prometon (Pramitol) Herbicide Profile 2/85
CHEMICAL NAME: 2,4-bis (isopropylamino)-6-methoxy-s-triazine (56)
TRADE NAME(S): Ontracic 800, Pramitol 25E (56)
FORMULATION(S): Emulsifiable concentrate, wettable powder, and
pellets (56); 25% EC, 80% WP (8b).
TYPE: Triazine herbicide
BASIC PRODUCER(S): Ciba-Geigy Corp.
P.O. Box 18300
Greensboro, NC 27419
STATUS: General use
PRINCIPAL USES: A nonselective herbicide which can be applied
before or following weed emergence. It controls most annual and many
perennial broadleaf weeds and grasses, generally for a full season or
longer. It is adapted to industrial use (56).
APPLICATION METHOD(S): Application of sprays or granules can be made
either before or after weed emergence. Since much of its activity is
through the roots, adequate rainfall is required to move the chemical
into the root zone (58).
Applied at either time of weed emergence or 2-3 months afterwards.
Most effective when applied 2-3 months following weed emergence (8b).
Important Weeds Controlled: Johsongrass, Bermudagrass, foxtail,
mustards, ragweeed, plantain, quackgrass, horsetail, watergrass,
chickweed, catchfly, cocklebur, mullein, crabgrass, dock, goosegrass,
Jimsonweed, lambsquarters, nightshade, puncture vine, purslane, pigweed,
velvetleaf, wild oats, and many others (8b).
Faster acting than simazine, but does not have as long a residual
effect as either simazine or atrazine. Controls for a full season or
longer. Requires rainfall to move it into the soil. Synergistic with
both simazine and atrazine. Proven and used under all climatic
II. PHYSICAL PROPERTIES
MOLECULAR FORMULA: C10 H19 N5 O (62)
MOLECULAR WEIGHT: 225.3 (62)
PHYSICAL STATE: Colorless powder (pure compound) (62)
MELTING POINT: 91-92 C (pure compound) (62)
VAPOR PRESSURE: 2.3 x 10-6 mmHg at 20 C (pure compound) (58)
SOLUBILITY: 620 mg/l water at 20 C (pure compound) (62)
III. HEALTH HAZARD INFORMATION
OSHA STANDARD: NA
NIOSH RECOMMENDED LIMIT: NA
ACGIH RECOMMENDED LIMIT: NA
A. ACUTE TOXICITY
DERMAL: LD50 = >2,000 mg/kg (rabbit, technical); 2,200 mg/kg
(rabbit, Pramitol 25E); >10,000 mg/kg (rabbit,
Pramitol 80W) (56).
LD50 = 2,000-2,500 mg/kg (rabbit, intact skin);
1,500-2,000 mg/kg (rabbit, abraded skin) (58).
Minimal skin irritation (rabbit, technical); severe
skin irritation (rabbit, Pramitol 25E); mild skin
irritation (rabbit, Pramitol 80W) (56).
ORAL: LD50 = 2980 mg/kg (rat, technical); 2276 mg/kg (rat,
Pramitol 25E); 2100 mg/kg (rat, Pramitol 80W) (56).
INHALATION: LC50 = >3.26 mg/l for 4 hours (rat, technical);
36.0 mg/l for 4 hours (rat, Pramitol 25E); 3.26
mg/l for 4 hours (rat, Pramitol 80W) (56).
EYES: Non-irritating (rabbit, technical); severe irritation
(rabbit, Pramitol 25E); non-irritating (rabbit,
Pramitol 80W) (56).
B. SUBACUTE AND CHRONIC TOXICITY:
In 90-day feeding trials NEL for rats was 5.4 mg/kg daily (62).
Doses of 400 mg/kg of prometon were administered to rats by means
of a stomach tube on six consecutive days of the week during a period
of four weeks. All animals survived the treatment (58).
