Styrene

Classification

Flammable liquid, Category 3; Acute toxicity (inhalation), Category 4; Skin irritation, Category 2; Eye irritation, Category 2; Aspiration hazard, Category 1; STOT single exposure, Category 3 (respiratory irritation, drowsiness or dizziness); STOT repeated exposure, Category 1 (hearing organs); Germ cell mutagenicity, Category 2; Carcinogenicity, Category 2. Supplier classifications vary; some also list reproductive toxicity. Check your SDS.

Hazard statements

• H226 Flammable liquid and vapor.
• H304 May be fatal if swallowed and enters airways.
• H315 Causes skin irritation.
• H319 Causes serious eye irritation.
• H332 Harmful if inhaled.
• H335 May cause respiratory irritation.
• H336 May cause drowsiness or dizziness.
• H341 Suspected of causing genetic defects.
• H351 Suspected of causing cancer.
• H372 Causes damage to organs (hearing organs) through prolonged or repeated inhalation.

Key precautionary statements

• P210 Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
• P240 Ground and bond container and receiving equipment.
• P241 Use explosion-proof electrical, ventilating and lighting equipment.
• P260 Do not breathe vapors.
• P280 Wear protective gloves, protective clothing, eye protection and face protection.
• P301+P310 IF SWALLOWED: Immediately call a POISON CENTER or doctor.
• P331 Do NOT induce vomiting.
• P403+P235 Store in a well-ventilated place. Keep cool.

OSHA general industry limits come from Table Z-2: 100 ppm TWA, a 200 ppm ceiling, and a 600 ppm peak allowed for no more than 5 minutes in any 3 hours. NIOSH recommends 50 ppm as a 10-hour TWA with a 100 ppm STEL. The ACGIH TLV is 10 ppm TWA with a 20 ppm STEL, and ACGIH flags styrene as an ototoxicant. Cal/OSHA sets 50 ppm TWA, a 100 ppm STEL and a 500 ppm ceiling, with a skin notation. The NIOSH IDLH is 700 ppm. Open-mold fiberglass work can easily exceed the lower limits, so air monitoring is worthwhile. State OSHA plans may set different limits.

• Appearance: Colorless to yellowish, oily liquid
• Odor: Sweet, floral odor at low levels; sharp and unpleasant at higher levels
• Molecular weight: 104.2
• Boiling point: 293°F (145°C)
• Freezing point: -23°F (-31°C)
• Flash point: 88°F (31°C), Class IC flammable liquid
• Autoignition temperature: 914°F (490°C)
• Explosive limits: LEL 0.9%, UEL 6.8%
• Vapor pressure: 5 mmHg
• Vapor density: 3.6 (air = 1)
• Specific gravity: 0.91 (floats on water)
• Water solubility: 0.03%
• Stability: Shipped with a polymerization inhibitor (commonly tert-butylcatechol); can polymerize if heated, contaminated or if inhibitor or oxygen levels drop

Inhalation

Irritates the eyes, nose and throat. Causes headache, tiredness, dizziness, confusion, unsteadiness and drowsiness; very high levels can cause unconsciousness.

Skin

Irritates the skin; repeated contact removes skin oils and causes dermatitis.

Eyes

Causes serious eye irritation.

Ingestion

If swallowed, the liquid can be breathed into the lungs and cause chemical pneumonia. Do not induce vomiting; get medical attention immediately.

Target organs

Eyes, skin, respiratory system, central nervous system, liver, reproductive system

Long-term effects

Styrene is one of the recognized ototoxic chemicals: repeated exposure can damage hearing, and the effect adds to noise. It can also affect the nervous system and may injure the liver. NIOSH lists reproductive effects among its symptoms. NTP lists styrene as reasonably anticipated to be a human carcinogen, and suppliers classify it as a suspected carcinogen. Its solvent effects are similar to those of toluene and xylene.

Gloves

The New Jersey Department of Health lists Silver Shield/4H, Viton and Barrier gloves, with more than 8 hours of breakthrough time. Styrene attacks natural rubber. See hand protection.

Eyes and face

Chemical splash goggles; add a face shield for large transfers or spray-up work.

Respiratory

Use local exhaust ventilation, closed molding and low-styrene resins where possible. NIOSH lists organic vapor cartridge respirators up to 500 ppm and full-facepiece organic vapor protection or supplied air up to 700 ppm. NJDOH advises a full-facepiece respirator with organic vapor cartridges above 20 ppm and SCBA above 200 ppm. See respiratory protection.

Clothing

Chemical-resistant clothing (for example Tychem F, CPF3, BR, CSM or TK) where splashing is likely. Remove clothing promptly if wet, because it is flammable, and wash skin when contaminated.

Store in tightly closed containers in a cool, well-ventilated flammables area away from heat, sunlight and ignition sources. Styrene can polymerize on its own if it gets warm, is contaminated, or runs low on inhibitor or dissolved oxygen, releasing heat that can rupture containers. Keep stock rotated, and for long-term storage in warm conditions check inhibitor and polymer levels regularly (one manufacturer advises weekly when stored more than 30 days at 90°F/32°C).

Ground and bond containers during transfer, use non-sparking tools and explosion-proof equipment, and control static.

Keep away from

• Oxidizers and peroxides, including hydrogen peroxide and organic peroxide catalysts (except under controlled resin curing)
• Strong acids such as sulfuric acid, nitric acid and hydrochloric acid
• Metal salts such as aluminum chloride and iron chloride
• Rubber, copper and copper alloys, which styrene attacks

• Eliminate all ignition sources and ventilate the area.
• Evacuate unprotected people; isolate at least 50 m (150 ft) for a spill. Vapors are heavier than air and can travel to ignition sources.
• Use spark-proof tools and explosion-proof equipment.
• Absorb with vermiculite, dry sand, earth or another inert material and place in sealed containers for disposal.
• Keep out of drains, sewers and confined spaces; styrene is toxic to aquatic life.
• For larger spills, refer to ERG Guide 128P.

Suitable extinguishing media

• Dry chemical
• Carbon dioxide (CO₂)
• Foam
• Water spray to cool fire-exposed containers (water alone may not put out the fire)

Special hazards

Flammable. Heat from a fire can start runaway polymerization inside containers, causing them to rupture violently. Vapors are heavier than air and can flash back. Fires produce carbon monoxide and carbon dioxide. NJDOH lists a fire isolation distance of 800 m (1/2 mile). Firefighters should wear SCBA and full protective gear.

• OSHA Hazard Communication (29 CFR 1910.1200): Hazardous chemical; labels, safety data sheets and worker training required.
• OSHA Flammable Liquids (29 CFR 1910.106): Class IC flammable liquid.
• OSHA Air Contaminants (29 CFR 1910.1000 Table Z-2): 100 ppm TWA; 200 ppm ceiling; 600 ppm peak (5 minutes in any 3 hours).
• CERCLA hazardous substance (40 CFR 302.4): Reportable quantity 1,000 lb (454 kg).
• EPCRA Section 313 / TRI (40 CFR 372.65): Listed.
• Clean Air Act: Listed as a hazardous air pollutant.
• DOT Hazardous Materials (49 CFR 172.101): UN2055 Styrene monomer, stabilized, Class 3, PG III.

• NIOSH Pocket Guide: Styrene
• OSHA Occupational Chemical Database: Styrene
• NJ Department of Health Hazardous Substance Fact Sheet: Styrene Monomer
• Westlake SDS: Styrene Monomer, Stabilized
• ATSDR Toxicological Profile for Styrene: Regulations and Guidelines