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T-BUTYL METHYL ETHER.

Avoid CAS 1634-04-4 / SOLVENT

T-BUTYL METHYL ETHER, also known as Methyl tert-butyl ether (MTBE), is primarily an industrial solvent and gasoline additive. While sometimes listed as a cosmetic solvent, its application in skincare is highly contraindicated due to its severe toxicity and irritancy profile.

Solvent

Science

On the skin, T-BUTYL METHYL ETHER functions solely as a solvent, offering no recognized beneficial effects. Instead, its direct interaction with skin is associated with irritation and potential systemic toxicity.


Research

Low confidence
Effective range N/A
Optimal

N/A


Transparency

Not commonly dusted

The Formula

Solubility
Both
Optimal pH N/A
0 7 14

Stability

This compound demonstrates robust stability under alkaline, neutral, and weakly acidic conditions, but is susceptible to cleavage by strong acids. Critical safety considerations include its extreme flammability and propensity to form explosive peroxides when exposed to air.

Conflicts

  • Strong oxidizing agents
  • Strong acids
  • Heat
  • Sparks
  • Open flame

Safety

CIR Status
Not reviewed
Sensitization risk Low

T-BUTYL METHYL ETHER is recognized by NIOSH as a skin and eye irritant. Acute dermal exposure did not indicate sensitization, yet eye irritation was transient. Long-term rodent studies have linked exposure to various cancers, leading to its reclassification by the International Agency for Research on Cancer (IARC) in 2025 as Group 2B, indicating possible carcinogenicity in humans. It is also identified as a suspected endocrine disruptor and persistent environmental pollutant. Although currently unregulated in the EU regarding concentration, its comprehensive hazard profile warrants extreme caution.


Your Skin

No Normal
No Dry
No Oily
No Sensitive
Irritancy High
Comedogenicity Unknown

Our Assessment

Avoid

Due to its classification as a probable human carcinogen, suspected endocrine disruptor, and a known irritant, T-BUTYL METHYL ETHER must be avoided in all precision skincare formulations.


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