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E X T O X N E T
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EXTOXNET primary files maintained and archived at Oregon State
Revised June 1996
Trade and Other Names:
Trade names include Acarin, Cekudifol, Decofol, Dicaron,
Dicomite, Difol, Hilfol, Kelthane, and Mitigan.
The EPA has classified dicofol as toxicity class II - moderately
toxic, and toxicity class III - slightly toxic, depending on the
formulation. Products containing dicofol bear the Signal Word
WARNING or CAUTION, depending on the formulation. Products
containing dicofol are designated General Use Pesticides (GUPs).
Dicofol is an organochlorine miticide used on a wide variety of
fruit, vegetable, ornamental and field crops. Dicofol is
manufactured from DDT. In 1986, use of dicofol was temporarily
canceled by the EPA because of concerns raised by high levels of
DDT contamination. However, it was reinstated when it was shown
that modern manufacturing processes can produce technical grade
dicofol which contains less than 0.1% DDT.
- Acute toxicity: Dicofol is moderately
toxic to practically nontoxic and may be absorbed through
ingestion, inhalation, or skin contact. Symptoms of
exposure include nausea, dizziness, weakness, and
vomiting from ingestion or respiratory exposure, skin
irritation or rash from dermal exposure, and
conjunctivitis from eye contact. Poisoning may affect the
liver, kidneys, or the central nervous system.
Overexposure by any route may cause nervousness and
hyperactivity, headache, nausea, vomiting, unusual
sensations, and fatigue. Very severe cases may result in
convulsions, coma, or death from respiratory failure
[44,45]. Dicofol is a moderate skin and eye irritant
[17,45]. Since dicofol is stored in fatty tissues,
intense activity or starvation may mobilize the
pesticide, resulting in the reappearance of toxic
symptoms long after actual exposure . The oral LD50
for dicofol in rats is 575 to 960 mg/kg, in rabbits and
guinea pigs is 1810 mg/kg, and in mice is 420 to 675
mg/kg. The dermal LD50 in rats is 1000 to 5000 mg/kg, and
in rabbits is between 2000 and 5000 mg/kg. The inhalation
LC50 (4-hour) in rats is greater than 5 mg/L [9,7,45].
- Chronic toxicity: In a 2-year dietary
study with rats, liver growth, enzyme induction, and
other changes in the liver, adrenal gland, and urinary
bladder were observed at doses of 2.5 mg/kg/day and
above. Effects on the liver, kidney, and adrenals, and
reduced body weights were observed at doses of 6.25
mg/kg/day and above in a 3-month dietary study with mice
. When dicofol was fed to rats for 3 months, fewer
than half of the animals survived a 75 mg/kg/day dose.
Liver enzyme induction was observed at 75 mg/kg/day and
above. Decreased body weights, decreased cortisone
levels, and toxic changes in the liver, adrenal glands,
and kidneys were noted at 25 mg/kg/day. Similar results
were observed in a 3-month feeding study with mice .
When dogs were fed dicofol for 3 months, 2 two out of 12
survived at 25 mg/kg/day. Poisoning symptoms and effects
on the liver, heart, and testes were observed at the 7.5
mg/kg/day dose . When dicofol was fed to dogs, 4.5
mg/kg/day for 1 year caused toxic effects on the liver.
Long-term dermal exposure of rats to dicofol as an
emulsifiable concentrate formulation also produced toxic
effects on the liver .
- Reproductive effects: Reproductive
effects in rat offspring have been observed only at doses
high enough to also cause toxic effects on the livers,
ovaries, and feeding behavior of the parents. Rats fed
diets containing dicofol through two generations
exhibited adverse effects on the survival and/or growth
of newborns at 6.25 and 12.5 mg/kg/day .
- Teratogenic effects: No teratogenic
effects were observed when rats were given up to 25
mg/kg/day on days 6 through 15 of pregnancy .
- Mutagenic effects: Five separate
laboratory tests have shown that dicofol is not mutagenic
- Carcinogenic effects: No evidence of
carcinogenicity was observed in when rats were fed up to
47 mg/kg/day for 78 weeks. A 2-year oncogenicity study in
mice showed an increased incidence of liver tumors in
male mice at dietary concentration levels of 13.2 and
26.4 mg/kg/day . It is unlikely that dicofol poses a
carcinogenic risk to humans.
