1

OFFICE OF CHEMICAL SAFETY

AND POLLUTION PREVENTION

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

October 21, 2015

PC Code: 117101 

MEMORANDUM DP Barcode: D428649

SUBJECT: EFED Registration Review Problem Formulation for Alpha-Chlorohydrin 

FROM: N.E. Federoff, Wildlife Biologist 

James Lin, Environmental Engineer 

Environmental Risk Branch 2 

Environmental Fate and Effects Division (7507P) 

THROUGH: Brian Anderson, Chief 

Melissa Panger, Senior Science Advisor

R. David Jones, Senior Agronomist 

Environmental Risk Branch 2 

Environmental Fate and Effects Division (7507P) 

TO: Matthew Manupella, Chemical Review Manager

Cathryn Britton, Team Leader

Kevin Costello, Branch Chief 

Risk Management and Implementation Branch 2 

Pesticide Re-evaluation Division (7508P) 

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 alphachlorohydrin. The problem formulation describes the preliminary risk hypothesis and the process 

that will be used during the completion of drinking water and ecological risk assessments in 

support of registration review. This document draws on information from studies submitted by 

the registrants in response to data requirements in order to provide an overview of the 

environmental fate and ecological effects associated with the use of alpha-chlorohydrin as well as

outline uncertainties regarding residues and taxa of concern. 
2

Problem Formulation for the Environmental Fate,

Ecological Risk, Endangered Species, and Drinking 

Water Exposure Assessments in Support of the 

Registration Review of Alpha-Chlorohydrin

CAS Registry Number: 96-24-2

PC Code: 117101

DP Barcode: D428649

Prepared by:

N.E. Federoff, Wildlife Biologist

James Lin, Environmental Engineer

U. S. Environmental Protection Agency

Office of Pesticide Programs

Environmental Fate and Effects Division

Environmental Risk Branch II

1200 Pennsylvania Ave., NW

Mail Code 7507P

Washington, DC 20460

Reviewed by:

Brian Anderson, Branch Chief

R. David Jones, Ph.D., Senior Agronomist

Melissa Panger, Ph.D., Senior Advisor
3

TABLE OF CONTENTS

1. Purpose.................................................................................................................................... 4

2. Description of Regulatory Action........................................................................................... 4

3. Conclusions from Previous Assessments................................................................................ 4

3.1. Ecological Risk Assessments........................................................................................... 4

3.2. Drinking Water Exposure Assessments........................................................................... 5

3.3. Clean Water Act Programs............................................................................................... 5

4. Stressor Source and Distribution ............................................................................................ 5

4.1. Pesticidal Mechanism of Action ...................................................................................... 6

4.2. Overview of Pesticide Use and Usage ............................................................................. 6

4.3. Environmental Fate and Transport................................................................................... 6

5. Receptors................................................................................................................................. 7

5.1. Effects to Terrestrial Species............................................................................................ 8

5.1.1. Birds and Mammals.................................................................................................. 8

5.1.2. Beneficial Insects...................................................................................................... 9

5.1.3. Plants......................................................................................................................... 9

5.2. Effects to Aquatic Species................................................................................................ 9

5.2.1. Parent Toxicity ............................................................................................................. 9

5.2.1.1. Fish............................................................................................................................ 9

5.2.1.2. Aquatic Invertebrates................................................................................................ 9

5.2.1.3. Aquatic Plants......................................................................................................... 10

5.3. Degradate Toxicity......................................................................................................... 10

5.4. Incident Database Review.............................................................................................. 10

6. Ecosystems Potentially at Risk ............................................................................................. 10

7. Risk Hypothesis.................................................................................................................... 11

8. Analysis Plan ........................................................................................................................ 11

8.1. Measures of Exposure .................................................................................................... 11

8.2. Measures of Effect ......................................................................................................... 12

8.3. Integration of Exposure and Effects............................................................................... 12

8.4. Endangered Species Assessments.................................................................................. 12

8.5. Drinking Water Assessment........................................................................................... 13

9. Endocrine Disruptor Screening Program.............................................................................. 13

10. Preliminary Identification of Data Gaps........................................................................... 13

10.1. Ecological Effects....................................................................................................... 14

11. References......................................................................................................................... 16
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1. Purpose

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

and ecological effects of the registered indoor uses of alpha-chlorohydrin. Alpha-chlorohydrin is 

a rodenticide that causes reversible infertility in male mammals at low doses and testicular lesions 

and/or mortality at higher doses. This problem formulation provides a plan for analyzing data 

relevant to alpha-chlorohydrin and for conducting environmental fate and ecological risk, 

endangered species, and drinking water assessments for all current, active registrations. 

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 use of alpha-chlorohydrin.

