Yi-Chun Lin
Yi-Chun LinPh.D.Taiwan
Laser Materials Processing
Published
Dec 24, 2025

Styrene (C₈H₈)

Chemical Properties

Chemical Identity

CAS Number
100-42-5
Formula
C₈H₈
Molecular Weight
104.15 g/mol

Exposure Limits Comparison

OSHA PEL
100 ppm
NIOSH REL
50 ppm
ACGIH TLV
20 ppm

Health Effects

Respiratory Irritation
Yes
Neurological Effects
Yes
Reproductive Toxicity
Yes
Suspected Carcinogen
Yes

Styrene (C₈H₈) safety information

Comprehensive safety and handling requirements

Detection Monitoring
Sensor Types
  • Photoionization detector (PID)
  • Flame ionization detector (FID)
  • Infrared
Detection Range0-200 ppm typical
Alarm Setpoints
Low20 ppm (ACGIH TLV)
High50 ppm (NIOSH REL)
Evacuate700 ppm (NIOSH IDLH)
Colorimetric Tubes
  • Dräger Styrene 1/a
  • Gastec 132
Analytical Methods
MethodTechniqueDetection Limit
NIOSH 1501GC-FID0.005 ppm
OSHA Method 89GC-FID0.01 ppm
Odor Threshold0.05-0.5 ppm - WARNING: Olfactory fatigue occurs. Cannot rely on odor for protection.
Environmental Impact
Aquatic ToxicityToxic to aquatic life. LC50 (fish, 96h): 4-10 mg/L.
BiodegradabilityReadily biodegradable (>60% in 28 days).
BioaccumulationModerate bioaccumulation potential. BCF: 25-150. Log Kow: 2.95.
Soil MobilityModerate mobility. Adsorbs to soil organic matter. Volatilizes from soil.
Atmospheric FatePhotolyzes via hydroxyl radicals. Atmospheric half-life: 1-2 days. Forms ozone.
Ozone Depletionfalse
Reportable Releases
Water1000 lbs to navigable waters
Air1000 lbs/day (CERCLA RQ)
Ppe Requirements
RespiratoryNIOSH-approved organic vapor respirator for <50 ppm. SCBA for >50 ppm or unknown concentrations.
Eye ProtectionChemical safety goggles, face shield for splash hazard.
Skin ProtectionNitrile or butyl rubber gloves. Chemical-resistant clothing. Styrene absorbs through skin.
Reactivity
StabilityUNSTABLE. Polymerizes when heated or contaminated. Inhibitor required.
PolymerizationExothermic polymerization with peroxides, oxidizers, or heat. May be explosive. Check inhibitor level.
Incompatible Materials
  • Oxidizers
  • Peroxides
  • Strong acids
  • Aluminum chloride
  • Copper
  • Brass
  • Iron compounds
  • Sulfuric acid
Hazardous Decomposition
  • Carbon monoxide
  • Carbon dioxide
  • Toxic styrene vapors
  • Benzene
Conditions To Avoid
  • Heat
  • Light
  • Oxidizers
  • Peroxides
  • Contamination
  • Sparks
  • Flames
Reactivity HazardMay polymerize violently. Reacts with oxidizers. Attacks some plastics, rubber, and coatings. Forms peroxides on prolonged storage.
Regulatory Classification
Un NumberUN2055 (monomer, stabilized)
Dot Hazard Class3 (Flammable liquid)
Dot LabelFlammable Liquid
Nfpa Codes
Health2
Flammability3
Reactivity2
Epa Hazard Categories
  • Flammability
  • Acute toxicity
  • Carcinogenicity (probable)
  • Neurotoxicity
  • Aquatic toxicity
Sara Title Iiitrue
Cercla Rq1000 pounds (454 kg)
Storage Requirements
Temperature RangeStore below 32°C. Keep cool. Avoid excessive heat.
VentilationLocal exhaust ventilation. Mechanical ventilation with emergency backup.
Incompatibilities
  • Oxidizers
  • Peroxides
  • Strong acids
  • Aluminum chloride
  • Copper
  • Brass
  • Iron
Container MaterialStainless steel or aluminum. Must contain inhibitor (tert-butylcatechol). Check inhibitor level regularly.
SegregationSeparate from oxidizers by 20 feet. Flammable liquid storage cabinet.
Quantity LimitsMinimize quantities. Follow NFPA 30 for flammable liquids.
Special RequirementsCRITICAL: Store with polymerization inhibitor (10-15 ppm tert-butylcatechol). Monitor inhibitor level monthly. Avoid light and heat. Post "FLAMMABLE" and "CANCER HAZARD" signs. Date containers.

Produced From Contaminants

Z-Beam Logo
Z-Beam Logo

Produced From Materials

Ceramic Matrix Composites CMCs
Epoxy Resin Composites
Fiberglass
Metal Matrix Composites MMCs
Phenolic Resin Composites
Polyester Resin Composites
Urethane Composites

Exposure Limits

Regulatory exposure thresholds and safe concentration levels

Osha Pel Ppm
100
Osha Pel Mg M3
425
Niosh Rel Ppm
50
Niosh Rel Mg M3
215
Acgih Tlv Ppm
20
Acgih Tlv Mg M3
85
Workplace Exposure
Osha Pel
twa_8hr: 100 ppm (425 mg/m³)
stel_15min: 200 ppm (850 mg/m³)
ceiling: null
Niosh Rel
twa_8hr: 50 ppm (215 mg/m³)
stel_15min: 100 ppm (425 mg/m³)
ceiling: null
idlh: 700 ppm
Acgih Tlv
twa_8hr: 20 ppm
stel_15min: 40 ppm
ceiling: null
Biological Exposure Indices
0: [object Object]
1: [object Object]

Physical Properties

Physical characteristics and state information

Boiling Point
145°C (293°F)
Melting Point
-30.6°C (-23°F)
Vapor Pressure
5 mmHg @ 20°C
Vapor Density
3.6 (Air=1)
Specific Gravity
0.906
Flash Point
31°C (88°F) closed cup
Autoignition Temp
490°C (914°F)
Explosive Limits
LEL: 1.1%, UEL: 6.1%
Appearance
Colorless to yellowish oily liquid
Odor
Sweet, floral odor @ 0.05-0.5 ppm (odor fatigue occurs)

Reactivity

Chemical reactivity and compatibility with other substances

Stability
UNSTABLE. Polymerizes when heated or contaminated. Inhibitor required.
Polymerization
Exothermic polymerization with peroxides, oxidizers, or heat. May be explosive. Check inhibitor level.
Incompatible Materials
  • Oxidizers
  • Peroxides
  • Strong acids
  • Aluminum chloride
  • Copper
  • Brass
  • Iron compounds
  • Sulfuric acid
Hazardous Decomposition
  • Carbon monoxide
  • Carbon dioxide
  • Toxic styrene vapors
  • Benzene
Conditions To Avoid
  • Heat
  • Light
  • Oxidizers
  • Peroxides
  • Contamination
  • Sparks
  • Flames
Reactivity Hazard
May polymerize violently. Reacts with oxidizers. Attacks some plastics, rubber, and coatings. Forms peroxides on prolonged storage.

Synonyms & Identifiers

Alternative names and chemical identifiers (CAS numbers)

Synonyms
  • Vinyl benzene
  • Phenylethylene
  • Cinnamene
  • Styrol
  • Ethenylbenzene
Common Trade Names
    Other Identifiers
    Rtecs Number
    WL3675000
    Ec Number
    202-851-5
    Pubchem Cid
    7501