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.