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

UN 1013: Carbon dioxide

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 1013 is assigned the proper shipping name Carbon dioxide 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 120)

Hazards: Vapors may cause dizziness or asphyxiation. Contact with liquid may cause frostbite. Containers may rocket if heated.

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

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

Chemical and Physical Properties

Carbon dioxide appears as a colorless odorless gas at atmospheric temperatures and pressures. Relatively nontoxic and noncombustible. Heavier than air and may asphyxiate by the displacement of air. Soluble in water. Forms carbonic acid, a mild acid. Under prolonged exposure to heat or fire the container may rupture violently and rocket. Used to freeze food, to control chemical reactions, and as a fire extinguishing agent.

CAS Number: 124-38-9
Molecular Formula: CO2
Molecular Weight: 44.009 g/mol
Color / Form: Colorless gas
Odor: Odorless
Boiling Point: Sublimes
Melting Point: -109.3 °F (USCG, 1999)
Flash Point: Not applicable
Specific Gravity: 1.56 at -110.2 F
Vapor Pressure: 56.5 atm
Vapor Density: 1.53 (heavier than air)
Water Solubility: 0.2 % at 77 F
Log P: 0.83
pH: The pH of saturated CO2 solutions varies from 3.7 at 101 kPa (1 atm) to 3.2 at 2370 kPa (23.4 atm)

Regulatory Data

OSHA PEL
5000 9000 5000 ppm (ST) 30,000 ppm
NIOSH REL
TWA 5000 ppm (9000 mg/m 3 ) ST 30,000 ppm (54,000 mg/m 3 )
IDLH
40,000 ppm

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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.