☣️ UN 1651 • CLASS 6
UN 1651 — Naphthylthiourea
Placard: Toxic. ERG Guide 153. 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.
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UN 1651 Quick Details
UN 1651
Product name: Naphthylthiourea
DOT Class: 6
Placard type: Toxic
ERG Guide: 153 (check current ERG)
Initial isolation: ERG 153: isolate spill 25m all directions; for large spill isolate 50m; if fire/large spill consider evacuation 800m downwind
Common Hazards of UN 1651
- TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury
- Methyl bromoacetate (UN2643) is an eye irritant/lachrymator (causes flow of tears).
- 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
- Combustible material: may burn but does not ignite readily.
- When heated, vapors may form explosive mixtures with air: indoors, outdoors and sewers explosion
Chemical Identity & Physical Properties
| Also known as | ANTUAlpha-naphthylthiourea1-NaphthylthioureaRattrackBantu |
| CAS Number | 86-88-4 |
| Appearance | White to gray odorless crystalline powder or solid at room temperature. May have a slight bitter taste. |
| Flash Point | Not applicable (non-flammable solid) |
| Boiling Point | Not applicable (decomposes before boiling) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | No significant reaction with water |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1651
Extinguishing Media
Water spray, dry chemical, CO2, or foam suitable for surrounding fire
PPE Requirements
⚠️ Level B minimum with SCBA; avoid all skin contact, use chemical-resistant protective clothing and gloves
Isolation & Evacuation
ERG 153: isolate spill 25m all directions; for large spill isolate 50m; if fire/large spill consider evacuation 800m downwind
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 153).
First Actions for a UN 1651 Incident
- 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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📋 Copy & Share Field Card
UN 1651 — NaphthylthioureaHAZMAT RADIO NOTE — UN 1651
Product: Naphthylthiourea
Class 6 / Toxic / ERG 153
PPE: Level B minimum with SCBA; avoid all skin contact, use chemical-resistant protective clothing and gloves
ISOLATION: ERG 153: isolate spill 25m all directions; for large spill isolate 50m; if fire/large spill consider evacuation 800m downwind
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 1651 — Naphthylthiourea
Class: 6 | Placard: Toxic | ERG Guide: 153
Appearance: White to gray odorless crystalline powder or solid at room temperature. May have a slight bitter taste.
Water Reactivity: No significant reaction with water
Extinguishing: Water spray, dry chemical, CO2, or foam suitable for surrounding fire
PPE: Level B minimum with SCBA; avoid all skin contact, use chemical-resistant protective clothing and gloves
Isolation: ERG 153: isolate spill 25m all directions; for large spill isolate 50m; if fire/large spill consider evacuation 800m downwind
— Key Hazards —
• TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury
• Methyl bromoacetate (UN2643) is an eye irritant/lachrymator (causes flow of tears).
• Contact with molten substance may cause severe burns to skin and eyes.
— 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/1651 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1651 Naphthylthiourea Cls6 ERG153 | ERG 153: isolate spill 25m all directions; for large spill isolate 50m; if fire/ | allfirefighter.com/hazmat/un/1651SMS / 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/1651
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Frequently Asked Questions about UN 1651
TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury Methyl bromoacetate (UN2643) is an eye irritant/lachrymator (causes flow of tears). 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 Combustible material: may burn but does not ignite readily. When heated, vapors may form explosive mixtures with air: indoors, outdoors and sewers explosion
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 SCBA; avoid all skin contact, use chemical-resistant protective clothing and gloves
Water reactivity: No significant reaction with water. Recommended extinguishing: Water spray, dry chemical, CO2, or foam suitable for surrounding fire.
ERG Guide 153 recommendation: ERG 153: isolate spill 25m all directions; for large spill isolate 50m; if fire/large spill consider evacuation 800m downwind
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 153 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.