Is Styrene (Monomer) safe in cosmetics?
Styrene (Monomer) has a safety rating of "POOR" in our database. EU status: permitted. US status: permitted. 10 toxicological study endpoint(s) are available in our database.
Styrene (Monomer)
Also known as: Ethenylbenzene, Phenylethylene, Vinylbenzene, Benzene, vinyl-, Bulstren K-525-19 (+15 more)
INCI: STYRENE
Styrene (Monomer) (CAS 100-42-5) is a cosmetic cosmetic ingredient functioning as Not used as a direct cosmetic ingredient — present as residual monomer in. NOAEL 0.21 mg/kg bw/day (cross-referenced against ToxValDB ECHA IUCLID); EU Regulation 1223/2009 status: permitted; GHS signal word DANGER. Industrial safety data is also available in the chemical safety database. Same-CAS public records also appear in industrial chemical safety and pharmaceutical data.
View industrial chemical safety profile for CAS 100-42-5 →
Auto-generated CPSR Part A draft with source citations
Cross-Vertical Regulatory Divergence
Styrene (Monomer) is classified GHS Danger (H226, H304, H315, H319, H332, H335, H361, H372) in the chemicals database but is allowed in EU cosmetics.
Source: Cosmetics: ingredients.eu_status; Chemicals: ghs_classifications.signal_word/hazard_statement_code
Function
Not used as a direct cosmetic ingredient — present as residual monomer in styrene-based polymers
Safety Rating
POOR
Chemistry & Identifiers
IUPAC Name
styrene
InChIKey
PPBRXRYQALVLMV-UHFFFAOYSA-N
Regulatory Status
EU EU Status
permitted
US US Status
permitted
US Notes
Not approved as a direct cosmetic ingredient. CIR assessment concluded residual styrene in copolymer products at detectable levels would be substantially below levels of concern
For full compliance data across multiple jurisdictions, use the Substance Compliance tool.
Safety Data
Margin of Safety, dermal absorption, and sensitization profile summaries for Styrene (Monomer).
Calculate MoS for your specific formulation with the MoS Calculator.
Toxicological Studies
10 study endpoints found for Styrene (Monomer). NOAEL (No Observed Adverse Effect Level) values are used to calculate the Margin of Safety per SCCS methodology.
| Endpoint | Value | Route | Species | Study Type | Source |
|---|---|---|---|---|---|
| NOAEL | 21 mg/kg bw/day | oral | rat | Carcinogenicity | COSMOS_DB |
| NOAEL | 25 mg/kg bw/day | oral | rat | Multigeneration Reproductive | COSMOS_DB |
| NOAEL | 34.6 mg/kg bw/day | oral | rat | Short Term Toxicity | COSMOS_DB |
| NOAEL | 36 mg/kg bw/day | oral | mouse | Special Toxicology Study | COSMOS_DB |
| NOAEL | 100 mg/kg bw/day | oral | rat | Neurotoxicity | COSMOS_DB |
| NOAEL | 114 mg/kg bw/day | oral | guinea pig | Special Toxicology Study | COSMOS_DB |
| NOAEL | 229 mg/kg bw/day | oral | rat | Special Toxicology Study | COSMOS_DB |
| NOAEL | 250 mg/kg bw/day | oral | rat | Carcinogenicity | COSMOS_DB |
| NOAEL | 300 mg/kg bw/day | oral | mouse | Carcinogenicity | COSMOS_DB |
| NOAEL | 357 mg/kg bw/day | oral | rat | Neurotoxicity | COSMOS_DB |
GHS Hazard Classification
Globally Harmonized System classification per ECHA C&L inventory and ILO/WHO International Chemical Safety Cards.
