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v>EPA Pesticide
Fact Sheet
Name of Chemical: Ethephon
Reason for Issuance: Registration Standard
Date Issued: September 29, 1988
Fact Sheet Number: 176
1. Description of Chemical
Generic Name: Ethephon
Common Name: Ethephon
Trade Names: Broneflor, Cerone, Chlorethephon (New Zealand), Ethrel,
Florel, Prep and Flordimex
EPA Shaughnessy Code: 099801
Chemical Abstracts Service (CAS) Number: 16672-87-0
Year of Initial Registration: 1973
Pesticide Type: Growth Regulator
U.S. and Foreign Producers: AmChem/Union Carbide
Rhone-Poulenc
2. Use Patterns and Formulations .
Application Sites: To enhance fruit ripening, flower initiation,.
fruit and leaf abscission, and breaking of apical dominance in
apples, barley, wheat, blackberries, boysenberry, blueberry,
cantaloupe, cherry (tart and sweet), cotton, cucumber, squash
and pumpkin (hybrid seed production), figs, cucumber (pickling),
filberts, grapes, lemon, tangerine, tangelo, pepper, pimento,
tomato, walnut, tobacco (flue cured), ornamentals, guava,
grapes for table and raisin production, pineapples, sugarcane,
coffee beans, cottonseed, macadamia nuts, trees (forest and
shelterbelt) and cranberries.
Mechanism of Action: Generation of ethylene after application (ethylene
is a naturally-produced plant hormone).
Types of Formulations: Emulsifiable concentrate, soluble
concentrates/liquids, ready-to-use liquids.
Types and Methods of Application: Broadcast by ground or aerial
equipment.
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Application Rates: Vary from 0.08 to 2.0 pounds of active ingredient
per acre depending upon the use site and desired effects.
3. Science Findings
Chemical Characteristics;
Empirical Formula:
Molecular Weight: 144.5
Physical State: Waxy, solid
Color: White
Melting Point: 74 to 75 °C
Solubility: Very soluble in water, alcohol, propylene glycol;
very slightly soluble in aromatic solvents.
Toxicology Characteristics:
Acute Effects
Acute Oral Toxicity: 1.6 g/kg rats (Toxicity Category III)
Acute Dermal Toxicity: > 5 g/kg rabbits (Toxicity Category III)
Acute Inhalation: Not available
Primary Eye Irritation: Not available, but assumed to be corrosive
based on the primary dermal results
Primary Skin Irritation: Score 6.75 (Corrosive) rabbits
(Toxicity Category I)
Delayed Neurotoxicity Hen: No signs of neurotoxicity
Sub-Chronic Effects
No adequate data are available on subchronic oral toxicity in
rats or dogs. However, the requirement for subchronic studies in
the rodent and non-rodent will be waived if the required chronic
studies are acceptable.
Chronic Effects
Sprague-Dawley Rats - 18 Months: NOEL for cholinest erase activity
is 15 mg/kg/day ( supplementary data).
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Beagle Dogs - 2-Year: NOEL for source A* ethephon was 7.5 mg/
kg/day (supplementary data).
Swiss Albino Mouse - 18-Month oncogenicity study: NOEL for RBC
c hoi in est erase activity is < 4. 5mg/kg/day which was the lowest
dose tested (LOT) (supplementary data).
Oncogenicity
The available data are not adequate to assess the oncogenic potential
of ethephon. In the rat and mouse studies submitted, only chronic
effects were observed and these effects are discussed under the
chronic toxicity section.
Teratology
Rat: NOEL for maternal and embryo/fetal toxicity is 600 mg/kg/day.
NOEL for teratogenic effects is 600 mg/kg/day.
Rabbit: NOEL is 50 mg/kg/day based on fetal resorptions at
higher dose levels tested.
Reproduction: No adequate data available.
Mutagenicity: Salmonella typhimurium indicate no mutagenic effect
up to 1000 ug/100 uL without activation. No acceptable data
are available for chromosomal -aberrations, primary DNA damage,
or other genotoxic effects.
Metabolism: A rat metabolism study is required.
Possible Presence of Contaminant of lexicological Concern
The Agency finds that residues of moncchloroacetic acid may be
found in ethephon-treated commodities. Monochloroacetic acid
is a potential degradation product of an impurity in ethephon,
monochloroethyl ester of (2-chloroethyl)-phosphonic acid.
Monochloroacetic acid is an extrenely toxic metabolic inhibitor
and has been prohibited from addition to food under 21 CFR
189.155. Analysis of certain food and feed crops for residues
of this contaminant are required.
Major Routes of Exposure
Dermal, Inhalation
Physiological and Biochemical Behavioral Characteristics:
Metabolism: Acceptable metabolism data are available for plants and
ruminants. The residue of concern in plant commodities, ruminant
tissues and milk is ethephon per se. Additional data are required
regarding metabolism in poultry tissues and eggs.
