Hazmat UN Number Lookup

Search hazardous materials database, check safety specifications, and view Emergency Response guides.

🏷️ Primary Hazard Class Filter

UN2857

Refrigerating machines, containing non-flammable, non-toxic gases, or ammonia solutions (UN2672)

Gases

Class 2.2

CAS Registry7664-41-7

Hazchem / EAC2T

ERG Guide Number120

49 CFR Placards & Labels

Non-Flammable GasClass 2.2

⇩ SVG

Reportable Quantity — 100 lb (45.4 kg)

Any release meeting or exceeding this amount must be reported to the National Response Center at 1-800-424-8802 under 40 CFR 302.6 and 49 CFR 171.15.

Marine Pollutant

Marine-pollutant mark (§172.322) required for bulk packages by vessel; IMDG segregation and stowage rules apply.

Regulatory Facts

Packing Group

—

Symbols (col 1)

—

Labels (col 6)

2.2

PIH Zone

—

Packaging references (49 CFR §173.xxx)

Exceptions (col 8A)

§173.306, 307

Non-Bulk (col 8B)

§173.306

Bulk (col 8C)

§173.306, 307

Aircraft quantity limits (col 9)

Passenger / Rail (9A)

450 kg

Cargo Aircraft Only (9B)

450 kg

Vessel stowage (col 10)

Location (10A)

Other codes (10B)

—

Special provisions (col 7 — §172.102)

A53

Hazard Classification & Risks

Class 2.2 — Non-flammable, non-toxic gas (includes asphyxiant and oxidizing gases). Pressure ≥280 kPa at 20°C or refrigerated liquefied (49 CFR §173.115).

Transport Regulations

Hazard class 2.2. Placard/label codes: 2.2. Special provisions: A53. Packaging (49 CFR §173): exceptions §306, 307, non-bulk §306, bulk §306, 307. Quantity limits: passenger aircraft/rail 450 kg, cargo aircraft only 450 kg. Vessel stowage: A. Classified per 49 CFR §172.101.

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Source & sourcing note

Regulatory data mirrors the U.S. 49 CFR §172.101 Hazardous Materials Table and companion columns (packaging, quantity limits, vessel stowage, special provisions) as published by the U.S. Pipeline and Hazardous Materials Safety Administration (PHMSA).

Emergency-response content is drawn from the 2024 Emergency Response Guidebook (ERG), a joint publication of PHMSA, Transport Canada, and Mexico’s SCT.

The U.S. edition of the ERG and all U.S. federal regulations are public-domain works under 17 U.S.C. §105. Descriptions on this page are plain-English paraphrases; for any compliance decision, consult the authoritative text on eCFR Title 49 and the ERG at PHMSA.dot.gov. “ERG™” is attributed to PHMSA / Transport Canada / SCT and used nominatively.

Regulatory Facts

Packing Group

—

Symbols (col 1)

—

Labels (col 6)

2.2

PIH Zone

—

Packaging references (49 CFR §173.xxx)

Exceptions (col 8A)

§173.306, 307

Non-Bulk (col 8B)

§173.306

Bulk (col 8C)

§173.306, 307

Aircraft quantity limits (col 9)

Passenger / Rail (9A)

450 kg

Cargo Aircraft Only (9B)

450 kg

Vessel stowage (col 10)

Location (10A)

Other codes (10B)

—

Special provisions (col 7 — §172.102)

A53

Source & sourcing note

Emergency-response content is drawn from the 2024 Emergency Response Guidebook (ERG), a joint publication of PHMSA, Transport Canada, and Mexico’s SCT.