UN/NA Number Reference
DOT Class 3 Flammable Liquid placard

UN 1235: Methylamine, aqueous solution

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 1235 is assigned the proper shipping name Methylamine, aqueous solution 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, 8.

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 132)

Hazards: HIGHLY FLAMMABLE. CORROSIVE. Causes burns. Vapors may form explosive mixture with air.

Fire: Alcohol-resistant foam, dry chemical, CO2. Do not use water jet. Cool containers.

Spill: Eliminate ignition sources. Do not touch. Stop leak if safe. Use foam.

Chemical and Physical Properties

Methylamine, anhydrous appears as a colorless gas or a liquid. Pungent fishy odor resembling odor of ammonia. The liquid boils at cold temperatures, hence it vaporizes rapidly when unconfined. Vapors are heavier than air and may collect in low-lying areas. Easily ignited under most conditions. Under prolonged exposure to intense heat the containers may rupture violently and rocket. Used for making pharmaceuticals, insecticides, paint removers, surfactants, rubber chemicals.

CAS Number: 74-89-5
Molecular Formula: CH5N
Molecular Weight: 31.057 g/mol
Color / Form: Colorless gas [Note: A liquid below 21 degrees F. Shipped as a liquefied compressed gas]
Odor: Fish or ammonia-like odor
Boiling Point: 20.3 °F at 760 mmHg (USCG, 1999)
Melting Point: -134.5 °F (USCG, 1999)
Flash Point: 14 °F (Liquid) (NIOSH, 2024)
Autoignition: 806 °F (USCG, 1999)
Specific Gravity: 0.693 at 20.3 °F (USCG, 1999) - Less dense than water; will float
Vapor Pressure: 1972.92 mmHg at 60 °F (USCG, 1999)
Vapor Density: 1.1 (USCG, 1999) - Heavier than air; will sink (Relative to Air)
Water Solubility: greater than or equal to 100 mg/mL at 70 °F (NTP, 1992)
Log P: -0.57
pH: Stronger base than ammonia

Regulatory Data

CERCLA RQ (40 CFR 302.4)
100 lb
OSHA PEL
TWA 10 ppm (12 mg/m 3 )
NIOSH REL
TWA 10 ppm (12 mg/m 3 )
IDLH
100 ppm

A release of this material at or above its CERCLA reportable quantity (100 lb) requires immediate notification to the National Response Center at 800-424-8802.

Special Provisions

49 CFR 172.102 special provision codes for this entry: B1, IB2, T7, TP1. 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 1235 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.