Signal Word
DANGER
Pictograms
FlamFlameExcl markWarnCancerHealth haz
Hazard Statements
Flammable liquid and vapour Harmful if inhaled Causes skin and eye irritation Suspected of causing cancer Causes damage to the central nervous system and the liver through prolonged or repeated exposure Toxic to aquatic life
Short-term Exposure Effects
The substance is irritating to the eyes, skin and respiratory tract. If this liquid is swallowed, aspiration into the lungs may result in chemical pneumonitis. The substance may cause effects on the central nervous system. Exposure at high levels could cause unconsciousness.
Long-term Exposure Effects
The substance defats the skin, which may cause dryness or cracking. The substance may have effects on the central nervous system. Exposure to the substance may increase noise-induced hearing loss. This substance is possibly carcinogenic to humans. See Notes.
Routes of Exposure
The substance can be absorbed into the body by inhalation of its vapour.
Pre-Calculated Safety Assessment
Pre-calculated NOAEL → SED → MoS audit trail for Styrene (Monomer) across SCCS product categories, with measured dermal absorption where available.
EPA ToxValDB — Toxicity Values
10 toxicity values from EPA ToxValDB (aggregated from CCTE, HPV, ToxRefDB, IRIS, and other regulatory dossiers).
| Endpoint | Value | Species | Route | Duration | Source |
|---|---|---|---|---|---|
| LEL | =511.178 mg/m3 | Mouse | inhalation | chronic | EPA TSCA 8e |
| MRL | =21.2991 mg/m3 | Human | inhalation | - | ATSDR MRLs |
| MRL | =0.851963 mg/m3 | Human | inhalation | - | ATSDR MRLs |
| MRL | =0.1 mg/kg-day | Human | oral | - | ATSDR MRLs |
| NOAEL | =217.251 mg/m3 | Human | inhalation | acute | Cal OEHHA REL derivations |
| LEL | =38338.4 mg/m3 | Human | inhalation | - | DOE Protective Action Criteria |
| NOAEL | =12 mg/kg-day | Rat | oral | chronic (developmental) | Health Canada |
| TDI | =0.12 mg/kg-day | Human | oral | chronic (developmental) | Health Canada |
| LEL | =851.963 mg/m3 | Human | inhalation | acute | NIOSH IDLH |
| LEL | =1601.69 mg/m3 | Human | inhalation | acute | NIOSH IDLH |
IARC Carcinogenicity
International Agency for Research on Cancer (WHO) monograph evaluation.
IARC Group
2A
Volume
60, 82, 121
Evaluation Year
2018
EU CLP Annex VI Harmonized Classification
Legally binding harmonized classification per Regulation (EC) No 1272/2008 (CLP) Annex VI.
Signal Word
Danger
Pictograms
FlammableHealth HazardHarmful / Irritant
Hazard Class and Category
Flam. Liq. 3; Repr. 2; Acute Tox. 4 *; STOT RE 1; Skin Irrit. 2; Eye Irrit. 2
Hazard Statements
- H226 Flammable liquid and vapour
- H361d
- H332 Harmful if inhaled
- H372 (hearing organs)
- H315 Causes skin irritation
- H319 Causes serious eye irritation
Specific Concentration Limits / M-factors
*
Inserted via ATP: ATP06
ECHA REACH Registration
European Chemicals Agency REACH dossier and Substances of Very High Concern listing.
Registration Type
Full
Tonnage Band
1,000,000 - 10,000,000 tonnes
Substance Type
SUBSTANCE
SVHC Candidate
No
Hazard classification: Restricted (Annex XVII)
EU CosIng Annex Listing
European Commission CosIng database Annex references per Regulation (EC) No 1223/2009.
Annex II — Prohibited
Ref: 1575
(EU) 2019/831
CMR: Reprotoxic Cat. 2()
Expanded Jurisdictional Detail
Additional regulatory detail beyond the 7-jurisdiction summary: Saudi SFDA, Korea MFDS, ASEAN ACD, Japan/Korea, Brazil/India, and cross-jurisdictional restriction entries.
