UN 2796 — Sulphuric acid, with not more than 51% acid
Placard: Corrosive. ERG Guide 157. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
Sulphuric acid, with not more than 51% acid, is a corrosive aqueous acid shipped as UN 2796. Even at this dilution it can burn tissue, damage metals and create heat during dilution.
Hazard overview: The main hazard is corrosive injury from liquid, mist or contaminated runoff. Dilution can be exothermic, and contact with some metals may release hydrogen, creating a secondary flammability concern.
Response guidance: Isolate the spill area, keep people upwind and prevent runoff from reaching drains or waterways. Use water spray cautiously for vapor reduction or container cooling, and neutralize only under hazmat control with compatible agents such as soda ash or lime.
Firefighter training notes: Train responders to recognize acid dilution heat, hydrogen generation on metals and the need to protect drains. A common error is directing a hard water stream into pooled acid, which can spread contamination and increase splashing.
Regulatory context: UN 2796 is regulated as a Class 8 corrosive shipment. Use the current SDS, shipping papers and local hazardous-waste requirements to determine reporting, cleanup and disposal obligations.
Storage & handling: Store in corrosion-resistant containers with secondary containment, away from bases, reactive metals, oxidizers and organic materials. Keep containers closed, labeled and protected from impact.
UN 2796 Quick Details
Common Hazards of UN 2796
- Dilute sulphuric acid is strongly corrosive to skin, eyes and respiratory tissue.
- Dilution or contact with water can generate heat and cause splattering.
- Contact with metals may release flammable hydrogen gas.
- Heating or fire exposure may produce irritating sulfur oxides and acid mist.
- Spilled acid can damage concrete, metals and equipment and contaminate runoff.
- Vapors or mist may accumulate in low or poorly ventilated areas.
- Containers may fail when heated, damaged or exposed to incompatible materials.
Chemical Identity & Physical Properties
This material is generally a clear to pale yellow, low-volatility liquid with an oily feel. The exact boiling behavior and corrosivity depend on the acid concentration.
| Also known as | Dilute sulfuric acidBattery acid (dilute)Hydrogen sulfate (dilute)Oil of vitriol (dilute) |
| CAS Number | 7664-93-9 |
| Appearance | Clear to slightly cloudy, colorless to pale yellow liquid with no strong odor at this dilution. Oily consistency, highly corrosive to tissues. |
| Flash Point | Not applicable (non-flammable aqueous solution) |
| Boiling Point | Approximately 102-110C (216-230F) depending on concentration |
| Vapor Density | Not applicable (low volatility aqueous solution) |
| Water Reactivity | Dilutes exothermically; always add acid to water slowly, never reverse. Generates significant heat. |
Fireground Response Guidance — UN 2796
Extinguishing Media
PPE Requirements
Use acid-resistant chemical clothing, gloves, boots and face protection. SCBA is needed when acid mist, fire smoke or confined-space exposure is possible.
Isolation & Evacuation
First Actions for a UN 2796 Incident
- Call 911 and the emergency response number shown on the shipping papers or container documents.
- Keep unauthorized personnel away and establish an isolation perimeter before entry.
- Stay upwind, uphill and upstream; keep responders out of vapors, dusts and runoff.
- Avoid breathing vapors, dust, mist or smoke and avoid skin or eye contact.
- Do not touch damaged containers or spilled material unless properly trained and protected.
- Ventilate confined spaces only when personnel are trained, equipped and monitored.
- Use ERG guidance, SDS, shipping papers and air monitoring to confirm protective actions.
📋 Copy & Share Field Card
UN 2796 — Sulphuric acid, with not more than 51% aUse for: Quick radio or face-to-face size-up. Short, structured, field-ready.
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
Use for: Quick text to command or incoming units. Fits in a single SMS.