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Silicosis Among Pottery Workers -- New Jersey

In March 1985, two cases of silicosis in former employees of a sanitary-ware pottery (i.e., a manufacturer of china plumbing fixtures) were identified from death certificates by the New Jersey State Department of Health (NJSDH). A site visit to the pottery in January 1987 revealed potential overexposure of employees to crystalline silica throughout the plant. This report summarizes the investigation of employee exposure to silica.

During June 1988, CDC's National Institute for Occupational Safety and Health (NIOSH) and the NJSDH conducted a joint study at this facility to assess both crystalline silica exposures and the adequacy of control measures (1). Forty-seven percent of personal breathing-zone samples exceeded the Occupational Safety and Health Administration's (OSHA) permissible exposure limit (PEL) of 100 ug/m3 for crystalline silica; 53% exceeded the NIOSH recommended exposure limit (REL) of 50 ug/m3. Based on these findings, specific engineering controls and work practices were recommended to reduce exposures and prevent additional cases of silicosis.

During October 1988, NJSDH conducted an on-site medical screening of all 120 pottery employees and obtained employee medical and work histories, chest radiographs, and spirometry. The radiographs were evaluated by three NIOSH-certified "B" readers * (2). Radiographs of five (4%) current employees who were not previously known to have pneumoconiosis had readings of 1/0 or greater, generally regarded as positive for pneumoconiosis (3). Based on these findings, the company agreed to institute a surveillance program to continue medical monitoring of all plant employees.

During October 1988, a follow-up environmental survey by NJSDH to assess the extent of compliance with the recommended controls and work practices determined that, although the company had implemented many of these recommendations, some problems persisted. For example, respirator use remained sporadic despite documentation of substantial exposures to crystalline silica dust throughout the plant. NJSDH recommended that a comprehensive respirator program be vigorously enforced until these exposure levels are reduced below the NIOSH REL through appropriate engineering controls and work practices.

Reported by: D Valiante, MS, P Bost, MS, M Stanbury, MS, J Szenics, MD, Occupational Health Svc, New Jersey State Dept of Health. Div of Physical Sciences and Engineering, National Institute for Occupational Safety and Health, CDC.

Editorial Note

Editorial Note: Since 1984, the NJSDH has conducted surveillance of silicosis under several NIOSH Capacity Building Programs (4). This surveillance system uses both morbidity (i.e., hospital discharge) and mortality (i.e., death certificate) data to identify cases of silicosis. In addition, NJSDH participates in the Sentinel Event Notification System for Occupational Risks (SENSOR) program for surveillance of occupational asthma and silicosis, which includes physician reporting of cases of silicosis and combines surveillance with retrospective investigation (5). In conjunction with the SENSOR program, NIOSH has published surveillance guidelines for state health departments to use in promoting physicians' recognition and reporting of silicosis (6).

The sanitary-ware pottery industry is classified under standard industrial classification (SIC) 3261 -- vitreous china plumbing fixtures and china and earthenware fittings and bathroom accessories. In the United States, 34 manufacturing facilities have a primary SIC of 3261 (7); located in 14 states, half are concentrated in three states -- California, Ohio, and Texas. ** Of an estimated 6400 persons employed in this industry, approximately 4300 have occupational exposure to crystalline silica (NIOSH, unpublished data, 1991). In New Jersey, the predominant industries in which persons with silicosis have worked include sand and gravel mines, foundries, and ceramics (both china and sanitary ware).

Persons with silicosis are at substantially increased risk for other pulmonary diseases, particularly tuberculosis, bronchitis, and emphysema (8). In the United States, each year approximately 250 workers are reported with (9) and 135 die from silicosis (10).

The investigation described in this report underscores the potential health hazards associated with the use of crystalline silica in manufacturing sanitary ware. Assessments of similar facilities have detected the same problems and conditions (i.e., use of raw materials high in crystalline silica content, poor or inadequate ventilation to control dust sources, poor housekeeping practices, and lack of effective respiratory-protection programs for workers). Full implementation of recommended control measures should reduce the risk for silicosis among workers in this industry.


  1. Caplan PE, Cooper TC, Crouch KG, et al. Sentinel Event Notification System for Occupational Risks (SENSOR): recommendations for control of silica exposure. Cincinnati: US Department of Health and Human Services, Public Health Service, CDC, June 1989; ECTB report no. 171-11b.

  2. International Labour Office Committee on Pneumoconiosis. Classification of radiographs of the pneumoconioses. Med Radiogr Photogr 1981;57:2-17.

  3. Morgan RH. Radiology. In: Merchant JA, Boehlecke BA, Taylor G, Pickett-Harner M, eds. Occupational respiratory disease. Morgantown, West Virginia: US Department of Health and Human Services, Public Health Service, CDC, 1986; DHHS publication no. (NIOSH)86-102.

  4. Valiante DJ, Rosenman KD. Does silicosis still occur? JAMA 1989;262:3003-7.

  5. Baker EL. Sentinel Event Notification System for Occupational Risks (SENSOR): the concept. Am J Public Health 1989;79(suppl):18-20.

  6. CDC. Silicosis: cluster in sandblasters -- Texas, and occupational surveillance for silicosis. MMWR 1990;39:433-7.

  7. Dun and Bradstreet. Dun's market inventory (DMI). New York: Dun and Bradstreet Corporation, 1990.

  8. Peters JM. Silicosis. In: Merchant JA, Boehlecke BA, Taylor G, Pickett-Harner M, eds. Occupational respiratory disease. Morgantown, West Virginia: US Department of Health and Human Services, Public Health Service, CDC, 1986; DHHS publication no. (NIOSH)86-102.

  9. US Department of Labor. An interim report to Congress on occupational diseases. Washington, DC: US Department of Labor, 1980.

  10. NCHS. Health, United States, 1988. Hyattsville, Maryland: US Department of Health and Human Services, Public Health Service, CDC, 1989; DHHS publication no. (PHS)89-1232.

    • A physician certified by NIOSH to interpret chest radiographs to detect pneumoconiosis using the 1980 International Labour Office guidelines. ** This listing appears to be incomplete because it does not include the pottery in this report.

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