Exposure to Silica Dust. Proper Medical Diagnosis is the Key
Each year may cases of silicosis are misdiagnosed because physicians are unaware of their patent’s work history and unfamiliar with the signs associated with this occupational illness. As a result, these cases go unreported. Without proper diagnosis and reporting, workers cannot receive suitable medial treatment and advice.
“What Physicians Need to Know about Silicosis in Construction”
The following Physician’s Alert document was developed to help ensure that all construction workers at risk of developing silicosis are properly diagnosed, and that cases of silicosis are documented and reported to the appropriate state health agencies.
Please read and print out the following letter and the attached “Physician’s Alert” document. Give them both to your doctor for your medical records.
All Construction Workers are at Risk of Developing Silicosis:
Many construction workers are at risk of being exposed to crystalline silica dust through their work, or because they work in areas where this dust is being produced. Crystalline silica is found in brick, concrete products, stone, rock and abrasives. The dust is released from these materials through dry cutting, grinding, chipping, blasting and sweeping. Many trades perform these tasks and are at a high risk of being made ill by the dust many years after initial exposure. Trades affected include, but are not limited to: masonry and stone workers, abrasive blasters, laborers, painters, operating engineers, plasterers, plumbers and truck drivers.
Exposure to crystalline silica dust can result in serious illnesses – even death. Workers that breathe in crystalline silica dust are at an increased risk of developing silicosis (a respiratory lung disease), tuberculosis and lung cancer. Although most cases of silicosis are found in older workers and retirees, silicosis related deaths have been documented in workers as young as age 30.
Unfortunately, many cases of silicosis are misdiagnosed because physicians are unaware of their patient’s work history and unfamiliar with the signs associated with this occupational illness. As a result, cases go unreported. Without proper diagnosis and reporting, workers cannot receive suitable medical treatment and advice. In addition, silicosis is a disease that is compensational in some states. Therefore, workers with silicosis may be entitled to workers’ compensation depending on the state they are in.
Attached is a Physician’s Alert entitled “What Physicians Need to Know about Silicosis in Construction, Demolition and Renovation Workers.” The New Jersey Department of Health, with input from the Center to Protect Workers’ Rights and the building trades unions, developed this alert as part of a project funded by the National Institute for Occupational Safety and Health (NIOSH). It was developed to help ensure that all construction workers at risk of developing silicosis are properly diagnosed, and that cases of silicosis are documented and reported to the appropriate state health agencies.
This Physician’s Alert will only be effective in improving the diagnosis and documentation of silicosis and related illnesses if:
• Workers make their doctor(s) aware of their work history and unique exposure risk.
Workers need to give this alert to their doctor(s), and let them know how they have been exposed to silica dust – construction materials used and tasks performed that may have exposed them to silica dust.
• Doctors become familiar with the information in the attached physician’s alert and emphasize the respiratory system in the worker’s annual physical exam. Medical exams should include: a pulmonary function test (PFT) to look for evidence of respiratory impairment, a baseline PPD skin test for tuberculosis, and chest x-rays (at the frequency recommended in this ‘alert’ or by OSHA in future regulations). It is important that the chest x-rays be read by a certified class “B” reader because silicosis is sometimes confused with sarcoidosis, asbestosis, coal miner’s pneumoconiosis, and other pneumoconiosis. Cases of silicosis should then be reported to the state health department. Doctors should be aware that there is no medical treatment to reverse silicosis. Corticosteroids are not useful to reduce the progression of the disease; however, appropriate treatment for heart failure and tuberculosis should be begun if these complications exist. In addition, because the risk of silicosis increases if a person smokes, all individuals should be strongly advised to stop smoking and offered smoking cessation information and support.
While this Physician’s Alert deals with the proper diagnosis and reporting of silicosis cases, as noted earlier, it is important to understand this is a disease that can be prevented. It is the goal of the International Union of Bricklayers and Allied Craftworkers, as well as all building trades unions to prevent silicosis by eliminating or reducing the risk of exposure through changes in work practices and the use of dust control mechanisms. We are working towards that goal both through the collective bargaining process and better OSHA regulations.
