UN/NA Number Reference
DOT Class 2.3 Toxic Gas placard

UN 303: Compressed gas, toxic, oxidizing, n.o.s.

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 303 is assigned the proper shipping name Compressed gas, toxic, oxidizing, n.o.s. in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 2.3 Toxic Gas material. Required label(s): 2.3, 5.1.

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 124)

Hazards: TOXIC. Oxidizer. May accelerate fire. Corrosive. May cause severe burns.

Fire: Use water spray or fog. Do not use dry chemical or CO2. Cool containers.

Spill: Do not touch. Stop leak if safe. Keep combustibles away from spilled material.

Need the full interactive record? Open UN 303 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.