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in 1996. EXTOXNET no longer updates this information, but it may be useful
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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 for commercial products containing bromoxynil include
Brominal, Bromotril, Bronate, Buctril, Certrol B, Litarol,
M&B 10064, Merit, Pardner, Sabre, and Torch. This compound
may also be found in mixed formulations with other herbicides
including MCPA, linuron, dicamba, mecoprop, and 2,4-D.
Bromoxynil is a Restricted Use Pesticide (RUP), and is not
registered for homeowner use. RUPs may be purchased and used only
by certified applicators. It is categorized as toxicity class II
- moderately toxic. Products containing bromoxynil carry the
Signal Word WARNING on their labels.
Chemical Class: nitrile
Bromoxynil is a nitrile herbicide that is used for post-emergent
control of annual broadleaf weeds. It is especially effective in
the control of weeds in cereal, corn, sorghum, onions, flax,
mint, turf, and on non-cropland. The compound works by inhibiting
photosynthesis in the target plants. It is available as an
emulsifiable concentrate and a suspension concentrate.
Formulation: It is
available as an emulsifiable concentrate and a suspension
- Acute toxicity: The bromoxynil product
Buctril, has an oral acute LD50 of 779 mg/kg in the rat,
and Bronate's LD50 is 691 mg/kg in the rat. Technical
bromoxynil has an oral LD50 of 190 mg/kg in rats, an LD50
of 260 mg/kg in rabbits, and an LD50 of 63 mg/kg in
guinea pigs, indicating moderate acute toxicity [8,22].
The dermal LD50 of bromoxynil is greater than 2000 mg/kg
in rabbits. The compound is a slight eye irritant but it
is not a skin irritant in rabbits [1,22]. However, when
in contact with abraded skin, bromoxynil may produce a
mild irritation .
- Chronic toxicity: In one documented case
of chronic exposure (about 1 year) of humans to
bromoxynil, workers showed symptoms of weight loss,
fever, vomiting, headache, and urinary problems .
Studies have shown that bromoxynil has no effect on rats
given dietary doses of 15 and 50 mg/kg/day for 90 days
. Doses up to 5 mg/kg/day for 2 years had no impact on
blood chemistry or urine .
- Reproductive effects: No changes in
reproduction were noted in female rats fed 15 mg/kg/day
of bromoxynil over three generations . This suggests
that bromoxynil does ot cause reproductive effects.
- Teratogenic effects: Bromoxynil is a
suspected teratogen. The compound produced birth defects
in rats at oral doses above 35 mg/kg. Toxic effects
included abnormal rib formation and reduced fetal weight.
Newborn rabbits had birth defects when bromoxynil was
administered to pregnant mothers at doses above 30 mg/kg
. In the rabbit, birth defects included changes in
bone formation in the skull and hydrocephaly.
- Mutagenic effects: No data are currently
- Carcinogenic effects: Rats fed
bromoxynil at low levels of 5 mg/kg and below did not
develop any cancer related effects .
- Organ toxicity: No data were available
regarding the target organs affected by bromoxynil.
- Fate in humans and animals: No
bromoxynil was present in the milk or feces of cows 9
days after exposure to low doses of the herbicide. Less
than 20% of the compound was excreted in urine as the
parent compound .
- Effects on birds: Bromoxynil is highly
toxic to pheasants (LD50 of 50 mg/kg) and is moderately
toxic to hens (LD50 of 240 mg/kg), quail (LD50 of 100
mg/kg), and mallard ducks (LD50 of 200 mg/kg) .
- Effects on aquatic organisms: Bromoxynil is very highly
toxic to moderately toxic to freshwater fish; the
potassium salt of bromoxynil has an LC50 of 5.0 mg/L in
harlequin fish, 0.46 mg/L in goldfish, and 0.063 mg/L in
catfish . Bromoxynil has an LC50 of 0.05 mg/L in
rainbow trout .
- Effects on other organisms: Bromoxynil
is not toxic to bees .
- Breakdown in soil and groundwater:
Bromoxynil has a low persistence in soil. In sandy soil,
the half-life is about 10 days . Degradation in clay
was slower, with half of the bromoxynil degraded to its
metabolites in about a 2-week period at 25 C . The
persistence of the compound is also slightly longer in
peat field soils than in the sandy soils . The
evidence suggests that, while bromoxynil is broken down
by some soil bacteria, it may inhibit the action of other
bacteria that promote the formation of nitrite by a
process called nitrification .
- Breakdown in water: No data are
- Breakdown in vegetation: The herbicide
works by disrupting the plants ability to produce energy
for cell-related activities. It is not readily
translocated throughout the plant once it has been
- Appearance: Bromoxynil is a colorless
crystalline solid at room temperature.
- Chemical Name:
- CAS Number: 1689-84-5
- Molecular Weight: 276.93
- Water Solubility: 130 mg/L @ 25 C 
- Solubility in Other Solvents: methanol
v.s.; ethanol v.s.; acetone v.s.; cyclohexane v.s.;
tetrahydrofuran v.s.; all at 25 C 
- Melting Point: 194-195 C 
- Vapor Pressure: <1 mPa @ 20 C 
- Partition Coefficient: Not Available
- Adsorption Coefficient: Not Available
- ADI: Not Available
- MCL: Not Available
- RfD: 0.02 mg/kg/day 
- PEL: Not Available
- HA: Not Available
- TLV: Not Available
Rhone-Poulenc Ag. Co.
P.O. Box 12014
2 T. W. Alexander Dr.
Research Triangle Park, NC 27709
- Phone: 919-549-2000
- Emergency: 800-334-7577
References for the information in this PIP can be found in
Reference List Number 10
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