propham (Chem Hoe) Herbicide Profile 2/85
CHEMICAL NAME: Isopropyl carbanilate
TRADE NAME(S): Chem Hoe (58)
FORMULATION(S): Emulsifiable concentrate (2 lb/gal), granules
(15%), flowable suspension (3-4 lb/gal) (56).
BASIC PRODUCER(S): PPG Industries, Inc.
Chemcal Div. - U.S.
1 Gateway Center
Pittsburg, PA 15272
STATUS: General use
PRINCIPAL USES: For control of weeds in alfalfa, ladino clover,
white clover, red or crimson clover, flax, lettuce,
safflower, spinach, lentils, peas, fallow land
APPLICATION METHODS: Preemergence, preplant incorporated,
postemergence, general (58).
Preemergence: A number of annual grasses are controlled by propham,
including shallow-seeded volunteer grains, annual ryegrass, downy
brome, annual bluegrass, rattail fescue, canarygrass, rabbitfoot grass,
foxtail barley, and wild oats. Crabgrass, barnyardgrass, and yellow
and giant foxtails are quite tolerant. Broadleaf weeds controlled
include dodder, smartweeds, curly dock, red correl, small nettle, and
purslane. Most common broadleaf weeds are tolerant.
Preplant incorporated: Propham can be used to control such weeds as
volunteer barley, wild oats, stinging nettle, annual bluegrass,
chickweed, and nightshade.
Postemergence: Propham can be assured to control selectively such
susceptible weeds as volunteer barley, wild oats, annual ryegrass,
downy brome, annual bluegrass and foxtail barley (58). No perennial
weed control is to be expected. No control may be expected of
established weeds. No control of foxtails, crabgrass or watergrass can
be expected (8b).
II. PHYSICAL PROPERTIES
MOLECULAR FORMULA: C10 H13 NO2 (58)
MOLECULAR WEIGHT: 179.2 (58)
PHYSICAL STATE: Light tan solid (pure compound) (58)
MELTING POINT: 87-88 C (pure compound) (58)
BOILING POINT: Sublimes upon heating (pure compund) (58)
DECOMOPSITION TEMPERATURE: 150 C and above (pure compound) (58)
VAPOR PRESSURE: Sublimes slowly at room temperature (pure compound)
SOLUBILITY: 32-250 mg/l water at 20-25 C (pure compound) (62)
III. HEALTH HAZARD INFORMATION
OSHA STANDARD: NA
NIOSH RECOMMENDED LIMIT: NA
ACGIH RECOMMENDED LIMIT: NA
A. ACUTE TOXICITY
DERMAL: LD50 = 10,200 mg/kg (rabbit, 4 lb/gal flowable) (58).
ORAL: LD50 = 9,000 mg/kg (rat, technical product); 3,000
mg/kg (mouse, technical product); 10,200 mg/kg
(rat, 4 lb/gal flowable); 7,600 mg/kg (rat, 15%
INHALATION: Aerosol inhalation LC50 for albino rats, 24 mg/l
air at 4-hr exposure (58).
B. SUBACUTE AND CHRONIC TOXICITY:
The no-effect level for propham in the diet of albino rats and beagle
dogs over a period of 90 days was 200 ppm and 2,000 ppm, respectively.
Neither rats nor mice fed, respectively, 20,000 ppm or 1,000 ppm in
their diets for an 18 month period or receiving intramuscular
injections of 40 mg propham per 100 g of body weight over the 18-month
period developed either benign or malignant tumors in any organs.
Similar results were obtained from at least four additional studies
where levels ranging from 1,000 to 20,000 ppm were fed mice, rats, or
hamsters for periods ranging fom 18 to 33 months (58).
In 30-day feeding trials rats receiving 10,000 mg/kg diet suffered no
ill-effect and there was no evidence of carcinogenic activity (62).
IV. ENVIRONMENTAL CONSIDERATIONS
Propham may be considered to be a relatively safe pesticide to
mammals, fish, and other wildlife. The LD50 of propham to mallard ducks
is greater than 2,000 mg/kg. No visible effects were noted on fish
living in a 10 ppm water solution of propham (58).
