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2517

UN 25171-Chloro-1,1-difluoroethane or Refrigerant gas R 142b

Division 2.1

Flammable gases

Summary

UN 2517 is the UN number for 1-Chloro-1,1-difluoroethane or Refrigerant gas R 142b. It is classed in Division 2.1 (flammable gases) of Class 2 for transport. Emergency responders use ERG guide 115.

Emergency response

The Emergency Response Guidebook (ERG2024) guide for this number:

  • Guide1151-Chloro-1,1-difluoroethaneDifluorochloroethanesRefrigerant gas R-142b

From the 2024 Emergency Response Guidebook (ERG2024), published by U.S. Department of Transportation, PHMSA. Read the full guide in the ERG or on CAMEO Chemicals.

Identification

UN number
UN 2517
Name
1-Chloro-1,1-difluoroethane or Refrigerant gas R 142b
Hazard class
Class 2: Gases
Division
2.1: Flammable gases
What the class covers
Gases which ignite on contact with an ignition source.

U.S. Hazardous Materials Table

The entry for this number in 49 CFR 172.101.

  • UN25171-Chloro-1,1-difluoroethane or Refrigerant gas R 142b

    Special provisions: T50

    Class
    2.1
    Packing group
    None
    Labels
    2.1

From the eCFR edition of 49 CFR 172.101 dated 2026-10-05 (section last amended 2026-09-08). The eCFR is an editorial compilation, not the official legal edition. Read the current table.

About Class 2

Class 2 covers gases, whether compressed, liquefied, dissolved under pressure or refrigerated. Division 2.1 is flammable gases such as propane, 2.2 is non-flammable, non-toxic gases such as nitrogen, and 2.3 is toxic gases such as chlorine.

See all Class 2 UN numbers

Check the official sources

For emergency response, packaging and quantity limits, use these: