United States           Office of Pesticides and Toxic Substances
                 Environmental Protection      Office of Pesticide Programs (TS-766C)
                                       tiN« nr
&EPA      Pesticide
                 Fact Sheet
                 Name of Chemical:  FENITROTHION
                 Reason for Issuance:  REGISTRATION STANDARD

                 Date Issued:  July 30, 198?

                 Fact Sheet Number:
                 	142	_^^^___—^_—^^—


         Generic Name:  0,0-dimethyl 0-(4-nitro-m-toly1)
         (Chemical)     phosphorothioate
         Common Name:  Fenitrothion
         Other Chemical
         Nomenclature:    0,0-dimethy1  0-(3-methyl-4-nitrophenyl)
                         phosphorothioate;  0,0-dimethyl 0-(4-nitro-m-
                         tolyl) phosphorothioate
         Trade Names:  Bayer 41831; Bayer S-5660;  Bayer S-1102A;
                      AC-47,300; C 47114;  Accothion; Cytel; Cyfen;
                      Folithion; Sumithion; Agrothion; Dicofen:
                      Fenstan; Metathion E-50;  Verthion; Cekutrothion;
                      Dybar; Fenitox; Novathion;  and Nuvanol.
         EPA Shaughnessy  Code:  105901
         Chemical Abstracts Service (CAS) Number:   122-14-5
         Year of Initial  Registration:  1975
         Pesticide Type:  Insecticide/Acaricide
         Chemical Family:  Organophosphate
         U.S. and Foreign Producers:  Sumitomo Chemical Company  (Japan)


         Application  Sites:  Ornamentals (including outdoor, greenhouse,
                            and nursery); in forests  for spruce
                            budworm and southern  pine  beetle control;
                            and in and around non-food domestic,
                            commercial, institutional  and industrial
                            areas for household pest  control.
         Formulation  Types:  40% wettable powder (for  control of
                            adult anopheline mosquitoes  in  human
                            dwellings), 4 (45.5%) and  8  (76.8%)
                            pound per gallon emulsifiable concentrates
                             (forestry, ornamental and  domestic,
                            commercial, institutional  and industrial
                            use), and a 93% soluble concentrate/liquid
                             (forestry use).
         Application'Methods:- Primarily by ground application equipment;
                              aerial equipment is used for  spruce budworm

Summary Science Statement
Fenitrothion is a moderately acutely toxic cholinester
aseinhibiting pesticide. It is in Toxicity Category II for
the oral and dermal routes of exposure and Toxicity Category
111 for the inhalation route of exposure and is mildly
irritating to the eyes and skin (Toxicity Category III).
It has not been shown to be a dermal sensitizer and does
not demonstrate acute delayed neuotoxic effects. Substantial
chronic toxicology and residue chemistry data gaps exist,
including metabolism, oncogenicity, mutagenicity, terato—
genicity, and reproductive effects. Human epidemiological
evidence and a dog chronic feeding study have implicated
fenitrothion in causing human eye effects, such as retinal
degeneration and myopia. Laboratory data show that fenitro—
thion is potentially highly to very highly toxic to birds,
fish, and aquatic invertebrates, including certain endangered
species. Preliminary data indicate that groundwater contamin-
ation probably is not a potential threat; however the
Agency is unable to conduct a full assessment due to data
gaps. The Agency is particularly concerned with potential
exposure to applicators using ground application techniques
to control southern pine beetles; reentry workers in green-
houses and nurseries; and non—target organisms following
forestry uses.
Chemical/Physical Characteristics of the Technical Material
Physical State: oily liquid
Color: Yellow—brownish
Molecular weight and formula: 277.2 — C 9 H 12 NO 5 PS
Boiling Point: 118 °C at 0.01 mm Hg
Melting Point: 0.3 °C
Specific Gravity: 1.32— 1.34
Vapor Pressure: data gap
Solubility in various solvents: data gap
pH: data gap
Stability: data gap
Toxicology Characteristics (Technical Grade)
Acute Oral: Toxicity Category II (800 and 330 mg/kg in male and
female rats, respectively)
Acute Dermal: Toxicity Category II (1200 and 890 mg/kg in female
and male rats, respectively)
Acute Inhalation: Toxicity Category III (5.0 mg/L in rats)
Primary Dermal Irritation: Toxicity Category III; mild dermal
irritation was reported in a
rabbit study.

Primary Eye Irritation: Toxicity Category III; mild irritation
after a single application of 0.1 mL
into unwashed eyes of albino rabbits.
Skjn Sensitization: Not a skin sensitizer
Delayed neurotoxicity: Negative in the hen.
Subchronic Oral (rodent) Testing: Data gap for rodent
species (for plasma
cholinesterase effects)
Oncogenicity: Data gap for the mouse
Chronic Feeding: NOEL for brain and red blood cell
cholinesteraSe in rats is 10 ppm;
systemic NOEL for plasma inhibition
in the dog is S ppm.
Metabolism: Data gap
Teratogenicity: Data gap
Reproduction: Data gap
Mutagenicity: Data gap for point mutation assay in mammalian
cells, structural chromosomal aberration, and
other genotoxic effects
Major routes of exposure: Inhalation and dermal exposure to
occupants of treated dwellings; derrnal
and respiratory exposure to applicators
and reentry workers.
Environmental Characteristics
Data gaps exist for most studies. Preliminary data indicate that
fenitrothion degrades fairly rapidly in soil with a half—life
of less than a week in non—sterile muck and sandy loam soils.
Preliminary data also suggest fenitrothion is intermediately mobile
in a variety of soils ranging in texture from sandy loam to clay.
The potential for groundwater cannot be assessed until acceptable
environmental fate data are received.
Ecological Characteristics (technical grade)
Avian oral toxicity: highly toxic to upland gamebirds and
slightly toxic to waterfowl (acute
oral toxicity value to bobwhite quails
and mallards was determined to be 23.6
mg/kg and 1190, respectively)
Avian dietary toxicity: highly toxic to upland gamebirds and
(8 day) and slightly toxic to waterfowl (sub-
acute toxicity value of 157 ppm for
bobwhite quail and 2482 ppm for
Freshwater fish acute toxicity: moderately toxic to both
(96 hr. LC 50 ) warmwater and coidwater fish
(1.7 ppm for brook trout;
3.8 ppm for bluegill)

