Dustbusting can prevent deadly silicosis
Dustbusting can prevent deadly silicosis
Education, simple measures can eliminate risk
More than a million workers are exposed to silica dust on the job every day, and 100,000 of them are at high risk of developing silicosis, a disabling and potentially fatal lung disease.
The good news is that silicosis is 100% preventable. However, 250 workers die from silicosis every year because employers and occupational health providers did not take simple measures to reduce worker exposure to the silica dust. A primary stumbling block is that the dangerous agent seems so common and harmless. It’s just dust, right?
Not if it contains crystalline silica, the second most common mineral in the earth’s crust. Silica dust is most commonly stirred up at construction sites and mines, but just about any other workplace can provide exposure also. Any groundbreaking activity or handling of some silica-containing products can expose workers to dangerous levels of silica dust.
Some common work activities that can expose workers to silica dust include removing paint and rust from buildings, bridges, tanks and other surfaces; cleaning foundry castings; and etching or frosting glass.
Inhaling the crystalline silica can lead to chronic, accelerated, or acute silicosis and is associated with bronchitis and tuberculosis. Some researchers also suspect an association with lung cancer.
NIOSH campaign seeks to reduce risk
The danger of silicosis is getting more attention now as the federal government joins with industry leaders in a campaign called "If It’s Silica, It’s Not Just Dust." The education effort is being conducted jointly by the National Institute for Occupational Safety and Health (NIOSH), the Occupational Safety and Health Administration, the American Lung Association, and the Mine Safety and Health Administration, all based in Washington, DC.
Federal inspectors will distribute silica educational materials when they inspect mines, construction sites, and other affected work sites. NIOSH is staffing a toll-free information line to answer questions about reducing silica exposure, and the agency also is making available a free package of information that includes a guide for working safely with silica. The package includes hard hat stickers reminding workers that silica is more than just dust.
The agencies and concerned industry leaders also are sponsoring a conference in Washington, DC, in March to address silicosis.
Silicosis results when a worker’s lungs are scarred by years of inhaling small particles of crystalline silica, which is quartz, explains Kelly Bailey, CIH, manager of occupational health for Vulcan Materials Company in Birmingham, AL, the country’s largest producer of construction aggregates. With enough scarring, the lung loses elasticity and the ability to transfer gases efficiently, which in turn causes the heart to beat harder to oxygenate the blood. In late-stage silicosis, most victims suffer from heart enlargement and die from heart failure.
The key diagnostic tool is a chest X-ray, along with a comprehensive work history. Bailey cautions that diagnosing dust diseases requires specially trained radiologists. A list of locally available radiologists trained in dust diseases is available from the NIOSH information line.
Routine monitoring should be performed for any workers chronically exposed to silica dust. Since silicosis can take up to 15 years to develop, Bailey cautions that workers must be screened carefully even if a hazard reduction program minimizes current exposure.
"Medical testing reveals cases that arose from exposure years ago, so you have to keep up with it," Bailey says. "And if you see one case of silicosis, you probably have more than one person affected."
There are three types of silicosis. Chronic silicosis usually occurs after 10 years or more of overexposure. Accelerated silicosis results from higher exposures after five to 10 years, and acute silicosis occurs with even higher exposure in as little as a few weeks. Symptoms of silicosis include shortness of breath following exertion, severe cough, fatigue, loss of appetite, chest pains, and fever.
Problem overlooked in some procedures
The vexing part of silicosis is that it does not have to afflict any worker. Significantly reducing a worker’s exposure to crystalline silica can be simple, at least in comparison to the measures necessary to reduce exposure to many other disease-causing agents. Adequate ventilation, filters, and simple housekeeping steps can make all the difference in many workplaces. (For more tips on preventing silica exposure, see story, p. 9.)
"It is realistic to say this problem is totally preventable," Bailey says. "Preventing silicosis depends on good education because the exposure is chronic and doesn’t cause much physical discomfort at the time of the exposure."
Educating workers about the risk of silicosis can be more difficult than warning about other dangers. Employees will readily grasp the idea that a moving saw blade will cut them, but it takes more effort to explain that silica exposure can lead to silicosis many years later. Bailey explains what the results can be and asks the workers if they really want to cart around an oxygen bottle for the rest of their lives.
Prolonged exposure requires testing
A wide range of employers will have workers exposed to crystalline silica, Bailey warns. If the exposure is more than just occasional, a formal testing and hazard reduction program will be necessary. The program begins with testing workers’ exposure with a filter worn on the clothing during the work day to determine how much crystalline silica is present and whether it is small enough to be respirable. Typical sand found at a beach, for instance, is far too large to be respirable.
The testing and hazard reduction steps take awhile, so they are not feasible for just a one-time work activity that involves digging into the earth, for instance, and kicking up a lot of dust. Exposing workers to silica in that situation is not ideal, but Bailey explains that silicosis is unlikely because it results from chronic exposure over years.
On the other hand, there are some work situations in which the silica exposure is so concentrated that silicosis can develop in as little as six months. In sandblasting, for instance, the abrasive agent sometimes is pure crystalline silica that is broken down into even smaller, more respirable particles. Extensive protection is necessary in the form of a protective hood with an air supply.
[Editor’s note: To request a free package of information that includes a guide for working safely with silica and hard hat stickers reminding workers that silica is more than just dust, call the NIOSH silicosis information line at (800) 356-4674.]
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