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Preventing Silicosis
U.S. Department of Labor
October 31, 1996
What Is Silicosis?
Silicosis is a disabling, nonreversible and sometimes fatal lung disease
caused by overexposure to respirable crystalline silica. Silica is the second most
common mineral in the earth's crust and is a major component of sand, rock,
and mineral ores. Overexposure to dust that contains microscopic particles of
crystalline silica can cause scar tissue to form in the lungs, which reduces
the lungs' ability to extract oxygen from the air we breathe. Typical sand found
at the beach does not pose a silicosis threat.
More than 1 million U.S. workers are exposed to crystalline silica. Each
year, more than 250 American workers die with silicosis. There is no cure for the
disease, but it is 100 percent preventable if employers, workers, and health
professionals work together to reduce exposures.
In addition to silicosis, inhalation of crystalline silica particles has been
associated with other diseases, such as bronchitis and tuberculosis. Some
studies also indicate an association with lung cancer.
Who Is at Risk?
Working in any dusty environment where crystalline silica is present
potentially can increase a person's chances of getting silicosis. If a number of
workers are working in a dusty environment and one is diagnosed with the silicosis,
the others should be examined to see if they might also be developing
silicosis.
Some examples of the industries and activities that pose the greatest
potential risk for worker exposure include:
construction (sandblasting, rock stone cutting (sawing, abrasive
drilling, masonry work, jack blasting, chipping, grinding)
hammering, tunneling) glass manufacturing
mining (cutting or drilling through
sandstone and granite) agriculture (dusty conditions from
disturbing
the soil, such as plowing or
harvesting)
foundry work (grinding, moldings,
shakeout, core room) shipbuilding (abrasive blasting)
ceramics, clay, and pottery railroad (setting and laying
track)
manufacturing of soaps and manufacturing and use of abrasives
detergents
More than 100,000 workers in the United States encounter high-risk, silica
exposures through sandblasting, rock drilling, and mining. Workers who remove
paint and rust from buildings, bridges, tanks, and other surfaces; clean foundry
castings; work with stone or clay; etch or frost glass; and work in
construction are at risk of overexposure to crystalline silica.
What Are the Types, Symptoms and Complications of Silicosis?
There are three types of silicosis, depending upon the airborne concentration
of crystalline silica to which a worker has been exposed: Chronic silicosis
usually occurs after 10 or more years of overexposure. Accelerated silicosis
results from higher exposures and develops over 5-10 years. Acute silicosis
occurs where exposures are the highest and can cause symptoms to develop within a
few weeks or up to 5 years. Chronic silicosis, the most common form of the
disease, may go undetected for years in the early stages; in fact, a chest X-ray
may not reveal an abnormality until after 15 or 20 years of exposure. The
body's ability to fight infections may be overwhelmed by silica dust in the lungs,
making workers more susceptible to certain illnesses, such as tuberculosis.
As a result, workers may exhibit one or more of the following symptoms:
shortness of breath following physical exertion
severe cough
fatigue
loss of appetite
chest pains
fever
How Can Workers Determine If They Have Silicosis?
A medical examination that includes a complete work history and a chest X-ray
and lung function test is the only sure way to determine if a person has
silicosis. Workers who believe they are overexposed to silica dust should visit a
doctor who knows about lung diseases. The National Institute for Occupational
Safety and Health (NIOSH) recommends that medical examinations occur before
job placement or upon entering a trade, and at least every 3 years thereafter.
How Can Silicosis Be Prevented?
Beginning tomorrow, workers and employers will be able to get a package of
free materials on how to prevent silicosis by calling a toll-free telephone
information service operated by NIOSH in the U.S. Department of Health and Human
Services (1-800-35-NIOSH; select option 2, then option 5). The package contains
a tip sheet of ideas for preventing silicosis, a guide for working safely
with silica, and stickers for hard hats to remind workers that, If it's silica,
it's not just dust. Spanish - language versions of materials also will be
available soon.
Department of Labor staff will distribute silica materials when they inspect
mines, construction sites, and other affected industries.
************************
James A. Kaufman, Ph.D.
President/CEO
The Laboratory Safety Institute
Safety in Science and Science Education
192 Worcester Road, Natick, MA 01760
508-647-1900 Fax: 508-647-0062
Cell: 508-574-6264 Res: 781-237-1335
[log in to unmask] www.labsafety.org
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