Freshwater invertebrate toxicity: very highly toxic to
(48 hr. or 96 hr. EC 50 ) aquatic invertebrates
(3 ppb for Gammarus
Tolerance Reassessment
There are no domestic uses for fenitrothion on food or
feed commodities. There is one established U.S. food additive
tolerance which covers residues of fenitrothion in wheat gluten
imported from Australia arising from the stored wheat grain
treatment registered in that country (2 CFR 193.156 [ 9fl. The
nature of fenitrothion residues in plants is adequately
understood. Submitted data indicate that fenitrothion per se (I),
desmethyl fenitrothion (IV), and p—nitrocresol (VII) are the major
components of the residue. Animal metabolism studies are not
available. In the event that future federal registrations for use
of fenitrothion on plant commodities used for animal feeds are
established, or regulations covering importation of animal products
from countries in which fenitrothion is registered for use are
established, additional animal metabolism studies may be required.
Analytical methodology for determining levels of residues
of fenitrothion, fenitrooxon, and p—nitrocresol in plants is
adequate for data collection and tolerance enforcement purposes,
Storage stability and residue data are required to support
the wheat gluten tolerance. A provisional acceptable daily
intake (PADI), based on a one—year dog study with a NOEL of
0.125 mg/kg/day and using a 30—fold safety factor is calculated
to be 0.004 mg/kg/day. A Theoretical Maximum Residue Contribu-
tion (TMRC) for the U.S. population is calculated to be 0.000038
mg/kg/day, which utilizes 0.94 percent of the PADI.
4. Summary of Regulatory Positions and Rationales
Fenitrothion is not being placed into Special Review
at this time. Although the Agency is concerned over the poten-
tial adverse impact of fenitrothion on birds and aquatic organisms
resulting from the forestry use pattern, comprehensive aquatic
and terrestrial field studies are needed in order to evaluate
the potential risks to birds and aquatic organisms. The Agency
is also requiring submission of special acute and subchronic rat
studies to provide additional information to confirm the potential
for fenitrothion to cause retinal degeneration and changes in
corneal shape and structure in the human eye. Pending receipt and
evaluation of these data, labeling modifications or other regulatory
action may be warranted.
The Agency is classifying the forestry uses of
fenitrothion (spruce budworm and southern pine beetle) for
restricted—use due to avian and aquatic invertebrate hazards
on an interim basis pending receipt and evaluation of the

aquatic and terrestrial field studies.
o Fenitrothion is highly toxic to honeybees, aquatic
invertebrates, and avian species. E,hdangered species label
restrictions are required to protect endangered and threatened
species in forest areas.
O Special indoor air residue’monitoring studies
are required to support continued use of the 40% wettable powder
formulation in homes to control adult Anopheline mosquitoes.
o No new tolerances or new food uses will be granted
until the Agency has received data sufficient to evaluate the
dietary exposure of fenitrothion. —
O The Agency is imposing an interim 24 hour reentry
interval for the greenhouse and nursery ornamental use pending
receipt and evaluation of reentry data.
o Protective clothing statements are required for
all products containing tenitrothion.
Time Frame*
Subchronic oral toxicity——rodent species (for plasma
cholinesterase effects) 12 Months
21—day dermal——rabbit 9
90—day inhalation——rat 15
Oncogenicity——mouse 50
Teratogenicity——rat and rabbit 15
Reproduction——rat 39
Mutagenicity 12
Metabolism study 12 “
Special tests——acute and subchronic tests 24
in rats for eye effects 9 “
Environmental Fate/Exposure
Hydrolysis study 9 Months
Photodegradation in water, soil and air 9
Aerobic soil metabolism study 27
Anaerobic aquatic metabolism study 27
Lab volatility study 12
Leaching and adsorption/desorption 12
Soil dissipation study 27 “
Forestry dissipation study 27
Fish accumulation study 12
Applicator exposure studies 9
* based upon receipt of the Standard by the registrant.

Indoor air/surface residue exposure study 12
Reentry Data 27
Fish and Wildlife
Avian reproduction 24 Months
Actual field testing——birds and aquatic organisms 48
Acute toxicity to freshwater invertebrates——
typical end—use product 9
Fish early life stage and aquatic
invertebrate life cycle 15
Plant Testing Requirements
Seed germination/seedling emergence 9 Months
Vegetative vigor 9
Aquatic plant growth 9
Residue Chemistry
Residue analytical methods 18 Months
Storage stability 18
Residue data (wheat gluten) 24
Product Chemistry 9—15 Months
William H. Miller
Product Manager (16)
Insecticide—Rodenticide Branch
Registration Division (TS—767C)
Otfice of Pesticide Programs
Environmental Protection Agency
401 M Street, S. W.
Washington, D. C. 20460
Office location and telephone number:
Room 211, Crystal Mall #2
1921 Jefferson Davis Highway
Arlington, VA 22202
(703) 557—2400
DISCLAIMER: The information presented in this Chemical Information
Fact Sheet is for informational purposes only and may not be used
to fulfill data requirements for pesticide registration and