UN/NA Number Reference
DOT Class 8 Corrosive placard

UN 2491: Ethanolamine or ethanolamine solution

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 2491 is assigned the proper shipping name Ethanolamine or ethanolamine solution in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 8 Corrosive material, Packing Group III. Required label(s): 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 154)

Hazards: TOXIC. Corrosive. Non-combustible but may decompose producing toxic fumes when heated.

Fire: Use agent appropriate for surrounding fire. Cool containers.

Spill: Do not touch. Avoid inhalation. Use water spray to reduce fumes.

Chemical and Physical Properties

Ethanolamine appears as a clear colorless liquid with an odor resembling that of ammonia. Flash point 185 °F. May attack copper, brass, and rubber. Corrosive to tissue. Moderately toxic. Produces toxic oxides of nitrogen during combustion.

CAS Number: 141-43-5
Molecular Formula: C2H7NO
Molecular Weight: 61.08 g/mol
Color / Form: Colorless, viscous liquid or solid (below 51 °F)
Odor: Unpleasant, ammonia-like
Boiling Point: 338°F (170°C)
Melting Point: 50.5 °F (NTP, 1992)
Flash Point: 185°F (85°C)
Autoignition: 770 °F (NTP, 1992)
Specific Gravity: 1.01 (about same as water)
Vapor Pressure: 0.4 mmHg at 68 °F ; 6 mmHg at 140 °F (NTP, 1992)
Vapor Density: 2.11 (heavier than air)
Water Solubility: Miscible (fully soluble)
Log P: -1.31
pH: 25% aqueous solution: 12.1; 0.1 N aqueous solution: 12.05

Regulatory Data

OSHA PEL
TWA 3 ppm (6 mg/m 3 )
NIOSH REL
TWA 3 ppm (8 mg/m 3 ) ST 6 ppm (15 mg/m 3 )
IDLH
30 ppm

Special Provisions

49 CFR 172.102 special provision codes for this entry: IB3, T4, 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.

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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.