UN 1855 — Calcium alloys, pyrophoric
Placard: Spontaneously Combustible. ERG Guide 135. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1855 is Calcium alloys, pyrophoric, a Class 4 pyrophoric metal alloy assigned to ERG Guide 135. It may ignite on contact with air, moisture or water and can produce flammable hydrogen gas.
Hazard overview: UN 1855 presents spontaneous ignition, water reaction, hydrogen gas and re-ignition hazards. Use only dry compatible agents such as Class D powder when directed by incident command.
Response guidance: For a UN 1855 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 135. Establish incident command, isolate the area, stay upwind, control ignition or incompatibility hazards, prevent runoff or vapor spread and choose entry/fire-control actions based on monitoring, SDS and local SOP.
Firefighter training notes: Training for UN 1855 should emphasize pyrophoric ignition, moisture exclusion, Class D agent selection, re-ignition, metal dust control and cylinder/container exposure. Use ERG 135, SDS and local SOP.
Regulatory context: Calcium alloys, pyrophoric 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: Calcium alloys, pyrophoric should be stored dry in compatible sealed containers or inerted packaging as specified by SDS, away from water, moisture, air exposure where applicable, oxidizers, ignition sources and unauthorized access. Keep Class D extinguishing media available.
UN 1855 Quick Details
Common Hazards of UN 1855
- PYROPHORIC metal alloy; may ignite spontaneously on exposure to air, moisture or humid conditions.
- Reacts with water to produce heat and flammable hydrogen gas.
- Powder, granules or damaged material may burn rapidly and re-ignite after apparent extinguishment.
- Water, foam, CO2 or halogenated agents may worsen the reaction depending on alloy and SDS.
- Fire may produce irritating or toxic metal oxide smoke.
- Runoff or water application may create fire, explosion or contamination hazards.
- Containers may rupture or explode when heated.
Chemical Identity & Physical Properties
Silvery-gray to dark gray metallic solid alloy, often in powder or granular form. Odorless. Pyrophoric nature means spontaneous ignition possible upon exposure to air or moisture.
| Also known as | Pyrophoric calcium alloysCalcium metal alloysCalcium-magnesium alloysCalcium-aluminum alloys |
| Appearance | Silvery-gray to dark gray metallic solid alloy, often in powder or granular form. Odorless. Pyrophoric nature means spontaneous ignition possible upon exposure to air or moisture. |
| Flash Point | Not applicable (pyrophoric solid - ignites spontaneously) |
| Boiling Point | Not applicable (varies by alloy composition, typically >1400C) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Reacts violently with water producing flammable hydrogen gas and heat; may ignite spontaneously |
Fireground Response Guidance — UN 1855
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for smoke, fire or dust exposure. Wear fire-resistant protective clothing and dry chemical-compatible gloves/eye protection selected from SDS; avoid moisture contamination and metal dust contact.
Isolation & Evacuation
First Actions for a UN 1855 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, smoke or gas and avoid skin or eye contact.
- Keep water, foam, moisture and incompatible extinguishing agents away unless incident command confirms a compatible use.
- Eliminate ignition sources where safe and avoid disturbing powder or granules.
- 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, gas accumulation or unknown concentration is present.
- Use ERG Guide 135, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1855 — Calcium alloys, pyrophoricUse 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.