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        Syndicate





Silica, amorphous																				Related Pages
Synonyms & Trade Names
			Diatomaceous earth, Diatomaceous silica, Diatomite, Precipitated amorphous silica, Silica gel, Silicon dioxide (amorphous)
CAS No.
			7631-86-9
	RTECS No.
			VV7310000
	DOT ID & Guide

FormulaSiO2
	Conversion
	IDLH
			3000 mg/m3See: 7631869

Exposure Limits
			NIOSH RELTWA 6 mg/m3OSHA PEL TWA 20 mppcf (80 mg/m3/%SiO2) See Appendix C (Mineral Dusts) See Appendix G
	Measurement Methods
			**NIOSH** 7501
					
					See: NMAM or OSHA Methods
										
Physical Description
			Transparent to gray, odorless powder.
					[Note: Amorphous silica is the non-crystalline form of SiO2.]													
										
Molecular Weight60.1	
	Boiling Point4046°F
	Melting Point3110°F
	SolubilityInsoluble
	Vapor Pressure0 mmHg (approx)
	Ionization PotentialNA											
Specific Gravity2.20	
	Flash PointNA
	Upper Explosive LimitNA
	Lower Explosive LimitNA
Noncombustible Solid
Incompatibilities & Reactivities
			Fluorine, oxygen difluoride, chlorine trifluoride
Exposure Routes
			inhalation, skin and/or eye contact
Symptoms
			irritation eyes, pneumoconiosis
Target Organs
			Eyes, respiratory system
										
Personal Protection/Sanitation
			(See protection codes) **Skin:**No recommendation
							**Eyes:**No recommendation
							**Wash skin:**No recommendation
							**Remove:**No recommendation
							**Change:**No recommendation
	First Aid
			(See procedures)**Eye:**Irrigate immediately
							**Breathing:**Fresh air
Respirator Recommendations
			**NIOSH****Up to 30 mg/m3**: (APF = 5) Any quarter-mask respirator. Click here for information on selection of N, R, or P filters.**Up to 60 mg/m3**: (APF = 10) Any particulate respirator equipped with an N95, R95, or P95 filter (including N95, R95, and P95 filtering facepieces) except quarter-mask respirators. The following filters may also be used: N99, R99, P99, N100, R100, P100. Click here for information on selection of N, R, or P filters.(APF = 10) Any supplied-air respirator**Up to 150 mg/m3**: (APF = 25) Any supplied-air respirator operated in a continuous-flow mode(APF = 25) Any powered, air-purifying respirator with a high-efficiency particulate filter.**Up to 300 mg/m3**:(APF = 50) Any air-purifying, full-facepiece respirator with an N100, R100, or P100 filter. Click here for information on selection of N, R, or P filters.(APF = 50) Any supplied-air respirator that has a tight-fitting facepiece and is operated in a continuous-flow mode(APF = 50) Any powered, air-purifying respirator with a tight-fitting facepiece and a high-efficiency particulate filter(APF = 50) Any self-contained breathing apparatus with a full facepiece(APF = 50) Any supplied-air respirator with a full facepiece**Up to 3000 mg/m3**: (APF = 1000) Any supplied-air respirator operated in a pressure-demand or other positive-pressure mode**Emergency or planned entry into unknown concentrations or IDLH conditions:** (APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus**Escape:**(APF = 50) Any air-purifying, full-facepiece respirator with an N100, R100, or P100 filter. Click here for information on selection of N, R, or P filters.Any appropriate escape-type, self-contained breathing apparatus
					Important additional information about respirator selection
See also
			INTRODUCTION

			
							

			Page last reviewed:  October 30, 2019						Content
							source: 	National Institute for Occupational Safety and Health NIOSH Pocket Guide to Chemical Hazards
Introduction
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Chemical Names, Synonyms and Trade Names
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Appendices
A – NIOSH Potential Occupational Carcinogens
B – Thirteen OSHA-Regulated Carcinogens
C – Supplementary Exposure Limits
D – Substances with No Established RELs
E – OSHA Respirator Requirements for Selected Chemicals
F – Miscellaneous Notes
G – 1989 Air Contaminants Update Project: Exposure Limits NOT in Effect
Type C & CE – Definitions for Type C and Type CE Respirators
Personal Protection and Sanitation Codes
First Aid Procedures Follow NIOSH Facebook
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