- Organ toxicity: Chronic exposure to
dicofol can cause damage to the kidney, liver, and heart.
Prolonged or repeated exposure to dicofol can cause the
same effects and symptoms as acute exposure .
Prolonged or repeated skin contact can cause moderate
skin irritation and/or sensitization of the skin .
- Fate in humans and animals: Dicofol is
converted in rats to the metabolites
4,4'-dichloro-benzophenone and 4,4'-dichlorodicofol
[2,46]. Studies of the metabolism of dicofol in rats,
mice, and rabbits have shown that ingested dicofol is
rapidly absorbed, distributed primarily to fat, and
readily eliminated in feces. When mice were given a
single oral dose of 25 mg/kg dicofol, approximately 60%
of the dose was eliminated within 96 hours, 20% in the
urine, and 40% in the feces. Concentrations in body
tissues peaked between 24 and 48 hours following dosing,
with 10% of the dose found in fat, followed by the liver
and other tissues. Levels in tissues other than fat
declined sharply after the peak. When rats were given a
single oral dose of 50 mg/kg of dicofol, all but 2% of
the dose was eliminated within 192 hours, with peak
concentrations in body tissues occurring between 24 and
48 hours after dosing .
- Effects on birds: Dicofol is slightly
toxic to birds. The 8-day dietary LC50 is 3010 ppm in
bobwhite quail, 1418 ppm in Japanese quail, and 2126 ppm
in ring-necked pheasant. Eggshell thinning and reduced
offspring survival were noted in the mallard duck,
American kestrel, ring dove, and screech owl .
- Effects on aquatic organisms: Dicofol is
highly toxic to fish, aquatic invertebrates, and algae.
The LC50 is 0.12 mg/L in rainbow trout, 0.37 mg/L in
sheepshead minnow, 0.06 mg/L in mysid shrimp, 0.015 mg/L
in shell oysters, and 0.075 mg/L in algae .
- Effects on other organisms: Dicofol is
not toxic to bees .
- Breakdown in soil and groundwater:
Dicofol is moderately persistent in soil, with a
half-life of 60 days [14,46]. Dicofol is susceptible to
chemical breakdown in moist soils . It is also
subject to degradation by UV light. In a silty loam soil,
its photodegradation half-life was 30 days. Under
anaerobic soil conditions, the half-life for dicofol was
15.9 days . Dicofol is practically insoluble in water
and adsorbs very strongly to soil particles. It is
therefore nearly immobile in soils and unlikely to
infiltrate groundwater. Even in sandy soil, dicofol was
not detected below the top 3 inches in standard soil
column tests. It is possible for dicofol to enter surface
waters when soil erosion occurs [46,14].
- Breakdown in water: Dicofol degrades in
water or when exposed to UV light at pH levels above 7.
Its half-life in solution at pH 5 is 47 to 85 days.
Because of its very high absorption coefficient (Koc),
dicofol is expected to adsorb to sediment when released
into open waters .
- Breakdown in vegetation: In a number of
studies, dicofol residues on treated plant tissues have
been shown to remain unchanged for up to 2 years .
- Appearance: Pure dicofol is a white
crystalline solid. Technical dicofol is a red-brown or
amber viscous liquid with an odor like fresh-cut hay
- Chemical Name:
- CAS Number: 115-32-2
- Molecular Weight: 370.51
- Water Solubility: 0.8 mg/L @ 25 C 
- Solubility in Other Solvents: s. in most
organic solvents 
- Melting Point: 78.5-79.5 C for pure
dicofol [1,5]; 50 C for technical dicofol [9,45]
- Vapor Pressure: Negligible at room
- Partition Coefficient: 4.2788 [9,45]
- Adsorption Coefficient: 5000 (estimated)
- ADI: 0.002 mg/kg/day 
- MCL: Not Available
- RfD: Not Available
- PEL: Not Available
- HA: Not Available
- TLV: Not Available
Rohm and Haas Co.
100 Independence Mall West
Philadelphia, PA 19106
- Phone: 215-592-3000
- Emergency: Not Available
References for the information in this PIP can be found in
Reference List Number 6
information in this profile does not in any way replace or
supersede the information on the pesticide product labeling or
other regulatory requirements. Please refer to the pesticide