2. Description 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 review1. All pesticides distributed or sold in the 

United States must be registered by the Agency. 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 ability to assess risk evolves and as 

policies and practices change, all registered pesticides continue to meet the statutory standard of 

no unreasonable adverse effects to human health and the environment. Changes in science, public 

policy, and pesticide use practices will occur over time. Through the new registration review 

program, the Agency periodically reevaluates pesticides to ensure that as change occurs, products 

in the marketplace can be used safely. 

As part of the implementation of the new registration review program pursuant to Section 3(g) of 

the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), the Agency is beginning its 

evaluation to determine whether use of alpha-chlorohydrin continues to meet the FIFRA standard 

for registration. This problem formulation for the environmental fate and ecological risk 

assessments in support of the registration review is intended for the initial docket opening, which 

starts the public phase of the review process.

3. Conclusions from Previous Assessments

3.1. Previous Ecological Risk Assessments

In 2005 alpha-chlorohydrin was reviewed under a new chemical screen (D213183). It failed the 

screen because valid avian reproduction studies were needed. Literature studies were submitted 

using Japanese quail (MRID 45690911). 

Secondary toxicity testing and determination of residue levels in the target species were required, 

because secondary exposure of predators and scavengers to poisoned rodents is a major concern 

for rodenticides. EFED recommended that the registrant develop a protocol to be reviewed by 

EFED prior to conducting these tests. Environmental fate data have not been adequately 

 1 (http://www.epa.gov/oppsrrd1/registration_review/)
5

addressed; information supplied is either insufficient, obsolete, or inapplicable. 

3.2. Drinking Water Exposure Assessments

There are no registered outdoor uses of alpha-chlorohydrin, therefore no drinking water exposure 

assessment is needed.

3.3. Clean Water Act Programs

Alpha-chlorohydrin is not identified as a cause of impairment for any water bodies listed as 

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

2 No Total Maximum Daily Load (TMDL) 

criteria have been developed for alpha-chlorohydrin.

3 No aquatic life benchmarks have been 

established for alpha-chlorohydrin.

4 Any data submitted or otherwise located as part of the 

registration review process may be used to create aquatic life benchmarks if applicable. 

4. Stressor Source and Distribution

Chemical Identity

Alpha-chlorohydrin is the active ingredient (a.i.) registered to control Norway rats. The a.i. exists 

as a racemic mixture of R- and S-alpha-chlorohydrin. The structure, chemical name, and other 

identifiers are found in the chemical identity table (Table 4.1).

Table 4.1. Nomenclature of α-Chlorohydrin.

Chemical structure

Common name α-chlorohydrin

Company experimental name U-5897

IUPAC Name (RS)-3-chloropropylene glycol

CAS name 3-chloro-1,2-propanediol

CAS registry number 96-24-2

End-use product (EP) Epibloc® Rodenticide (1% alpha-chlorohydrin) 

 

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

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

_group_name=PESTICIDES

4 http://www.epa.gov/oppefed1/ecorisk_ders/aquatic_life_benchmark.htm
6

4.1. Pesticidal Mechanism of Action

Alpha-chlorohydrin, also known by the trade name Epibloc®, is a Restricted Use rodenticide. It 

is also a chemical sterilant of male mammals. Alpha-chlorohydrin produces male infertility 

(decreases in sperm count and motility) when given in low oral doses to rats, rams, boars, guinea 

pigs, hamsters, & monkeys. At the doses used, there is no interference with libido & the 

antifertility effects are reversible after the agent is withdrawn. At higher doses, testicular 

pathology and/or mortality can occur. 

The active ingredient exists as a racemic mixture of R and S alpha-chlorohydrin. S alphachlorohydrin is converted to S 3-chlorolactaldehyde which then inhibits glyceraldehyde 3-

phosphate dehydrogenase, an essential enzyme in sperm glycolysis (Jones 1998). 

4.2. Overview of Pesticide Use and Usage

Epibloc® rodenticide (produced by Gametrics, Ltd., EPA Reg. No. 42882-2) is the only registered 

label containing alpha-chlorohydrin. Epibloc is a unique rodenticide for control of Norway rats 

only for indoors of industrial and commercial facilities and sanitary sewers. Bait sachets must 

always be placed in tamper resistant stations except for sanitary sewer placements. Each bait 

contains 1% ai (50 mg ai). The label states that it cannot be used in any facility (i.e., schools, 

libraries, etc.) where children may be present. For use in sanitary sewer, Epibloc label specifies 

the language below:

Determine where Norway rats will most likely find and consume bait. Generally these 

areas are manholes, tramlines, tributaries, sewer line junctions or any other accessible 

places with signs of recent rat activity. Once suitable application points have been 

determined, place 2 to 4 sachets of prebait at each point. If prebait can be washed 

away, wire sachets in place. Maintain prebait at application points for at least 2 days. 

