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cristobalite from occupational sources is carcinogenic to humans (Group 1).” The IARC evaluation noted that
“carcinogenicity was not detected in all industrial circumstances studies. Carcinogenicity may be dependent on
inherent characteristics of the crystalline silica or on external factors affecting its biological activity or distribution
of it polymorphs.” For further information on the IARC evaluation, see IARC Monographs on the Evaluation of
Carcinogenic Risks to Humans, Volume 68, “Silica, Some Silicates…” (1997).
NTP: The National Toxicology Program, in its Ninth Annual Report on Carcinogens, classified “silica,
crystalline (respirable)” as a known human carcinogen.
OSHA: Crystalline silica (quartz) is not regulated by the US Occupational Safety and Health
Administration as a carcinogen.
There have been many articles published on the carcinogenicity of crystalline silica, which the reader should consult
for additional information. The following are examples of recently published articles:
“Crystalline Silica and Lung Cancer: The Problem of Conflicting Evidence”, Indoor Built Environ, Volume
8, pp.121-126 (1998);
Crystalline Silica and the Risk of Lung Cancer on the Potteries”, Occup. Environ. Med., Volume 55,
pp.779-785 (1998);
Is Silicosis Required for Silica-Associated Lung Cancer?” American Journal of Industrial Medicine,
Volume 37, pp. 252-259 (2000);
Silica, Silicosis, and Lung Cancer: A Risk Assessment”, American Journal of Industrial Medicine, Volume
38, pp. 8-18 (2000);
Silica, Silicosis, and Lung Cancer: A Response to a Recent Working Group Report”, Journal of
Occupational and Environmental Medicine, Volume 42, pp. 704-720 (2000).
Autoimmune Diseases: There is evidence that exposure to respirable crystalline silica (without silicosis) or that the
disease silicosis is associated with the increased incidence of several autoimmune disorders, --scleroderma, systemic
lupus erythematosus, rheumatoid arthritis and diseases affecting the kidneys. For a review of the subject, the
following may be consulted:
Occupational Exposure to Crystalline Silica and Autoimmune Disease”, Environmental Health
Prospectives Volume 107, Supplement 5, pp. 793-802 (1999);
Occupational Scleroderma”, Current Opinion in Rheumatology, Volume 11, pp. 490-494 (1999).
Tuberculosis: Individuals with silicosis are at increased risk to develop pulmonary tuberculosis, if exposed to
persons with tuberculosis. The following may be consulted for further information:
Occupational Lung Disorders, Third Edition, Chapter 12, entitled “Silicosis and Related Diseases”, Parkes,
w. Raymond (1994);
Risk of pulmonary tuberculosis relative to silicosis and exposure to silica dust in South African gold
miners,” Occup. Environ. Med., Volume 55, pp. 496-502 (1998).
Kidney Disease: There is evidence that exposure to respirable crystalline silica (without silicosis) or that the disease
silicosis is associated with the increased incidence of kidney diseases, including end stage renal disease. For
additional information on the subject, the following may be consulted:
“Kidney Disease and Silicosis”, Nephron, Volume 85, pp. 14-19 (2000).
XII. ECOLOGICAL INFORMATION
Crystalline silica (quartz) is not known to be ecotoxic; i.e., there is no data that suggests that crystalline silica
(quartz) is toxic to birds, fish, invertebrates, microorganisms or plants. For additional information on crystalline
silica (quartz), see Sections 9 (physical and chemical properties) and 10 (stability and reactivity) of this MSDS.
XIII. DISPOSAL CONSIDERATIONS
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