UN/NA Number Reference
DOT Class 2.1 Flammable Gas placard

UN 1083: Trimethylamine, anhydrous

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 1083 is assigned the proper shipping name Trimethylamine, anhydrous in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 2.1 Flammable Gas material. Required label(s): 2.1.

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 118)

Hazards: Flammable. May be ignited by heat, sparks, flames. Corrosive. Causes burns to skin and eyes.

Fire: Use dry chemical, CO2, or water spray. Do not use water jet. Cool containers with flooding water.

Spill: Stop leak if safe. Use water spray to reduce vapor. Prevent runoff to waterways.

Chemical and Physical Properties

Trimethylamine, anhydrous appears as a colorless gas with a fishlike odor at low concentrations changing to ammonia-like odor at higher concentrations. Shipped as a liquid under its own vapor pressure. Contact with the unconfined liquid can cause frostbite from evaporative cooling or chemical type burns. The gasis corrosive and dissolves in water to form flammable, corrosive solutions. Gas is an asphyxiate by the displacement of air. Produces toxic oxides of nitrogen during combustion. Prolonged exposure to heat can cause the containers to rupture violently and rocket. Long-term inhalation of low concentrations or short -term inhalation of high concentrations has adverse health effects.

CAS Number: 75-50-3
Molecular Formula: C3H9N
Molecular Weight: 59.11 g/mol
Color / Form: Colorless gas at room temperature
Odor: Pungent, fishy, ammoniacal
Boiling Point: 37.2 F
Melting Point: -178.8 °F (USCG, 1999)
Flash Point: Not Applicable. Gas.
Autoignition: 374 °F (USCG, 1999)
Specific Gravity: 0.633 (floats on water)
Vapor Pressure: 1487.83 mmHg at 70 F
Vapor Density: 2 (heavier than air)
Water Solubility: 48 % at 86 F
Log P: log Kow = 0.16
pH: Strong base

Regulatory Data

CERCLA RQ (40 CFR 302.4)
100 lb
OSHA PEL
none
NIOSH REL
TWA 10 ppm (24 mg/m 3 ) ST 15 ppm (36 mg/m 3 )
IDLH
N

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: N87, T50. 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 1083 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.