SA Saudi SFDA (II - Prohibited)
ASEAN Cosmetic Directive (II)
Ref: 1575
BRIN Brazil/India Cosmetics
India: Prohibited (GNRAS)
Additional Jurisdictional Restrictions (2)
| Jurisdiction | Status | Max % | Product Type |
|---|---|---|---|
| ID | banned | - | All cosmetic products prohibited |
| ID | banned | 0% | All cosmetic products |
PubChem Annotations
Safety and regulatory annotations from PubChem (NCBI) aggregated sources.
Safety (7)
Carcinogen Classification
2B, possibly carcinogenic to humans. (L135)
Source: Toxin and Toxin Target Database (T3DB)
Carcinogen Classification
Styrene | Group 2A: Probably carcinogenic to humans | Volume 60: (1994) Some Industrial Chemicals | Volume 82: (2002) Some Traditional Herbal Medicines, Some Mycotoxins, Naphthalene and Styrene | Volume 121: (2019) Styrene, Styrene-7,8-oxide, and Quinoline
Source: International Agency for Research on Cancer (IARC)
Carcinogen Classification
Styrene | TR-185: Bioassay of Styrene for Possible Carcinogenicity (CASRN 100-42-5) (1979 ) | 10/25/78 | No Evidence | No Evidence | Equivocal Evidence | No Evidence | The findings of an increased incidence of a combination of adenomas and carcinomas of the lung provided suggestive evidence for the carcinogenicity of styrene in male B6C3F1 mice. However, it is concluded that, under the co
Source: NTP Technical Reports
Evidence for Carcinogenicity
Styrene is reasonably anticipated to be a human carcinogen based on limited evidence of carcinogenicity from studies in humans, sufficient evidence of carcinogenicity from studies in experimental animals, and supporting data on mechanisms of carcinogenesis. | Evaluation: There is limited evidence in humans for the carcinogenicity of styrene. There is limited evidence in experimental animals for th
Source: Hazardous Substances Data Bank (HSDB)
Endocrine Disruptors
Potential endocrine disrupting compound
Source: NORMAN Suspect List Exchange
Regulatory (1)
JECFA Evaluation
STYRENE | 1984 | The available data indicate that styrene may have carcinogenic activity in mice; however, styrene has not demonstrated carcinogenic activity in rats or in humans. On the basis of the lack of evidence of carcinogenicity from epidemiology studies, the Committee considered it appropriate to establish a PMTDI of 0.04 mg/kg bw/d for styrene based on the NOEL of 7.7 mg/kg bw/d from a 2-
Source: Joint FAO/WHO Expert Committee on Food Additives (JECFA)
Function Categories & List Membership
Cosmetic/Chemical Function Categories
Binder
Flavouring and nutrient
Fragrance
Monomers
Viscosity modifier
Regulatory List Membership (6)
California Proposition 65 (OEHHA)
EU Banned in Cosmetics
IFRA Fragrance Transparency List
FDA Substances Added to Food (EAFUS)
Consumer Product Chemical
EU CosIng Cosmetics Ingredient Database
Expert Verdict
Expert safety assessment and concern-level summary for Styrene (Monomer).
Regulatory Flags
prop65
eu_banned_cosmetics
ifra_fragrance
fda_food_additive
eu_cosing_listed
NOAEL Studies Summary
View details ->Public NOAEL study rows linked to Styrene (Monomer) by CAS number or substance name.
