Methyl Tertiary Butyl Ether (MTBE) Material Safety Data Sheet

Identification

Product Name: Methyl Tertiary Butyl Ether
Synonyms: MTBE, 2-Methoxy-2-methylpropane, Methyl tert-butyl ether
Chemical Formula: C5H12O
Recommended Use: Gasoline additive, octane enhancer
CAS Number: 1634-04-4
Manufacturer: Provided by supplier or distributor
Contact Information: Emergency numbers and address as specified by supplier

Hazard Identification

Hazard Classification: Flammable liquid, acute toxicity (oral, inhalation), carcinogenic potential, eye and skin irritation
Signal Word: Danger
Hazard Statements: Highly flammable liquid and vapor, causes serious eye and skin irritation, may be harmful if swallowed or inhaled, suspected of causing cancer based on animal studies
Precautionary Statements: Keep away from heat and sources of ignition, avoid breathing vapors or mist, wash thoroughly after handling, wear protective gear

Composition / Information on Ingredients

Chemical Name: Methyl Tertiary Butyl Ether
Common Name: MTBE
Concentration: ≥99%
CAS Number: 1634-04-4
Impurities: Trace levels of water, methanol, hydrocarbons; concentrations vary with supplier

First Aid Measures

Inhalation: Move the exposed person to fresh air, maintain breathing, assist with oxygen if available, seek medical attention for symptoms like headache, dizziness, or respiratory irritation
Skin Contact: Remove contaminated clothing, wash skin with soap and water, seek medical attention for persistent irritation
Eye Contact: Rinse immediately with plenty of water for several minutes; remove contact lenses if present and easy to do; continue rinsing and seek medical attention
Ingestion: Do not induce vomiting, rinse mouth with water, seek immediate medical help, never give anything by mouth to an unconscious person

Fire-Fighting Measures

Suitable Extinguishing Media: Use dry chemical, foam, carbon dioxide, or water mist
Specific Hazards: Fire releases toxic vapors such as carbon oxides and potentially explosive peroxides; vapors may form explosive mixtures with air
Protective Equipment for Firefighters: Self-contained breathing apparatus, full protective suit
Special Procedures: Cool containers near fire with water spray; avoid using water jets which can spread fire

Accidental Release Measures

Personal Precautions: Evacuate unnecessary personnel, ventilate area, prevent skin and eye contact, remove all sources of ignition
Environmental Precautions: Prevent entry into sewers or waterways, contain spill with non-combustible absorbents, notify relevant authorities if contamination occurs
Clean-Up Methods: Absorb spill with sand, earth, or suitable material, collect in a chemical waste container, dispose according to regulations

Handling and Storage

Safe Handling: Use with adequate ventilation, ground and bond containers during transfer, keep away from sparks, open flames, or hot surfaces, avoid inhaling vapors
Storage Recommendations: Store in tightly closed, clearly labeled containers in a cool, well-ventilated, flammable-liquid-approved area away from oxidizers, acids, and direct sunlight; maintain proper inventory checks

Exposure Controls and Personal Protection

Occupational Exposure Limits: ACGIH TLV (USA): 50 ppm TWA, OSHA PEL: 1000 ppm TWA
Engineering Controls: Use local exhaust ventilation, explosion-proof equipment, and vapor detectors
Personal Protective Equipment: Chemical splash goggles, flame-resistant gloves, anti-static footwear, flame-retardant clothing, use a NIOSH-approved respirator during high vapor concentrations

Physical and Chemical Properties

Appearance: Clear, colorless liquid
Odor: Strong, aromatic, volatile
Boiling Point: 55.2°C (131.4°F)
Melting Point: -109°C (-164°F)
Flash Point: -27°C (-17°F) closed cup
Explosion Limits: 1.6-8.4% by volume in air
Vapor Pressure: 245 mmHg at 20°C
Vapor Density: 2.55 (air=1)
Solubility: Slightly soluble in water, completely miscible with most organic solvents
Partition Coefficient (log Kow): 1.24
Relative Density: 0.74 at 20°C

Stability and Reactivity

Chemical Stability: Stable under recommended handling and storage; sensitive to light and air over long periods
Hazardous Reactions: Can form peroxides on prolonged exposure to air or with contamination
Incompatible Materials: Strong oxidizers, acids, halogens, alkali metals
Decomposition Products: Carbon monoxide, carbon dioxide, possible peroxides, other organic compounds
Conditions to Avoid: Open flames, heat, sparks, prolonged air exposure

Toxicological Information

Acute Toxicity: Oral LD50 (rat): ~4000 mg/kg; Inhalation LC50 (rat, 4h): >20000 ppm
Routes of Exposure: Inhalation, ingestion, dermal, ocular
Effects of Exposure: Irritation of eyes, skin, respiratory tract; dizziness, nausea, headache, central nervous system depression with high exposure
Chronic Toxicity: Animal studies suggest potential for liver and kidney effects, possible carcinogenicity
Sensitization: Not reported for most workers, but repeated exposure can worsen symptoms

Ecological Information

Aquatic Toxicity: Moderately toxic to aquatic organisms
Persistence and Degradability: Degrades slowly in soil and water, resistant to natural breakdown processes, mobile in groundwater
Bioaccumulation Potential: Low log Kow suggests limited potential, yet MTBE can travel easily through water systems
Mobility: High mobility in soil, risk of contaminating groundwater noted in several spill sites
Other Ecological Effects: Alters taste and odor of potable water at very low concentrations, detected in water supplies after gasoline leaks

Disposal Considerations

Waste Treatment Methods: Collect and package waste for disposal by licensed chemical waste contractors; incinerate or treat in approved facilities
Disposal of Containers: Decontaminate and destroy empty containers, do not reuse, puncture or burn
Local Regulations: Disposal must follow country, regional, or local legal requirements, with documentation of handling

Transport Information

UN Number: 2398
Proper Shipping Name: Methyl tert-butyl ether
Transport Hazard Class: 3 (flammable liquids)
Packing Group: II
Labels Required: Flammable Liquid
Special Precautions: Avoid temperature extremes and rough handling, ship in approved containers, document quantity and emergency contacts

Regulatory Information

OSHA Status: Regulated hazardous material; required safety training for handling
SARA Title III: MTBE is listed under Section 313 (Toxic Release Inventory)
TSCA (USA): Listed
WHMIS (Canada): Class B2, D2A, D2B
Other Regulation: Subject to control under Clean Air Act amendments; groundwater contamination has led to bans or restrictions in some US states and many countries
EU regulations: REACH registered substance; identified as a dangerous substance for environmental and health monitoring
DNEL/PNEC: Derived no effect levels and predicted no effect concentrations reviewed by regulatory agencies