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.

This page was last updated: October 31, 1996