After acceptance of prebait has been established, replace prebait sachets with sachets 

of Epibloc, use 6 to 10 sachets per application point. Do not apply Epibloc in sewers 

if heavy rains and/or flooding are forecasted. Sachet is moisture resistant to preserve 

bait freshness. Collect all uneaten and partial uneaten sachets 5 to 10 days after 

placement.

Epibloc is classified as a restricted use pesticide. As required by law for retail sale to and use only 

by Certified Applicators or persons under their direct supervision and only for those uses covered 

by the Certified Applicator’s certification. 

Prebaiting is required with the use of Epibloc. Rats may shy away from unfamiliar food or food 

that has made them sick without killing them. Prebaiting rats with bait similar to Epibloc but 

lacking the active ingredient is needed to promote acceptance of Epibloc when it is applied. 

4.3. Environmental Fate and Transport

The available physical/chemical and environmental fate properties are summarized in Table 4.2.
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Table 4.2. General Physical/Chemical Properties and Environmental Fate Parameters of alphachlorohydrin.

Parameter Value Reference

Physical/Chemical Parameters

Molecular mass 110.54 C3H7ClO2

Melting point -40°C

The Pesticide properties 

Database:

http://sitem.herts.ac.uk/aeru/iu

pac/index.htm

Density (20°C) 1.322 g/cm3

Water solubility (20°C) 1000g/L 

Octanol-water partition coefficient ( 

Log POW) (20°C and pH 7) -0.85 

Persistence in Water

Hydrolysis half-life Study passed the screen, but was not reviewed.

5. Receptors

Consistent with current methods, the risk assessment 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. 

The Agency evaluates the potential for adverse effects as a result of alpha-chlorohydrin usage. As 

described in the Agency’s Overview Document (USEPA, 2004), the most sensitive endpoint for 

each taxon is used for RQ calculations. Assessment endpoints include direct toxic effects on the 

survival, reproduction, and growth of terrestrial and aquatic life, as well as indirect effects, such 

as reduction in prey base and/or modification of habitat. The evaluated taxa include freshwater 

fish, freshwater aquatic invertebrates, birds, small mammals, terrestrial invertebrates, algae, and 

terrestrial plants. 

Acute (short-term) and chronic (long-term) toxicity information is characterized based on 

registrant-submitted studies and a comprehensive review of the open literature on alpha 

chlororhydrin. Other sources of information and reviews of the Ecological Incident Information 

System (EIIS), are conducted to further refine the characterization of potential ecological effects 

associated with exposure. A summary of the available ecotoxicity information and the incident 

information is provided below. 

Table 5.1 provides a summary of the assessment endpoints identified as measures of effects. 

Table 5.1 Measures of Ecological Effects for Alpha-chlorohydrin

Assessment Endpoint Selected Surrogate Species and Measure of 

Ecological Effect Comments

Birds Survival Mallard duck oral LD50 = 331 mg ai/kg-bw MRID 242999

Survival

Mallard duck subacute dietary LC50 = 5620 ppm

Bobwhite quail subacute dietary LC50 = 1658 ppm

MRID 242999

MRID 242999
8

Assessment Endpoint Selected Surrogate Species and Measure of 

Ecological Effect Comments

Reproduction 

and growth

Treated male Japanese quail had significantly smaller 

testes but not reduced fertility or impaired reproductive 

functioning. NOT a guideline study.

MRID 45690911

Mammals Survival Rat LD50 = 131 mg ai/kg bw MRID 45690902

Reproduction 

and growth

No standard guideline studies were available N/A

Freshwater fish Survival Rainbow trout acute 96-hr LC50 = 5000 ppm ai

Bluegill sunfish 96-hr LC50 = 4207ppm ai

MRID 246029

MRID 246032

Reproduction 

and growth

N/A N/A

Freshwater 

invertebrates

Survival Daphnia acute 48-hr EC50 = 972 ppm ai MRID 246031

Reproduction 

and growth

N/A N/A

Estuarine/marine 

fish

Survival N/A N/A

Reproduction 

and growth

N/A N/A

Estuarine/marine 

invertebrates

Survival N/A N/A

Reproduction 

and growth

N/A N/A

Terrestrial plants Survival and 

growth

N/A N/A

Insects Survival N/A N/A

Aquatic plants Biomass and 

Growth Rate

N/A N/A

LD50 = Lethal dose to 50% of the test population; NOAEC = No observed adverse effect concentration; NOAEL = 

No observed adverse effect level; LC50 = Lethal concentration to 50% of the test population; EC50 = Effect 

concentration to 50% of the test population; IC50= concentration resulting in a 50% inhibition in the test population 

response (e.g., growth)

N/A = Not applicable and/or none available

5.1. Effects to Terrestrial Species

5.1.1. Birds and Mammals

The avian acute oral LD50 is 331 mg/kg-bw for the mallard duck. Alpha-chlorohydrin is

categorized as moderately toxic to avian species on an acute oral basis (MRID 242999). This was 

consistent with the LD50s (MRID 45690911) reported for Japanese quail (316 mg/kg-bw for males 

and 421 mg/kg-bw for females). 

