Acetic Acid

Classification

Classification shown is for glacial (nearly 100%) acetic acid; household vinegar is a dilute solution and is far less hazardous. Flammable liquid, Category 3; Skin corrosion, Category 1A; Serious eye damage, Category 1

Hazard statements

• H226 Flammable liquid and vapor.
• H314 Causes severe skin burns and eye damage.

Key precautionary statements

• P210 Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
• P240 Ground and bond container and receiving equipment.
• P260 Do not breathe vapors or mist.
• P280 Wear protective gloves, protective clothing, eye protection and face protection.
• P301+P330+P331 IF SWALLOWED: Rinse mouth. Do NOT induce vomiting.
• P303+P361+P353 IF ON SKIN (or hair): Take off immediately all contaminated clothing. Rinse skin with water or shower.
• P305+P351+P338+P310 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing. Immediately call a POISON CENTER or doctor.
• P403+P235 Store in a well-ventilated place. Keep cool.

The OSHA PEL in Table Z-1 is 10 ppm (25 mg/m³) as an 8-hour TWA, with no short-term limit. NIOSH recommends 10 ppm as a 10-hour TWA and a 15 ppm STEL, and the ACGIH TLV is also 10 ppm TWA with a 15 ppm STEL. Cal/OSHA adds a 40 ppm ceiling to its 10 ppm TWA and 15 ppm STEL. The NIOSH IDLH is 50 ppm. NIOSH advises an eyewash where solutions stronger than 5% are used and a quick drench shower above 50%. State OSHA plans may set different limits.

• Appearance: Colorless liquid, or crystals below 62°F (17°C)
• Odor: Sharp, sour, vinegar-like odor
• Molecular weight: 60.1
• Boiling point: 244°F (118°C)
• Freezing point: 62°F (17°C)
• Flash point: 103°F (39°C), Category 3 flammable liquid
• Autoignition temperature: 865°F (463°C)
• Explosive limits: LEL 4.0%, UEL 19.9% (at 200°F)
• Vapor pressure: 11 mmHg
• Specific gravity: 1.05
• Water solubility: Miscible

Inhalation

Vapor irritates the nose, throat and lungs, causing coughing and shortness of breath. High exposure can cause fluid buildup in the lungs (pulmonary edema), a medical emergency that may be delayed.

Skin

Glacial acid causes chemical burns. Repeated contact can darken, thicken and crack the skin, especially on the hands, a form of occupational dermatitis. NIOSH also lists skin sensitization.

Eyes

Vapor causes tearing and irritation; liquid causes burns that can permanently damage the eyes.

Ingestion

Concentrated acid burns the mouth, throat and stomach. Get medical attention immediately.

Target organs

Eyes, skin, respiratory system, teeth

Long-term effects

Repeated exposure can cause chronic bronchitis and erosion of the teeth. NJDOH reports no evidence of cancer or reproductive effects from animal testing.

Gloves

The New Jersey Department of Health lists neoprene and butyl rubber. Check the glove maker's breakthrough data for glacial acid.

Eyes and face

Chemical splash goggles, plus a face shield when pouring or transferring glacial acid.

Respiratory

Use local exhaust ventilation first. Above exposure limits, NIOSH lists respirators with organic vapor cartridges (including full-facepiece and powered air-purifying types) up to 50 ppm. Use a pressure-demand SCBA for emergencies or unknown concentrations.

Clothing

Chemical-resistant clothing for splash risk; NJDOH lists Tychem CPF 4, Responder and TK among suitable suit materials. Remove clothing promptly if wet, because it is both corrosive and flammable.

Store in tightly closed containers in a cool, well-ventilated area approved for flammable and corrosive liquids, away from heat, sparks and flame. Ground and bond containers during transfer and use non-sparking tools.

Glacial acid freezes at 62°F (17°C). Thaw frozen containers slowly in a warm room, never with an open flame. Store separately from oxidizers and bases.

Keep away from

• Strong oxidizers such as chromic acid, nitric acid, sodium peroxide, perchlorates and peroxides
• Strong bases such as sodium hydroxide and potassium hydroxide
• Many metals (corrosion releases flammable hydrogen gas)
• Acetone and ammonium nitrate

• Eliminate all ignition sources and ventilate the area.
• Evacuate unprotected people; vapor is heavier than air.
• Wear goggles, face shield, chemical-resistant gloves and clothing; use respiratory protection for large spills.
• Soak up with dry sand, earth or another inert absorbent using non-sparking tools, and place in closed containers.
• Keep out of drains, sewers and confined spaces.
• For larger spills, refer to ERG Guide 132 (glacial, UN2789) or Guide 153 (10–80% solutions, UN2790).

Suitable extinguishing media

• Dry chemical
• Carbon dioxide (CO₂)
• Alcohol-resistant foam
• Water spray to cool closed containers and disperse vapors

Special hazards

Combustible liquid. Vapor is heavier than air and can explode if ignited in an enclosed space. Containers may explode when heated, and fires produce irritating and toxic 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.
• OSHA Flammable Liquids (29 CFR 1910.106): Category 3 flammable liquid (glacial).
• OSHA Air Contaminants (29 CFR 1910.1000 Table Z-1): PEL 10 ppm TWA.
• CERCLA hazardous substance (40 CFR 302.4): Reportable quantity 5,000 lb (2,270 kg).
• EPCRA Section 302 (40 CFR 355): Not listed as an extremely hazardous substance.
• EPCRA Section 313 / TRI (40 CFR 372.65): Not listed.
• DOT Hazardous Materials (49 CFR 172.101): UN2789 Acetic acid, glacial (or solutions over 80%), Class 8 with subsidiary Class 3, PG II. Solutions of 10–80% ship as UN2790.

• NIOSH Pocket Guide: Acetic acid
• OSHA Occupational Chemical Database: Acetic acid
• NJ Department of Health Hazardous Substance Fact Sheet: Acetic acid
• Safety data sheet: Acetic acid, glacial
• 40 CFR 302.4: CERCLA hazardous substances and reportable quantities