bromacil (Hyvar X, XL) Herbicide Profile 2/85
CHEMICAL NAME: 5-Bromo-3-sec-butyl-6-methyluracil (56)
TRADE NAME(S): Hyvar X, Hyvar XL (56)
FORMULATION(S): Wettable powder (80%) (Hyvar X); water-soluble
liquid (2 pounds/gallon) (Hyvar X-L). 40.8%, 4
pounds bromacil per gallon (Bromax 4L). Various
granular and liquid formulations are available
from formulators (56).
BASIC PRODUCER(S): E.I. duPont de Nemours and Co., Inc.
1007 Market St.
Wilmington, DE 19898
STATUS: General use
PRINCIPAL USES: For general weed or brush control in noncrop areas;
particularly useful against perennial grasses. Also recommended for
selective weed control in pineapple and citrus (56).
APPLICATION METHOD(S): Bromacil is sprayed or spred dry (as granules,
etc.) on the soil surface, preferably just before or during a period of
active growth of weeds (58).
To be developed.
II. PHYSICAL PROPERTIES
MOLECULAR FORMULA: C9 H13 Br N2 O2 (62)
MOLECULAR WEIGHT: 261.1 (62)
PHYSICAL STATE: Colorless crystalline solid (pure chemical) (62)
ODOR: Odorless (pure chemical) (58)
MELTING POINT: 158-159 C (pure chemical) (62)
VAPOR PRESSURE: 33 uPa at 25 C (pure chemical) (62)
SOLUBILITY: 815 mg/l water at 25 C (pure chemical) (62)
III. HEALTH HAZARD INFORMATION
OSHA STANDARD: NA
NIOSH RECOMMENDED LIMIT: NA
ACGIH RECOMMENDED LIMIT: TWA (Time Weighted Average) = 1 ppm, 10
mg/m3; STEL (Short Term Exposure Limit) = 2 ppm, 20 mg/m3 (15a).
A. ACUTE TOXICITY
DERMAL: It did not cause skin sensitization and was
mildly irritating to guinea pigs. Rabbits showed no clinical
signs of toxicity as a result of skin applications of 5000 mg/kg,
the maximum feasible dose under test conditions. Autopsy showed no
gross pathologic changes (15b).
ORAL: LD50 = 5200 mg/kg (male rat) (15b).
INHALATION: All rats tolerated a 4-hr. exposure at the
equivalent of 4800 mg/m3 (4.8 mg/L) indicating a low order of
acute inhalation toxicity. Higher concentrations were impractical
under test conditions (15b).
EYES: Administration of 10 mg of dry 50% powder, or
0.1 ml of a 10% suspension in mineral oil, to rabbits' eyes
produced only a slight, transient conjunctival irritation; there
was no corneal injury (31j).
B. SUBACUTE AND CHRONIC TOXICITY:
No-effect dietary concentration levels in two-year feeding studies
are considered to be greater than 250 ppm but less than 1250 ppm for
rats and 1250 ppm for dogs. Dietary concentrations of 250 ppm did not
adversely affect reproduction of rats and rabbits. There was no
evidence of teratogenicity or carcinogenicity in these chronic studies
IV. ENVIRONMENTAL CONSIDERATIONS
LC50 (96 hr) for mallard ducklings and bobwhite quail 10,000
mg/l. LC50 (48 hr) is: for bluegill 71 mg/l; for carp 164 mg/l (62).
LC50 (48 hours) for bluegill sunfish is 71 ppm
LC50 (48 hours) for carp is 164 ppm
LC50 (72 hours) for rainbow trout is 28 ppm
LC50 (96 hours) for fathead minnows is 182 ppm (31j).
Half-life of bromacil was approximately 5 to 6 months when 4 lbs
(active) per acre was applied to the surface of Butlertown silt loam.
About 90% of the residual activity recovered from the soil was intact
Subject to microbial decomposition under moist conditions in soil
Bromacil is much less subject to adsorption on soil colloids than
many commercial herbicides. For example, the amount of bromacil
adsorbed on Keyport silt loam in equilibrium with 1 ppm in soil
solution at room temperature is 1.5 ppm compared with 2.6 ppm of
monuron and 4.0 ppm of diuron. Bromacil falls in group three of the
mobility classification suggested by Helling and Turner (1968) (58).
Microbiological degradation apparently is a mode of disappearance
from soils. Soil diphtheroids, Pseudomonas and Penicillium species are
among the organisms involved (58).
