UN/NA Number Reference
DOT Class 2.2 Non-Flammable Gas placard

UN 1066: Nitrogen, compressed

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 1066 is assigned the proper shipping name Nitrogen, compressed in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 2.2 Non-Flammable Gas material. Required label(s): 2.2.

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 121)

Hazards: May cause asphyxiation in confined areas. Rapid expansion may cause frostbite. Containers may BLEVE.

Fire: Use agent for surrounding fire. Cool containers with water from distance.

Spill: Ventilate area. Do not touch liquid. Stop leak if safe.

Chemical and Physical Properties

Nitrogen appears as a colorless odorless gas. Noncombustible and nontoxic. Makes up the major portion of the atmosphere, but will not support life by itself. Used in food processing, in purging air conditioning and refrigeration systems, and in pressurizing aircraft tires. May cause asphyxiation by displacement of air. Under prolonged exposure to fire or heat containers may rupture violently and rocket.

CAS Number: 7727-37-9
Molecular Formula: N2
Molecular Weight: 28.014 g/mol
Color / Form: Colorless gas
Odor: Odorless gas
Boiling Point: -320.1 F
Melting Point: -354 °F (USCG, 1999)
Specific Gravity: 0.807 at -319.9 F
Vapor Pressure: -236 C at 1Pa (solid)
Vapor Density: 0.96737 (lighter than air)
Water Solubility: In water, 1.81X10+4 mg/L at 21 C
Log P: log Kow = 0.67

Need the full interactive record? Open UN 1066 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.