The most sensitive avian species tested on a subacute 5-d dietary basis is the bobwhite quail. The 

LC50 is 1658 ppm and is categorized as slightly toxic (MRID 242999).
9

Treated male Japanese quail had significantly smaller testes than controls but not reduced fertility 

or impaired reproductive functioning (MRID 45690911). This was not a standard guideline study

for avian reproduction. Birds (7 pairs) were given a single dose of alpha-chlorohydrin (100 and 

316 mg/kg treatment groups). Multiple sterilants were tested in the study. Standard avian 

reproduction testing would not be applicable because the product is a bait contained in bait stations 

and used on mammals (rodents). 

Acute oral LD50 data for laboratory rats submitted to the Health Effects Division (HED) for 

evaluation of human toxicity were used to assess the mammalian acute toxicity of alphachlorohydrin. The LD50 for rats is 131 mg ai/kg (Glenn and Burr, 1968). These results classify 

alpha-chlorohydrin as moderately toxic to mammals on an acute exposure basis. There were no 

standard reproduction studies available. 

5.1.2. Beneficial Insects

No studies were needed because the product is a bait used in a manner such that little to no exposure 

potential exists for these organisms.

5.1.3. Plants

No studies were submitted because the product is a bait used in a manner such that little to no 

exposure potential exists for plants.

5.2. Effects to Aquatic Species

5.2.1. Parent Toxicity

5.2.1.1. Fish

Acute Exposure

The most sensitive freshwater fish species tested for alpha-chlorohydrin was the bluegill sunfish. 

The LC50 was 4207 ppm for the bluegill sunfish, which is characterized as practically non-toxic to 

freshwater fish (MRID 246032). 

Chronic Exposure

No Studies were submitted because the product is a bait used in a manner such that little to no 

chronic exposure potential exists to these organisms.

5.2.1.2. Aquatic Invertebrates

Acute Exposure

A Daphnia magna acceptable study determined the EC50 to be 972 ppm (MRID 246031),

categorizing the chemical as practically non-toxic to aquatic freshwater invertebrates on an acute
10

exposure basis. 

Chronic Exposure

No studies have been submitted because the product is a bait used in a manner such that little to 

no chronic exposure potential exists to these organisms.

5.2.1.3. Aquatic Plants

No studies have been submitted because the product is a bait used in a manner such that little to 

no exposure potential exists to these organisms.

5.3. Degradate Toxicity

No degradate toxicity studies have been submitted. 

5.4. Incident Database Review

A search was made on June 2, 2015 of the Ecological Incident Information System (EIIS, version 

2.1) and the Incident Data System (IDS), which are maintained by the Agency’s Office of Pesticide 

Programs, and the Avian Incident Montoring System (AIMS), which is maintained by the 

American Bird Conservancy. There were no incidents for alpha-chlorohydrin reported to the 

Agency. 

It should be noted, that the lack of reported incidences should not be construed as the absence of 

incidents. Incident reports for non-target organisms typically provide information only on 

mortality events and plant damage. Sublethal effects in organisms such as abnormal behavior, 

reduced growth and/or impaired reproduction are rarely reported, except for phytotoxic effects in 

terrestrial plants. Incidents often are not seen, due to scavenger removal of carcasses, decay in the 

field, or simply because carcasses may be hard to see on many sites and/or few people are 

systematically looking. Poisoned animals may also move off-site to less conspicuous areas before 

dying. Incidents may not get reported to appropriate authorities capable of investigating the 

incident for a variety of reasons including the finder may not know of the importance of reporting 

incidents, may not know who to call, may not feel they have the time or desire to call, or may 

hesitate to call because of their own involvement in the kill. Incidents reported may not get 

investigated if resources are limited or may not get investigated thoroughly, with residue analyses, 

for example. Also, if kills are not reported and investigated promptly, there will be little chance 

of documenting the cause, since tissues and residues may deteriorate quickly. Reports of 

investigated incidents often do not get submitted to EPA, since reporting by states is voluntary. 

