Methyl Ethyl Ketone

Classification

Flammable liquid, Category 2; Eye irritation, Category 2A; STOT single exposure, Category 3 (central nervous system: drowsiness or dizziness)

Hazard statements

• H225 Highly flammable liquid and vapor.
• H319 Causes serious eye irritation.
• H336 May cause drowsiness or dizziness.

Key precautionary statements

• P210 Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
• P233 Keep container tightly closed.
• P240 Ground and bond container and receiving equipment.
• P241 Use explosion-proof electrical, ventilating and lighting equipment.
• P261 Avoid breathing vapors.
• P280 Wear protective gloves, protective clothing, eye protection and face protection.
• P305+P351+P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
• P403+P235 Store in a well-ventilated place. Keep cool.

The federal OSHA permissible exposure limit is 200 ppm (590 mg/m³) as an 8-hour TWA, from Table Z-1, with no short-term limit. NIOSH recommends 200 ppm as a 10-hour TWA plus a 300 ppm STEL, and the ACGIH TLV is 200 ppm TWA with a 300 ppm STEL. Cal/OSHA also adds a 300 ppm STEL. ACGIH publishes a biological exposure index for MEK. The IDLH is 3000 ppm. Skin contact can add to the total dose even when air levels are below the limits. State OSHA plans may set different limits.

• Appearance: Colorless liquid
• Odor: Sharp, sweet, mint- or acetone-like odor; it is a close chemical relative of acetone
• Molecular weight: 72.1
• Boiling point: 175°F (79°C)
• Freezing point: -123°F (-86°C)
• Flash point: 16°F (-9°C), Class IB flammable liquid
• Autoignition temperature: 961°F (516°C)
• Explosive limits: LEL 1.4%, UEL 11.4% (measured at 200°F)
• Vapor pressure: 78 mmHg
• Vapor density: 2.42 (heavier than air)
• Specific gravity: 0.81 (floats on water)
• Water solubility: 28% (quite soluble)

Inhalation

Irritates the nose and throat. Higher levels cause headache, dizziness, nausea, vomiting, blurred vision and lightheadedness, and can lead to fainting.

Skin

Can cause redness or a burning feeling. Repeated contact strips natural oils, leaving skin dry and cracked (dermatitis).

Eyes

Vapor and splashes cause serious eye irritation; a direct splash can injure the eye.

Ingestion

Swallowing causes nausea and vomiting along with nervous system effects. Get medical attention immediately.

Target organs

Eyes, skin, respiratory system, central nervous system

Long-term effects

Repeated high exposure may affect the nervous system, a typical pattern of organic solvent exposure. MEK is known to make the nerve damage caused by n-hexane worse, so mixed exposures deserve extra care. The New Jersey Department of Health notes limited animal evidence of harm to the developing fetus.

Gloves

Butyl rubber is the recommended material; one supplier SDS reports more than 290 minutes of breakthrough time for 0.3 mm butyl gloves. Nitrile and latex hold up poorly against ketones. Check the glove maker's permeation data.

Eyes and face

Indirect-vent chemical splash goggles; add a face shield for large transfers. Provide an eyewash.

Respiratory

Rely on local exhaust ventilation first. Above exposure limits, NIOSH lists air-purifying respirators with organic vapor cartridges or canisters up to 3000 ppm. Use a pressure-demand SCBA for emergencies or unknown concentrations, as part of a written respiratory protection program.

Clothing

Solvent-resistant clothing where splashes are likely. Remove clothing promptly if wet, because it is flammable, and wash skin when contaminated.

Store in tightly closed containers in a flammable-liquid cabinet or approved flammables area that is cool and well ventilated, away from heat, sparks and flame.

Ground and bond metal containers during transfer, use non-sparking tools and explosion-proof equipment, and keep containers closed when not in use. Vapors are heavier than air and collect in low spots.

Keep away from

• Strong oxidizers (such as peroxides, nitrates, perchlorates, chlorine and bromine)
• Amines and ammonia
• Inorganic acids and caustics
• Isocyanates and pyridines
• Chloroform

• Eliminate all ignition sources and ventilate the area.
• Evacuate unprotected people until cleanup is complete; vapors can travel to an ignition source and flash back.
• Use spark-proof tools and explosion-proof equipment.
• Absorb with vermiculite, dry sand, earth or another inert material and place in sealed containers for disposal.
• Keep out of sewers, drains and confined spaces because of explosion risk.
• Waste may need to be handled as hazardous waste (RCRA U159).
• For larger spills, refer to ERG Guide 127.

Suitable extinguishing media

• Alcohol-resistant foam
• Dry chemical
• Carbon dioxide (CO₂)
• Water spray to cool fire-exposed containers (water may not put out the fire)

Special hazards

Highly flammable, with a flash point well below room temperature. Vapors are heavier than air and can flash back from a distant ignition source. Containers may explode in a fire, and burning releases poisonous gases. Firefighters should wear SCBA and full protective gear.

• OSHA Hazard Communication (29 CFR 1910.1200): Hazardous chemical; labels, safety data sheets and worker training required (see HazCom).
• OSHA Flammable Liquids (29 CFR 1910.106): Class IB flammable liquid.
• OSHA Air Contaminants (29 CFR 1910.1000 Table Z-1): 200 ppm (590 mg/m³) TWA.
• CERCLA hazardous substance (40 CFR 302.4): Reportable quantity 5,000 lb; RCRA waste code U159.
• EPCRA Section 302 (40 CFR 355): Not listed as an extremely hazardous substance.
• EPCRA Section 313 / TRI: Removed from the TRI list in 2005 (70 FR 37698, June 30, 2005).
• Clean Air Act: Removed from the hazardous air pollutant list in 2005 (70 FR 75047, December 19, 2005); not listed under the 112(r) Risk Management Program.
• DOT Hazardous Materials (49 CFR 172.101): UN1193, Class 3, PG II.

• NIOSH Pocket Guide: 2-Butanone (MEK)
• OSHA Occupational Chemical Database: 2-Butanone
• NJ Department of Health Hazardous Substance Fact Sheet: Methyl Ethyl Ketone
• NOAA CAMEO Chemicals: Methyl Ethyl Ketone
• Sigma-Aldrich SDS: 2-Butanone
• EPA TRI Program: Methyl ethyl ketone deletion
• Federal Register: Removal of MEK from the HAP list (70 FR 75047)