NIOSH Publication No. 2005-151:

NIOSH Pocket Guide to Chemical Hazards

September 2005

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 See: 98839
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 100F and below 140F.
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
See: NMAM or OSHA Methods
Personal Protection & Sanitation
(See protection)
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
Important additional information about respirator selection
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   See ICSC CARD: 0732   See MEDICAL TESTS: 0257