# NIOSH Pocket Guide to Chemical Hazards
Styrene | CAS 100-42-5
C6H5CH=CH2 | RTECS WL3675000
Synonyms & Trade Names Ethenyl benzene, Phenylethylene, Styrene monomer, Styrol, Vinyl benzene | DOT ID & Guide 2055 128P (inhibited)
Exposure Limits | NIOSH REL: TWA 50 ppm (215 mg/m3) ST 100 ppm (425 mg/m3)
OSHA PEL†: TWA 100 ppm C 200 ppm 600 ppm (5-minute maximum peak in any 3 hours)
IDLH 700 ppm | Conversion 1 ppm = 4.26 mg/m3
Physical Description Colorless to yellow, oily liquid with a sweet, floral odor.
MW: 104.2 | BP: 293°F | FRZ: -23°F | Sol: 0.03%
VP: 5 mmHg | IP: 8.40 eV |  | Sp.Gr: 0.91
Fl.P: 88°F | UEL: 6.8% | LEL: 0.9% |
Class IC Flammable Liquid: Fl.P. at or above 73°F and below 100°F.
Incompatibilities & Reactivities Oxidizers, catalysts for vinyl polymers, peroxides, strong acids, aluminum chloride [Note: May polymerize if contaminated or subjected to heat. Usually contains an inhibitor such as tert-butylcatechol.]
Measurement Methods NIOSH 1501, 3800; OSHA 9, 89
Personal Protection & Sanitation Skin: Prevent skin contact Eyes: Prevent eye contact Wash skin: When contaminated Remove: When wet (flammable) Change: No recommendation | First Aid (See procedures) Eye: Irrigate immediately Skin: Water flush 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, skin absorption, ingestion, skin and/or eye contact
Symptoms Irritation eyes, nose, respiratory system; headache, lassitude (weakness, exhaustion), dizziness, confusion, malaise (vague feeling of discomfort), drowsiness, unsteady gait; narcosis; defatting dermatitis; possible liver injury; reproductive effects
Target Organs Eyes, skin, respiratory system, central nervous system, liver, reproductive system
See also: INTRODUCTION