IV. ENVIRONMENTAL CONSIDERATIONS
LC50 (96-hr) is: for rainbow trout 12 mg/l; for crucian carp
70 mg/l; for bluegill 40 mg/l. It is slightly toxic to birds and
practically non-toxic to honeybees (62).
Toxicological investigations conducted with bobwhite quail,
mallard ducks, goldfish, rainbow trout, and bluegill sunfish have shown
prometon to have very low toxicity to these species (58).
96-hr LC50 (ppm)
Fish Species prometon technical
Rainbow trout 20
Bluegill sunfish >32
8-day dietary LC50 (ppm)
Bird Species Pramitol 25 E
Bobwhite quail chicks >5080
Mallard ducklings 4572 (58).
Behavior In Or On Soils
1. Adsorption and leaching characteristics in basic soil types:
Prometon is more readily adsorbed on muck or clay soils than on
soils of low clay or organic matter content. (Talbert, R.E. and
O.H. Fletchall. 1965. The adsorption of some s-triazines in
soils. Weeds 13:46-52).
2. Microbial breakdown: Microbial action probably accounts for the
major breakdown of prometon in the soil. A range of soil
microorganisms can utilize it as a source of energy and nitrogen.
The effects of prometon on these and other soil organisms appear
to be small, if at all. (Bryant, J.B. 1963. Bacterial
decomposition of some aromatic and aliphatic herbicides. Ph.D.
Thesis. Pennyslvania State University, University Park.)
3. Loss from photodecomposition and/or volatilization:
Photodecomposition and/or volatilization of prometon from the soil
is little understood. Available data suggest that these factors
are of little direct importance in prometon dissipation.
4. Resultant average persistence at recommended rates: The residual
activity of prometon in soil depends mainly upon soil type,
moisture, and application rate. Under arid conditions, it can
persist for extended periods (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
KNOWN OR SUSPECTED ADVERSE EFFECTS: Some triazines are mildly
irritating to skin, eyes, and upper respiratory tract. Systemic
toxicity is unlikely unless very large amounts have been ingested (25).
No cases of poisoning in man have been reported from prometon
ingestion. Symptoms from large doses in rats include hypoactivity,
ptosis, muscular weakness, salivation, anorexia, hyperpnea,
hypothermia, tremors, loss of righting reflex, dysporea, hemorrhagic,
SKIN CONTACT: Wash contaminated skin with soap and water (25).
INGESTION: Ingestions of small amounts (less than 10 mg/kg body
weight) occurring less than an hour before treatment, are probably best
A. Syrup of Ipecac, followed by 1-2 glasses of water. Dose for
adults and children over 12 years: 30 ml. Dose for children
under 12 years: 15 ml.
B. Activated Charcoal - Administer 30-50 gm as a slurry in tap water,
after vomiting stops.
C. Sodium or Magnesium Sulfate, 0.25 g/kg in tap water as a cathartic
INHALATION: Remove from contaminated atmosphere. If symptoms
appear or person is unconscious, get medical attention (Pramitol 25E)
EYE CONTACT: Flush contaminated eyes with copious amounts of
fresh water for 15 minutes (25).
Immediately flush the eyes with large amounts of running water for
a minimum of 15 minutes. Hold the eyelids apart during the flushing to
ensure rinsing of the entire surface of the eye and lids with water.
Do not attempt to neutralize with chemical agents. Obtain medical
attention as soon as possible (Pramitol 25E) (24i).
NOTES TO PHYSICIAN:
1. INGESTIONS of LARGE amounts (more than 10 mg/kg) occurring less
than an hour before treatment, should probably be treated by
A. INTUBATE stomach and ASPIRATE contents.
B. LAVAGE stomach with slurry of ACTIVATED CHARCOAL in 0.9%
saline. Leave 30-50 gm activated charcoal in the stomach
before withdrawing tube.
C. SODIUM SULFATE, 0.25 gm/kg in tap water, as a cathartic.
CAUTION: Hydrocarbons (kerosene, petroleum distillates) are
included in some formulations of these chemicals.
