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United States	Office of Pesticides and Toxic Substances
Environmental Protection	Office of Pesticide Programs (TS-766C)
Ag«icy	Washinqio n,DC 20460
SEPA Pesticide
Fact Sheet

Name of Chemical: alachlor
Reason for Issuance: special review
Date Issued: DEC I 4 1987
Fact Sheet Number: g7il
Description of the Chemical
Chemical name: 2-chloro-2'-6'-diethy1-N-(methoxymethy1)-
acetani1ide
Common name: Alachlor
Trade names: Lasso®, Pillarzo®, Alanex®
EPA Shaughnessy number: 090501
Chemical abstracts service (CAS) number: 15972-60-8
Year of initial registration: 1969
Pesticide type: Herbicide
Chemical Family: Acetanilide
Use Patterns and Formulations
Application sites: preemergent use on field corn (including
sweet corn, popcorn), soybeans,
peanuts, dry beans, lima beans, green peas,
cotton, grain sorghum, sunflowers, ornamental
plants.
Types of formulations: emulsifiable concentrate, granular,
microencapsulate
Types and methods of application: ground or aerial methods
Application rates: rate and frequency vary according to
site application; typically 1 to 4 pounds
of active ingredient per acre.

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Science Findings:
Physical and Chemical Properties
Color
Whi te
Melting Point
40 to 41°C
Speci fic Gravi ty
1.133 (25/15.6°C)
Solubility
Soluble in ether, acetone,
benzene, alcohol (unspecified)
and ethyl acetate; slightly
soluble in hexane; solubility
in water - 24 0 ppm
Physical and Chemical Properties;
Octanol/Water Partition
Coefficient
434
Stability
Stable (first detectable heat
evolution at 105°C)
Appearance at room
temperature
White, crystalline solid at
2 3°C
Tolerance Assessment; Tolerances were established in 40 CFR
180.249 for residues of alachlor and
its metabolites.
Toxicology Summary;
Acute toxicity - Technical alachlor is not an acutely
toxic product by any route of exposure. The acute oral
LD50 in rats is .93 g/kg (Category III), the acute dermal
LD50 in rabbits is 13.3 g/kg (Category III), and alachlor
does not cause significant eye or skin irritation in rabbits
(Category IV).
Chronic Toxicity - Alachlor is oncogenic in both mice and
rats. In mice, alachlor causes a statistically significant
increase in lung bronchioalveolar tumors in females at
260 mg/kg/day (Highest Dose Tested). In rats, alachlor causes
statistically significant increases at 42 mg/kg/day and above
in nasal turbinate and stomach tumors in both sexes and thyroid
follicular tumors in males. The following No Observed Effect
Levels (NOELS) have been established for non-oncogenic effects;
1 mg/kg/day for liver and kidney effects; 2.5 mg/kg/day for
uveal degeneration syndrome (UDS) of the eyes; 10 mg/kg/day
for reproductive effects to kidneys of offspring. No birth
defects were seen in highest dose tested for rats (400 mg/kg
/day), but an additional teratogenicity study in rabbits is
pending completion in 1988.

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4• Summary of Agency's Regulatory Position
The Agency position is tiat current registrations for
the use of alachlor on agricultural and nonfood crops will
be allowed to continue provided the following conditions and
label modifications are met to reduce applicator exposure:
a.	Reclassification as restricted use pesticide.
The application of alachlor is restricted to use by
certified applicators or persons under their direct
supervis ion.
b.	Continue use of tumor warning on label.
The following tuaor warning statement imposed in the
alachlor Registration Standard must remain on the label:
"The use of this product may be hazardous to
your health. This product contains alachlor
which has been determined to cause tumors
in laboratory animals."
c.	Require the use of mechanical transfer devices by
all mixer/loaders and/or applicators who treat
300 acres or more annually with alachlor.
d.	Reinstate aerial application on the alachlor label
with the following additional label restriction:
"Human flacgers prohibited. Aerial application
may be performed using mechanical flaggers only."
The Agency has determined that the upper bound U.S. dietary
risk from alachlor residues on food crops is in the range of
10~6 (approximately one increased tumor case per million
persons exposed) based on the actual percent of crops treated with
alachlor. The Agency believes this risk is reasonable given the
benefits of continued use.
The Agency has determined that the risks associated with
alachlor exposure through ground water cannot be adequately
assessed at this time. The true extent of alachlor occurrence
in ground water is not known and cannot be properly estimated
for most areas of the country. Further monitoring will be
necessary considering the large volume, multiregional use of
alachlor, and the lack of statistically representative data from
the available studies. The Agency's final evaluation of the

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potential for alachlor contamination of ground water is being
deferred, pending receipt of required monitoring data being
generated by the registrant under an EPA-approved p-otocol.
This study is scheduled for completion in late 1989, and the
results will be evaluated by EPA in early 1990.
Existing data on alachlor residues in surface water indicate
that the risk from drinking water sources supplied by surface water
will generally not exceed a range of 10"^. The Agency believes
this level of risk is reasonable given the benefits of continued
use of alachlor products, and is not proposing regulatory act ion
under FIFRA on alachlor residues in surface water. The Agency
plans to promulgate regulations establishing a Maximum Contaminant
Level (MCL) for alachlor under the Safe Drinking Water Act in
the near future. These regulations would require the treatment
of drinking water which contains alachlor residues in excess of
the MCL, thereby maintaining the level of risk from exposure at
reasonable levels.
5. Contact person:
James V. Roelofs
Review Manager
Special Review Branch
Registration Division (TS-767C)
Office of Pesticide Programs
U.S. Environmental Protection Agency
Washington, D.C. 20460
(703)-557-0064
DISCLAIMER: The information in this Chemical Information
Sheet is for informational purposes only, and
may not be used to fulfill data requirements
for pesticide registration or reregistration.

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