UN 1796 — Nitrating acid mixture with not more than 50% nitric acid
Placard: Corrosive. ERG Guide 157. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1796 is Nitrating acid mixture with not more than 50% nitric acid, a corrosive hazardous material assigned to ERG Guide 157. Responders should verify the exact product with shipping papers, package markings and SDS before close action.
Hazard overview: UN 1796 presents corrosive exposure hazards and may create toxic/corrosive gases or runoff in fire or incompatible contact. Use ERG, SDS and incident command to set isolation, PPE and control actions.
Response guidance: For a UN 1796 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 157. Establish incident command, isolate the area, stay upwind, prevent incompatible contact, control runoff and choose entry or fire-control actions based on monitoring, SDS and local SOP.
Firefighter training notes: Training for UN 1796 should emphasize corrosive exposure routes, water or oxidizer incompatibility where applicable, air monitoring, PPE selection, decontamination and runoff containment. Use ERG 157, SDS and local SOP.
Regulatory context: Nitrating acid mixture with not more than 50% nitric acid is regulated as a hazardous material for transportation and emergency response purposes. Transportation, workplace exposure, spill reporting, waste handling, storage and environmental requirements may vary by concentration, formulation, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, facility documents and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Nitrating acid mixture with not more than 50% nitric acid should be stored in tightly closed compatible containers in a secure, cool, dry, well-ventilated hazardous-material area according to SDS and local procedures.
UN 1796 Quick Details
Common Hazards of UN 1796
- CORROSIVE material; inhalation, ingestion or skin/eye contact may cause severe injury.
- Fire may produce irritating, corrosive and/or toxic gases.
- Runoff may be corrosive and may pollute waterways.
- Containers may rupture or fail when heated.
- Specific hazards depend on the exact product, concentration and SDS.
Chemical Identity & Physical Properties
Clear to yellowish oily liquid mixture, typically containing nitric acid and sulfuric acid. Pungent, acrid odor. Fuming in moist air.
| Also known as | Mixed acidNitrating acidNitric-sulfuric acid mixtureSpent acid mixture |
| Appearance | Clear to yellowish oily liquid mixture, typically containing nitric acid and sulfuric acid. Pungent, acrid odor. Fuming in moist air. |
| Flash Point | Not applicable (non-flammable oxidizing liquid) |
| Boiling Point | Varies with composition, typically 110-120C (230-248F) |
| Vapor Density | Heavier than air, approximately 1.5-1.7 |
| Water Reactivity | Reacts violently with water generating intense heat and toxic nitrogen oxide fumes; add acid to water slowly, never reverse |
Fireground Response Guidance — UN 1796
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for vapor, mist, fire or confined-space exposure. Wear chemical-resistant gloves, boots, eye/face protection and protective clothing selected from SDS for corrosive liquid contact.
Isolation & Evacuation
First Actions for a UN 1796 Incident
- CALL 911. Then call the emergency response telephone number on the shipping paper, if available.
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Avoid breathing vapors, fumes, dust, mist or spray and avoid skin or eye contact.
- Do not touch or walk through spilled material unless properly trained and wearing appropriate protective equipment.
- Ventilate closed spaces before entering, but only if properly trained, equipped, monitored and authorized by incident command.
- Isolate the spill or leak area and expand the perimeter if vapor, dust, fire involvement, water reaction or unknown concentration is present.
- Use ERG Guide 157, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1796 — Nitrating acid mixture with not more thaUse 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.