Benzene
What is Benzene?
Benzene is a natural component of petroleum and petroleum based
products. It is not usually encountered in its pure form these
days, however, significant occupational exposure to benzene-containing
products occurs virtually all the time, especially in oil refineries
and chemical plants. Since the names of the products do not reflect
their benzene content, workers are exposed to benzene as a result
of working around products they do not suspect of containing
benzene, but do contain significant quantities of benzene.
When pure, benzene is a clear, colorless liquid with a fruity,
sweet odor that burns readily.
Where is Benzene found?
Benzene is obtained from crude petroleum or from coal tar pitch
volatiles. Significant quantities of benzene are manufactured
or used in all oil refineries and certain types of chemical plants.
Benzene found at these facilities is either in its pure form,
or more commonly and more importantly, in many internal process
streams at these facilities.
Additionally, benzene has also been used in more common commercial
and even household products such as paint, paint thinners, degreasers,
solvents, glues, pesticides, and gasoline.
What immediate health effects may be caused
by exposure to Benzene?
Breathing benzene vapor in small amounts may cause headache,
euphoria (a “high”), a light-headed feeling, dizziness,
drowsiness, or nausea. With more serious exposure, benzene may
cause sleepiness, stumbling, irregular heart beats, passing out,
or even death.
Benzene vapors are mildly irritating to the skin, eyes, and
lungs. If liquid benzene contacts the skin or dyes, it may cause
burning pain. Liquid benzene splashed in the eyes can damage
the cornea of the eyes.
However, chronic diseases such as cancer and blood disorders
may result from benzene exposures that cause no apparent immediate
(or acute) effects in the exposed person.
What is the treatment for Benzene poisoning?
There is no antidote for benzene poisoning, but its effects
can be treated and most exposed persons do fully recover. Persons
who have experienced serious symptoms may need close medical
observation for 24 hours.
What are the long-term health effects caused
by Benzene exposure?
After a single, small exposure, no delayed or long-term effects
are likely to occur. After significant exposures, however, symptoms
may develop in as little as a few days or may develop over a
period of decades. It is not unusual for twenty or more years
to pass before the benzene related disease becomes manifest and
the worker develops symptoms.
Apart from immediate effects, short-term high level or even
relatively “low” level worker exposures to benzene
that occurred many years ago may result in the development of
a wide variety of non-malignant and malignant adverse health
effects years later. Most of these adverse health effects concern
the blood and blood forming organs. These include various anemias,
thrombocytopenia, polycythemia, myelodystplastic syndrome, myelodysplasia,
myelofibrosis, acute myelogenous leukemia (AML), chronic myelogenous
leukemia (CML), acute lymphocytic leukemia (ALL), chronic lymphocytic
leukemia (CLL), or other forms of leukemia. Besides leukemia,
benzene exposure may also cause non-Hodgkin’s lymphomas
and multiple myeloma. Repeated exposure to benzene may cause
blood disorders and cancer of blood-forming cells. Aplastic anemia,
leukemia, lymphoma and multiple myeloma have been reported in
workers exposed to benzene.
What tests can be done if a person has been
exposed to Benzene?
Specific tests for the presence of benzene in blood are not
medically useful. Phenol, a metabolite of benzene, can be measured
in urine if the benzene exposure was high. In cases of severe
exposure, other tests may show if injury has occurred in the
heart, kidneys, blood, or nervous system. The severity of symptoms
is usually the best measure of the seriousness of the exposure.
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