data be used? 

Currently there are no photodegradation in water studies that provide information on the 

fate of cyphenothrin. The submitted data will be used to help characterize and quantify the 

environmental fate of cyphenothrin and any potential degradates in aquatic environments. 

For quantitative exposure estimation, these data will be used in modeling estimated 

environmental concentrations (EECs) of cyphenothrin for the aquatic exposure assessment. 

How could the data change the Agency’s decision, or impact the Agency’s future 

decision-making? 

In the absence of the requested data, cyphenothrin will be assumed to be stable to 

photodegradation. This assumption will constitute an uncertainty in the risk assessment. 

Additionally, the identity of any potential degradates that could be of toxic concern would 

remain an unknown.

Guideline Number: 835.4100 

Study Title: Aerobic Soil Metabolism 

Rationale for Requiring the Data 

Acceptable data on the aerobic soil metabolism of cyphenothrin are required under 40 CFR 

Part 158, Subpart N (revised July 1, 2008) for labeling that includes residential outdoor 

uses. The Agency has a limited understanding of the environmental fate of cyphenothrin. 

Aerobic soil metabolism data have not been submitted to the Agency. 

Practical Utility of the Data 

How will the data be used? 

Currently there are no aerobic soil metabolism studies that provide information on the fate 

of cyphenothrin in soil. The submitted data will be used to help characterize and quantify 

the environmental fate of cyphenothrin and any potential degradates in the environment. 

For quantitative exposure estimation, these data will be used in modeling estimated 

environmental concentrations (EECs) of cyphenothrin for the aquatic exposure assessment. 

How could the data change the Agency’s decision or impact the Agency’s future 

decision-making? 

In the absence of the requested data, cyphenothrin will be assumed to be stable to 

microbial metabolism in soil. This assumption will constitute an uncertainty in the risk 

Page 40 of 41 
Page 41 of 41 

assessment. Additionally, the identity of any potential degradates that could be of toxic 

concern would remain an unknown. 

Guideline Number: 835.1230 and 835.1240 

Study Title: Leaching and adsorption/desorption 

Rationale for Requiring the Data 

Acceptable data on the leaching and adsorption/desorption of cyphenothrin are required 

under 40 CFR Part 158, Subpart N (revised July 1, 2008) for labeling that includes 

residential outdoor uses. The Agency has a limited understanding of the environmental 

fate of cyphenothrin. Adsorption/desorption data have not been submitted to the Agency. 

Practical Utility of the Data 

How will the data be used? 

Currently there are no leaching and adsorption/desorption studies that provide information 

on the potential leaching behavior of cyphenothrin in soil. The submitted data will be used 

to help characterize and the environmental fate of cyphenothrin in the environment. For 

quantitative exposure estimation, these data will be used in modeling estimated 

environmental concentrations (EECs) of cyphenothrin for the aquatic exposure assessment. 

Adsorption/ desorption data using the batch equilibrium method are preferred. If the 

compound is found to rapidly degrade to a major compound in soil, then soil column 

leaching methods (aged and unaged) may be more appropriate. If the compound rapidly 

degrades in soil to a major degradate(s), then adsorption/desorption data on the major 

degradate(s) should also be submitted. 

How could the data change the Agency’s decision or impact the Agency’s future 

decision-making? 

In the absence of the requested data, the potential leaching behavior of cyphenothrin will 

be an unknown, and will constitute an uncertainty in the risk assessment.