Tests at elevated temperatures and long exposures to sunlight
indicate that loss from soil due to volatilization and
photodecomposition are negligible (58).
When sterilant rates are applied, activity usually is noted for
more than one season. The half-life of 2-C14-labeled bromacil was
determined to be approximately 5 to 6 months when 4 lb/A were applied
to the surface of Butlertown silt loam (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: Irritant to skin, eyes, and
respiratory tract (25).
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 treated by: 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 (25).
EYE CONTACT: Flush contaminated eyes with copious amounts of
fresh water for 15 minutes (25).
NOTES TO PHYSICIAN:
INGESTIONS of LARGE amounts (more than 10 mg/kg) occurring less than an
hour before treatment, should probably be treated by gastric lavage:
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
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
(1) If the victim is unconscious or obtunded and
facilties are at hand, insert an ENDOTRACHEAL TUBE
(cuffed, if available) prior to gastric intubation.
(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 the left.
(3) ASPIRATE PHARYNX as regularly as possible to remove
gagged or vomited stomach contents.
INGESTIONS occurring MORE THAN an HOUR before treatment are probably
best treated only by ACTIVATED CHARCOAL, 30-50 gm, and SODIUM or
MAGNESIUM SULFATE, 0.25 gm/kg, as described above.
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 promptly (25).
VI. FIRE AND EXPLOSION INFORMATION
GENERAL: Hyvar X-L weed killer is a combustible mixture; keep away
from heat and open flame (31j).
Hyvar X: May be ignited by heat or open flame. Fine dust
dispersed in air (particularly in confined spaces) may ignite if
exposed to high temperature ignition source. These conditions are
unlikely to occur in normal, outdoor use of this product (31k).
EXTINGUISHER TYPE: On small fire use dry chemical, CO2, foam or water
spray. If area is heavily exposed to fire and if conditions permit,
let fire burn itself out since water may increase the contamination
hazard. If conditions do not permit, extinguish with water spray. If
conditions permit, cool containers with water if exposed to fire. Wear
self-contained breathing apparatus (Hyvar X) (31k).
Bromacil formulations are compatible with most herbicides with
which they might be mixed. Certain ester formulations of phenoxy
herbicides may create physical problems with the wettable powder in the
spray tank. Water-soluble formulations are not compatible with
products which markedly reduce pH of spray suspensions (AMS, amitrole,
etc.). Weed killers containing soluble calcium salts form precipitates
when used with the water-soluble formulation (58).
VIII. PROTECTIVE MEASURES
STORAGE AND HANDLING: Keep from contact with fertilizers,
insecticides, fungicides, and seeds. Keep container closed when not in
use. Do not reuse container; bury when empty (31j).
Do not apply (except as recommended for crop use) or drain or
flush equipment on or near desirable trees or other plants, or on areas
where the chemical may be washed or moved into contact with their
roots. Do not contaminate domestic waters. Keep out of reach of
children (Hyvar X) (31k).
Store in a cool, dry place. May irritate eyes, nose, throat, and
skin. Avoid breathing dust or spray mist. Avoid contact with skin,
eyes, and clothing (56).
IX. PROCEDURES FOR SPILLS AND LEAKS
IN CASE OF EMERGENCY, CALL, DAY OR NIGHT
PESTICIDE TEAM SAFETY NETWORK/CHEMTREC
Clean up promptly. Do not flush with water, pick up dry by
sweeping or other effective means. If spill area is on ground near
trees or other valuable plants, remove top 2 inches of soil after
initial cleanup (31k).
X. LITERATURE CITED
15a. American Conference of Governmental Industrial Hygienists. 1983.
TLVs: threshold limit values for chemical substances and
physical agents in the work environment with intended changes
for 1983-84. Cincinnati, OH. 93 pp.
15b. American Conference of Governmental Industrial Hygienists. 1971.
Documentation of the threshold limit values for substances in
workroom air with supplements for those substances added or
changed since 1971, 3rd ed., 4th printing (1977). Cincinnati,
OH. 484 pp.
25. Morgan, D.P. 1982. Recognition and management of pesticide
poisonings, 3rd ed. U.S. Environmental Protection Agency,
Washington, DC. 120 pp.
31j. E. I. du Pont de Nemours and Co., Inc., Biochemicals Department.
1979. Technical data sheet: bromacil. Wilmington, DE.
31k. E. I. du Pont de Nemours and Co., Inc., Biochemicals Department.
1977. Material safety data sheet for Hyvar X weed killer.
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.