Silicosis: Am I At Risk?
It all started when Leslie Blevins was 45. Once hardy and energetic, she felt tired all the time. Just walking around the block near his Logan, West Virginia, home or strolling for a few minutes down the family's driveway defeated him. Pretty soon, he couldn't even make it from room to room inside the house without staggering. Even when he was finally hooked up to an oxygen machine, he was constantly struggling to catch his breath. "The least little thing had me gasping for air," he says.
Blevins, as it turned out, was dying. An ex-coal miner, he learned he was suffering from silicosis, a disease that causes scarring and hardening of lung tissue as a result of prolonged or extensive exposure to free crystalline silica dust. He was diagnosed with an advanced case of the disease and given only a few years to live.
Silica is the second most common mineral in the earth's crust and is a major component of sand, rock and mineral ores. When workers inhale the crystalline dust, it may start a chain reaction that ends in silicosis. In the disease's most common form, which occurs after 20 or more years of exposure, silica is inhaled and deposited in the lung, causing inflammation.
"The lungs react by developing fibrotic nodules around the trapped silica particles," explains Daniel Banks, MD, Blevins' physician in Morgantown, West Virginia. If the nodules grow too large and coalesce, he says, breathing may become agonizingly difficult. As if that weren't enough, many workers who have silicosis develop tuberculosis as well.
Chronic silicosis usually takes anywhere from 20 to 45 years to develop, but even 5 to 10 years exposure time at higher concentrations can result in an accelerated version of the disease. (The combination of cigarette smoking and silica exposure also results in much more severe lung damage.) The rarest form of the disease, known as acute silicosis, can involve a single lethal dose or many exposures to a high concentration of silica within two years or less. The silica particles land in the air sacs of the lung, leading to inflammation that causes the sacs to fill up and makes gas exchange impossible. This form is progressive and often fatal.
Unfortunately for Blevins, his silicosis was progressing at a very rapid pace. The coal miner isn't sure when he contracted the disease. But for three consecutive months in late 1993, he remembers, he was heavily exposed to silica dust while cutting through a thick sandstone wall to get at a coal seam. Every night he'd come home utterly exhausted and covered from head to toe with the telltale white dust. "A doctor told me back in 1995 that if I didn't quit mining, I might live two more years," Blevins says. After working as a miner for 21 years, he finally renounced his position in December 1995 at the non-union company RMI Contracting -- where he'd been working for the previous two years -- and he hasn't gone underground since.
Who's at risk?
Some workers think of silicosis as a disease of the past. But while the numbers are declining, workers are still dying from the disease. Since 1968, the federal government has recorded a total of 16,305 silicosis-associated deaths. The World Health Organization says of the workers in the United States who are exposed to silica dust, 59,000 develop silicosis and about 166 die every year from the disease.
Those are disturbing numbers for something that's "100 percent preventable," says Joe Cocalis, an industrial hygienist with the National Institute for Occupational Safety and Health (NIOSH). Cocalis has monitored surface coal mine drillers in West Virginia since 1992.
According to the CDC, industries that pose the greatest potential risk for worker exposure are agriculture, construction, mining, ceramics (clay and pottery), soap and detergent manufacture, stone cutting, glass manufacturing, agriculture, ship building, railroading, and the manufacture and use of abrasives. Quarry workers, sandblasters, and foundry workers are among those most affected.
In all these trades, prevention is important because no good treatment has been found to reverse the disease. Although corticosteroids, some immunosuppressive drugs, and a few experimental medications appear to slow down the inflammation, the effect is only temporary. The only good treatment for end-stage silicosis is a lung transplant.
A life-saving treatment
Confronted with the severity of Blevin's advanced silicosis, his doctors opted for palliative treatments that would ease his suffering. Other than administering oxygen and steroids to help Blevins breathe, there really wasn't much anyone could do but watch the disease run its course. Then Blevins underwent transplant surgery at the Cleveland Clinic in Ohio to remove his severely diseased left lung. His right lung, although not free of the disease, was left intact. Ever since the operation, Blevins has been feeling like a new man. For the first time in years he's even breathing without the help of supplemental oxygen.
Hiding the problem?
"Silicosis has been around as long as people have crushed rock," says Dr. Banks. "Epidemics have been reported even in the 1990s."
Part of this problem can be traced to various employers' failure to comply with federal standards. Blevins' company, for example, concealed the sandstone mining it did from federal inspectors, according to Blevins. Not wanting to risk losing his job at RMI, the miner helped them do so. "If one did show up," Blevins says, "my bosses would tell me to quit, shut off the power to the area, and go some place else to work."
Mine operators are required to test the air every two months to make sure dust levels don't exceed federal limits. But Blevins reports that he never once took a dust test in all the time he was hammering away at the sandstone wall, nor was he asked to provide a proper dust sample during his entire two years at RMI. (RMI refused comment for this story.)
How to prevent silicosis
Preventing silicosis takes awareness and planning, according to the Occupational Safety and Health Administration (OSHA). The agency's safety recommendations are outlined in its Special Emphasis Program for Silicosis. Among other things, OSHA asks employers to:
- Inspect work areas to determine the source of silica dust
- Isolate work processes that produce silica dust
- Suppress airborne dust with moisture by installing sprays
- Check the ventilation equipment every three months
- Use only approved respirators
- Offer periodic medical exams, including a chest x-ray and pulmonary function tests for all workers
- Train employees on correct personal hygiene and work habits to help reduce their risk of exposure
- Store silica -- if it's found in large quantities -- in airtight bins or hoppers
- Make all employees aware of the dangers of breathing silica dust
- Don't smoke -- exposure to both cigarettes and silica dust results in more severe lung disease than exposure to silica alone.
- If sand blasting, use non-crystalline silica material
For the complete report, visit OSHA at http://www.osha.gov/Training/Silicosis.html. Workers and employers can also get a package of free materials on how to prevent silicosis along with a guide for working safely with silica by calling 800-35-NIOSH; select option 2, then option 5.
Centers for Disease Control. Silicosis Mortality, Prevention, and Control -- United States, 1968 -- 2002. April 2005. http://www.cdc.gov/MMWR/preview/mmwrhtml/mm5416a2.htm
New Edition of Lung Disease Data Report Updates Resource With Newest Available Statistics. NIOSH Update July 7, 2003.
Occupational Lung Disease Fact Sheet. American Lung Association.
World Health Organization. Silicosis. May 2000. http://www.who.int/mediacentre/factsheets/fs238/en/
Centers for Disease Control. Silica. http://www.cdc.gov/niosh/topics/silica
Occupational Safety and Health Administration. Protect Yourself: Silicosis. http://www.osha.gov/Publications/silicosis.html