Construction, Demolition, Masonry and Concrete Restoration Workers Are at Risk of Developing Silicosis
Crystalline silica is found in materials, such as those listed below, which are often present during construction, demolition, and renovation projects. When these materials are made into a fine dust by tasks listed below, the inhalation and deposition of these fine particles can produce silicosis over time.
Construction Materials Containing Crystalline Silica:
Blasting abrasives, brick, refractory brick, concrete, concrete block, cement mortar, granite, sandstone, quartzite, slate, gunite, mineral deposits, rock and stone, sand, fill dirt, topsoil, asphalt containing rock or stone.
Tasks Associated with Silica Exposure:
Abrasive blasting using sand or other abrasive containing crystalline silica. Abrasive blasting of concrete. Demolition of concrete and masonry structures. Chipping, cutting, sawing, grinding, drilling, jack hammering concrete, masonry, or mortar. Crushing, loading, hauling, dumping rock, stone, or sand. Gunite spraying. Chipping, hammering, drilling rock. Dry sweeping or pressurized air blocking of concrete, rock, or sand dust.
High Risk Trades and Occupations
Many construction, demolition, and renovation occupations are at risk, including: Abrasive blasters, masonry workers (bricklayers, stone masons), laborers, operating engineers, painters and plasterers, plumbers, and truck drivers.
Other occupations that do not work directly with construction materials or tasks involving silica may be exposed as bystanders if they are in the construction, demolition, or renovation area when crystalline silica containing materials are being used.
Definition and Clinical Features
Silicosis is a diffuse, nodular, interstitial pulmonary fibrosis caused by a tissue reaction to inhaled crystalline silica dust. It can take the acute form under conditions of intense exposure but usually takes the chronic form, requiring several to many years to develop.
People who have silicosis have increased susceptibility to infections such as tuberculosis, complicating the patient’s prognosis. There is also increasing evidence that crystalline silica causes cancer and that the individuals with silicosis are at increased risk of developing lung cancer.
Except in its acute form, silicosis begins with a few, if any, symptoms. When clinical symptoms of silicosis are present, they could include cough and shortness of breath of increasing severity. On physical examination, breath sounds may be normal or distant and, with increased severity, there may be signs of heart failure. Evidence of pathological response to silica exposure exists well before symptoms occur.
Chronic reactions, occurring after 10 or more years from first exposure, involve nodular lesions, (bilateral, multiple, rounded opacities) often more prominent in the upper lobes. In this simple stage of silicosis, nodules are usually small (1 centimeter or less). There may be little effect on pulmonary function at this stage.
Complicated silicosis or progressive massive fibrosis (PMF) also usually develops in the upper lobes but the nodules go on to consolidate and exceed 1 centimeter and encompass blood vessels and airways. Lung function may be severely compromised, often with a mixed restrictive/obstructive pattern, but either pure restriction or obstruction may be seen.
Acute reactions may appear within a few weeks to two years after the onset of massive exposure. The distinguishing feature of acute silicosis is intraalveolar deposits, similar to those seen with alveolar proteinosis. In contrast to the nodular fibrosis seen in the chronic form, diffuse interstitial fibrosis is not found. Silicosis developing in less than 10 years, the accelerated form, has been described most often in sandblasters. In these cases, diffuse fibrosis is likely to develop and may be located throughout all lobes of the lung.
Clinical Signs of Silicosis
Simple: Mild restrictive and/or obstructive defects, small rounded opacities on x-ray. Accelerated: diffuse, small rounded opacities on x-ray, more severe restrictive and/or obstructive defects. Advanced: increased profusion of small opacities and development of large opacities on x-ray, more severe restrictive and/or obstructive defects. Acute: diffuse perihilar alveolar filling process with ground glass opacities on x-ray. Progression of disease and radiographic findings can continue even after exposure has ended.
Recommended Medical Surveillance
The following are recommended by the New Jersey Department of Health and Senior Services as a baseline for exposure, then periodically noted:
1. Occupational history to determine years of exposure-update annually. Inquire about the materials used and tasks performed listed above. In addition, inquire about employment in non-construction industries with silica exposure-foundries, quarries, mining, tile, clay, glass, and cement manufacture.