* In. the study there were two, apparently different, sources of the
chemical tested and reported as source A and source B.
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Possible Presence of impurities: Available data indicate that technical
ethephon products may contain 2-chloroethanol as an impurity.
2-Chloroethanol is extrenely toxic via the inhalation route and
has caused human deaths. Because of its volatility, 2-choroethanol
is unlikely to be present in ethephon end use products in amounts
high enough to pose an inhalation hazard. However, the impurity
could pose a hazard when technical or manufacuring use products
are stored or used in poorly ventilated spaces., Under these
conditions, 2-chloroethanol vapors could accumulate to levels
which may be hazardous to workers in the area. The Agency is
requiring submission of product chemistry data to assess the
extent of hazard posed by 2-choroethanol.
Environmental Characteristics;
Preliminary Adsorption and Leaching Characteristics: Data are required
on leaching, volatility, and hydrolysis of ethephon to characterize
the potential to reach ground water.
Ecological Cha rac t eri stic s;
Data are sufficient to characterize ethephon as slightly toxic to
birds (Lc50 804 mg/kg quail, 3750 ppm ducks). Laboratory and
field studies indicate that ethephon is slightly toxic to fish
(Lc50 180 mg/L bluegill, 170 mg/L trout (average)).
Tolerance Assessment;
List of crops and Tolerances: (CFR 40 180.300)
Commodity Tolerance (ppm)
Apples 5
Barley, grain 2.0
Barley, straw 10.0
Blackberries 30
Blueberries 20
Cantaloupes 2
Cattle, meat byproducts 0.1
(mbyp)
Cattle meat 0.1
Cattle fat 0.1
Cherries 10
Coffee beans 0.1 (N)
Cottonseed 2.0
Cranberries 5
Cucumbers 0.1
Figs 5
Filberts 0.5
Goats, fat 0.1
Goats, mbyp 0.1
Goats, meat 0.1
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Coircnodity Tolerance (ppm)
Grapes 2.0
Hogs, fat 0.1
Hogs, mbyp 0.1
Hogs, meat 0.1
Horses, fat 0.1
Horses, mbyp 0.1
Horses, meat 0.1
Lemons 2
Macadamia nuts 0.5
Milk 0.1
Peppers 30
Pineapples 2
Pineapple fodder 3
Pineapple forage 3
Pumpkins 0.1
Sheep, fat 0.1
Sheep, mbyp 0.1
Sheep, meat 0.1
Tangerines 0.5
Tangerine hybrids 0.5
Tomatoes 2
Walnuts 0.5
Wheat, grain . 2.0
Wheat, straw ' 10.0
Guavas 0.1
Sugarcane Hawaii only 0.1
40 CFR 185.2700 and 186.2700 (food and feed additive)
Barley milling fractions
except flour 5.0
Wheat milling fractions
except flour 5.0
Raisins 12.0
Raisin waste 65.0
Sugarcane molasses 1.5
Barley milling fractions
except flour 5.0
Wheat milling fractions
except flour 5.0
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Results of Tolerance Assessment: The PADI for ethephon has
recently been revised by the Agency ADI Committee and is
now established at 0.005 mg/kg/day (0.5 mg/kg/day for a
LEL, and an uncertainty factor of 100). This value is
based on an LEL of 0*5 mg/kg/day for a decrease in
plasma choiinesterase activity in a 16-day study in
humans. An uncertainty factor of 100 is derived from a
factor of 10 for the variation in the susceptibility of
humans, and a factor of 10 for the use of an LEL instead
of a NOEL. The PADI will be reevaluated when the required
toxicity and residue chemistry data are submitted and
evaluated.
4. Label warning Statements:
All Manufacturing-Use Products
Do not discharge effluent containing this product
into lakes, streams, ponds, estuaries, oceans, or
public water unless this product is specifically
identified and addressed in an NPDES permit. Do
not discharge effluent containing this product to
sewer systems without previously notifying the
sewage treatment plant authority. For guidance
contact your-.State Water Board or Regional Office
of the EPA.
Technical grade ethephon must be stored and used in
ventilated areas only.
End-Use Products
Do not apply directly to water or wetlands (swamps,
bogs, marshes, and potholes). Do not contaminate
water when disposing of equipment washwaters.
Mixers, loaders and applicators must wear a full
face shield, long trousers, long sleeved shirt,
gloves, and boots to avoid as much skin and eye
contact as possible.
Do not enter treated fields within 24-hours after
application.
The following interim pre-harvest intervals (PHI)
must be included on end use product labels for the
raw agricultural commodities listed. These interim
PHI's may be revised after the required field residue
data have been submitted and evaluated.
