Adverse Effects of Crystalline Silica Exposure

Details

• Personal Author:
  Abraham J ; Beckett W ; Becklake M ; Christiani D ; Cowie R ; Davis G ; Jones, Richard ; Kreiss, Kathleen ; Parker J ; Wagner G
• Description:
  In the absence of effective specific treatment for silica-related diseases, the only approach remains primary prevention, i.e., control of exposure to respirable silica. Public awareness of the hazards of silica is currently low in many countries, including the United States, and improved preventive and educational measures are needed. Many workers and employers have not heard of silicosis and are unaware of how it is acquired. Prevention involves anticipation that a hazardous exposure might occur, the evaluation of the circumstances leading to exposure to crystalline silica, and the use of effective controls. Proved methods of control include engineering controls such as dust suppression, process isolation, and ventilation; administrative controls include substitution of alternative abrasives in blasting; and, as a temporary and last resort, the use of personal respiratory protection. Education plays a critical role in alerting employers and workers to the potential for a problem, selection of appropriate workplace controls, and in assisting ongoing surveillance efforts. Education should begin in vocational programs for high risk occupations (such as apprenticeship programs for heavy equipment operators) and continue at the work site as part of training for hazardous jobs and ongoing prevention programs. Yet in the absence of a comprehensive preventive effort, education alone may not be effective. Because of the widespread presence of naturally found silica containing minerals, it is not practicable to label silica everywhere it occurs. It may, however, be practicable to label equipment designed to cut and drill rock, and to set industrywide standards for work practices (such as those currently in operation for exposure to coal dust in coal mining). High-risk materials (such as ground silica for industrial use and other respirable forms of crystalline silica) should always be labeled with easily comprehended messages as to the hazard. In many cases, safer materials can be substituted for silica-containing materials. Because silica sandblasting has been such a persistently high-risk occupation, and because alternative abrasive materials without silica are in wide use, available, and of equivalent cost, restricting the use of silica-containing abrasives for abrasive blasting is strongly recommended. Reporting of all cases of silicosis is a legal responsibility of physicians in many countries, states, and provinces, and active investigation of all cases may be important in detecting workplaces with excessive exposures. In the United States, the appropriate agency to which to report new cases is usually the local Health Department. If ongoing overexposure is suspected in others at the same workplace, a health inspection by the local office of the federal or state Occupational Safety and Health Administration may be requested by the physician. In addition, a health hazard evaluation by NIOSH may be requested by workers or employers. The technology to control silica dust exposure is simple and relatively inexpensive. In mining, cutting, and drilling, the addition of water to the cutting surface effectively reduces dust levels in the breathing air of those working nearby. Where a dry process is necessary, enclosures or local exhaust ventilation can be designed to carry dust to a filtering apparatus where it can be recycled or disposed of safely. Although they are the least efficacious preventive measure, industrial respirators may effectively lower individual exposures. The use of respirators requires that silica levels in the air have been measured to establish what type of respirator is needed to provide effective protection. Respirators with a variety of protection factors appropriate to progressively higher air levels of silica dust have been certified by NIOSH laboratories in conditions of inadequately controlled air levels. Physicians who certify workers for respirator use should be aware of the kind of device to be used in determining whether the individual can perform the requirements of the job both without and with the respirator. The paucity of scientific investigation of exposure-response relationships is striking for an occupational disease with such worldwide morbidity and mortality. The conflicting exposure response estimates in the literature point to the need of further study of groups whose exposures have been well-characterized and who are followed up after they have left the silica-exposed industries as a basis for reconsideration of existing standards. Such research will provide a better scientific basis for establishing preventive exposure regulations. Under circumstances where preventive approaches do not succeed, a better understanding of the biologic mechanisms involved in causing and sustaining silicosis may also lead to effective means of halting or slowing the progression of established disease in the future. [Description provided by NIOSH]
• Subjects:
  Lung Lung Diseases Neoplasms Occupational Health Respiratory System Respiratory Tract Diseases Safety Silicon Dioxide Tuberculosis
• Keywords:
  Bronchitis Crystalline Silica Lung Cancer Mycobacterium Pneumonia Silicosis TB
• ISSN:
  1073-449X
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  DRDS - Division of Respiratory Disease Studies
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  155
• Issue:
  2
• NIOSHTIC Number:
  nn:20052405
• Citation:
  Am J Respir Crit Care Med 1997 Feb; 155(2):761-765
• Federal Fiscal Year:
  1997
• Peer Reviewed:
  True
• Source Full Name:
  American Journal of Respiratory and Critical Care Medicine
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:f8db19f74c522d50f00a68ddbde8ebe5807dd8ec81020cbe568a0398640be99d8b5bc83ad83ce5094e5d41918b2b8693403e1bf90d6ca58653fbe655a0e9344f
• Download URL:
  https://stacks.cdc.gov/view/cdc/211933/cdc_211933_DS1.pdf
• File Type:
  [PDF - 1.05 MB ]