☣️ UN 3495 • CLASS 8
Iodine
Placard: Corrosive. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ 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.
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Quick details
UN 3495
Class: 8
Placard type: Corrosive
ERG: Guide 154 (check current ERG)
Isolation: ERG 154: isolate spill/leak area 25m in all directions; if tank/rail/tank truck involved in fire isolate 800m and consider initial evacuation 800m
Chemical & Response Details
| Also known as | Molecular iodineI2DiiodineIodine crystalsIodine sublimed |
| CAS Number | 7553-56-2 |
| Appearance | Bluish-black to violet-black crystalline solid or lustrous plates with a sharp, characteristic pungent odor. Sublimes readily at room temperature producing violet vapor. |
| Flash Point | Not applicable (non-flammable solid) |
| Boiling Point | 184C (363F) - sublimes readily below boiling point |
| Vapor Density | 8.8 (much heavier than air) |
| Water Reactivity | Slightly soluble in water, no significant reaction but forms acidic solution |
| Extinguishing | Water spray to reduce vapors, dry chemical, CO2; avoid direct water contact with large quantities |
| PPE | ⚠️ Level B minimum with full-face respirator or SCBA; chemical-resistant suit, gloves, and boots required; avoid all skin and eye contact |
| Isolation | ERG 154: isolate spill/leak area 25m in all directions; if tank/rail/tank truck involved in fire isolate 800m and consider initial evacuation 800m |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury
- Contact with molten substance may cause severe burns to skin and eyes.
- Avoid any skin contact.
- Fire may produce irritating, corrosive and/or toxic gases.
- Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental
- Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive
- Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.).
- Corrosives in contact with metals may evolve flammable hydrogen gas.
First actions (field-minded)
- CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
- For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.
- For non-highlighted materials: increase the immediate precautionary measure distance, in the downwind
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UN 3495 — Iodine HAZMAT RADIO NOTE — UN 3495
Product: Iodine
Class 8 / Corrosive / ERG 154
PPE: Level B minimum with full-face respirator or SCBA; chemical-resistant suit, gloves, and boots required; avoid all skin and eye contact
ISOLATION: ERG 154: isolate spill/leak area 25m in all directions; if tank/rail/tank truck involved in fire isolate 800m and consider initial evacuation 800m
ACTION: Stage upwind · Isolate · Deny entry · Request HazmatRADIO
Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.
=== IC HAZMAT BRIEFING ===
UN 3495 — Iodine
Class: 8 | Placard: Corrosive | ERG Guide: 154
Appearance: Bluish-black to violet-black crystalline solid or lustrous plates with a sharp, characteristic pungent odor. Sublimes readily at room temperature producing violet vapor.
Water Reactivity: Slightly soluble in water, no significant reaction but forms acidic solution
Extinguishing: Water spray to reduce vapors, dry chemical, CO2; avoid direct water contact with large quantities
PPE: Level B minimum with full-face respirator or SCBA; chemical-resistant suit, gloves, and boots required; avoid all skin and eye contact
Isolation: ERG 154: isolate spill/leak area 25m in all directions; if tank/rail/tank truck involved in fire isolate 800m and consider initial evacuation 800m
— Key Hazards —
• TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury
• Contact with molten substance may cause severe burns to skin and eyes.
• Avoid any skin contact.
— First Actions —
• CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
SOURCE: allfirefighter.com/hazmat/un/3495 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3495 Iodine Cls8 ERG154 | ERG 154: isolate spill/leak area 25m in all directions; if tank/rail/tank truck | allfirefighter.com/hazmat/un/3495SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS. Includes link to full page.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions. Page: https://allfirefighter.com/hazmat/un/3495
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FAQ
TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury Contact with molten substance may cause severe burns to skin and eyes. Avoid any skin contact. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Corrosives in contact with metals may evolve flammable hydrogen gas.
CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper Keep unauthorized personnel away. Stay upwind, uphill and/or upstream.
Level B minimum with full-face respirator or SCBA; chemical-resistant suit, gloves, and boots required; avoid all skin and eye contact
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 154 and your department SOP/SOG for incident-specific protective actions.
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.