UN/NA Number Reference
DOT Class 6.1 Toxic Substance placard

UN 1687: Sodium azide

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 1687 is assigned the proper shipping name Sodium azide in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 6.1 Toxic Substance material, Packing Group II. Required label(s): 6.1.

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 153)

Hazards: TOXIC. Combustible. Corrosive. Causes burns. Toxic fumes when heated.

Fire: Small: dry chemical, CO2, water spray. Large: water spray, foam.

Spill: Do not touch. Stop leak if safe. Use water spray to reduce vapor.

Chemical and Physical Properties

Sodium azide appears as a colorless crystalline solid. Density 1.85 g / cm3. Burns in air and may explode if large quantities are involved. Toxic by ingestion. Toxic oxides of nitrogen are produced in fires.

CAS Number: 26628-22-8
Molecular Formula: N3Na
Molecular Weight: 65.010 g/mol
Color / Form: Colorless hexagonal crystals
Odor: Odorless (with traces of water fishy smelling because of HN3 formation)
Boiling Point: Decomposes in vacuum
Melting Point: Decomposes at 527 °F to sodium and nitrogen (EPA, 1998)
Flash Point: Not flammable
Specific Gravity: 1.846 (sinks in water)
Vapor Pressure: 1 Pa at 20 C
Water Solubility: 50 to 100 mg/mL at 72 F

Regulatory Data

CERCLA RQ (40 CFR 302.4)
1000 lb
EPCRA TPQ (40 CFR 355)
500 lb
OSHA PEL
none
NIOSH REL
C 0.1 ppm (as HN 3 ) [skin] C 0.3 mg/m 3 (as NaN 3 ) [skin]
IDLH
N
RCRA Waste Code(s)
[object Object]

A release of this material at or above its CERCLA reportable quantity (1000 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: IB8, IP2, IP4. 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 1687 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.