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Apples minimum 7 days, barley 40 days, blackberries and
blueberries 42 days, cherries minimum 7 days, coffee
beans 14 days, cotton 14-21 days, cranberries 17-21 days,
cucumbers 17-21 days, figs 14 days, filberts 7 days,
grapes 14 days, guavas 7 months, melons 2 days, peppers
14 days, pineapples 2 days, tangerines 5-10 days,
tomatoes 14-20 days for processing and 3-6 days fresh
market California only, walnuts 5-10 days, wheat 40 days.
6. Summary of Regulatory Positions
1. Ethephon does not meet any of the criteria specified
in 40 CFR 154.7; therefore a Special Review is not
being initiated at this time.
2. The Agency will not require restricted use classification
for ethephon end-use products.
3. The Agency is deferring decisions concerning ethephon1 s
potential for contaminating ground water until information
on its environmental characteristics and fate have been
submitted and and reviewed.
4. The Agency has identified certain data that will
receive immediate review when submitted.
5. The Agency has determined that foliar and soil dislogeable
residue data are required to establish reentry intervals
for all crops. An interim reentry interval of 24 hours
is being imposed for all crops until final reentry reentry
intervals are established.
6. Pre-harvest intervals are required on product labeling
for a variety of currently registered use sites.
7. The Agency is requiring data on animal metabolism
as well as storage stability studies and residue studies for
poultry and eggs. In order to remain in compliance with FIFRA,
registrants must do one of the following:
a. Submit data which demonstrate that no residues
remain in eggs and poultry as a result of feeding treated
commodities;
b. Propose tolerances and provide appropriate
supporting data for residues in poultry tissues and eggs.
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8. Additional residue data, including processing data,
must be submitted for the following raw agricultural
commodities: peppers, tomatoes, cucumbers, melons, lemons,
tangerines, apples, cherries, blackberries, boysenberries,
blueberries, cranberries, grapes, filberts, walnuts,
barley (wheat data may substitute), wheat, (and wheat
straw), coffee beans, cotton seed, figs, guavas, pineapples,
sugarcane, and tobacco. For tobacco, pyrolysis data
must be submitted. If residues concentrate in any of
the processed products, the appropriate food additive
tolerance(s) must be proposed. Specific data requirements
may be found in the data tables.
9. The Agency is requiring the proposal of either
a tolerance for sugarcane forage or a grazing prohbition
for sugarcane forage.
10. The Agency has determined that the following
revisions in the tolerances listed in 40 CFR 180.300 and
21 CFR 193.186 are necessary.
o The designation "N" (negligible) must be
deleted from all tolerances entries.
o The commodity "pineapple fodder" must be
deleted from 40 CFR 180.300.
o The tolerance for guava must be added to
40 CFR 180.300.
o The tolerance for raisins must be added to
21 CFR 193.186.
11. Product chemistry and residue data are required
depicting residues of monochloroacetic acid in or on
food and feed commidities following registered applications
of ethephon. Monochloroacetic acid may be a toxic metabolic
residue derived from an impurity in technical ethephon.
12. The Agency has identified 2-chloroethanol as a
contaminant of toxicological concern. The Agency is
requiring data to assess the extent of contamination
with this substance. Additionally, the Agency is requiring
that manufacturing use products bear a label statement
advising users to store and use the product in well-ventilated
areas.
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13. While the data gaps are being filled, currently
registered manufacturing-use products and end-use products
containing ethephon as the sole active ingredient nay be sold,
distributed, formulated, and used in the United States, subject
to the terms and conditions specified in this Standard.
Registrants must provide or agree to develop additional data,
required in the Registration Standard.
The Agency will issue registrations for substantially
similar products and new uses will be issued after considering
the effects on the theoretical maximum residue contribution
(TMRC) and the maximum permissable intake (MPI).
7. Summary of Major Data Gaps
Due Date (After Issuance
Data Required of the Standard)
Product Chemistry 6-12 Months
Hydrolysis 9 Months
Photodegradation 9 Months
Soil Metabolism 27 Months
Fish Accumulation 12 Months
Rotational Crops 39 Months
Leaching and Adsorption/ 12 Months
Desorption
Terrestrial Field Dissipation 27 Months
Acute Estuarine and Marine 12 Months
Organisms
Acute Inhalation 9 Months
Reproduction 39 Months
Mutagenicity 12 Months
Animal Metabolism 18 Months
Magnitude of Plant Residues 6-24 Months
Analytical Methods 15 Months
Storage Stability 18 Months
Chronic Toxicity Rodent 9 Months*
Oncogenicity data 9 Months*
*These studies may be upgraded or they will have to be repeated.
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6. Contact Person at EPA
Robert J. Taylor
Product Manager 25
Fungicide-Herbicide Branch
Registration Division (TS-767C)
Office of Pesticide Programs
Environmental Protection Agency
401 M Street SW.
Washington, DC 20460
(703) 557-1800
DISCLAIMER: The information presented in this Pesticide Fact
Sheet is for informational purposes only and may not be used to
fulfill data requirements for pesticide registration and
reregistration.
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