# NIOSH Pocket Guide to Chemical Hazards
alpha-Methyl styrene | CAS 98-83-9
C6H5C(CH3)=CH2 | RTECS WL5075300
Synonyms & Trade Names AMS, Isopropenyl benzene, 1-Methyl-1-phenylethylene, 2-Phenyl propylene | DOT ID & Guide
Exposure Limits | NIOSH REL: TWA 50 ppm (240 mg/m3) ST 100 ppm (485 mg/m3)
OSHA PEL†: C 100 ppm (480 mg/m3)
IDLH 700 ppm | Conversion 1 ppm = 4.83 mg/m3
Physical Description Colorless liquid with a characteristic odor.
MW: 118.2 | BP: 330°F | FRZ: -10°F | Sol: Insoluble
VP: 2 mmHg | IP: 8.35 eV |  | Sp.Gr: 0.91
Fl.P: 129°F | UEL: 6.1% | LEL: 1.9% |
Class II Combustible Liquid: Fl.P. at or above 100°F and below 140°F.
Incompatibilities & Reactivities Oxidizers, peroxides, halogens, catalysts for vinyl or ionic polymers; aluminum, iron chloride, copper [Note: Usually contains an inhibitor such as tert-butyl catechol.]
Measurement Methods NIOSH 1501; OSHA 7
Personal Protection & Sanitation Skin: Prevent skin contact Eyes: Prevent eye contact Wash skin: When contaminated Remove: When wet or contaminated Change: No recommendation | First Aid (See procedures) Eye: Irrigate immediately Skin: Water flush promptly Breathing: Respiratory support Swallow: Medical attention immediately
Respirator Recommendations NIOSH Up to 500 ppm: (APF = 10) Any chemical cartridge respirator with organic vapor cartridge(s)*/(APF = 10) Any supplied-air respirator* Up to 700 ppm: (APF = 25) Any supplied-air respirator operated in a continuous-flow mode*/(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 = 25) Any powered, air-purifying respirator with 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 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 canister/Any appropriate escape-type, self-contained breathing apparatus
Exposure Routes inhalation, ingestion, skin and/or eye contact
Symptoms Irritation eyes, skin, nose, throat; drowsiness; dermatitis
Target Organs Eyes, skin, respiratory system, central nervous system
See also: INTRODUCTION