6. Ecosystems Potentially at Risk

For this problem formulation, potential for effects to aquatic and terrestrial ecosystems were 

considered. Alpha-chlorohydrin is expected to pose little risk to terrestrial or aquatic ecosystems

due to its limited use and exposure potential as well as low toxicity to most non-target organisms

as discussed further in Section 8.1. Epibloc is a Restricted Use rodenticide for control of Norway 

rats only for indoors of industrial and commercial facilities and sanitary sewers. Bait sachets must 
11

always be placed in tamper resistant stations except for sanitary sewer placements. Potential 

exposure routes of concern include secondary exposure to predator and scavenger animals from 

consumption of contaminated carcasses and aquatic systems that could contain alphachlorohydrim from use in sanitary sewers. However, as discussed further in Section 8.1, ecological 

effects from these exposure routes are unlikely to occur due to rapid metabolism of the chemical 

within target animals (which alleviates the concern for secondary poisoning) and low exposure 

potential relative to its toxicity in aquatic systems.

7. Risk Hypothesis

A risk hypothesis describes the predicted relationship among the stressor, exposure, and 

assessment endpoint response along with the rationale for their selection. The following ecological 

risk hypothesis is being employed for this national-level ecological risk assessment:

When used according to the label, alpha-chlorohydrin may affect non-target wildlife through 

secondary exposures to predators and scavengers that consume contaminated carcasses and aquatic 

organisms from its use in sanitary sewers. However, as previously summarized and discussed 

further in Section 8.1, risks to non-target terrestrial and aquatic organisms are expected to be 

minimal.

8. Analysis Plan

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

estimated. The use, environmental fate, and ecological effects are characterized and integrated to 

assess the risks. As described below, a full ecological risk assessment will not be needed for alphachlorohydrin due to low toxicity and limited exposure potential to non-target organisms.

8.1. Measures of Exposure

Due to no registered outdoor uses of alpha-chlorohydrin, the exposure to off-site non-target 

organisms is limited, especially for the indoors of industrial and commercial facilities use. 

Most sanitary sewers are enclosed and eventually will be discharged into wastewater treatment 

plants. The impacts to natural aquatic habitats will be limited. The possible impact may be due 

to the corpses of dead rats that may fall into the sewer and into the wastewater treatment plant.

The following back of the envelope calculation provides a quick and simple method to quantify 

any potential aquatic risk. A single Epibloc sachet weighs 5 grams, which contains 1% alphachlorohydrin. Therefore, the number of sachets that need to wash into a receiving pond to result in 

risks of concern can be calculated assuming all the sachets are dopped into the sewer leading 

straight into the receiving standard ecological pond. In order for the aquatic estimated 

environmental concentration (EEC) in the standard EPA pond (1-hectare surface area and 2-meter 

depth) to reach the fish LC50 of 4207 ppm (i.e., RQ = 1) more than 1.68 billion sachets are needed. 

Similarly in order to reach the daphnia LC50 of 972 ppm, more than 388 million sachets are needed. 

In reality, it would be impossible to apply so many sachets into a sewer system leading to a single 

water body of the assumed volume; therefore, aquatic risk can be excluded.
12

Potential secondary exposure and risk to terrestrial animals is expected to be minimal because the 

compound is reportedly rapidly metabolized in target animals (D428647).

Since applications are all bait in nature, standard models including T-REX, TerrPlant, AgDRIFT, 

SIP and STIR do not apply.

8.2. Measures of Effect

Ecological effects data presented in Section 5 are used as measures of direct and indirect effects 

to biological receptors. Data were obtained from registrant-submitted studies or from literature 

studies identified by the ECOTOXicology database (ECOTOX). ECOTOX was searched in order 

to provide more ecological effects data to bridge existing data gaps. 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, 2007a).

8.3. Integration of Exposure and Effects

Risk characterization is the integration of exposure and ecological effects characterization to 

determine the potential ecological risk and the likelihood of direct and indirect effects to non-target 

organisms in aquatic and terrestrial habitats. The exposure and toxicity effects data are typically

integrated in order to evaluate the risks of adverse ecological effects on non-target species. For 

the assessment of risks, the risk quotient (RQ) method is used to compare exposure and measured 

toxicity values. EECs are divided by acute and chronic toxicity values. The resulting RQs are 

then compared to the Agency’s LOCs (USEPA, 2004). These criteria are used to indicate the 

potential to cause adverse direct or indirect effects to non-target organisms. As noted previously, 

where toxicity data are lacking, risk will be presumed. In the case of alpha-chlorohydrin, RQs 

were not calculated. However, risks were determined to not be of concern for non-target organisms 

for the following reasons:

(1) Direct consumption of bait is unlikely to be a concern due to location of use sites (indoor 

only) and label directions and restricted use designation (sanitary sewers);

(2) Secondary poisoning due to consumption of contaminated carcasses is unlikely due to rapid 

clearance of the chemical in target animals; and

(3) Aquatic contamination is unlikely to reach levels of concern due to the bait location in the 

case of indoor uses and the low exposure potential for sanitary sewer uses based on the 

high number of sachets that would need to wash into receiving waters to be a concern (see 

Section 8). 

