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CAS 1 record

CAS 100-42-5

CAS 100-42-5 matches 1 EU annex record across Annex II–VI of Regulation 1223/2009.

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Chemical identity and properties

PubChem 2D chemical structure for CAS 100-42-5
CAS 100-42-5PubChem CID 7501

Styrene

Styrene is a vinylarene that is benzene carrying a vinyl group. It has been isolated from the benzoin resin produced by Styrax species. It has a role as a mutagen, a mouse metabolite and a plant metabolite. It is a volatile organic compound, a member of styrenes and a vinylarene. — ChEBI

IUPAC name
styrene
Molecular formula
C8H8
Molecular weight
104.15 g/mol
Exact mass
104.062600255 Da
XLogP3
2.9
Topological polar surface area
0.0 Ų
Hydrogen-bond donors
0
Hydrogen-bond acceptors
0
Covalent units
1
Defined stereocentres
0

Also known as

EthenylbenzenePhenylethyleneVinylbenzeneStyrolCinnameneStyrene monomerBenzene, ethenyl-Phenylethene
16 more reported names
StyrolenePhenethyleneVinylbenzolStyroleVinyl benzeneStyropol SOCinnamolStyrenBenzene, vinyl-CinnamenolEthylene, phenyl-VinylbenzenStiroloStyreenVinyl-benzeneNCI-C02200
Open full PubChem recordPubChem annotations3D structure image
External database identifiers

Evidence from additional scientific databases

EMBL-EBI ChEBI
Exact identifier matchCHEBI:27452

styrene

A vinylarene that is benzene carrying a vinyl group. It has been isolated from the benzoin resin produced by Styrax species.

Formula
C8H8
Average mass
104.152 g/mol
Monoisotopic mass
104.06260 Da
Formal charge
0
  • styrenes — is a (CHEBI:26799)
  • vinylarene — is a (CHEBI:51324)
  • volatile organic compound — is a (CHEBI:134179)
  • mutagen — has role (CHEBI:25435)
  • plant metabolite — has role (CHEBI:76924)
  • mouse metabolite — has role (CHEBI:75771)
  • mutagen — has role (CHEBI:25435)
  • plant metabolite — has role (CHEBI:76924)
  • mouse metabolite — has role (CHEBI:75771)
  • styrenes — is a (CHEBI:26799)
  • vinylarene — is a (CHEBI:51324)
  • volatile organic compound — is a (CHEBI:134179)
Additional curated names
styreneethenylbenzenephenylethenePhenylethyleneStyrenStyreneStyrolvinylbenzene
Cross-references from this source
  • CAS: 100-42-5 — NIST Chemistry WebBook
  • CAS: 100-42-5 — KEGG COMPOUND
  • CAS: 100-42-5 — ChemIDplus
  • REGISTRY_NUMBER: 1071236 — Reaxys
  • REGISTRY_NUMBER: 2991 — Gmelin
  • MANUAL_X_REF: c0115 — UM-BBD
  • MANUAL_X_REF: C07083 — KEGG COMPOUND
  • MANUAL_X_REF: C07083 — KEGG COMPOUND
  • MANUAL_X_REF: CPD-1092 — MetaCyc
  • MANUAL_X_REF: HMDB0034240 — HMDB
  • MANUAL_X_REF: Styrene — Wikipedia

Mapped by: Exact CAS cross-reference in the ChEBI compound record. Source updated: 2021-03-05. Retrieved: 2026-08-31. Open source record

NIH PubChem PUG-View
Exact identifier match7501

Attributed physical-property, hazard, environmental and use annotations.

