UN/NA Number Reference
DOT Class 2.3 Toxic Gas placard

UN 1016: Carbon monoxide, compressed

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 1016 is assigned the proper shipping name Carbon monoxide, compressed 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, 2.1.

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 119)

Hazards: TOXIC. May be fatal if inhaled or absorbed through skin. Flammable. Vapors heavier than air.

Fire: Small: dry chemical or CO2. Large: water spray or fog. Fight from maximum distance.

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

Chemical and Physical Properties

Carbon monoxide is a colorless, odorless gas. Prolonged exposure to carbon monoxide rich atmospheres may be fatal. It is easily ignited. It is just lighter than air and a flame can flash back to the source of leak very easily. Under prolonged exposure to fire or intense heat the containers may violently rupture and rocket.

CAS Number: 630-08-0
Molecular Formula: CO
Molecular Weight: 28.010 g/mol
Color / Form: Colorless gas [Note: Shipped as a nonliquefied or liquefied compressed gas].
Odor: Odorless
Boiling Point: -312.7 F
Melting Point: -326 °F (USCG, 1999)
Flash Point: Flammable gas
Autoignition: 1128 °F (USCG, 1999)
Specific Gravity: 0.791 at -312.7 F
Vapor Pressure: greater than 35 atm
Vapor Density: 0.97 (lighter than air)
Water Solubility: 2 %
Log P: 0.83

Regulatory Data

OSHA PEL
50 55 25 ppm (C) 200 ppm
NIOSH REL
TWA 35 ppm (40 mg/m 3 ) C 200 ppm (229 mg/m 3 )
IDLH
1200 ppm

Special Provisions

49 CFR 172.102 special provision codes for this entry: 4. 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.

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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.