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Chemical Sampling Information (CSI)
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General Description

Synonyms: Diatomaceous earth; Diatomaceous silica; Diatomite; Silicon dioxide (amorphous); Vitreous silica

OSHA IMIS Code Number: 9050
IMIS Name History: Silica (amorphous) prior to 9/1/89

Chemical Abstracts Service (CAS) Registry Number: 7631-86-9 (Silica, Amorphous); 7699-41-4 (Silica, Gel); 60676-86-0 (Vitreous silica); 61790-53-2 (Diatomaceous earth (uncalcined)); 68855-54-9 (Flux-calcined diatomaceous earth); 112926-00-8 (Precipitated silica; silica gel); 112945-52-5 (Pyrogenic (fumed) amorphous silica)

NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: VV7310000

NIOSH Pocket Guide to Chemical Hazards, Silica, Amorphous: chemical description, physical properties, potentially hazardous incompatibilities, and more

Exposure Limits

OSHA Permissible Exposure Limit (PEL):
General Industry: 29 CFR 1910.1000 Z-3 Table -- 20 mppcf, 80 mg/m3/%SiO2 TWA (PEL listed under Silica, Amorphous, including natural diatomaceous earth)

Construction Industry: 29 CFR 1926.55 Appendix A -- 20 mppcf TWA (PEL listed under Silica, Cristobalite, Amorphous, including natural diatomaceous earth)

Maritime: 29 CFR 1915.1000 Table Z-Shipyards - Mineral Dusts -- 20 mppcf TWA (PEL listed under Silica, Cristobalite, Amorphous, including natural diatomaceous earth)
National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL): 6 mg/m3 TWA; Appendix C - Supplementary Exposure Limits (Mineral Dusts)

Health Factors

Carcinogenic Classification:
International Agency for Research on Cancer (IARC): Group 3, not classifiable as to its carcinogenicity to humans [71 KB PDF, 24 pages]
NIOSH Immediately Dangerous To Life or Health Concentration (IDLH): 3,000 mg/m3

Potential Symptoms: Pneumoconiosis

Health Effects: Possible Pneumoconiosis (HE10)

Affected Organs: Respiratory system
Monitoring Methods used by OSHA

Laboratory Sampling/Analytical Method:
  • note: See Particulates not otherwise regulated (Total Dust)
    note: Amorphous Silica does not diffract x-rays; evaluate gravimetically. Submit respirable sample to SLTC for quartz analysis. See Silica, Crystalline Quartz (as Quartz), Respirable Dust.

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Page last updated: 12/08/2006

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