UN 1612 — Hexaethyl tetraphosphate and compressed gas mixture
Placard: Toxic Gas. ERG Guide 123. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1612 is Hexaethyl tetraphosphate and compressed gas mixture, a toxic compressed gas mixture assigned to ERG Guide 123. It combines toxic vapor or mist exposure with organophosphate skin absorption and cylinder-release hazards.
Hazard overview: UN 1612 presents toxic gas, organophosphate poisoning, heavier-than-air vapor and cylinder heating hazards. Leaks can spread downwind or into low areas and contaminate equipment or clothing.
Response guidance: For a UN 1612 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 123. Establish incident command, isolate the area, stay upwind, prevent dust or vapor exposure, control runoff and choose entry or cleanup actions based on monitoring, SDS and local SOP.
Firefighter training notes: Training for UN 1612 should emphasize organophosphate toxicity, skin absorption, cholinesterase inhibitor recognition, decontamination, medical coordination and contaminated runoff control. Use ERG 123, SDS and local SOP.
Regulatory context: Hexaethyl tetraphosphate and compressed gas mixture is regulated as a toxic organophosphate hazardous material. Transportation, occupational exposure, medical surveillance, spill reporting, pesticide/waste handling and environmental requirements may vary by jurisdiction. Verify current requirements through shipping papers, SDS, facility documents and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Hexaethyl tetraphosphate and compressed gas mixture should be stored in tightly closed compatible containers in a secure, cool, well-ventilated toxic-material area away from heat, food/feed, oxidizers and unauthorized access. Storage should include spill containment, decontamination supplies and medical/emergency planning appropriate to the SDS.
UN 1612 Quick Details
Common Hazards of UN 1612
- TOXIC compressed gas or aerosolized mixture; inhalation or skin absorption may be fatal.
- Organic phosphate component can inhibit cholinesterase and contaminate clothing or equipment.
- Vapors or mist may be heavier than air and collect in low or confined areas.
- Contact with liquefied gas or pressurized release may cause frostbite or chemical injury.
- Fire may produce irritating, corrosive and/or toxic gases.
- Cylinders or containers may rupture or vent when heated.
- Runoff or water spray may spread toxic pesticide contamination.
Chemical Identity & Physical Properties
Colorless to pale yellow liquid (pure HETP) compressed with gas. May have a faint fruity or ester-like odor. Liquefied gas mixture at room temperature under pressure.
| Also known as | HETPHexaethyl tetraphosphateTetraphosphoric acid hexaethyl esterBladan |
| CAS Number | 757-58-4 |
| Appearance | Colorless to pale yellow liquid (pure HETP) compressed with gas. May have a faint fruity or ester-like odor. Liquefied gas mixture at room temperature under pressure. |
| Flash Point | Not applicable (compressed gas mixture) |
| Boiling Point | Not applicable (compressed gas mixture under pressure) |
| Vapor Density | Heavier than air (organic phosphate component) |
| Water Reactivity | Hydrolyzes slowly in water; avoid prolonged contact with moisture |
Fireground Response Guidance — UN 1612
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA and chemical protective clothing selected by hazmat specialists. Level A may be needed for close entry or unknown concentrations; avoid skin absorption and use decontamination and medical coordination for possible cholinesterase inhibitor exposure.
Isolation & Evacuation
First Actions for a UN 1612 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 low areas, basements, trenches and confined spaces where toxic vapors may accumulate.
- Avoid breathing vapors, fumes, dust or mist and avoid all 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 leak area and expand protective actions downwind based on monitoring, wind and ERG Table 1 when applicable.
- Use ERG Guide 123, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1612 — Hexaethyl tetraphosphate and compressedUse 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.