fenac (Fenatrol) Herbicide Profile 2/85
CHEMICAL NAME: (2,3,6-Trichlorophenyl)acetic acid (56)
TRADE NAME(S): Fenatrol (56)
FORMULATION(S): Available as 1.5 and 2.5 pounds/gallon aqueous
solution of the sodium salt; also granular
TYPE: Chlorophenoxy herbicide
BASIC PRODUCER(S): Union Carbide Agricultural Products Co., Inc.
P. O. Box 12014
T. W. Alexander Dr.
Research Triangle Park, NC 27709
STATUS: General use
PRINCIPAL USES: For preemergence season-long control of weeds,
particularly seedling johnsongrass in sugarcane (for use in Louisiana
and Florida); also of many annual broadleaves and grasses and perennial
broadleaf weeds in noncrop areas such as railroad rights-of-way, around
buildings, under highway guard rails, etc. Effective against submerged
aquatic weeds when applied to soil before flooding (56).
APPLICATION METHOD(S): Spray or granular (58).
To be developed.
II. PHYSICAL PROPERTIES
MOLECULAR FORMULA: C8 H5 Cl3 O2 (62)
MOLECULAR WEIGHT: 239.5 (62)
PHYSICAL STATE: Colorless solid (pure compound) (62)
ODOR: Odorless (pure compound) (58)
MELTING POINT: 156 C (pure compound) (62); 157-160 C (pure
VAPOR PRESSURE: 1.1 Pa at 100 C (pure compound) (62)
SOLUBILITY: 200 mg/l water at 28 C (pure comound) (62); very
slightly soluble in water (pure compound) (58).
III. HEALTH HAZARD INFORMATION
OSHA STANDARD: NA
NIOSH RECOMMENDED LIMIT: NA
ACGIH RECOMMENDED LIMIT: NA
A. ACUTE TOXICITY
DERMAL: LD50 = 1440-3160 mg/kg (rabbit) (62)
Slight irritation from 3160 mg/kg (rabbit) (58)
ORAL: LD50 = 576-1780 mg/kg (rat) (62)
LD50 = 1780 mg/kg (rat); 1040 mg/kg (mouse) (58).
INHALATION: 6-hr exposure to 0.1 mg/liter sodium salt dust
decreased respiration for 24 hr (rat) (58).
EYES: 3 mg was moderately irritating. Slight erythemia
and endemia disappeared after 48 hr (rabbit) (58).
B. SUBACUTE AND CHRONIC TOXICITY:
In 2-year feeding trials rats receiving 2000 mg/kg diet showed no
No significant effect from 100 ppm fenac in the diet of rats or
1000 ppm in the diet of dogs for 2 years (58).
IV. ENVIRONMENTAL CONSIDERATIONS
Adsorbed on soils; resists leaching. Microbial breakdown very
slow. Loss from photodecomposition and/or volatilization possible.
Average persistence at recommended rates: approximately 1 to 2 years
No toxicity to fish or wildlife when used as recommended (58).
V. EMERGENCY AND FIRST AID PROCEDURES
The chemical information provided below has been condensed
from original source documents, primarily from "Recognition and
Management of Pesticide Poisonings", 3rd ed. by Donald P. Morgan,
which have been footnoted. This information has been provided in
this form for your convenience and general guidance only. In
specific cases, further consultation and reference may be required
and is recommended. This information is not intended as a sub-
stitute for a more exhaustive review of the literature nor for the
judgement of a physician or other trained professional.
If poisoning is suspected, do not wait for symptoms to develop.
Contact a physician, the nearest hospital, or the nearest Poison
FREQUENT SYMPTOMS AND SIGNS OF POISONING
Chlorophenoxy compounds are moderately IRRITATING to skin and
mucous membranes. Inhalation of sprays may cause burning sensations in
the nasopharynx and chest, and coughing may result. Prolonged
inhalation sometimes causes dizziness.
When INGESTED, high concentrations of chlorophenoxy compounds may
irritate the mouth, throat, and gastrointestinal tract. Prompt EMESIS,
CHEST PAIN (from esophagitis), ABDOMINAL PAIN, and DIARRHEA commonly
ensue. Injury to the GI tract does not usually progress to ulceration
or perforation. Absorbed chlorophenoxy compounds have caused
FIBRILLARY MUSCLE TWITCHING, skeletal muscle tenderness, and MYOTONIA
(stiffness of muscles of the extremities). Ingestion of very large
amounts has produced METABOLIC ACIDOSIS, fever, tachycardia,
hyperventilation, vasodilatation and sweating. Particular cases have
been characterized by coma and convulsions (25).
