☣️ UN 0004 • CLASS 1

UN 0004 — Ammonium picrate, dry or wetted with less than 10% water

Placard: Explosive 1.1D. ERG Guide 112. 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.

Ammonium picrate, dry or wetted with less than 10% water, is a highly sensitive explosive material that poses a significant mass explosion hazard. It is essential to handle this substance with extreme caution, as it becomes increasingly dangerous when dry.

Hazard overview: The primary hazards associated with UN 0004 are mass explosion and fragmentation, which can result in severe consequences. It is crucial to exercise extreme caution when handling this substance, as it is highly sensitive and can detonate with minimal provocation.

Response guidance: In the event of an emergency involving UN 0004, it is essential to isolate the area and evacuate the surrounding region. Water spray can be used to extinguish surrounding fires, but it is crucial not to direct the water stream onto the explosive itself.

UN 0004 Quick Details

UN 0004

Product name: Ammonium picrate, dry or wetted with less than 10% water

DOT Class: 1

Placard type: Explosive 1.1D

ERG Guide: 112 (check current ERG)

Initial isolation: ERG 112: Isolate 800m (1/2 mile) in all directions; evacuate 1600m (1 mile) if fire or detonation risk; consider evacuation of entire area

Common Hazards of UN 0004

Mass explosion hazard
Fragmentation and blast pressure
Sensitive to heat, shock, and friction

Chemical Identity & Physical Properties

Ammonium picrate is a yellow to orange crystalline solid with no characteristic odor, and it is highly sensitive to heat and shock.

Also known as	Picrate of ammoniaAmmonium picrate explosiveAmmonium 2,4,6-trinitrophenolateExplosive D
CAS Number	131-74-8
Appearance	Yellow to orange crystalline solid with no characteristic odor. Highly sensitive explosive material that becomes increasingly dangerous when dry.
Flash Point	Not applicable (explosive solid)
Boiling Point	Not applicable (detonates before boiling)
Vapor Density	Not applicable (solid)
Water Reactivity	Relatively stable in water; wetting reduces sensitivity. Keep wetted with at least 10% water for safe handling.

Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.

Fireground Response Guidance — UN 0004

Extinguishing Media

Water spray only for surrounding fires; do not direct water stream onto explosive. No foam or dry chemical on explosive itself.

PPE Requirements

⚠️ Full protective gear including blast-resistant suit if available; SCBA required; remote handling preferred; treat as Class 1.1D mass explosion hazard

Full protective gear, including a blast-resistant suit and SCBA, is required when handling UN 0004, and remote handling is preferred due to the high risk of explosion.

Isolation & Evacuation

ERG 112: Isolate 800m (1/2 mile) in all directions; evacuate 1600m (1 mile) if fire or detonation risk; consider evacuation of entire area

Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 112).

First Actions for a UN 0004 Incident

CALL 911. Then call emergency response telephone number on shipping paper.
Establish large isolation zone immediately — minimum 500 meters initial
Stage upwind, uphill; limit personnel
Request Hazmat + law enforcement
Protect exposures only if safe and directed
Consult current ERG Guide 112 and SOP/SOG

📋 Copy & Share Field Card

UN 0004 — Ammonium picrate, dry or wetted with les

HAZMAT RADIO NOTE — UN 0004 Product: Ammonium picrate, dry or wetted with less than 10% water Class 1 / Explosive 1.1D / ERG 112 PPE: Full protective gear including blast-resistant suit if available; SCBA required; remote handling preferred; treat as Class 1.1D mass explosion hazard ISOLATION: ERG 112: Isolate 800m (1/2 mile) in all directions; evacuate 1600m (1 mile) if fire or detonation risk; consider evacuation of entire area 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 0004 — Ammonium picrate, dry or wetted with less than 10% water Class: 1 | Placard: Explosive 1.1D | ERG Guide: 112 Appearance: Yellow to orange crystalline solid with no characteristic odor. Highly sensitive explosive material that becomes increasingly dangerous when dry. Water Reactivity: Relatively stable in water; wetting reduces sensitivity. Keep wetted with at least 10% water for safe handling. Extinguishing: Water spray only for surrounding fires; do not direct water stream onto explosive. No foam or dry chemical on explosive itself. PPE: Full protective gear including blast-resistant suit if available; SCBA required; remote handling preferred; treat as Class 1.1D mass explosion hazard Isolation: ERG 112: Isolate 800m (1/2 mile) in all directions; evacuate 1600m (1 mile) if fire or detonation risk; consider evacuation of entire area — Key Hazards — • Mass explosion hazard • Fragmentation and blast pressure • Sensitive to heat, shock, and friction — First Actions — • CALL 911. Then call emergency response telephone number on shipping paper. • Establish large isolation zone immediately — minimum 500 meters initial • Stage upwind, uphill; limit personnel • Request Hazmat + law enforcement SOURCE: allfirefighter.com/hazmat/un/ammonium-picrate-dry-or-un-0004 | Always use current ERG + SOP/SOGIC BRIEFING

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

SMS (short)

UN0004 Ammonium picrate, dry or wetted with less than 10% water Cls1 ERG112 | allfirefighter.com/hazmat/un/ammonium-picrate-dry-or-un-0004SMS / 160 CHAR

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

Open in Messages WhatsApp

⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions. Page: https://allfirefighter.com/hazmat/un/ammonium-picrate-dry-or-un-0004

Related UN Numbers in Class 1

Open Class Guide →Hazmat Hub →

UN 0012 UN 0027 UN 0028 UN 0030 UN 0033 UN 0042 UN 0043 UN 0048 UN 0055 UN 0056 UN 0058 UN 0059

Next (UN 0012) →

Discovery block for training / quick reference. Always consult the current ERG + your SOP/SOG for operations.

Frequently Asked Questions about UN 0004

UN 0004 is relatively stable in water, and wetting reduces its sensitivity, but it is still a highly hazardous substance.

The recommended isolation distance for UN 0004 is 800m in all directions, and 1600m if there is a fire or detonation risk.

No, foam should not be used to extinguish fires involving UN 0004, as it can exacerbate the situation; instead, water spray can be used for surrounding fires.

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.