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Sulfur dioxide																				Related Pages
Synonyms & Trade Names
			Sulfur oxide, Sulfurous acid anhydride, Sulfurous oxide
CAS No.
			7446-09-5
	RTECS No.
			WS4550000
	DOT ID & Guide
			1079 125

FormulaSO2
	Conversion
			1 ppm = 2.62 mg/m3
	IDLH
			100 ppmSee: 7446095

Exposure Limits
			NIOSH RELTWA 2 ppm (5 mg/m3) ST 5 ppm (13 mg/m3)
					OSHA PEL TWA 5 ppm (13 mg/m3) See Appendix G
	Measurement Methods
			**NIOSH** 3800 , 6004;**OSHA** ID104 , ID200
					
					See: NMAM or OSHA Methods
										
Physical Description
			Colorless gas with a characteristic, irritating, pungent odor.
					[Note: A liquid below 14°F. Shipped as a liquefied compressed gas.]													
										
Molecular Weight64.1	
	Boiling Point14°F
	Freezing Point-104°F
	Solubility10%
	Vapor Pressure3.2 atm
	Ionization Potential12.30 eV											
Flash PointNA
	Upper Explosive LimitNA
	Lower Explosive LimitNA
	Relative Gas Density2.26
Nonflammable Gas
Incompatibilities & Reactivities
			Powdered alkali metals (such as sodium & potassium), water, ammonia, zinc, aluminum, brass, copper
					[Note: Reacts with water to form sulfurous acid (H2SO3).]
Exposure Routes
			inhalation, skin and/or eye contact
Symptoms
			irritation eyes, nose, throat; rhinorrhea (discharge of thin nasal mucus); choking, cough; reflex bronchoconstriction; liquid: frostbite
Target Organs
			Eyes, skin, respiratory system
										
Personal Protection/Sanitation
			(See protection codes) **Skin:**Frostbite
							**Eyes:**Frostbite
							**Wash skin:**No recommendation
							**Remove:**When wet or contaminated (liquid)
							**Change:**No recommendation
							**Provide:**Frostbite wash
	First Aid
			(See procedures)**Eye:**Frostbite
							**Skin:**Frostbite
							**Breathing:**Respiratory support
Respirator Recommendations
			**NIOSH****Up to 20 ppm**: (APF = 10) Any chemical cartridge respirator with cartridge(s) providing protection against the compound of concern*(APF = 10) Any supplied-air respirator***Up to 50 ppm**: (APF = 25) Any supplied-air respirator operated in a continuous-flow mode*(APF = 25) Any powered, air-purifying respirator with cartridge(s) providing protection against the compound of concern***Up to 100 ppm**: (APF = 50) Any chemical cartridge respirator with a full facepiece and cartridge(s) providing protection against the compound of concern(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted canister providing protection against the compound of concern(APF = 50) Any powered, air-purifying respirator with a tight-fitting facepiece and cartridge(s) providing protection against the compound of concern*(APF = 50) Any supplied-air respirator that has a tight-fitting facepiece and is operated in a continuous-flow mode*(APF = 50) Any self-contained breathing apparatus with a full facepiece(APF = 50) Any supplied-air respirator with a full facepiece**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 (gas mask) with a chin-style, front- or back-mounted canister providing protection against the compound of concernAny appropriate escape-type, self-contained breathing apparatus
				Important additional information about respirator selection
See also
			INTRODUCTION
					  ICSC CARD: 0074

			
							

			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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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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