SKIN CONTACT: Bathe and shampoo with soap and water to remove
chemicals from skin and hair. Individuals with chronic skin disease or
known sensitivity to chemicals should either avoid using these
herbicides or take extraordinary measures to avoid contact (25).
INGESTION: If vigorous emesis has not occurred and if victim
is fully alert, induce emesis with Syrup of Ipecac (adults 12 years and
older, 30 ml; children under 12 years, 15 ml), followed by 1-2 glasses
of water (25).
INHALATION: If symptoms of illness occur during or following
inhalation of spray, remove victim from contact with the material for
at least two days. Allow subsequent contact with chlorophenoxy
compounds only if effective respiratory protection is practiced (25).
EYE CONTACT: Flush contaminating chemicals from eyes with
copious amounts of clean water for 10-15 minutes (25).
NOTES TO PHYSICIAN:
IF CONSCIOUSNESS LEVEL IS DEPRESSED or other signs of NEUROTOXICITY
appear, SUSPECT additional or alternative ingested toxicants. Evacuate
the stomach by INTUBATION, ASPIRATION, and LAVAGE. Because petroleum
distillates are commonly included in chlorophenoxy formulations,
gastric intubation incurs a risk of hydrocarbon pneumonitis from
aspiration. For this reason:
A. If victim is unconscious or obtunded and facilities are at hand,
insert an ENDOTRACHEAL TUBE (cuffed, if available) prior to
B. Keep victim's HEAD BELOW LEVEL OF THE STOMACH during intubation
and lavage (Trendelenburg, or left lateral decubitus, with head of
table tipped downward). Keep victim's head turned to left.
C. ASPIRATE PHARYNX as regularly as possible to remove gagged or
vomited stomach contents.
After aspiration of gastric contents and washing of stomach, instill
30-50 gm of ACTIVATED CHARCOAL in 3-4 ounces of water through the
stomach tube to limit absorption of remaining toxicant. Do NOT instill
milk, cream, or other materials containing vegetable or animal fats, as
these are likely to enhance absorption.
If bowel movement has not occurred in 4 hours and patient is fully
conscious, give SODIUM SULFATE, 0.25 gm/kg, as a cathartic. Magnesium
sulfate and citrate, in comparable dosages, are equally suitable if
renal function is adequate. Retained magnesium may depress CNS
In SEVERE POISONINGS by very large amounts of ingested chlorophenoxy
acids, forced ALKALINE DIURESIS may save the victim's life. Assess
serum electrolyte concentrations, and serum and urine pH. If a
metabolic acidosis is present, infuse solutions of sodium bicarbonate
at rates sufficient to keep the urine distinctly alkaline, continuing
until plasma concentrations of chlorophenoxy compounds are less than
about 10 ug/ml. [Prescott, L.F. et al., Br.J.Clin.Pharmacol. 7:11
VI. FIRE AND EXPLOSION INFORMATION
Commercial formulation is sequestered against the formation of
hard water salts in waters of up to 1000 ppm hardness. Mixes with most
other pesticides in dilute solution. Noncorrosive (58).
VIII. PROTECTIVE MEASURES
STORAGE AND HANDLING: No shelf life limitations. Not harmed by
freeze-thaw cycles (58).
IX. PROCEDURES FOR SPILLS AND LEAKS
IN CASE OF EMERGENCY, CALL, DAY OR NIGHT
PESTICIDE TEAM SAFETY NETWORK/CHEMTREC
X. LITERATURE CITED
25. Morgan, D.P. 1982. Recognition and management of pesticide
poisonings, 3rd ed. U.S. Environmental Protection Agency,
Washington, DC. 120 pp.
56. Farm Chemicals Handbook, 70th ed. 1984. R. T. Meister, G. L.
Berg, C. Sine, S. Meister, and J. Poplyk, eds. Meister
Publishing Co., Willoughby, OH.
58. Weed Science Society of America, Herbicide Handbook Committee.
1983. Herbicide handbook of the weed science society of
America, 5th ed. Weed Science Society of America, Champaign,
IL. 515 pp.
62. The Pesticide Manual: A World Compendium, 7th ed. 1983. C.R.
Worthing, ed. The British Crop Protection Council, Croydon,
England. 695 pp.