Studies
49
Lowest NOAEL
2 mg/kg bw/day
Highest NOAEL
1350 mg/kg bw/day
COSMOS_DB
ECHA_REACH_reach_study_results_dossiers_23-05-2023.zip
Known Synonyms
Ethenylbenzene
Phenylethylene
Vinylbenzene
Benzene, vinyl-
Bulstren K-525-19
EINECS 202-851-5
Ethylene, phenyl-
FEMA No. 3233
FEMA Number 3234
NCI-C02200
Stirolo
Styreen
Vinylbenzen
UNII-44LJ2U959V
Cinnamenol
Cinnaminol
Cinnamol
Ethenyl-Benzene
Ethenylbenzene, 9CI
Phenyl-Ethylene
Chemical Function
Fragrance
Viscosity modifier
Flavouring and nutrient
Binder
Regulatory Lists
air; detected; emissions; Europe; Other direct contact consumer goods
Arts and crafts/Office supplies - general arts and crafts supplies - arts and crafts paint; detected; Europe
drinking_water; Europe; manufacturing; plastic_additive
inert_ingredient; non_food_use; Pesticides
Arts and crafts/Office supplies - fabric treatment and dye; detected
air; Arts and crafts/Office supplies - fabric treatment and dye; Arts and crafts/Office supplies - home office - pens and markers; detected; emissions; Europe
Arts and crafts/Office supplies - fabric treatment and dye; detected; Europe
air; detected; emissions; Europe; Toys and children's products
CEDI
OEHHA Proposition 65 (3/2019)
detected; Europe; Toys and children's products
detected; Europe; Toys and children's products
detected; Europe; Toys and children's products
detected; Europe; Toys and children's products
detected; Europe; Toys and children's products
detected; Europe; Toys and children's products
air; detected; emissions; Europe; Other direct contact consumer goods
air; emissions; Europe; nondetect; Other direct contact consumer goods
Australian Status
AICIS status: listed
Cross-Vertical Safety Context
Same-CAS public records found in pharmaceutical data.
SOURCE
ChEMBL / DrugCentral / FAERS
DB_PHARMA CAS match
Pharmaceutical Data
Same-CAS rows from the pharmaceutical spoke database.
Compound
STYRENE
ChEMBL ID
CHEMBL285235
Frequently Asked Questions
Is Styrene (Monomer) allowed in the EU?
Styrene (Monomer) EU regulatory status: permitted. This is based on EU Regulation 1223/2009 and its amendments.
What does Styrene (Monomer) do in cosmetics?
Styrene (Monomer) functions as: Not used as a direct cosmetic ingredient — present as residual monomer in styrene-based polymers. It is classified as a cosmetic ingredient in our database. CAS number: 100-42-5.
What is the NOAEL for Styrene (Monomer)?
The NOAEL (No Observed Adverse Effect Level) for Styrene (Monomer) is 21 mg/kg bw/day based on a Carcinogenicity study via oral route in rat. A total of 10 study endpoints are available. Source: COSMOS_DB.
Is Styrene (Monomer) classified as hazardous under GHS?
Styrene (Monomer) carries a GHS signal word of "DANGER". Hazard statements: Flammable liquid and vapour Harmful if inhaled Causes skin and eye irritation Suspected of causing cancer Causes damage to the central nervous system and the liver through prolonged or repeated exposure Toxic to aquatic life. This classification is based on the ILO/WHO International Chemical Safety Card and ECHA C&L inventory data. Note: GHS classification applies to the pure substance — at cosmetic use concentrations, hazard thresholds may not be met.
Is Styrene (Monomer) used outside cosmetics?
Styrene (Monomer) also appears in industrial chemical safety and pharmaceutical data. The cross-vertical cards on this page render same-CAS public rows from the matched databases.
Does Styrene (Monomer) have different safety status in cosmetics vs industrial chemicals?
Styrene (Monomer) is classified GHS Danger (H226, H304, H315, H319, H332, H335, H361, H372) in the chemicals database but is allowed in EU cosmetics.
Compliance Tools
Check Styrene (Monomer) compliance across multiple jurisdictions:
Ingredient Decoder
Paste a full ingredient list for instant analysis
82 Allergen Checker
Check for EU declarable fragrance allergens
Substance Compliance
Check compliance across multiple jurisdictions
MoS Calculator
Calculate Margin of Safety using SCCS methodology
Heavy Metal Limits
Compare limits across jurisdictions
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