Benzene is a widely used chemical formed from both natural resources
(volcanoes and forest fires) and human activities. It is a highly flammable
colorless liquid that evaporates quickly. Relatively soluble in water, it can
be mixed with some polar solvents (alcohol, chloroform, and carbon
tetrachloride) without separating into two phases.
Its chemical formula is C6H6 and it is made up of 92.3%carbon and 7.7%
hydrogen. The Benzene molecule is represented by six sets of carbon and
hydrogen atoms connected as a hexagon and held together with alternating single
and double bonds.Its chemical and physical properties are as follow:
Molecular Weight 78.11 g/moleMelting Point 5.5 degrees CelsiusBoiling Point
80.1 degrees CelsiusDensity at 20 degrees Celsius 0.879 g/mlVapor Pressure at
25 degrees Celsius 0.13 atm.Flash Point (closed cup) -11.1 degrees Celsius
Solubility in Water at 25 degrees Celsius 1.8 g/LConversions at 25 degrees
Celsius 1 ppm = 3.25 mg/m31 mg/liter = 313 ppm
ppm = part per million
Is it Dangerous?
In the 1980’s, benzene replaced lead in gasoline, when the latter was proven
to be toxic. Unfortunately, the trade off turned out to be merely one poisonous
substance for another.
Benzene has been confirmed as a human carcinogen (cancer-causing agent) by
the International Agency for Research on Cancer, the Department of Health and
Human Services (DHHS), and the Environmental Protection Agency (EPA).
Is it Regulated?
The EPA requires that spills or accidental releases into the environment of
10 pounds or more of benzene be reported to the EPA. The EPA has set the
maximum permissible level of benzene in drinking water at 0.005 milligrams per
liter (0.005 mg/L).
The Occupational Safety and Health Administration (OSHA) has set an exposure
limit of 1 part of benzene per million parts of air (1ppm) in the workplace
during an 8-hour workday in a 40-hour workweek, with a short term exposure of
limit of 5ppm. Long term exposure has been shown to affect bone marrow and
cause serious and life-threatening health conditions.
What are its Uses and Side Effects?
While benzene as a solvent has been banned for more than two decades, it is
still used to make other chemicals and exposure to the toxic substance is still
rampant. It is used to make the chemicals used in the production of nylons,
plastics, lubricants, dyes, resins, synthetic fibers, detergents, drugs,
pesticides, and rubber. Benzene is also a natural part of crude oil and
cigarette smoke.
The average person is exposed to possible benzene poisoning both inside and
outside the home. Inside hazards include glues, paints, detergents, and
furniture wax. Outside hazards include the air around automobile service
stations, industrial emissions, and motor vehicle exhaust. Of course, many
people are exposed to cigarette smoke both inside, outside, or both.
Effects of benzene poisoning by breathing it in include drowsiness,
dizziness, unconsciousness, accelerated heart rate, headaches, and tremors.
Some women who breathed high levels of benzene for many months had irregular
menstrual periods and a decrease in the size of their ovaries. And while it is
not known whether benzene exposure affects the developing fetus in pregnant
women, animal studies have shown low birth weights, delayed bone formation, and
bone marrow damage when pregnant animals breathed benzene. The effects on the
fertility of men are still unknown.
Benzene in the air can attach to rain or snow and be carried back down to
the ground. It breaks down slowly in water and soil, and can pass through the
soil into underground water. Leakage from hazardous waste sites and faulty
pipes can also result in contaminated drinking water. Benzene ingested orally
causes vomiting, stomach irritation, dizziness, sleepiness, convulsions,
accelerated heart rate, and death.
Deaths caused by benzene have been attributed to asphyxiation, respiratory
arrest, and CNS (central nervous system) depression. Autopsies have also shown
lung hemorrhages, cerebral edema, and congestion.
Cancer cases have been associated with people exposed to benzene for less
than five years to more than thirty years. Benzene has been linked to multiple
leukemia cases, usually acute myelogenous leukemia (AML), but also chronic
myelogenous leukemia (CML), acute lymphocytic leukemia (ALL), chronic
lymphohcytic leukemia (CLL), and Hairy-Cell Leukemia (HCL). It has also been
associated with multiple myeloma, non-Hodgkin’s lymphoma, myelodyplastic syndrome,
myelodysplasia, and secondary aplastic anemia. These diseases are a result of
the chronic damage done to the body’s bone marrow.
More than 300,000 people per year are exposed to the chemical through their
workplace, and over 10,000 deaths per year are attributed to benzene exposure
in the United States
alone. People working with petroleum products are exposed to significant
amounts of benzene.
The following jobs fall under the high risk category.
Painters
Adhesive Production Workers
Chemical Workers
Dock Workers
Paper and Pulp Production
Workers
Pipe Fitters
Barge Workers
Offshore Workers
Refinery Workers
Gas Station Attendants
Pesticide Manufacturers
Industrial Plant Workers
(using solvents)
Rubber Workers
Shoe/Leather Workers
Truck Drivers
Can I Be Tested?
There are breath and blood tests available for determining the presence of
benzene in a person; unfortunately, they are only accurate for recent exposure.
There is also a urine test but it works on a slightly different premise.
Benzene converts to metabolites in the body and some of them can be measured by
urinalysis. This too is only accurate for recent exposure.
What about Workplace Precautions?
Wear solvent-resistant gloves and clothing as benzene can be absorbed
through the skin. Neoprene, Silver Shield, Polyvinyl Alcohol and Butyl Neoprene
are often recommended as protective materials, but contact manufacturers and
safety equipment suppliers for recommendations on the glove/clothing material
that offers the most protection in your daily exposure. Keep all protective
clothing clean and put them on every day before arriving at work. Wash
thoroughly at the end of the work shift and immediately after any exposure to
benzene.
Do not wear contact lenses when working with benzene; do wear impact and splash
resistant goggles when working with liquids. If you work with corrosive, highly
irritating, or toxic substances, wear a face shield along with the goggles.
Where the potential exists for exposure over the 1ppm standard, a
supplied-air respirator with a full face piece operated in a positive-pressure
mode. Improper use of respirators is dangerous and should only be used
according to a written program as described in OSHA 1910.34.
Workplaces should have a regulated, marked area where all benzene is handled,
used, or stored. Hazard and warning information should be posted in plain view,
and potentially exposed workers should receive training and education on the
health and safety hazards of working with benzene.
Is There Any Legal Recourse?
Under the law, victims of benzene-related health effects may be eligible for
compensation. A simple internet search will produce multiple class-action suits
as well as attorneys and organizations that stand ready to assist you. If you
think you have been harmed by benzene exposure, you may want to consider
seeking consultation to learn more about your options.