UN 2794 — Batteries, wet, filled with acid
Placard: Corrosive. ERG Guide 154. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
Batteries, wet, filled with acid are corrosive articles containing acidic electrolyte and stored electrical energy. Damaged units can leak acid and release hydrogen.
Hazard overview: Wet acid batteries contain corrosive sulfuric acid electrolyte. Acid contact can burn skin and eyes and damage respiratory tissue if mist is generated. Charging, damage or short circuits can release flammable hydrogen gas.
Response guidance: Keep batteries upright if safe, isolate leaking units and prevent short circuits. Use acid-resistant PPE and SCBA for fire or mist; contain electrolyte and contaminated runoff.
Firefighter training notes: Train responders to identify the UN number, product name, placard, container type and exposure route before committing personnel to the hot zone.
Regulatory context: Use the proper DOT shipping description, ERG guide, SDS and site-specific response plan; do not substitute this summary for regulatory compliance.
Storage & handling: Store upright in ventilated areas away from sparks, flames, metal tools, incompatible chemicals and floor drains; protect terminals from short circuit.
UN 2794 Quick Details
Common Hazards of UN 2794
- Wet acid batteries contain corrosive sulfuric acid electrolyte.
- Acid contact can burn skin and eyes and damage respiratory tissue if mist is generated.
- Charging, damage or short circuits can release flammable hydrogen gas.
- Electrical energy can cause arcing, burns or ignition of nearby combustibles.
- Fire may produce toxic and corrosive fumes from acid, lead compounds and battery materials.
- Damaged batteries can leak corrosive electrolyte and contaminate runoff.
- Containers or battery cases may rupture when heated.
- Do not allow acid to contact incompatible metals, bases or reactive materials.
Chemical Identity & Physical Properties
Batteries containing liquid sulfuric acid electrolyte solution, typically lead-acid type. Electrolyte is colorless to slightly yellowish corrosive liquid. Batteries are heavy, solid units with internal lead plates.
| Also known as | Lead-acid batteriesStorage batteries wetElectric storage batteriesAutomotive batteries filledBattery acid filled |
| Appearance | Batteries containing liquid sulfuric acid electrolyte solution, typically lead-acid type. Electrolyte is colorless to slightly yellowish corrosive liquid. Batteries are heavy, solid units with internal lead plates. |
| Flash Point | Not applicable (non-flammable device, though hydrogen gas may be generated during charging) |
| Boiling Point | Not applicable (electrolyte boils at approximately 338C/640F) |
| Vapor Density | Not applicable (contained liquid electrolyte) |
| Water Reactivity | Water can dilute acid but runoff remains corrosive; avoid uncontrolled washdown and contain leaking electrolyte. |
Fireground Response Guidance — UN 2794
Extinguishing Media
PPE Requirements
Acid-resistant gloves, face shield, chemical splash goggles, acid-resistant apron; avoid skin contact with electrolyte
Isolation & Evacuation
First Actions for a UN 2794 Incident
- Call 911 and the emergency response number shown on the shipping papers.
- Keep unauthorized personnel away and establish an initial isolation perimeter.
- Stay upwind, uphill and upstream; avoid low areas where vapors or runoff may collect.
- Avoid breathing vapors, dust, mist or smoke and prevent skin and eye contact.
- Do not touch damaged packages, leaking containers or spilled material without appropriate PPE.
- Ventilate confined spaces only when responders are trained, equipped and monitoring conditions.
- Use ERG, SDS, shipping papers and air monitoring to set final isolation, evacuation and decon actions.
📋 Copy & Share Field Card
UN 2794 — Batteries, wet, filled with acidUse 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.