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EXTOXNET primary files maintained and archived at Oregon State
Revised June 1996
Trade and Other Names:
Trade names include Hydram, Molinate, Ordram, and Yalan.
Molinate is a slightly to moderately toxic compound in EPA
toxicity class III, and is a registered as a General Use
Pesticide (GUP). Products containing molinate must bear the
Signal Word WARNING or CAUTION.
Molinate is a selective thiocarbamate herbicide used to control
broad-leaved and grassy plants in rice and other crops. Molinate
is available in granular and emulsifiable liquid formulations.
is available in granular and emulsifiable liquid formulations.
- Acute toxicity: Molinate is moderately
toxic by ingestion with reported oral LD50 values of 369
to 720 mg/kg in rats, and 530 to 795 mg/kg in mice.
Dermal LD50 values are 4000 to 4800 mg/kg in rats [3,7].
It is mildly irritating to rabbit skin and moderately
irritating to rabbit eyes, and is not a skin sensitizer
. The 4-hour inhalation LC50 of 1.36 mg/L indicates
moderate toxicity by this route as well . Some
formulations show a lower degree of acute toxicity [6,7].
Symptoms of exposure to molinate include nausea,
diarrhea, abdominal pain, fever, weakness, and
- Chronic toxicity: The only reported
human exposure to molinate resulting in adverse health
effects comes from a report of well contamination in
Japan. After field application of approximately 60 kg
active ingredient to a 2-hectare rice paddy, several
people noticed an odor emitted from a nearby well, and
fell ill as a result of repeated consumption of water
from that well . Their symptoms, which were apparently
quite rapid in onset, included abdominal and
gastrointestinal disorders, fever, weakness, and
conjuntivitis . These symptoms disappeared following
the use of an alternative water source, and there were no
reports of long-term complications or lingering effects
due to this exposure . The concentration of the well
water sampled 15 days following the first reported
symptoms was 6 ug/L; it is not known what the initial
concentration was .
- Reproductive effects: Administration of
molinate to young male rats at a dose of 3.6 mg/kg/day
for 2 months caused changes in spermatozoa but did not
decrease sperm fertility . When these rats were mated
to normal females, many of the embryos were resorbed and
postnatal mortality was increased . It is unlikely
that such effects will occur in humans at expected
- Teratogenic effects: Reports on the
teratogenicity of molinate are conflicting, with one
suggestion that it is teratogenic  and another that
it is not . Thus, its teratogenicity is unknown.
- Mutagenic effects: No data were located
regarding the potential mutagenic effects of molinate
although it has been reported to be nongenotoxic [4,7].
- Carcinogenic effects: In a 2-year assay
in rats, no carcinogenic activity was reported at doses
up to 2 mg/kg/day .
- Organ toxicity: The primary target organ
affected by molinate is the thyroid.
- Fate in humans and animals: Molinate is
only fairly well absorbed through oral, dermal, and
inhalation exposure . It is metabolized in the rat
liver, and rapid excretion occurs primarily through the
urine (88% of the applied dose) with a small amount lost
in the feces (11% of the applied dose). Excretion by rats
was practically complete within 48 hours .
- Effects on birds: Molinate appears to be
practically nontoxic to birds. The reported 5-day dietary
LC50 in Japanese quail is greater than 5000 ppm, and that
in mallards is greater than 13,000 ppm [4,13].
- Effects on aquatic organisms: The
reported toxicity to fish varies greatly, from slightly
to highly toxic. One source reports the 96-hour LC50
values at 0.21 mg/L in rainbow trout and 0.32 mg/L in
bluegill sunfish , while another reports tham as 1.3
and 29 mg/L, respectively . A 96-hour LC50 value of 30
mg/L in goldfish has also been reported . Fish kills
of carp due to molinate were observed in Japan. The
pesticide caused an anemia-like condition in these fish
. Reported 96-hour LC50 values in aquatic
invertebrates such as Daphnia and stoneflies are about
0.3 to 0.6 mg/L, indicating that molinate is highly toxic
to these invertebrates [4,16].
- Effects on other organisms: No data are
- Breakdown in soil and groundwater:
Molinate is of low persistence in the soil environment,
with a field half-life of 5 to 21 days . It is poorly
bound to soils, soluble in water, and thus may be mobile
 and present a risk to groundwater contamination.
Soil microorganisms are responsible for most molinate
breakdown . Molinate may rapidly volatilize if not
plowed into the soil, and may undergo breakdown by
- Breakdown in water: Molinate may be
degraded by hydrolysis (reaction with water).
- Breakdown in vegetation: Molinate is
rapidly taken up by plant roots and transported to the
leaves. In the leaves, molinate inhibits leaf growth and
development. It is rapidly metabolized to carbon dioxide
and other naturally occurring plant products such as
amino acids and organic acids in nonsusceptable plants.
- Appearance: Molinate is a noncorrosive,
clear liquid with an aromatic or spicy odor .
- Chemical Name: S-ethyl hexhydro-1
- CAS Number: 2212-67-1
- Molecular Weight: 187.30
- Water Solubility: 880 mg/L 
- Solubility in Other Solvents: v.s. in
acetone, xylene, ethanol, kerosene, and
- Melting Point: Not Available
- Vapor Pressure: 746 mPa @ 25 C 
- Partition Coefficient: 2.8808 
- Adsorption Coefficient: 190 
- ADI: Not Available
- MCL: Not Available
- RfD: 0.002 mg/kg/day 
- PEL: Not Available
- HA: Not Available
- TLV: Not Available
Zeneca Ag Products
1800 Concord Pike
Wilmington, DE 19897
- Phone: 800-759-4500
- Emergency: 800-759-2500
References for the information in this PIP can be found in
Reference List Number 4
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