UN/NA Number Reference
DOT Class 6.1 Toxic Substance placard

UN 1251: Methyl vinyl ketone, stabilized

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 1251 is assigned the proper shipping name Methyl vinyl ketone, stabilized in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 6.1 Toxic Substance material, Packing Group I. Required label(s): 6.1, 3.

Packing group indicates the degree of danger within a hazard class: PG I is high danger, PG II medium, PG III low. The proper shipping name, hazard class, UN number, and packing group together form the basic shipping description that must appear on shipping papers and, where required, on the package and placard.

Emergency Response (ERG Guide 131)

Hazards: HIGHLY FLAMMABLE. TOXIC. May be fatal if inhaled, swallowed, or absorbed through skin. Vapors heavier than air.

Fire: Small: dry chemical, CO2, water spray, alcohol-resistant foam. Large: water spray, fog, alcohol-resistant foam.

Spill: Eliminate ignition sources. Do not touch. Stop leak if safe. Use vapor-suppressing foam. Ventilate area.

Chemical and Physical Properties

Methyl vinyl ketone appears as a clear colorless liquid with a pungent odor. Flash point 20 °F. May polymerize with the release of heat under exposure to heat or contamination. Less dense than water. Highly toxic by inhalation. Causes burns to skin, eyes and mucous membranes.

CAS Number: 78-94-4
Molecular Formula: C4H6O
Molecular Weight: 70.09 g/mol
Color / Form: Colorless liquid
Odor: Pungent odor
Boiling Point: 179 F
Melting Point: 20 °F (EPA, 1998)
Flash Point: 20 F
Autoignition: 915 °F (USCG, 1999)
Specific Gravity: 0.8407 to 0.8636
Vapor Pressure: 86 mmHg at 72 F
Vapor Density: 2.41 (heavier than air)
Water Solubility: greater than or equal to 100 mg/mL at 72 F
Log P: 0.117 (estimated)

Regulatory Data

EPCRA TPQ (40 CFR 355)
10 lb

Special Provisions

49 CFR 172.102 special provision codes for this entry: 1, 387, B9, B14, B30, T22, TP2, TP13, TP38, TP44. These codes modify the general requirements (packaging, quantity limits, exceptions) for this specific material. Look up each code in 49 CFR 172.102 for the full text.

Need the full interactive record? Open UN 1251 in the SpillNerd lookup tool for the live database entry with placard graphics, GHS pictograms, full segregation tables, and synonym search. For another material, use the UN number and chemical lookup.

Reference data compiled from the DOT Hazardous Materials Table (49 CFR 172.101), the 2024 Emergency Response Guidebook, and public chemical databases (PubChem, NIOSH, EPA). Always verify the correct shipping description against the current regulation and the manufacturer's SDS Section 14 before shipping.