UN 1906 — Acid, sludge
Placard: Corrosive. ERG Guide 153. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1906 is Acid, sludge, a Class 8 corrosive acid sludge assigned to ERG Guide 153. It is a variable spent or process material, so composition and contaminants must be confirmed from SDS and shipping papers.
Hazard overview: UN 1906 presents acid burn, toxic contaminant, heat-retention, vapor and contaminated-runoff hazards. Sludge can cling to PPE and surfaces and may release fumes when disturbed.
Response guidance: For a UN 1906 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 153. 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 1906 should emphasize exposure routes, air monitoring, PPE selection, decontamination, runoff containment and ERG/SDS verification. Use ERG 153, SDS and local SOP.
Regulatory context: Acid, sludge 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 formulation, concentration, 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: Acid, sludge should be stored in compatible corrosion-resistant containers with secondary containment, away from incompatible chemicals, heat and unauthorized access. Follow SDS for oxidizers, acids, bases, solvents or toxic ingredients in the specific product.
UN 1906 Quick Details
Common Hazards of UN 1906
- CORROSIVE acid sludge; skin, eye or respiratory contact may cause severe injury.
- Composition varies and may include strong acids, hydrocarbons, metals, tar, spent process residues or toxic contaminants.
- Sludge can retain heat, trap vapors and cling to surfaces or PPE.
- Water addition may generate heat, splattering and acidic runoff depending on composition.
- Fire may produce irritating, corrosive and/or toxic gases.
- Runoff may be acidic, oily and environmentally harmful.
- Exact hazards must be confirmed from shipping papers and SDS.
Chemical Identity & Physical Properties
Dark brown to black viscous liquid or sludge with a pungent, acrid odor. Highly corrosive mixture of sulfuric acid and organic compounds from petroleum refining processes.
| Also known as | Acid sludgeSpent sulfuric acidAlkylation sludgeRefinery acid sludge |
| Appearance | Dark brown to black viscous liquid or sludge with a pungent, acrid odor. Highly corrosive mixture of sulfuric acid and organic compounds from petroleum refining processes. |
| Flash Point | Varies by composition, typically not applicable due to high water content and corrosive nature |
| Boiling Point | Varies by composition, typically >150C (302F) with decomposition |
| Vapor Density | Heavier than air; vapors may travel to ignition sources |
| Water Reactivity | May generate heat when diluted with water; add acid to water slowly, never water to acid |
Fireground Response Guidance — UN 1906
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for vapor, mist, dust, fire or confined-space exposure. Wear chemical-resistant gloves, boots, eye/face protection and protective clothing selected from SDS for corrosive contact.
Isolation & Evacuation
First Actions for a UN 1906 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 153, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1906 — Acid, sludgeUse 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.