UN 1831Sulfuric acid, fuming with 30 percent or more free sulfur trioxide or Sulfuric acid, fuming with less than 30 percent free sulfur trioxide
Class 8
Corrosives
Summary
UN 1831 is the UN number for sulfuric acid, fuming with 30 percent or more free sulfur trioxide or Sulfuric acid, fuming with less than 30 percent free sulfur trioxide. It is classed in Class 8 (corrosives) for transport. Packing group I. Emergency responders use ERG guide 137.
Emergency response
The Emergency Response Guidebook (ERG2024) guide for this number:
- Guide137Sulfuric acid, fumingSulphuric acid, fumingHighlighted in green: see Table 1
Highlighted in green in the ERG. If there is no fire, go to ERG Table 1 for initial isolation and protective action distances, and also use the guide. If a fire is involved, use the guide's evacuation distances and protect downwind according to Table 1.
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 1831
- Name
- Sulfuric acid, fuming with 30 percent or more free sulfur trioxide or Sulfuric acid, fuming with less than 30 percent free sulfur trioxide
- Hazard class
- Class 8: Corrosives
- Packing group
- I
- What the class covers
- Substances which can damage living tissue or other goods and materials on contact.
U.S. Hazardous Materials Table
2 entries share this number in 49 CFR 172.101, by name, packing group or where the shipment is going.
UN1831Sulfuric acid, fuming
with less than 30 percent free sulfur trioxide
Special provisions: A7, N34, T20, TP2, TP13
- Class
- 8
- Packing group
- I
- Labels
- 8
UN1831Sulfuric acid, fuming
with 30 percent or more free sulfur trioxide
Special provisions: 2, B9, B14, B32, B77, B84, N34, T20, TP2, TP12, TP13
- Class
- 8
- Packing group
- I
- Labels
- 8, 6.1
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 8
Class 8 covers corrosive substances such as acids, alkalis and battery fluid, which can destroy skin or corrode metal on contact.
Check the official sources
For emergency response, packaging and quantity limits, use these:
- CAMEO Chemicals: UN/NA 1831NOAA datasheets with the ERG response guide and isolation distances
- Emergency Response Guidebook (ERG)PHMSA's guide for first responders, free as a PDF or app
- 49 CFR 172.101 Hazardous Materials TableThe legal U.S. entry: proper shipping name, packing group, labels and special provisions