Pesticide Fact Sheet Fensulfothion

United State* office of Petttod* ind Toxic SubctanM*
Environmental Protection Office of Pestiade Program* (TS-766C)
Agency Washington, DC 20460
v>EPA Pesticide
Fact Sheet
Name of Chemical: FENSULFOTHION
Reason for Issuance:
REGISTRATION STANDARD AMENDMENT
Date Issued: Feb. 28, 1985
Fact Sheet Number:
14.1

1. Description of chemical

Generic name: 0,0-diethyl 0-[p-(methylsulfinyl) phenyl] phosphorothioate
Cannon name: fensulfothion
Trade names: Dasanit, BAY 25141, S-767, TERRAOJR P
EPA Shaughnessy code: 032701-5
Chemical abstracts service (CAS) number: 115-90-2
Year of initial registration: 1965
Pesticide type: insecticide-nematicide
U.S. and foreign producer: MOBAY Chemical Corporation

2. Use Patterns and Formulations

Fensulfothion is registered for use as preplant or at-planting soil
application to tobacco, and various fruits and vegetables. Postplant
topical applications are permitted in addition to the at-planting
application on corn, peanuts, and rutabagas. Topical application is
also permitted on commercial and ornamental turf.

Fensulfothion is formulated into a 63% (61b/gallon) B.C.(restricted
use), and 10% and 15% granulars, and at various percentages with
disulfoton, thiram, or pebulate.

3. Science Findings

Summary science statement: Fensulfothion is an organophosphate
insecticide-nematicide of high toxicity to man and other non-target
terrestrial and aquatic organisms. Tier III data (field studies) have
been requested in response to the three RPAR triggers (mammalian,
avian, and aquatic) that have been exceeded. The current NOEL, ADI,
and MPI are now only partially supported by data, but will be used in
the interim. Available data are insufficient to fully assess the toxi-
cology of fensulfothion, its fate in the environment, or the exposure
of humans and non-target organisms to the chemical or its degradates.

Chemical Characteristics: Technical fensulfothion is a brown liquid
organophosphate, stable under normal use conditions, with a boiling
point of 138-141°C at 0.01 mm Hg. It is soluble in most organic
solvents except aliphatics. The chemical is acutely toxic and extreme
caution is necessary in handling of contaminated articles and during
mixing, loading, and application. Respirator and protective clothing
are required during these operations.

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lbxiColoXiCal characteristics:
Fensulfothion is highly toxic (‘I’bx. Category I) fran acute oral and
dermal routes of exposure.
Science Findings (continued)
Toxicoloxical Characteristics (continued):
Many of the toxicology studies do not meet present guideline require nts
and need to be replaced, ever no significant risks have been identified
fr a n the existing data base.
Toxicology studies on fensulfothion are as follows:
— Oral L1 in rats: 2.2 mg/kg (female), 10.5 mg/kg (male) (Acceptable]
— Detmal LD 50 in rats: 3.5 n Jkg (female), 30.0 mg/kg (male) [ Acceptable]
— Acute delayed neurotoxicity in chickens: none observed (Suppl nentary]
— Metabolisii study in rats: [ Acceptable)
— 90 Day feeding—rodent; non—rodent: (Suppl rentary; Invalid — data gap]
— Chronic toxicity, non-rodent: (Invalid — data gap]
— Chronic toxicity, rodent: No NOEL found [ Suppl nentary1
— Oncxgenicty, rat: [ Suppl nentary1
— Teratogenicity, rabbit: [ Supplementary]
— Reproduction study: NOEL 1 or 4 ppn [ Suppl nentary]
— Mutagenicity, gene mutation: Negative [ Partially satisfied study]
Physiological and Biological Characteristics
Fensulfothion is an organophosphate insecticide—nematicide that kills
primarily by contact action but also provides sane systemic control of
insects attacking the foliage of treated plants.
The node of action is by phosphorylating the acetylcholinesterase enzyme
of tissues, allowing accunulation of acetylcholine at nerve junctions
with subsequent blocking effects upon the central nervous system.
The rnetabolisn of fensulfothion is basically similar in both plants and
animals. By the processes of hydrolysis, oxidation and reduction the
parent ccrnpound may be broken down to 13 kr ,n metabolites, 5 of which
are themselves cholinesterase inhibitors • On the basis of this knowledge,
all presently established fensulfothion tolerances are expressed in terms
of the canbined residues of the parent ca ound and these five cholinesterase
inhibiting metabolites. Fensulfothion is metabolized fairly rapidily by
both plants and animals. In animals, hydrolytic degradation in liver and
other tissues results in excretion of low toxicity degradation products,
with half the pesticide eliminated within 24 hours and a].nxst total
elimination of the pesticide and its netabolites within a ek.
Enviromental Characteristics:
Fensulfothion is degraded in soils under aerobic conditions with half—
lives of 3—28 days and is due to microbial degradation. Half—life is
rapid in silty clay loam and organic soil (3—7 days) and fairly rapid
in sandy loam, silt loam and loam soils (around 28 days). Fensulfothion
degrades rapidly in the water and silt of a simulated pond with
half—lives of 10 and 12 days, respectively.
The rwbility of fensulfoth ion and aged residues is low to ncderate in a
wide range of soils. Dissipation of fensulfothion is fairly rapid
fran field soils with half—lives ranging fran <30 days to >182 days.

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Fensulfoth.ion 3
fact sheet
Science Findings (continued)
Enviromental Characteristics (continued):
Fensulfothion residues are taken up by rotational cr s grown in the
greenhouse but are not taken up by field rotational c. s.
Available data are insufficient to fully assess the fate of fen-
sulfothion in the envirorm nt; however, ground water contanination
does not appear to be a problem with this chemical.
Fensulfothion has a low potential to bioaccumulate in bluegill sunfish.
Data are insufficient to fully assess the exposure of hunans and
non-target organi ns to the chemical or its degradates, ver,
hunan exposure should be minimal by use of current restricted use
classification and labeling precautions requiring approved respirators
and protective clothing.
Exposure during reentry operations should be minimal, iever, data are
not available to fully assess such exposures. A 7 day reentry period
is being required for unprotected rkers following soil application
if the soil is wet • A 24 hour reentry period is being required for
applications of fensulfothion where agricultural practice will involve
hand labor with prolonged, intimate foliar contact, or if the soil is dry.
Ecological Characteristics:
Avian oral LD5 0: 0.749 p n (very high toxicity)
Avian dietary LC 5 : 22 pçin (high toxicity)
Fish LC 5 O: 0.07 ppn (very high toxicity)
The toxicity of fensulfothion to terrestrial and aquatic non-target
organi is very high. Residue calculations indicate that 3 RPAR
triggers (rnaninalian, avian, and aquatic) may be exceeded. In all
cases the Standard has asked for Tier III data (field studies) to
gather qualitative and quantitative data to support the registration
ar4/or need for special review.
Because of fensulfothion’ s extensive ruxnber of use patterns and its
high toxicity to wildlife, nu erous endangered species have been
identified that could be impacted. The Agency is currently considering
various approaches to address the problem for this and other chemicals,
and the Standard may be anerxied to incorporate the results of this
additional review.

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Fensulfothion
fact sheet
Science Fir ir s (continued)
1 1erance asses ent:
The foll ing tolerances (in parts per million) have been established
for fensulfothion:
International
Ccitt dity United States Canada Mexico (Codex)
Bananas 0.02 — — 0.02
Beets, sugar 0.05 —
Beets, sugar, t s 0.05 —
Cattle, fat 0.02 0.02
Cattle, MBYP 0.02 0.02
Cattle, neat 0.02 0.02
corn, field, fodder 1.0 —
Corn, field, forage 1.0
Corn, fresh (inc. sweet)
(K+C 41R) 0.1 0.1 0.1
Corn, grain 0.1 0.1 0.1
Corn, pop, fodder 1.0 — —
Corn, pop, forage 1 0 — —
Corn pop, grain 0.1 0.1 0.1
Corn, sweet, fodder 1.0 — —
Corn, sweet, forage 1.0 — —
Cotton, seed 0.02 —
Goats, fat 0.02 0.02
Goats, MBYP 0.02. 0.02
Goats, neat 0.02 0.02
Hogs, fat 0.02 —
Hogs, MBYP 0.02 —
Hogs, neat 0.02
Horses, fat 0.02
Horses, MBYP 0.02 —
Horses, neat 0.02 — —
Onions, dry txilb 0.1 0.1 0 • 1
Peanuts 0.05 — 0.05
Peanuts, hulls 5.0 — —
Pineapples 0.05 — 0.05
Pineapples, forage 0.05 — —
Plantains 0.02 — —
Potatoes 0.1 0.1 0 • 1
Rutabagas, roots 0.1 0.1 0.1
Sheep, fat 0.02 — 0.02
Sheep, MBYP 0.02 — 0.02
Sheep, neat 0.02 — 0.02
Sorghun, fodder 1.0 — —
Sorghun, forage 1.0
Sorghum, grain 0.1
Soybeans 0.02
Soybeans, forage 0 • 1
Sugarcane 0.02
Sweet potatoes 0.05 —
Tauatoes 0.1 0.1

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Fensulfothion 5
fact sheet
3. Science Findings (continued)
Tblerance asses nt (continued):
Most tolerances for residues are supported with data, h evez, additional -
data must be sut:znitted to support tolerances for residues in or on the
foll ing ca iy jdities: bananas, peanuts, peanut hulls, plantain, and
potatoes (processing data only).
There is no reasonable expectation of finite residues in milk, eggs,
poultry meat, fat, or meat by-products and no tolerances are required.
Reported pesticide incidents involving fensulfothion alone between 1966
and 1983 include 25 involving hunan injury and 4 involving animals • Most
of the hunan incidents resulted fran failure to use safety equigxt nt
while applying fensulfothion. Other incidents were the result of improper
disposal, handling, or storage. Because the incidents involve occasions
of misuse, no additional precautionary stat nts are necessary at this
tisrc to minimize the risk of injury.
4. Srtxrinary of Regulatory Position and Rationale
o The previous “Restricted Use” classifications required in 40 CFR §162.31
will be continued. In addition, granular formulations are n being restricted
All granular formulation products released fro shi ient after Sept nber 1, 1985
must be labeled for restricted use. Also, all products still in channels of
trade after sept nber 1, 1986 must be labeled for restricted use.
o The foll ing Enviromental Hazards text will be required on manufacturing
use products because of the hazards posed to non-target terrestrial and
aquatic wildlife:
“This product is toxic to fish and extr ly toxic to wildlife. Do
not discharge into lakes, streams, ponds, or public waters unless
in accordance with an NPDES permit. For guidance, contact your
Regional Office of the EPA.”
o The following environnental state nts are required for end-use products:
“This product is toxic to fish and extr nely toxic to wildlife. Use
with care when applying in areas frequented by wildlife. Birds
feeding on treated areas may be killed. Cover, disc, or incorporate
spill areas. Drift and runoff fran treated areas may be hazardous
to aquatic organi ns in neighboring areas. Do not apply directly
to water or wetlands. Do not contaninate water by cleaning of equip-
ment or disposal of wastes. This product is highly toxic to bees
exposed to direct treatnent on bloaning crops or weeds • Do not apply
this product or allow it to drift to bloaning crops or weeds while
bees are actively visiting the treatnent area.”
o The following reentry precautions are required on end-use products in
‘the interim until requested reentry data has been received and reviewed
y the Agency:
“Unprotected rkers should not re-enter treated fields until 24 hours
after application. Unprotected rkers should not re—enter fields where

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Fensulfothion 6
fact sheet
the soil is t until 7 days after soil application.”
inary of Major Data Gaps
tXze Date
product Chet istry
— Description of manufacturing process 6/84
— Description of formation of impurities 6/84
— preliminary analysis 6/84
— Certification of limits 6/84
— Odor 6/84
— Solubility 6/84
— Vapor pressure 6/84
— Dissociation constant 6/84
— Octanol/water partition coefficient 6/84
—pH 6/84
— Analytical nethod for enforc nt of limits 6/84
— Oxidizing or reducing action 6/84
— Flamability 6/84
— Explodability 6/84
— Viscosity 6/84
— Miscibility 6/84
o Residue Ch niStry
— Storage stability 1/87
— Processed food/feed studies on potatoes 1/87
— Crop field trials on bananas, peanuts, and plantain 1/87
) ixxicology
— Inhalation LC 5 O — rat 6/84
— Acute delayed neurotoxicity — hen 6/84
— 90—Day feeding — rodent, non—rodent 1/87
— 90—Day inhalation — rat 1/87
— Chronic toxicity — 2 species 1/87
— cogenic study — 2 species 1/87
— Teratogenicity — 2 species 1/87
— Reproduction — 2 generation 1/87
— Gene mutatiOn 1/87
— Chra csanal aberration 1/87
o wildlife and Aquatic Organis”S
- Avian reproductiOn 1/87
— Simulated and actual field testing (mamals and birds) 1/87
— Acute LC freshwater invertebrates 1/87
— Acute LC5() estuarine and marine organi nS
(shrimp, marine fish, and oyster) 1/87
— Fish early life stage and aquatic invertebrate life—cycle 1/87
o EnvirOrulental Fate
— Hydrolysis
— photodegradation in water 1/87
- Anaerobic soil n taboli n 1/87
— volatility 1/87
— Soil dissipation 1/87
— Accunulat ion in rotational crops 1/87
— AccunulatiOn in fish 1/87

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Fensulfotb.ion
fact sheet
1/87
o I entry Protection
— Foliar dissipation 1/87
— Soil dissipation 1/87
- De al exposure 1/87
— Inhalation exposure 1/87
6. Contact person at EPA: George T. LaRocca
Product Man er 15
Insect ic ide— dent ic ide Branch (TS -767C)
401 M Street
Washir ton, DC 20460
DISCLAIMER: The information presented in this Ch nical Information Fact Sheet
is for informational purposes only and may not be used to fulfill data
requirarents for pesticide registration and reregistration.

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