UN/NA Number Reference
DOT Class 2.3 Toxic Gas placard

UN 1749: Chlorine trifluoride

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 1749 is assigned the proper shipping name Chlorine trifluoride 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, 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 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.

Chemical and Physical Properties

Chlorine trifluoride appears as a colorless gas or green liquid with a pungent odor. Boils at 53 °F. It reacts with water to form chlorine and hydrofluoric acid with release of heat. Contact with organic materials may result in spontaneous ignition. It is corrosive to metals and tissue. Prolonged exposure to low concentrations or short term exposure to high concentrations may result in adverse health effects. Under prolonged exposure to fire or intense heat the container may violently rupture and rocket.

CAS Number: 7790-91-2
Molecular Formula: ClF3
Molecular Weight: 92.45 g/mol
Color / Form: COLORLESS GAS; LIQUID IS YELLOW-GREEN IN COLOR; SOLID IS WHITE
Odor: SOMEWHAT SWEET, SUFFOCATING ODOR
Boiling Point: 53 F
Melting Point: -105 °F (USCG, 1999)
Specific Gravity: 1.85 (sinks in water)
Vapor Pressure: 1.4 atm
Vapor Density: 3.21 (heavier than air)
Water Solubility: Reacts with water

Regulatory Data

OSHA PEL
(C) 0.1 (C) 0.4 (C) 0.1 ppm
NIOSH REL
C 0.1 ppm (0.4 mg/m³)
IDLH
12 ppm

Special Provisions

49 CFR 172.102 special provision codes for this entry: 2, B7, B9, B14, N86. 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 1749 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.