  • First Aid: EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.; SKIN: IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. IMMEDIATELY call a hospital or poison control center even if no symptoms (such as redness or irritation) develop. IMMEDIATELY transport the victim to a hospital for treatment after washing the affected areas.; INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. IMMEDIATELY call a physician and be prepared to transport the victim to a hospital even if no symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop. Provide proper respiratory protection to rescuers entering an unknow Source: CAMEO Chemicals
  • ERG2024, Guide 128P (Styrene monomer, stabilized): General First Aid:; · Call 911 or emergency medical service.; · Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination.; · Move victim to fresh air if it can be done safely.; · Administer oxygen if breathing is difficult.; · If victim is not breathing:; -- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance.; -- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped with a one-way valve or other device).; -- If no pulse detected or no respiratory medical device available, provide continuous compressions. Conduct a pulse check every two minutes or monitor for any signs of spontaneous respirations.; · Remove and isolate contaminated clothing and shoes.; · For minor skin contact, avoid spreading material on unaffected skin.; · In case of contact with substance, remove immediately by flushing skin or eyes with running water for at least 20 minutes.; · For severe burns, immediate medical attention is required.; · Effects of exposure (inhalation, ingestion, Source: Emergency Response Guidebook (ERG)
  • First Aid: (General first aid procedures); Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately.; Skin: Water flush - If this chemical contacts the skin, flush the contaminated skin with water. Where there is evidence of skin irritation, get medical attention.; Breathing: Respiratory support; Swallow: Medical attention immediately - If this chemical has been swallowed, get medical attention immediately. Source: The National Institute for Occupational Safety and Health (NIOSH)
  • Signal: Danger Source: Regulation (EC) No 1272/2008 of the European Parliament and of the Council
  • GHS Hazard Statements: H226: Flammable liquid and vapor [Warning Flammable liquids]; H315: Causes skin irritation [Warning Skin corrosion/irritation]; H319: Causes serious eye irritation [Warning Serious eye damage/eye irritation]; H332: Harmful if inhaled [Warning Acute toxicity, inhalation]; H361d: Suspected of damaging the unborn child [Warning Reproductive toxicity]; H372: Causes damage to organs through prolonged or repeated exposure [Danger Specific target organ toxicity, repeated exposure] Source: Regulation (EC) No 1272/2008 of the European Parliament and of the Council
  • Precautionary Statement Codes: P203, P210, P233, P240, P241, P242, P243, P260, P261, P264, P264+P265, P270, P271, P280, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P317, P318, P319, P321, P332+P317, P337+P317, P362+P364, P370+P378, P403+P235, P405, and P501 (click each P-code to see the statement) Source: Regulation (EC) No 1272/2008 of the European Parliament and of the Council
  • Note: This chemical does not meet GHS hazard criteria for < 0.1% (3 of 6114) of reports. Source: European Chemicals Agency (ECHA)
  • Signal: Danger Source: European Chemicals Agency (ECHA)
  • GHS Hazard Statements: H226 (> 99.9%): Flammable liquid and vapor [Warning Flammable liquids]; H304 (50.6%): May be fatal if swallowed and enters airways [Danger Aspiration hazard]; H315 (> 99.9%): Causes skin irritation [Warning Skin corrosion/irritation]; H319 (99.9%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]; H332 (98%): Harmful if inhaled [Warning Acute toxicity, inhalation]; H335 (52%): May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]; H361 (35.1%): Suspected of damaging fertility or the unborn child [Warning Reproductive toxicity]; H372 (73.8%): Causes damage to organs through prolonged or repeated exposure [Danger Specific target organ toxicity, repeated exposure]; H412 (49%): Harmful to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard] Source: European Chemicals Agency (ECHA)
  • Precautionary Statement Codes: P203, P210, P233, P240, P241, P242, P243, P260, P261, P264, P264+P265, P270, P271, P273, P280, P301+P316, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P317, P318, P319, P321, P331, P332+P317, P337+P317, P362+P364, P370+P378, P403+P233, P403+P235, P405, and P501 (click each P-code to see the statement) Source: European Chemicals Agency (ECHA)
  • ECHA C&L Notifications Summary: Aggregated GHS information provided per 6114 reports by companies from 92 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.; Reported as not meeting GHS hazard criteria per 3 of 6114 reports by companies.; There are 91 notifications provided by 6111 of 6114 reports by companies with hazard statement code(s).; Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website. Source: European Chemicals Agency (ECHA)
