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This document may not reflect OSHA's respirable silica rule published on March 25, 2016.
For more information on the new rule, see OSHA's Final Rule on Respirable Crystalline Silica Page.

Silica (Quartz, Total)

General Description

  • Synonyms: Crystalline quartz (total dust)
  • OSHA IMIS Code Number: S103
  • Chemical Abstracts Service (CAS) Registry Number: 14808-60-7
  • NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: VV7330000

Exposure Limits

Exposure Limit Limit Values HE Codes Health Factors and Target Organs

OSHA Permissible Exposure Limit (PEL) - General Industry See 29 CFR 1910.1000 Table Z-3

30 mg/m3




National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL) (Listed under Crystalline Silica) See Appendix A

0.05 mg/m3 TWA




American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV)

Not established




0.3 mg/m3 TWA



Health Factors

  • National Toxicology Program (NTP) carcinogenic classification: Not listed
  • International Agency for Research on Cancer (IARC) carcinogenic classification: Group 1 (carcinogenic to humans); see also IARC Monograph 100C*
  • U.S. Environmental Protection Agency (EPA) carcinogenic classification: Not listed
  • EPA Inhalation Reference Concentration (RfC): Not established
  • Agency for Toxic Substances and Disease Registry (ATSDR) Inhalation Minimal Risk Level (MRL): Not established
  • NIOSH Immediately Dangerous to Life or Health (IDLH) concentration: Not listed
  • Notes on Other Potential Health Effects and Hazards
    1. Silicosis increases risk of tuberculosis and other respiratory diseases (American Thoracic Society 1997).
    2. Extrapulmonary silicosis has also been found, where lesions spread to the liver, spleen, kidneys, bone marrow, and extrathoracic lymph nodes (IARC 1997).
  • Literature Basis
  • Date Last Revised: 9/6/2012

Monitoring Methods used by OSHA

Primary Laboratory Sampling/Analytical Method (SLC1):

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