UN/NA Number Reference
DOT Class 5.1 Oxidizer placard

UN 1873: Perchloric acid

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 1873 is assigned the proper shipping name Perchloric acid in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 5.1 Oxidizer material, Packing Group I. Required label(s): 5.1, 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 143)

Hazards: May explode from heat or contamination. Strong oxidizer. May ignite combustibles.

Fire: Flood with water from distance. Cool containers. Evacuate area if fire reaches cargo.

Spill: Keep combustibles away. Do not touch. Use water spray.

Chemical and Physical Properties

Perchloric acid, with more than 50% but not more than 72% acid appears as a clear colorless odorless aqueous solution. Corrosive to metals and tissue. Closed containers may rupture violently under prolonged exposure to heat.

CAS Number: 7601-90-3
Molecular Formula: ClHO4
Molecular Weight: 100.46 g/mol
Color / Form: COLORLESS, OILY LIQUID
Odor: odorless
Boiling Point: 19 C @ 11 MM HG
Melting Point: -170 °F (USCG, 1999)
Specific Gravity: 1.6 to 1.7
Vapor Pressure: 6.8 [mmHg]
Vapor Density: 3.5 (heavier than air)
Water Solubility: MISCIBLE IN COLD WATER

Special Provisions

49 CFR 172.102 special provision codes for this entry: A2, N41, T10, 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 1873 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.