  • Signal: Warning Source: European Chemicals Agency (ECHA)
  • GHS Hazard Statements: H226 (100%): Flammable liquid and vapor [Warning Flammable liquids]; H315 (100%): Causes skin irritation [Warning Skin corrosion/irritation]; H319 (100%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]; H332 (100%): Harmful if inhaled [Warning Acute toxicity, inhalation] Source: European Chemicals Agency (ECHA)
  • Precautionary Statement Codes: P210, P233, P240, P241, P242, P243, P261, P264, P264+P265, P271, P280, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P317, P321, P332+P317, P337+P317, P362+P364, P370+P378, P403+P235, and P501 (click each P-code to see the statement) Source: European Chemicals Agency (ECHA)
  • ECHA C&L Notifications Summary: Aggregated GHS information provided per 39 reports by companies from 2 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.; Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website. Source: European Chemicals Agency (ECHA)
  • Health Effects: Styrene causes nervous system depression and may be carcinogenic. Animals studies have also shown that hearing loss and liver damage may occur. (L1831, L1832) Source: Toxin and Toxin Target Database (T3DB)
  • NFPA Health Rating: 2 - Materials that, under emergency conditions, can cause temporary incapacitation or residual injury. Source: Hazardous Substances Data Bank (HSDB)
  • NFPA Fire Rating: 3 - Liquids and solids that can be ignited under almost all ambient temperature conditions. Materials produce hazardous atmospheres with air under almost all ambient temperatures or, though unaffected by ambient temperatures, are readily ignited under almost all conditions. Source: Hazardous Substances Data Bank (HSDB)
  • NFPA Instability Rating: 2 - Materials that readily undergo violent chemical changes at elevated temperatures and pressures. Source: Hazardous Substances Data Bank (HSDB)
  • NFPA Specific Notice: W - No water: Materials that react violently or explosively with water. Source: Hazardous Substances Data Bank (HSDB)
  • Toxicity Summary: IDENTIFICATION AND USE: Styrene is a colorless to yellowish, oily liquid. It is used in the manufacture of plastics, synthetic rubber, and resins, and as an insulator. It is also used as a flavoring agent for ice cream and candy. HUMAN STUDIES: Humans acutely exposed to styrene by inhalation to 800 ppm (3.4 mg/L) for 3 hr experience immediate eye and throat irritation, increased nasal mucous secretion, metallic taste, drowsiness, and vertigo. After test termination, slight muscular weakness, accompanied by inertia and depression were noted. Long-term contact with styrene results in blistering of the skin and development of dermatitis, which is thought to result from defatting of the skin. Effects on the liver (e.g., increased serum bile acid and enhanced activity of plasma enzymes) and reproductive system (e.g., decreased frequency of births and increased frequency of spontaneous abortions in female workers) have been reported. Epidemiologic studies found styrene workers had increased mortality or incidences of lymphohematopoietic cancers (leukaemia or lymphoma or all), with suggestive evidence for pancreatic and esophageal tumors. No adequate human studies are available for styren Source: Hazardous Substances Data Bank (HSDB)
  • Toxicity Summary: Styrene 7,8-oxide, a metabolite of styrene, can form DNA adducts by binding to deoxyguanosine. It is also mutagenic and causes increased frequency of sister chromatid exchange, chromosomal aberrations, micronucleated cells, and DNA strand breaks. (L1831) Source: Toxin and Toxin Target Database (T3DB)
  • Environmental Bioconcentration: BCF ranges of 15-140 and 12-113 were measured in fish for styrene using carp (Cyprinus carpio) which were exposed over an 8-week period to 0.3 and 0.03 mg/L, respectively(1). A BCF of 13.5 was measured in goldfish for styrene(2). According to a classification scheme(3), these measured BCF values suggest the potential for bioconcentration in aquatic organisms is low to high(SRC). Calculated biomagnification factors (BMF) for styrene in water respiring organisms (zooplankton, forage and predatory fish) and air breathing organisms (reptile, amphibian, sea bird, marine mammal, terrestrial herbivore and carnivore, human) were all less than 1(4). [ Source: Hazardous Substances Data Bank (HSDB)
  • Environmental Fate: TERRESTRIAL FATE: Based on a classification scheme(1), an experimental Koc value of 912(2), indicates that styrene is expected to have low mobility in soil(SRC). Volatilization of styrene from moist soil surfaces may be an important fate process(SRC) given a Henry's Law constant of 2.75X10-3 atm-cu m/mole(3). Styrene is expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 6.4 mm Hg at 25 °C(4). In an experimental study using loamy soil, 26% of applied styrene (2 mg/kg) volatilized after 31 days(5); volatilization of styrene from soil surfaces is expected to be slower than in water(6). A 100% of theoretical BOD after 2 weeks using activated sludge in the Japanese MITI test(7) suggests that biodegradation is an important environmental fate process in soil(SRC). Source: Hazardous Substances Data Bank (HSDB)