8.4. Endangered Species Assessments

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

evaluate risks to federally listed threatened and endangered (listed) species from registered uses of 

pesticides in accordance with the Joint Interim Approaches developed to implement the 
13

recommendations of the April 2013 National Academy of Sciences (NAS) report, Assessing Risks 

to Endangered and Threatened Species from Pesticides. The NAS report outlines 

recommendations on specific scientific and technical issues related to the development of pesticide 

risk assessments that EPA and the Services must conduct in connection with their obligations 

under the ESA and FIFRA. EPA will address concerns specific to alpha-chlorohydrin in 

connection with the development of its final registration review decision.

In November 2013, EPA, the U.S. Fish and Wildlife Service, National Marine Fisheries (the 

Services), and USDA released a white paper containing a summary of their joint Interim 

Approaches for assessing risks to listed species from pesticides. These Interim Approaches were 

developed jointly by the agencies in response to the NAS recommendations, and reflect a common 

approach to risk assessment shared by the agencies as a way of addressing scientific differences 

between the EPA and the Services. Details of the joint Interim Approaches are contained in the 

November 1, 2013 white paper, Interim Approaches for National-Level Pesticide Endangered 

Species Act Assessments Based on the Recommendations of the National Academy of Sciences 

April 2013 Report.

Given that the agencies are continuing to develop and work toward implementation of the Interim 

Approaches to assess the potential risks of pesticides to listed species and their designated critical 

habitat, this ecological problem formulation supporting the Preliminary Work Plan for alphachlorohydrin does not describe the specific ESA analysis, including effects determinations for 

specific listed species or designated critical habitat, to be conducted during registration 

review. While the agencies continue to develop a common method for ESA analysis, the planned 

risk assessment for the registration review of alpha-chlorohydrn will describe the level of ESA 

analysis completed for this particular registration review case. This assessment will allow EPA to 

focus its future evaluations on the types of species where the potential for effects exists, once the 

scientific methods being developed by the agencies have been fully vetted. Once the agencies have 

fully developed and implemented the scientific methods necessary to complete risk assessments 

for listed species and their designated critical habitats, these methods will be applied to subsequent 

analyses of alpha-chlorohydrin as part of completing this registration review.

8.5. Drinking Water Assessment

There are no registered outdoor uses of alpha-chlorohydrin, therefore no drinking water exposure 

assessment is needed.

9. Endocrine Disruptor Screening Program

Alpha-chlorohydrin was not included in the first group of chemicals issued an order to conduct 

Tier 1 EDSP testing. For additional information on the EDSP program, visit

http://www.epa.gov/endo/.

10. Preliminary Identification of Data Gaps

No environmental fate testing is required for indoor uses (except the conditional requirement of 

hydrolysis study). However, based on the simple calcualtions, the aquatic risk can be excluded;
14

therefore, no fate guideline studies are required for alpha-chlorohydrin based on the label uses for 

the current registration review.

10.1. Ecological Effects

Table 10.1 identifies studies by MRIDs that offer data for each guideline requirement, as well as 

study classifications and whether or not further data are needed in order to support risk assessment.

Table 10.1 Submitted Ecological Toxicity Data for Alpha-chlorohydrin.

Guideline Data 

Requirement

Submitted 

Studies (MRID)

Study 

Classification

Additional 

Data 

Needed?

Current Additional Data Need

850.2100 Avian Acute Oral MRID 242999 Acceptable No

850.2200 Avian Subacute

Dietary

MRID 242999

MRID 242999

Acceptable

Acceptable

No

850.2300 Avian 

Reproduction

MRID 45690911 Supplemental No

870.3100 Mammal Acute MRID 45690902 Acceptable No

870.3800 Mammal 

Reproduction

MRID Acceptable No

850.3020 Honey Bee Acute 

Contact

No No exposure because product is a bait

850.1075 Freshwater Fish 

Acute

MRID 246032

MRID 246029

Acceptable

Acceptable

No

850.1400 Freshwater Fish 

Chronic

No

850.1010 Freshwater 

Invertebrate 

Acute

MRID 246031 Acceptable No

850.1300 Freshwater 

Invertebrate 

Chronic

No

850.1025 Estuarine/Marine

Fish Acute

No No exposure of concern

850.1400 Estuarine/Marine

Fish Chronic

No No exposure of concern

850.1035 Estuarine/Marine

Invertebrate 

Acute

No No exposure of concern

850.1350 Estuarine/Marine

Invertebrate 

Chronic

No No exposure of concern
15

Guideline Data 

Requirement

Submitted 

Studies (MRID)

Study 

Classification

Additional 

Data 

Needed?