2. Medical exam emphasizing the respiratory system-annually.
3. Chest x-ray to look for evidence of abnormality. Posteroanterior 14” x 17” or 14” x 14”, classified according to the 1980 Guidelines for the Use of ILO Classification of Radiographs of Pneumoconiosis by a certified class “B” reader, is recommended. The ILO system has the distinct advantage of a standardized set of comparison x-ray films. Names of B-readers are available from NIOSH. Information on how to contact NIOSH is given at the end of section. Recommendations for the frequency of x-rays are given below. NOTE: the potential for excessive x-rays given the multiemployer nature of construction and other possible construction exposures like asbestos for which OSHA may require employers to provide x-rays.
4. Pulmonary Function Tests (PFT) to look for evidence of respiratory impairment. Should include FEVI (forced expiratory volume in I second), FVC (forced vital capacity), and DLCO (diffusion capacity of the lungs) – annually. All PFT should use equipment and follow recommendations issued by the ATS (American Thoracic Society) and be administered by a technician who has successfully completed NIOSH-certified training.
5. A baseline PPD skin test for tuberculosis because people who have silicosis have increased susceptibility. Repeat annually if there is x-ray evidence of silicosis (1/0 or greater profusion category using the ILO classification) or 25 years or longer exposure.
Frequency of Chest X-rays for Silicosis
Every 3-5 years with normal x-ray, low exposure, and less than 20 years exposure. Every 1-3 years with normal x-ray, high exposure, or greater than 20 years exposure. Annually with x-ray evidence of silicosis (lLO 1/0 or greater or ILO results A, B, or C large opacities), massive exposure, or positive PPD test. See NOTE in item 3.
Physicians, radiologists, pathologists and other health care professionals should report cases of silicosis to the health department in their state so that it can be determined whether silica exposures are being controlled at the workplaces where the patient has been employed. Such reporting is mandatory in many states, including New Jersey. (In New Jersey, call 800-772-0062 to report cases or for reporting forms.)
If the state has no occupational health program, cases of concern should be discussed with NIOSH (National Institute for Occupational Safety and Health) or the local OSHA (Occupational Safety and Health Administration) office. Information on how to contact NIOSH and OSHA is given at the end of this bulletin.
The following elements define a case of silicosis for reporting purposes:
A physician’s provisional or working diagnosis of silicosis, or chest x-ray or other imaging technique interpreted as consistent with silicosis, or pathologic findings consistent with silicosis.
Because silicosis is sometimes confused with sarcoidosis, asbestosis, coal miner’s
pneumoconiosis, or other pneumoconiosis it is important that all chest x-rays be reviewed by a B-reader.
Medical Management of Silicosis
There is no known medical treatment to reverse silicosis, therefore prevention is critically important. Removal from exposure may decrease the rate of disease progression. Corticosteroids are not useful to reduce the progression of the disease. Appropriate treatment for heart failure and tuberculosis should be begun if these complications exist. All individuals should be strongly advised to stop smoking and offered smoking cessation information and support. Regular follow up exams to access progression and possibly to screen for lung cancer should be scheduled. Individuals who develop silicosis should be given the option of transfer to silica-free jobs. In order for this to be a realistic alternative, the individual should be able to maintain the same rate of pay and benefits without loss of seniority.
For additional information:
National Institute of Occupational Safety and Health
phone: 1-800-35-NIOSH (1-800-3564674) or (513) 533-8328, fax (513) 533-8573,
Internet site www.cdc.gov/niosh/silicpag.html
CDC/NIOSH Alert, Request for Assistance in Preventing Silicosis and Deaths in Construction Workers, DHHS (NIOSH) Publication No. 96-112, May 1996.
Contains details on case definition, case reports, control measures and 26 references.
Occupational Safety and Health Administration Local
Offices are listed in the government section of the telephone directory, usually under United States Department of Labor or the state Department of Labor.
Internet site www.osha.gov has a directory of all offices.
Or, call the national office for the number of your local office: (202) 219-8151.
American Thoracic Society
Adverse Effects of Crystalline Silica Exposure. American Journal Respiratory and Critical Care Medicine, 1997; 155: 761 -765.
Standardization of Spirometry-1 994 update. American Journal Respiratory and Critical Care Medicine, 1995; 152: 1107-1136.
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