Fish exposed to 5 mg/l suffered no ill-effect (62).
Behavior In Or On Soils
1. Adsorption and leaching characteristics in basic soil types: While
propham is readily adsorbed to activated carbon and organic
matter, the adsorption bond is rather weak, allowing water to
leach propham through a soil column.
Freed, V.H. 1951. Weeds 1:48-60.
Leopold, A.C. et al. 1960. Weeds 8:48-54.
Logan, A.V. et al. 1953. Weeds 2:24-26.
Parochetti, J.V. and G.F. Warren. 1966. Weeds 14:281-285.
Robocker, W.C. and C.L. Canode. 1965. Weeds 13:8-10.
2. Microbial breakdown: Soil microorganisms readily degrade propham,
as demonstrated by production of aniline, by an enzymatic
hydrolysis reaction with subsequent liberation of carbon dioxide.
Aniline has also been shown to be readily degraded by soil
microorganisms. Identified isolates found effective in degrading
propham are Pseudomonas striata Chester, a Flavobacterium sp., an
Agrobacterium p., and Achromobacter sp.
Clark C.G. and S.J.L. Wright. 1970. Soil Biol. Biochem. 2:217-266.
Kaufman, D.D. and P.C. Kearney. 1965. Appl. Microbiol. 13:443-446.
Kaufman, D.D. and J. Blake. 1973. Soil Biol. Biochem. 5:297-308.
Walker, N. and D. Harris. 1969. J. Appl. Bact. 32:457-462.
3. Loss from photodecomposition and/or volatilization: Propham does
not readily undergo photodecomposition. At 13 C, vapor losses of
propham from dry soil are negligible. Increasing field moisture
capacity and temperature greatly increases vapor losses to the
point where at 35 C volatility may be the major means of
Anderson, W.P. et al. 1952. Science 116:502-503.
Mitchell, L.C. 1961. J. Assoc. Off. Agr. Chem. 44:643.
Parochetti, J.V. and G.F. Warren. 1966. Weeds 14:281-285.
4. Resultant average persistence at recommended rates: Bioassay tests
indicate the half life of propham to be about 15 days at 17 C and
5 days at 29 C. However, the rate of dissipation can vary
greatly with the microbial activity and moisture level of a given
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
SYMPTOMS OF INTOXICATION: Lightheadedness and sluggishness,
indicative of anesthesia (58).
SKIN CONTACT: Wash with plenty of soap and water (58).
INGESTION: Induce vomiting. No specific antidote is known (58).
EYE CONTACT: Flush with water (58).
NOTES TO PHYSICIAN: No specific antidote is known (58).
VI. FIRE AND EXPLOSION INFORMATION
Not considered flammable (58).
The flowable suspension formulation of propham is compatible with
hard water and with other pesticides formulated as emulsifiable
concentrates. This formulation is also compatible with many liquid
fertilizers and pesticide suspensions, but a small laboratory
compatibility test with the specific fertilizer or pesticide is
suggested prior to attempting field applications. Noncorrosive (58).
VIII. PROTECTIVE MEASURES
STORAGE AND HANDLING: Unlimited shelf life. Not light sensitive. At
higher temperatures, propham sublimes from granular formulations and
may redeposit as crystals. Low temperatures may cause crystallization
and separation in the flowable suspension formulation. Avoid breathing
of vapor or spray mist. Use with adequate ventilation. Avoid contact
with skin and eyes. Keep out of reach of children. Do not contaminate
water by cleaning of equipment or disposal of wastes (58).
IX. PROCEDURES FOR SPILLS AND LEAKS
IN CASE OF EMERGENCY, CALL, DAY OR NIGHT
PESTICIDE TEAM SAFETY NETWORK/CHEMTREC
X. LITERATURE CITED
8b. Thomson, W.T. 1981. Agricultural chemicals - book 2:
herbicides. Revised ed. Thomson Publications, Fresno, CA.
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.