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EPA Pesticide
Fact Sheet
Name of Chemical:
Reason for Issuance:
Date Issued:
Fact Sheet Number:
Avermectin
Changed Use Pattern
JUL 20 iggo
89.2
- indoor Use
1.	Description of Chemical
Generic Name: Avermectin [A mixture of avermectins containing 80%
avermectin B^a (5-0-demethyl avermectin A^a) and <_ 20%
avermectin Bjh (5-0-demethyl-25-de(l-methylpropylT-25-
(l-methylethyl) avermectin Ala)]
Conmon Name: Abamectin
Trade Names: Affirm , Agrimec , Avid , MK-936, Zephyr , Avert
EPA Shaughnessy Code: 0122804
Chemical Abstracts Service (CAS) Numbers: 65195-55-3 and
65195-56-4
Year of Initial Registration: 1986
Pesticide Type: Insecticide/Miticide
Chemical Family: Avermectins (macrocylic lactones isolated from soil
organism fst- rppt-nmyrps auprmi h i 1
U.S. Producers: Merck S. Co., Inc.
2.	Use Pattern/Formulations/and Product Limitations*
Application Sites: Garages, Homes, Non-Patient Areas of Hospitals and
Nursing Homes and the Nonfood/feed Areas of Hotels, Motels, Nursing Homes,
Transportation Equipment (Buses, Boats, Ships, Trains, Planes), Utilities,
Warehouses, and Other Conmercial and Industrial Buildings.
Type of Formulation: Whitmire Avert PT 310 Abamectin dust containing
0.05% of the active ingredient abamectin.
Method of Application: Localized spot treatment, crack and crevice
treatment with hand or power duster.
* This fact, sheet, refers to indoor uses only. See EPA Fact. Sheet. 89.1 for
description of other uses of products containing Abamectin.

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Rate of Application: Dust lightly and uniformly to infested sites.
12-24 spot treatments (2 ft x 2 ft area) per 100 sq ft.
Limitations: For Use By Oosnercial Applicators. Not for use in the
food/feed areas of coranercial food/feed handling establishment,
restaurants or other areas where food is commercially prepared or
processed.
3. Science Findings
Summary Science Statement
Technical avermectin exhibits high mammalian acute toxicity. The results
of the acute toxicity tests on the indoor use formulation indicates that
the product is of low toxicity. It is not considered to be mutagenic and
does not sensitize skin. It is not readily absorbed by mammals and the
majority of the residue is excreted in the feces within 2 days. The 24-
month rat chronic feeding/oncogenicity study and 94-week mouse chronic
toxicity oncogenicity study were negative for oncogenic potential. The
results of a series of developmental toxicity studies (rat, rabbit, mouse)
have been evaluated and showed that avermec-tin B, produces developmental
toxicity (cleft palate) in the CFj mouse. Toxicology data were also
evaluated for the delta-8,9-isomer of avermectin B, which is a plant
photodegradate. This isomer possess avermectin like toxicological
activity, it was concluded that the delta-8,9-isomer also produces
developmental toxicity (cleft palate) in mice, but not in rats.
Sufficient data are available to characterize avermectin from an
environmental fate and ecological standpoint. Avermectin is extremely
toxic to manmals and aquatic invertebrates and highly toxic to fish and
bees. Avermectin is relatively non-toxic to birds.
Avermectin undergoes rapid photolysis, is readily degraded by soil
microorganisms and, due to its binding properties and low water
solubility, is expected to exhibit little or no potential for leaching.
Chemical/Physical Characteristics (Technical Grade)
Physical State: Crystalline powder
Color: Yellowish-white
Odor: Odorless
Melting Point; 155 - 157° C
Vapor Pressure: 1.5 x 10~® torr
Density: 1.16 + 0.05 at 21°C
Solubility: Insoluble in water (<_ 5 ug/mL), readily soluble in organic
solvents
pH: NA. The avermectin molecule has neither acidic nor basic
functional groups
Octanol/Water partition Coefficient: 9.9 x 10-*

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Toxicological Characteristics
Technical Grade Avermectin B-]
o Dermal Sensitization: Negative for skin sensitization
o Acute Oral LDjq - Rat; 10.6 mgAg (males), 11.3 mgAg (females)
o 14-Week Oral Study - Rat: NOEL 0,4 mgAg/day (HDT)
o 18-Week Oral Study - Dog: NOEL - 0.25 mgAg/day
o Teratology Study - Rat: Negative for terata up to 1.0 mgAg/day.
o Teratology Study - Rabbit: Teratogenic NOEL = 1.0 mgAg/day.
o Teratology Studies - Mouse: Teratogenic LEL - 0.4 mgAg/day (cleft
palate),* Teratogenic NOEL - 0.2 mgAg/day.
o Maternotoxicity Studies - Mouse: LEL «= 0.075 mgAg/day (lethality);
NOEL = 0.05 mgAg/day
o 2-Generation Reproduction Study - Rat: NOEL * 0.12 mgAg/day; LEL =
0.40 mgAg/day (increased retinal folds in weanlings, increased dead
pups at birth, decreased viability indices, decreased lactation
indices, decreased pup body weights)
o 1-Year Oral Study - Dog: NOEL = 0.25 mgAg/day; LEL = 0.50 mgAg/day
(mydriasis in males and females)
o 94-Week Chronic Toxicity/Oncogenicity Study - Mice: Oncogenic
potential: Negative up to 8 mgAg/day (HDT); Systemic NOEL = 4
mgAg/day; Systemic LEL - 8 mgAg/day (Dermatitis in males,
extramedullar hematopoiesis in the spleen in males, increased
mortality in males, treaors and body weight loss in females)
o 2-Year Chronic Toxicity/Oncogenicity Study - Rats: Oncogenic
potential: Negative up to 2.0 mgAg/day (HDT); Systemic NOEL = 1.5
mgAg/day; Systemic LEL = 2.0 mgAg/day tremors in both sexes)
o Metabolism Study - Rat: Hie metabolic T 1/2 in rats is 1.2 days
o Ames Mutagenicity Assay: Negative
o Mutagenicity Assay for Chromosomal Aberrations in vitro in Chinese
Hamster Ovary Cells

