General Description
White to yellow powder or flakes. Musty odor. The gamma isomer is known as lindane, a systemic insecticide. Toxic by ingestion or inhalation.
Reactivity Profile
Halogenated aliphatic compounds, such as HEXACHLOROCYCLOHEXANE, are moderately or very reactive. Reactivity generally decreases with increased degree of substitution of halogen for hydrogen atoms. Materials in this group may be incompatible with strong oxidizing and reducing agents. Also, they may be incompatible with many amines, nitrides, azo/diazo compounds, alkali metals, and epoxides.
Hazard
Highly toxic; questionable carcinogen.
Potential Exposure
The major commercial usage of BHC
is based upon its insecticidal properties. α-BCH is used as
an Agricultural chemical, pesticide, pharmaceutical, and
veterinary drug. The 7-isomer has the highest acute toxic ity, but the other isomers are not without activity. It is gen erally advantageous to purify the 7-isomer from the less
active isomers. The γ-isomer acts on the nervous system of
insects, principally at the level of the nerve ganglia. As a
result, lindane has been used against insects in a wide range
of applications including treatment of animals, buildings,
humans for ectoparasites, clothes; water for mosquitoes;
living plants; seeds and soils. Some applications have been
abandoned due to excessive residues, e.g., stored food stuffs. By voluntary action, the principal domestic producer
of technical grade BHC requested cancellation of its BHC
registrations on September 1, 1976. As of July 21, 1978, all
registrants of pesticide products containing BHC voluntar ily canceled their registrations or switched their former
BHC products to lindane formulations.
First aid
If this chemical gets into the eyes, remove any
contact lenses at once and irrigate immediately for at least
30 minutes, occasionally lifting upper and lower lids. Seek
medical attention immediately. If this chemical contacts the
skin, remove contaminated clothing and wash immediately
with soap and water. Speed in removing material from skin
is of extreme importance. Shampoo hair promptly if con taminated. Seek medical attention immediately. If this
chemical has been inhaled, remove from exposure, begin
rescue breathing (using universal precautions, including
resuscitation mask) if breathing has stopped and CPR if
heart action has stopped. Transfer promptly to a medical
facility. When this chemical has been swallowed, get medi cal attention. Give large quantities of water and induce
vomiting. Do not make an unconscious person vomit.
Shipping
UN2761 Organochlorine pesticides, solid, toxic,
Hazard Class: 6.1; Labels: 6.1-Poisonous materials.
Incompatibilities
Incompatible with oxidizers (chlorates,
nitrates, peroxides, permanganates, perchlorates, chlorine,
bromine, fluorine, etc.); contact may cause fires or explo sions. Keep away from alkaline materials, strong bases,
strong acids, oxoacids, epoxides. Decomposes on contact
with powdered iron, aluminum, zinc, and on contact with
strong bases producing trichlorobenzene.
Chemical Properties
BHC is a white-to-brownish crystalline solid
with a musty, phosgene-like odor.
Waste Disposal
A process has been developed
for the destructive pyrolysis of benzene hexachloride @
400 500℃ with a catalyst mixture which contains 5 10%
of either cupric chloride, ferric chloride; zinc chloride; or
aluminum chloride on activated carbon.
History
Benzene hexachloride (BHC) was first prepared in 1825, the insecticidal
properties were identified in 1944 with the γ-isomer (gamma-isomer),
which is about 1,000 times more toxic than any of the other diastereomers formed in the reaction. The structural differences between these individuals are in the orientations of the chlorine atoms with respect to the ring of carbon atoms.
Mechanism of action
Acts as stimulant to the nervous system with contact and stomach action. GABA-gated chloride channel antagonist.
Carcinogenicity
A bioassay of lindane of the NCI
was published in 1977. The compound was administered
for 80 weeks to groups of Osborne–Mendel rats and
B6C3F1 mice. Time-weighted dietary levels for male rats
were 236 or 472 ppm; for female rats, 135 or 270 ppm; and for
male and female mice, 80 or 160 ppm. Results were as
follows: in rats, no tumors occurred at a statistically
significant incidence in the treated groups of either sex but
(2) in mice, the incidence of hepatocellular carcinoma in lowdose
males was significant when compared with that in the
pooled controls (controls 5/49, low dose 19/49, p = 0.001).
This finding, by itself, is insufficient to establish the carcinogenicity
of lindane. The incidence of hepatocellular carcinoma
in high-dose male mice was not significantly
different from that in matched or pooled controls. It is
concluded that under the conditions of this bioassay lindane
was not carcinogenic for Osborne–Mendel rats or B6C3F1
mice.
As with most other chlorinated insecticides, lindane has
been shown to exhibit tumor promotional activity, possibly
via inhibition of intercellular communication. Lindane
exposures do inhibit formation of liver tumors following
exposures to aflatoxin B1, suggesting an activity other than
tumor promotion for lindane. Enhancement of enzymatic
deactivation of aflatoxin via induction of microsomal
enzymes may play a role in this phenomenon.
The combination of lindane’s lack of significant mutagenic
activity, its tumor promotional properties, and the lack
of epidemiologic evidence suggest that lindane poses a
minimal to nonexistent risk of cancer to humans under
reasonable and prescribed use conditions.
Pesticide Type
Insecticide; Acaricide; Veterinary substance