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2599

UN 2599Chlorotrifluoromethane and trifluoromethane azeotropic mixture or Refrigerant gas R 503 with approximately 60 percent chlorotrifluoromethane

Division 2.2

Non-flammable, non-toxic gases

Summary

UN 2599 is the UN number for chlorotrifluoromethane and trifluoromethane azeotropic mixture or Refrigerant gas R 503 with approximately 60 percent chlorotrifluoromethane. It is classed in Division 2.2 (non-flammable, non-toxic gases) of Class 2 for transport. Emergency responders use ERG guide 126.

Emergency response

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

  • Guide126Chlorotrifluoromethane and trifluoromethane azeotropic mixture with approximately 60% chlorotrifluoromethaneRefrigerant gas R-503

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 2599
Name
Chlorotrifluoromethane and trifluoromethane azeotropic mixture or Refrigerant gas R 503 with approximately 60 percent chlorotrifluoromethane
Hazard class
Class 2: Gases
Division
2.2: Non-flammable, non-toxic gases
What the class covers
Gases which are neither flammable nor toxic, including asphyxiant and oxidizing gases.

U.S. Hazardous Materials Table

The entry for this number in 49 CFR 172.101.

  • UN2599Chlorotrifluoromethane and trifluoromethane azeotropic mixture or Refrigerant gas R 503

    with approximately 60 percent chlorotrifluoromethane

    Class
    2.2
    Packing group
    None
    Labels
    2.2

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: