☣️ UN 1686 • CLASS 6

UN 1686 — Sodium arsenite, aqueous solution

Placard: Toxic. ERG Guide 154. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.

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⚠️ This page is a quick-reference aid. For real incidents: stage upwind, isolate, deny entry, request Hazmat early, and consult the current ERG + SOP/SOG.

UN 1686 is Sodium arsenite, aqueous solution, a toxic arsenic-containing material assigned to ERG Guide 154. The key responder concern is preventing inhalation of dust or fumes and preventing contaminated runoff.

Hazard overview: UN 1686 presents arsenic dust, fume and ingestion hazards. Heating or fire can create toxic arsenic-containing fumes, and dry powder can contaminate clothing, equipment and surfaces.

Response guidance: For a UN 1686 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 154. 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 1686 should emphasize arsenic/heavy-metal dust exposure, contamination control, SCBA use, runoff containment and decontamination. Use ERG 154, SDS and local SOP.

Regulatory context: Sodium arsenite, aqueous solution is regulated as a toxic arsenic/heavy-metal hazardous material. Transportation, workplace exposure, spill reporting, waste handling, storage and environmental requirements may vary by compound, 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: Sodium arsenite, aqueous solution should be stored in tightly closed compatible containers in a secure, cool, dry, well-ventilated toxic-material area away from food, incompatible chemicals, heat and unauthorized access. Prevent dust release, leaks and contaminated runoff.

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UN 1686 Quick Details

UN 1686
Product name: Sodium arsenite, aqueous solution
DOT Class: 6
Placard type: Toxic
ERG Guide: 154 (check current ERG)
Initial isolation: ERG 154: Initial isolation 25m in all directions; protective action distance 0.3 km downwind daytime, 0.8 km nighttime for small spills

Common Hazards of UN 1686

  • HIGHLY TOXIC arsenic-containing material; may be fatal if inhaled, ingested or absorbed through skin.
  • Dust or powder can create a serious inhalation and contamination hazard.
  • Avoid skin contact and prevent dust from becoming airborne.
  • Fire or heating may produce toxic arsenic-containing fumes.
  • Runoff from fire control or spill control may pollute waterways.
  • Containers may rupture or fail when heated.
  • Specific toxicity and solubility depend on the exact arsenic compound.

Chemical Identity & Physical Properties

Clear to slightly cloudy aqueous solution, colorless to pale straw-colored liquid. Odorless or faint garlic-like odor when concentrated.

Also known asSodium metaarseniteArsenous acid sodium saltSodium arsenite solutionPeniteProdalumnol
CAS Number7784-46-5
AppearanceClear to slightly cloudy aqueous solution, colorless to pale straw-colored liquid. Odorless or faint garlic-like odor when concentrated.
Flash PointNot applicable (aqueous solution, non-flammable)
Boiling PointApproximately 100C (212F), similar to water depending on concentration
Vapor DensityNot applicable (non-volatile aqueous solution)
Water ReactivitySoluble in water; solution itself is stable but highly toxic
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.

Fireground Response Guidance — UN 1686

Extinguishing Media

Use extinguishing agents appropriate for the surrounding fire and SDS. Water spray may cool containers or reduce dust only when runoff can be controlled as toxic heavy-metal contamination.

PPE Requirements

⚠️ Level B minimum with SCBA; full chemical-resistant suit, butyl rubber gloves; avoid all contact with skin, eyes, and clothing

Use positive-pressure SCBA for dust, fumes, fire or confined-space exposure. Chemical-resistant gloves, eye/face protection and protective clothing should be selected from SDS; avoid all skin contact and contaminated dust.

Isolation & Evacuation

ERG 154: Initial isolation 25m in all directions; protective action distance 0.3 km downwind daytime, 0.8 km nighttime for small spills
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 154).

First Actions for a UN 1686 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 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.
  • Avoid creating dust clouds or spreading contaminated liquid, powder, solution, runoff or debris.
  • 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 dust, vapor, fire involvement or unknown concentration is present.
  • Use ERG Guide 154, shipping papers, SDS, air monitoring and incident command for protective actions.
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📋 Copy & Share Field Card

UN 1686 — Sodium arsenite, aqueous solution
HAZMAT RADIO NOTE — UN 1686 Product: Sodium arsenite, aqueous solution Class 6 / Toxic / ERG 154 PPE: Level B minimum with SCBA; full chemical-resistant suit, butyl rubber gloves; avoid all contact with skin, eyes, and clothing ISOLATION: ERG 154: Initial isolation 25m in all directions; protective action distance 0.3 km downwind daytime, 0.8 km nighttime for small spills ACTION: Stage upwind · Isolate · Deny entry · Request HazmatRADIO

Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.

SMS WhatsApp
=== IC HAZMAT BRIEFING === UN 1686 — Sodium arsenite, aqueous solution Class: 6 | Placard: Toxic | ERG Guide: 154 Appearance: Clear to slightly cloudy aqueous solution, colorless to pale straw-colored liquid. Odorless or faint garlic-like odor when concentrated. Water Reactivity: Soluble in water; solution itself is stable but highly toxic Extinguishing: Use extinguishing agents appropriate for the surrounding fire and SDS. Water spray may cool containers or reduce dust only when runoff can be controlled as toxic heavy-metal contamination. PPE: Level B minimum with SCBA; full chemical-resistant suit, butyl rubber gloves; avoid all contact with skin, eyes, and clothing Isolation: ERG 154: Initial isolation 25m in all directions; protective action distance 0.3 km downwind daytime, 0.8 km nighttime for small spills — Key Hazards — • HIGHLY TOXIC arsenic-containing material; may be fatal if inhaled, ingested or absorbed through skin. • Dust or powder can create a serious inhalation and contamination hazard. • Avoid skin contact and prevent dust from becoming airborne. — First Actions — • 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 or mist and avoid all skin or eye contact. SOURCE: allfirefighter.com/hazmat/un/sodium-arsenite-aqueous-solution-un-1686 | Always use current ERG + SOP/SOGIC BRIEFING

Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.

SMS (short)
UN1686 Sodium arsenite, aqueous solution Cls6 ERG154 | allfirefighter.com/hazmat/un/sodium-arsenite-aqueous-solution-un-1686SMS / 160 CHAR

Use for: Quick text to command or incoming units. Fits in a single SMS.

⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions. Page: https://allfirefighter.com/hazmat/un/sodium-arsenite-aqueous-solution-un-1686

Related UN Numbers in Class 6

Discovery block for training / quick reference. Always consult the current ERG + your SOP/SOG for operations.
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Frequently Asked Questions about UN 1686

UN 1686 is Sodium arsenite, aqueous solution, a hazardous material assigned to ERG Guide 154.

No. It is generally not flammable, but fire or heating can produce toxic arsenic-containing fumes.

ERG Guide 154 applies to UN 1686 for initial isolation, protective actions and first response guidance.

UN 1686 presents arsenic dust, fume and ingestion hazards. Heating or fire can create toxic arsenic-containing fumes, and dry powder can contaminate clothing, equipment and surfaces.

Use positive-pressure SCBA for dust, fumes, fire or confined-space exposure. Chemical-resistant gloves, eye/face protection and protective clothing should be selected from SDS; avoid all skin contact and contaminated dust.

Arsenic or heavy-metal dust can contaminate clothing, equipment and surfaces and may be dangerous by inhalation or ingestion.
Sources (high level): DOT/PHMSA marking & class concepts + ERG usage principles. This page does not reproduce ERG guide text—always consult the current ERG for incident-specific protective actions.