UN/NA Number Reference
DOT Class 3 Flammable Liquid placard

UN 1261: Nitromethane

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 1261 is assigned the proper shipping name Nitromethane in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 3 Flammable Liquid material, Packing Group II. Required label(s): 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 129)

Hazards: Flammable. Irritating vapor. May cause dizziness. Toxic if inhaled or absorbed through skin.

Fire: Alcohol-resistant foam, dry chemical, CO2, water spray.

Spill: Eliminate ignition sources. Ventilate area. Absorb with earth or sand.

Chemical and Physical Properties

Nitromethane appears as a colorless oily liquid. Flash point 95 °F. May violently decompose if intensely heated when contaminated. Denser than water and slightly soluble in water. Hence sinks in water. Vapors are heavier than air. Moderately toxic. Produces toxic oxides of nitrogen during combustion.

CAS Number: 75-52-5
Molecular Formula: CH3NO2
Molecular Weight: 61.040 g/mol
Color / Form: Colorless liquid
Odor: Moderately strong, somewhat disagreeable odor
Boiling Point: 214.2 F
Melting Point: -20 °F (NTP, 1992)
Flash Point: 95 F
Autoignition: 785 °F (USCG, 1999)
Specific Gravity: 1.139 (sinks in water)
Vapor Pressure: 27.8 mmHg at 68 F
Vapor Density: 2.11 (heavier than air)
Water Solubility: greater than or equal to 100 mg/mL at 68 F
Log P: low Kow = -0.35
pH: pH of 0.01M aqueous solution = 6.12

Regulatory Data

OSHA PEL
TWA 100 ppm (250 mg/m 3 )
NIOSH REL
See Appendix D
IDLH
750 ppm

Need the full interactive record? Open UN 1261 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.