Ingestion of very LARGE AMOUNTS may cause CNS
depression. In this case, IPECAC IS
CONTRAINDICATED. Also, gastric intubation incurs a
risk of HYDROCARBON PNEUMONITIS. For this reason
observe the following precautions:
(1) If the victim is unconscious or obtunded and
facilities are at hand, insert an ENDOTRACHEAL
TUBE (cuffed, if available) prior to gastric
(2) Keep victim's HEAD BELOW LEVEL OF STOMACH
during intubation and lavage (Trendelenburg, or
left lateral decubitus, with head of table
tipped downward). Keep victim's head turned to
(3) ASPIRATE PHARYNX as regularly as possible to
remove gagged or vomited stomach contents.
2. INGESTIONS occurring MORE THAN an HOUR before treatment are
proably best treated only by ACTIVATED CHARCOAL, 30-50 gm, and
SODIUM or MAGNESIUM SULFATE, 0.25 gm/kg, as described above.
3. There are no specific antidotes for these chemicals. Because
manifestations of toxicity do occasionally occur in peculiarly
predisposed individuals, MAINTAIN CONTACT with victim for at least
72 hours so that unexpected adverse effects can be treated
VI. FIRE AND EXPLOSION INFORMATION
GENERAL: Nonflammable (58). Flammable material. As in any fire,
prevent human exposure to fire, smoke, fumes, or products of
combustion. Evacuate nonessential personnel from the area.
Firefighters should wear impervious clothing such as gloves, hoods,
suits and rubber boots (Pramitol 25E) (24i).
EXTINGUISHER TYPE: Use standard organic chemical firefighting
techniques in extinguishing fires involving this material - use dry
chemicals, foam or carbon dioxide. Use of contaminated buildings, area
and equipment must be prevented until they are properly decontaminated
(Pramitol 25E) (24i).
Compatible with most other pesticides when used at normal rates.
Noncorrosive under normal use conditions (58).
VIII. PROTECTIVE MEASURES
STORAGE AND HANDLING: Very stable over several years of shelf life,
and only slight sensitivity to natural light and extreme temperatures
which would occur normally. Avoid inhalation of dust. Avoid contact
with skin (58).
PROTECTIVE CLOTHING: Skin contact with the liquid should be prevented
through the use of rubber gloves and clothing consistent with good
pesticide handling practice. Eye contact with the liquid should be
avoided through the use of chemical safety glasses or goggles (Pramitol
PROTECTIVE EQUIPMENT: Where adequate ventilation is not available and
exposure to excessive mists or spray could occur, wear a Conflo II
(MSA) or other approved pesticide respirator (Pramitol 25E) (24i).
IX. PROCEDURES FOR SPILLS AND LEAKS
IN CASE OF EMERGENCY, CALL, DAY OR NIGHT
PESTICIDE TEAM SAFETY NETWORK/CHEMTREC
Make sure all personnel involved in spill cleanup follow good
industrial hygiene practices.
Small spills can be handled routinely. Cover the spill with an
absorbent material such as vermiculite or sawdust. Sweep up the
material and place in an appropriate chemical waste container. Seal
container and dispose of in an approved landfill. Wash the spill area
with a strong detergent and water. Flush the spill area with water to
remove any residue. Do not reuse container. Destroy by perforation or
crushing and burying in a safe place.
Disposal of material, spill residues, wash water, and containers
must be by methods consistent with local, state and federal health and
A spill of 1,000 gal. or more of this material is reportable to
the National Response Center, (800) 424-8802, under the Comprehensive
Environmental Response, Compensation and Liability Act (Superfund)
(Pramitol 25E) (24i).
X. LITERATURE CITED
8b. Thomson, W.T. 1981. Agricultural chemicals - book 2:
herbicides. Revised ed. Thomson Publications, Fresno, CA.
24i. Ciba-Geigy Corporation. 1982. Safety data sheet: Pramitol 25E.
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.