DOT transport classification

Sulfuric acid: UN number by concentration

Under 49 CFR 172.101, sulfuric acid ≤51% ships as UN2796 (class 8, packing group II); >51% ships as UN1830 (class 8, packing group II).

CAS 7664-93-9 · Source: 49 CFR 172.101 Hazardous Materials Table

Classification by concentration

Sulfuric acid — 49 CFR 172.101. Percentages are by mass (w/w).
Concentration	Ships as	Class	Packing group	What we stock in this band
≤51%	UN2796	8	II	Sulfuric Acid 30% Technical Grade Sulfuric Acid 37% - Battery Acid Technical Grade Sulfuric Acid 50% - Electrolyte Grade
>51%	UN1830	8	II	Sulfuric Acid 70% Technical Grade Drain Hammer - Sulfuric Acid Drain Cleaner Sulfuric Acid 93% Technical Grade Sulfuric Acid 96% ACS Grade

≤51%: Also the correct entry for 'Battery fluid, acid'.
>51%: Packing group does NOT escalate at this boundary — both sides are PG II; only the UN number changes. Fuming sulfuric acid (oleum) is UN1831, a different entry.

How to read this

Percentages are by mass. 49 CFR 172.101 thresholds are w/w, but product labels often state volume (v/v). Near a cutoff the two can fall on opposite sides, so confirm the basis before classifying a shipment.
Products listed are verified individually. A product appears in a band only when its own reviewed classification matches it. Where a product's classification is still under review, we leave it out rather than infer it from the table.
This page is a reference, not a shipping paper. Classification for an actual shipment depends on packaging, quantity and mode; consult the current eCFR entry and the product's safety data sheet.

Source

49 CFR 172.101 Hazardous Materials Table. Reference text: “Sulfuric acid <=51% => UN2796, Class 8 PG II (same PG II as >51% UN1830). Also the correct UN for 'Battery fluid, acid'. >51% => UN1830.”

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