  • Environmental Fate: AQUATIC FATE: Based on a classification scheme(1), an experimental Koc value of 912(2), indicates that styrene is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon a Henry's Law constant of 2.75X10-3 atm-cu m/mole(4). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 3 hours and 4 days, respectively(SRC). According to a classification scheme(5), measured BCF ranges from 12-140 in carp(6), suggests the potential for bioconcentration in aquatic organisms is high to low(SRC). A 100% of theoretical BOD after 2 weeks using activated sludge in the Japanese MITI test(7) suggests that biodegradation is an important environmental fate process in water(SRC). Source: Hazardous Substances Data Bank (HSDB)
  • Environmental Fate: ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), styrene, which has a vapor pressure of 6.4 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase styrene is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 6.6 hours(SRC), calculated from its rate constant of 5.8X10-11 cu cm/molecule-sec at 25 °C(3). Vapor-phase styrene is also degraded in the atmosphere by reaction with ozone and nitrate radicals; the half-lives for these reactions in air are 24 and 3.7 hours, respectively(4). Styrene does not strongly absorb light at wavelengths above 270 nm(5) and, therefore, is not expected to be susceptible to direct photolysis by sunlight since sunlight consists of wavelengths above 290 nm(SRC). Source: Hazardous Substances Data Bank (HSDB)
  • Consumer Uses: Antioxidant; Fuel agents; Monomers; Binder; Solvent; Adhesion/cohesion promoter; Intermediate; Filler; Not Known or Reasonably Ascertainable; Viscosity modifiers Source: EPA Chemical Data Reporting (CDR)
  • Industry Uses: Plasticizer; Filler; Not Known or Reasonably Ascertainable; Intermediate; Etching agent; Solvent; Other; Monomers; Antioxidant; Fuel agents Source: EPA Chemical Data Reporting (CDR)
  • Uses: Styrene is used predominately in the production of polystyrene plastics and resins. Styrene is also used as an intermediate in the synthesis of materials used for ion exchange resins and to produce copolymers. Source: EPA Hazardous Air Pollutants
  • Sources/Uses: Styrene is used extensively in the manufacture of plastics, rubber, and resins. About 90,000 workers, including those who make boats, tubs and showers, are potentially exposed to styrene. [http://www.osha-slc.gov/SLTC/styrene/] Used to make polystyrene for packaging, insulation for buildings and refrigeration equipment, and disposable cups and containers; Also used in styrene-butadiene rubber, other polymers, and resins to make boats, shower stalls, tires, automotive parts, etc.; [ACGIH] Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
  • Industrial Processes with risk of exposure: Plastic Composites Manufacturing [Category: Industry]; Burning Synthetic Polymers [Category: Burn] Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
  • Activities with risk of exposure: Sculpturing plastics [Category: Hobbies]; Smoking cigarettes [Category: Food & Drugs] Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
  • Uses: Manufacture of plastics; synthetic rubber; resins; insulator. Source: Hazardous Substances Data Bank (HSDB)
  • Uses: Polystyrene; SBR /styrene-butadiene-rubber/, ABS /acrylonitrile-butadiene-styrene/ and SAN /styrene-acrylonitrile/ resins; protective coatings (styrene-butadiene latex; alkyds); styrenated polyesters; rubber-modified polystyrene; copolymer resins; intermediate. Source: Hazardous Substances Data Bank (HSDB)
  • Uses: Reported uses (ppm):; Table: Reported uses (ppm): (Flavor and Extract Manufacturers' Association) [Table#625] Source: Hazardous Substances Data Bank (HSDB)
  • Uses: The major uses for styrene are in plastics, latex paints and coatings, synthetic rubbers, polyesters and styrene-alkyd coatings. The broad spectrum of uses of these products includes construction, packaging, automotive and household goods. Packaging is the single largest application for styrenecontaining resins, particularly foams, used as fillers and cushioning. Construction applications include pipes, fittings, tanks, lighting fixtures and corrosion-resistant products. Household goods include synthetic marble, flooring, disposable tableware and moulded furnishings. Transport applications range from tyres to reinforced plastics and automobile body putty. Source: Hazardous Substances Data Bank (HSDB)
  • Uses: For more Uses (Complete) data for Styrene (6 total), please visit the HSDB record page. Source: Hazardous Substances Data Bank (HSDB)
  • Uses: Styrene is used to make plastics and rubber. It is a precursor to polystyrene and may be found in insulation, fiberglass, plastic pipes, automobile parts, shoes, drinking cups and other food containers, and carpet backing. Low levels of styrene also occur naturally in a variety of foods such as fruits, vegetables, nuts, beverages, and meats. Small amounts of styrene can be transferred to food from styrene-based packaging material. (L1831) Source: Toxin and Toxin Target Database (T3DB)