Current Additional Data Need

850.4100

850.4150

Terrestrial plants No No exposure of concern

850.4400

850.5400

Aquatic plants No
16

11. References

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

EPA food-chain (Kenaga) nomogram, and instrument for estimating pesticide residues on 

plants. Environmental Toxicology and Chemistry 13 (9), 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.

Jones, A.R. 1998. Chemical interference with sperm metabolic pathways. J Reprod Fertil Suppl 

53:227-234. 

U.S. Environmental Protection Agency (U.S. EPA). 1998. Guidance for Ecological Risk 

Assessment. Risk Assessment Forum. EPA/630/R-95/002F, April 1998.

USEPA. 2004. Overview of the Ecological Risk Assessment Process in the Office of Pesticide 

Programs, United States Environmental Protection Agency (USEPA). Washington, D.C.: 

Government Printing Office. Available at http://www.epa.gov/espp/consultation/ecoriskoverview.pdf .

USEPA. 2007. Ecological Incident Information System. 

http://www.epa.gov/pesticides/science/efed/policy_guidance/team_authors/endangered_s

pecies_reregistration_workgroup/esa_incident_guidance.htm#eiis

USEPA. 2007a. 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/.

USFWS/NMFS 2004. Memorandum to Office of Prevention, Pesticides, and Toxic Substances, 

U.S. EPA conveying an evaluation by the U.S. Fish and Wildlife Service and National 

Marine Fisheries Service of an approach to assessing the ecological risks of pesticide 

products.

USEPA. 2009. Guidance for Selecting Input Parameters in Modeling the Environmental Fate 

and Transport of Pesticides. Version 2.1. U.S. Environmental Protection Agency, Office 

of Pesticide Programs, Environmental Fate and Effects Division, Oct. 22, 2009. Online 

at: http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm

U.S. Fisheries and Wildlife Service and National Marine Fisheries Service (USFWS/NMFS). 

1998. Endangered Species Consultation Handbook: Procedures for Conducting 

Consultation and Conference Activities Under Section 7 of the Endangered Species Act. 

Final Draft, United States Fish and Wildlife Service (USFWS) and National Marine 

Fisheries Service (NMFS), Washington, D.C.: Government Printing Office.
17

Appendix A. Submitted Environmental Fate & Ecological Effects Studies

Environmental Fate Studies

None
18

Ecological Effects Studies

71-1 Avian Single Dose Oral Toxicity

MRID Citation Reference

45532 Fink, R.; Beavers, J.B.; Brown, R.; et al. (1980) Acute Oral LD50-- Mallard Duck: 3-

Chloro-1,2-propanediol. Final rept. (Unpub- lished study received Jul 24, 1980 under 

42882-EX-1; prepared by Wildlife International, Ltd., submitted by Gametrics, Ltd., 

Sausalito, Calif.; CDL:242993-J) 

45690909 Beavers, J.; Fink, R.; Glenn, M.; et al. (1968) Avian Acute Oral: (Epibloc Rodenticide). 

Unpublished study prepared by Wildlife International, Ltd and The Upjohn Company. 

31 p. {OPPTS 850.2100} 

71-2 Avian Dietary Toxicity

MRID Citation Reference

45530 Fink, R.; Beavers, J.B.; Brown, R.; et al. (1980) Final Report: Eight-Day Dietary LC50-

-Bobwhite Quail: Project No. 172-101. (Unpublished study received Jul 24, 1980 

under 42882-EX-1; pre- pared by Wildlife International, Ltd., submitted by Gametrics, 

Ltd., Sausalito, Calif.; CDL:242993-H) 

45531 Fink, R.; Beavers, J.B.; Brown, R.; et al. (1980) Eight-Day Dietary LC50--Mallard 

Duck: 3-Chloro-1,2-propanediol. Final rept. (Un- published study received Jul 24, 

1980 under 42882-EX-1; pre- pared by Wildlife International, Ltd., submitted by 

Gametrics, Ltd., Sausalito, Calif.; CDL:242993-I) 

