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Mesityl oxide																				Related Pages
Synonyms & Trade Names
			Isobutenyl methyl ketone, Isopropylideneacetone, Methyl isobutenyl ketone, 4-Methyl-3-penten-2-one
CAS No.
			141-79-7
	RTECS No.
			SB4200000
	DOT ID & Guide
			1229 129

Formula(CH3)2C=CHCOCH3
	Conversion
			1 ppm = 4.02 mg/m3
	IDLH
			1400 ppm [10%LEL]See: 141797

Exposure Limits
			NIOSH RELTWA 10 ppm (40 mg/m3)
					OSHA PEL TWA 25 ppm (100 mg/m3) See Appendix G
	Measurement Methods
			**NIOSH** 1301 , 2553;**OSHA** 7
					
					See: NMAM or OSHA Methods
										
Physical Description
			Oily, colorless to light-yellow liquid with a peppermint- or honey-like odor.													
										
Molecular Weight98.2	
	Boiling Point266°F
	Freezing Point-52°F
	Solubility3%
	Vapor Pressure9 mmHg
	Ionization Potential9.08 eV											
Specific Gravity(59°F): 0.86	
	Flash Point87°F
	Upper Explosive Limit7.2%
	Lower Explosive Limit1.4%
Class IC Flammable Liquid: Fl.P. at or above 73°F and below 100°F.
Incompatibilities & Reactivities
			Oxidizers, acids
Exposure Routes
			inhalation, ingestion, skin and/or eye contact
Symptoms
			irritation eyes, skin, mucous membrane; narcosis, coma; In Animals: liver, kidney damage; central nervous system effects
Target Organs
			Eyes, skin, respiratory system, central nervous system, liver, kidneys
										
Personal Protection/Sanitation
			(See protection codes) **Skin:**Prevent skin contact
							**Eyes:**Prevent eye contact
							**Wash skin:**When contaminated
							**Remove:**When wet (flammable)
							**Change:**No recommendation
							**Provide:**Quick drench
	First Aid
			(See procedures)**Eye:**Irrigate immediately
							**Skin:**Water flush immediately
							**Breathing:**Respiratory support
							**Swallow:**Medical attention immediately
Respirator Recommendations
			**NIOSH****Up to 250 ppm**: (APF = 25) Any supplied-air respirator operated in a continuous-flow mode£(APF = 25) Any powered, air-purifying respirator with organic vapor cartridge(s)£**Up to 500 ppm**: (APF = 50) Any chemical cartridge respirator with a full facepiece and organic vapor cartridge(s)(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister(APF = 50) Any powered, air-purifying respirator with a tight-fitting facepiece and organic vapor cartridge(s)£(APF = 50) Any self-contained breathing apparatus with a full facepiece(APF = 50) Any supplied-air respirator with a full facepiece**Up to 1400 ppm**: (APF = 2000) Any supplied-air respirator that has a full facepiece and is 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 (gas mask) with a chin-style, front- or back-mounted organic vapor canisterAny appropriate escape-type, self-contained breathing apparatus
				Important additional information about respirator selection
See also
			INTRODUCTION
					  ICSC CARD: 0814

			
							

			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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