Mapped by: Existing checksum-valid CAS to unique PubChem CID match. Retrieved: 2026-08-31. Open source record

Scientific classifications and hazard annotations provide context and do not replace the market-specific regulatory decision shown above.

Additional source coverage and match status
SourceResultChecked
EMBL-EBI ChEBIExact match2026-08-31
NIH PubChem PUG-ViewExact match2026-08-31

A recorded no-match is useful evidence that the source was checked; it is not a claim that the substance does not exist elsewhere.

Retrieved from NIH PubChem on 2026-08-31 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

Records for CAS 100-42-5

1 total

How CAS 100-42-5 is used on this site

CAS 100-42-5 is the Chemical Abstracts Service identifier used to pin this page to a specific substance. In the current dataset, 1 EU annex record shares this identifier, which helps you cross-check whether the same substance appears under one regulatory context or several.

Use this page when a supplier specification, SDS or raw-material dossier gives you CAS 100-42-5 and you need to see every linked Annex II–VI record in one place. The entry cards above are the quickest route to concentration limits, warnings, annex placement and product-type conditions.

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A substance identified by CAS 100-42-5 may appear in multiple EU cosmetic regulation annexes when it is subject to different conditions in different contexts. For example, a substance might be restricted under Annex III with specific conditions, and the same CAS might also appear in Annex IV as an approved colorant under separate entry conditions. Each entry must be reviewed individually.

Cross-reference the CAS number against your raw material specification sheets and CoA documents. When a CAS appears in Annex II, verify absence. When it appears in Annex III, verify that concentration limits and product type conditions are met in your formulation. All annex entries sharing this CAS number are listed above.

A CAS number is assigned by the Chemical Abstracts Service (USA) and is globally recognised. An EC number is a European Commission identifier from inventories such as EINECS, ELINCS or the NLP list. Both identifiers may appear in EU cosmetic annex entries. Some substances have both, some have only one, and some older entries may have neither.

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