45690910 Beavers, J.; Fink, R. (1980) Avian Dietary Toxicity Test: (Epibloc Rodenticide): Lab 

Project Number: WI-447. Unpublished study prepared by Wildlife International, Ltd. 36 

p. {OPPTS 850.2200} 

71-4 Avian Reproduction

MRID Citation Reference

45690911 Jones, P.; Kominkova, H.; Jackson, H.; et al. (1976) Avian Reproduction Test: 

(Epibloc Rodenticide). Unpublished study prepared by American Society for Testing 

Materials, Bowling Green State University and University of California. 27 p. {OPPTS 

850.2300} 
19

72-1 Acute Toxicity to Freshwater Fish

MRID Citation Reference

91302 Vilkas, A.G.; Seminara, J. (1980) The Acute Toxicity of Epibloc (3-chloro-1,2-

propanediol) to the Rainbow Trout,~Salmo~ ?~gairdneri~Richardson: UCCES Project 

No. 11507-85-02. (Un- published study received Oct 6, 1981 under 42882-1; prepared 

by Union Carbide Corp., submitted by Gametrics, Ltd., Sausalito, Calif.; CDL:246029-

A) 

97838 Vilkas, A.G.; Seminara, J. (1980) The Acute Toxicity of Epibloc (3-chloro-1,2-

propanediol) to the Bluegill Sunfish,~Lepomis~ ?~macrochirus~Rafinesque: UCCES 

Project No. 11507-85-01. (Un- published study received Oct 6, 1981 under 42882-1; 

prepared by Union Carbide Corp., submitted by Gametrics, Ltd., Sausalito, Calif.; 

CDL:246032-A) 

45690912 Seminara, J. (1980) Freshwater Fish LC-50-Bluegill & Rainbow: (Epibloc 

Rodenticide): Lab Project Number: 11507-85-01: 11507-85-02. Unpublished study 

prepared by Union Carbide Corporation Environmental Services. 22 p. {OPPTS 

850.1075} 

72-2 Acute Toxicity to Freshwater Invertebrates

MRID Citation Reference

97837 Vilkas, A.G.; Browne, A.M. (1980) The Acute Toxicity of Epibloc (3-chloro-1,2-

propanediol) (99% Active Ingredient) to the Water Flea,~Daphnia magna~Straus: 

UCCES Project No. 11507-85-03. (Unpublished study received Oct 6, 1981 under 

428821; prepared by Union Carbide Corp., Environmental Services, submitted by 

Gametrics, Ltd., CDL:246031-A) 

45690913 Browne, A. (1980) Aquatic Invertebrate Acute Toxicity, Daphnia: Lab Project Number: 

11507-85-03. Unpublished study prepared by Union Carbide Environmental Services. 

12 p. {OPPTS 850.1010} 

81-1 Acute oral toxicity in rats

MRID Citation Reference

91195 Marshall, J.P.; Walker, D. (1978) The Acute Oral Toxicity of Epi- bloc Rodenticide in 

Male Rats: Experiment Reference S78CJ02. (Unpublished study received Jul 10, 

1979 under 42882-1; prepared by Wickham Research Laboratories, Ltd., England, 

submitted by Gametrics, Ltd., Sausalito, Calif.; CDL:238814-C) 

45690902 Glenn, M.; Burr, W. (1970) Acute Oral Toxicity: (Epibloc Rodenticide). Unpublished 

study prepared by The Upjohn Laboratory. 75 p. {OPPTS 870.1100} 
20

81-2 Acute dermal toxicity in rabbits or rats

MRID Citation Reference

45529 Dean, W.P.; Myer, J.; Marroquin, F. (1980) Acute Dermal Toxicity (LDI50^) Study in 

Rabbits: IRDC No. 467-003. (Unpublished study received Jul 24, 1980 under 42882-

EX-1; prepared by Inter- national Research and Development Corp., submitted by 

Gametrics, Ltd., Sausalito, Calif.; CDL:242993-G) 

91196 Glenn, M.W.; Burr, W.M. (1969) 3-Chloro-1,2-propanedial (U-5897): Acute Dermal 

LDI50^ in Rabbit. (Unpublished study received Jul 10, 1979 under 42882-1; prepared 

by Upjohn Co., submitted by Gametrics, Ltd., Sausalito, Calif.; CDL:238814-D) 

45690903 Glenn, M.; Burr, W. (1980) Acute Dermal Toxicity; Technical and Formulated: (Epibloc 

Rodenticide): Lab Project Number: 467-003. Unpublished study prepared by The 

Upjohn Laboratory and International Research and Development Corporation. 39 p. 

{OPPTS 870.1200} 

81-3 Acute inhalation toxicity in rats

MRID Citation Reference

45690904 Glenn, M.; Moe, L. (1969) Acute Inhalation Toxicity: (Epibloc Rodenticide). 

Unpublished study prepared by The Upjohn Company. 12 p. {870.1300}