Poor Cosmetic Ingredient NOAEL Data GHS Classified

Styrene (Monomer)

INCI: STYRENE

CAS Number
100-42-5
Function
Not used as a direct cosmetic ingredient — present as residual monomer in styrene-based polymers
Safety Rating
POOR

Regulatory Status

🇪🇺 EU Status permitted
🇺🇸 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 55 jurisdictions, use the Substance Compliance tool.

Safety Data

Margin of Safety (MoS)
not established
Dermal Absorption
moderate
Sensitization
low

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 400 mg/kg bw/day oral dog Chronic COSMOS_DB
NOAEL 1000 mg/kg bw/day oral rat Carcinogenicity COSMOS_DB
NOAEL 300 mg/kg bw/day oral mouse Carcinogenicity COSMOS_DB
NOAEL 300 mg/kg bw/day oral rat Developmental COSMOS_DB
NOAEL 500 mg/kg bw/day oral rat Short Term Toxicity COSMOS_DB
NOAEL 500 mg/kg bw/day oral rat Subchronic COSMOS_DB
NOAEL 400 mg/kg bw/day oral rat Subchronic COSMOS_DB
NOAEL 34.6 mg/kg bw/day oral rat Short Term Toxicity COSMOS_DB
NOAEL 2150 mg/kg bw/day oral rat Subchronic COSMOS_DB
NOAEL 464 mg/kg bw/day oral mouse Subchronic 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
flam;flame; excl mark;warn; cancer;health 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.

Expert Verdict

🔴 IARC Group 2A carcinogen. Neurotoxic, ototoxic. Reproductive toxicity concerns. Must not be intentionally added to cosmetic products. Residual levels in copolymers must be controlled and documented

⚠️
Concern Level: High

Regulatory Flags

prop65 eu_banned_cosmetics ifra_fragrance fda_food_additive eu_cosing_listed

Frequently Asked Questions

Is Styrene (Monomer) safe in cosmetics?

🔴 IARC Group 2A carcinogen. Neurotoxic, ototoxic. Reproductive toxicity concerns. Must not be intentionally added to cosmetic products. Residual levels in copolymers must be controlled and documented The EU classifies Styrene (Monomer) as "permitted". Safety rating: POOR. 10 toxicological study endpoint(s) are available in our database.

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 Margin of Safety for Styrene (Monomer)?

not established The Margin of Safety (MoS) is calculated using SCCS methodology. A MoS above 100 is generally considered safe. Use the MoS Calculator tool to calculate MoS for your specific formulation and product category.

What is the NOAEL for Styrene (Monomer)?

The NOAEL (No Observed Adverse Effect Level) for Styrene (Monomer) is 400 mg/kg bw/day based on a Chronic study via oral route in dog. 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.

Compliance Tools

Check Styrene (Monomer) compliance across multiple jurisdictions:

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Ingredient Decoder
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82 Allergen Checker
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Substance Compliance
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MoS Calculator
Calculate Margin of Safety using SCCS methodology
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Heavy Metal Limits
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