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o Rat Hepatocyte Mutagenicity Study: Under conditions of the study,
abamectin (0.3 and 0.6 raM) caused an induction of single strand DNA
breaks in rat hepatocytes _in vitro; no effect was observed when the
assay was carried out on hepatocytes from rats dosed in vivo at the
LDm dose level (10.6 mgAg> •
o In Vivo Bone Marrow Mutagenicity Cytogenic Study; Negative in male
mice at doses of 1.2 and 12.0 mgAg
Toxicity studies on the Delta-8#9-lsomer of Averinectin
o Acute Oral LD^g - Mouse: > 80 mgAg (HOT) (males and females)
o Teratology Study - Rat: Negative for terata up to 1.0 mgAg/day (HDT)
o Teratology studies - Mouse: Teratogenic LEL = 0.10 mgAg/day (cleft
palate); Teratogenic NOEL = 0.06 mgAg/day
o Maternotoxicity Studies - Mouse: LEL = 0.50 mgAg/day (lethality);
NOEL - 0.10 mgAg/day
o 1-Generation Reproduction Study - Rat: NOEL = 0.4 mg/kg/day (HDT)
o Ames Mutagenicity Assay: Negative
Toxicity Studies for Whitmire Formulation
Acute Oral Toxicity in Rats:
LD50 « > 5.0 gAg
Acute Dermal Toxicity in Rabbits:
ld50 = > 2.0 gAg
Acute Inhalation:
LC50 - >
Primary Eye Irritation in Rabbits:
Primary Dermal Irritation in Rabbits:
Dermal Sensitization:
Ecological Characteristics
Avian Oral (Bobwhite quail): lDcq > 2000 mgAg; LC50 - 3102 ppm
Avian Dietary (Mallard duck): LC^g ¦ 383 ppm
Freshwater Fish (Bluegill): LC50 - 9.6 ppb
Rainbow trout: DCcq - 3.2 ppb
Estuarine Fish (Fathead minnow): LCcq = 15 ppb
Oyster Embryo Larvae: LC5Q « 430 ppb.
Acute Freshwater Invertebrate (Daphnia): LC50 = 0.22 ppb
Acute Estuarine Invertebrate (Shrimp, mysid): LC50 = 0.02 ppb
Toxicity Category	IV
Toxicity Category	III
Waiver Granted
Toxicity Category	III
Toxicity category	IV
Not a sensitizer

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Environmental Characteristics
Avermectin is stable to hydrolysis at ph 5, 7, and 9 and thus is not
expected to hydrolyze in the environment. It photodegrades rapidly in
water and soil with half-lives of less than 12 hours and 1 day
respectively. Soil metabolism studies conducted in darkness indicate
degradation does occur with a half-life of 2 weeks to 2 months under
aerobic conditions. Anaerobic degradation is slower. It is not expected
to accumulate in fish. Avermectin's solubility in water is determined ?to
be 7.8 ppb. The field dissipation study indicates that avermectin, when
applied directly to the soil, dissipates with a half-life of about a week
but may persist longer if the pesticide is shaded. Due to its binding
properties and low water solubility, Avermectin is expected to exhibit
little or no potential for leaching.
Tolerance Assessment
This changed use pattern does not involve a food use and as such a
tolerance assessment is not needed.
Exposure Assessment
Because of adverse developmental effects seen in animal studies, a margin
of safety (MOS) for these effects (maternal toxicity and developmental
toxicity) were calculated with respect to dermal exposure to applicators
applying the dust product. Based upon surrogate exposure data and dermal
absorption data in the monkey, the calculated MOS for applicators was
found to exceed 100 in all instances. This MOS is sufficient to
adequately protect these workers.
4.	Sumwary of Regulatory Position and Rationale
The Agency has determined that it should allow the unconditional
registration of abamectin for indoor use in and around homes and the
nonfood/nonfeed areas of commercial establishments for control of
household pests, such as ants, cockroaches, etc. Adequate data are
available to assess the acute and chronic toxicological effects of
abamectin to humans. Since no crop, food or feed uses are proposed a
tolerance assessment is not necessary. Although technical abamectin is
highly toxic to aquatic organisms (invertebrates and fish) these use
patterns (indoor uses) should not pose any environmental hazard. None of
the criteria for unreasonable adverse effects listed in Section 154.7(a)
of Title 40 of the U.S. Code of Regulations have been met or exceeded for
this use.
5.	Sunroary of Data Gaps
There are no data gaps for this changed use pattern (non-food indoor use).

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6. Contact Person at EPA
George T. LaRocca
Product Manager 15
Insecticide-Rodenticide Branch
Registration Division (H7505C)
Office of Pesticide Program
U.S. Environmental Protection Agency
401 M Street S.W.
Washington, D.C. 20460
Office location and telephone number:
Rra. 204, CM #2
1921 Jefferson Davis Highway
Arlington, VA 22202
(703) 557-2400
Information Fact
used to fulfill
DISCLAIMER: Hie information presented in this Chemical
Sheet is for informational purposes only and may not be
data requirements for pesticide registration.

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