☣️ UN 2813 • CLASS 4

Water-reactive solid, n.o.s.

Placard: Dangerous When Wet. 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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Quick details
UN 2813
Class: 4
Placard type: Dangerous When Wet
ERG: Guide 138 (check current ERG)
Isolation: ERG 138: Initial isolation 25m in all directions. Protective action distance: Spill 100m downwind daytime, 300m nighttime. Fire: 800m radius evacuation.
Chemical & Response Details
Also known asWater-reactive solid not otherwise specifiedDangerous when wet solid n.o.s.Water-sensitive solidHydro-reactive solid
AppearanceAppearance varies widely as this is a generic classification. May be powder, granules, or solid pieces. Color and odor depend on specific substance. Reacts with water to produce flammable gases.
Flash PointNot applicable (reacts with water to produce flammable gases)
Boiling PointNot applicable (varies by specific substance)
Vapor DensityNot applicable (solid material)
Water ReactivityReacts with water or moisture to produce flammable gases. May ignite spontaneously. Some substances react violently or explosively. Keep dry at all times.
ExtinguishingDry chemical, dry sand, dry sodium chloride powder. DO NOT use water, foam, or any water-based extinguishing agents.
PPE⚠️ Level B minimum with SCBA required. Chemical-resistant suit and gloves. Keep upwind and avoid all contact with material and its water reaction products.
IsolationERG 138: Initial isolation 25m in all directions. Protective action distance: Spill 100m downwind daytime, 300m nighttime. Fire: 800m radius evacuation.
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
  • Produce flammable gases on contact with water.
  • May ignite on contact with water or moist air.
  • Some react vigorously or explosively on contact with water.
  • May be ignited by heat, sparks or flames.
  • May re-ignite after fire is extinguished.
  • Some are transported in highly flammable liquids.
  • Runoff may create fire or explosion hazard.
  • Inhalation or contact with vapors, substance or decomposition products may cause severe injury or
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
  • Consider initial downwind evacuation for at least 300 meters (1000 feet).
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UN 2813 — Water-reactive solid, n.o.s.
HAZMAT RADIO NOTE — UN 2813 Product: Water-reactive solid, n.o.s. Class 4 / Dangerous When Wet / ERG 138 PPE: Level B minimum with SCBA required. Chemical-resistant suit and gloves. Keep upwind and avoid all contact with material and its water reaction products. ISOLATION: ERG 138: Initial isolation 25m in all directions. Protective action distance: Spill 100m downwind daytime, 300m nighttime. Fire: 800m radius evacuation. 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 2813 — Water-reactive solid, n.o.s. Class: 4 | Placard: Dangerous When Wet | ERG Guide: 138 Appearance: Appearance varies widely as this is a generic classification. May be powder, granules, or solid pieces. Color and odor depend on specific substance. Reacts with water to produce flammable gases. Water Reactivity: Reacts with water or moisture to produce flammable gases. May ignite spontaneously. Some substances react violently or explosively. Keep dry at all times. Extinguishing: Dry chemical, dry sand, dry sodium chloride powder. DO NOT use water, foam, or any water-based extinguishing agents. PPE: Level B minimum with SCBA required. Chemical-resistant suit and gloves. Keep upwind and avoid all contact with material and its water reaction products. Isolation: ERG 138: Initial isolation 25m in all directions. Protective action distance: Spill 100m downwind daytime, 300m nighttime. Fire: 800m radius evacuation. — Key Hazards — • Produce flammable gases on contact with water. • May ignite on contact with water or moist air. • Some react vigorously or explosively on contact with water. — 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/2813 | Always use current ERG + SOP/SOGIC BRIEFING

Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.

SMS (short)
UN2813 Water-reactive solid, n.o.s. Cls4 ERG138 | allfirefighter.com/hazmat/un/2813SMS / 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/2813
Related UN numbers (same class)
Discovery block for training / quick reference. Always consult the current ERG + your SOP/SOG for operations.
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FAQ

Produce flammable gases on contact with water. May ignite on contact with water or moist air. Some react vigorously or explosively on contact with water. May be ignited by heat, sparks or flames. May re-ignite after fire is extinguished. Some are transported in highly flammable liquids. Runoff may create fire or explosion hazard. Inhalation or contact with vapors, substance or decomposition products may cause severe injury or

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 required. Chemical-resistant suit and gloves. Keep upwind and avoid all contact with material and its water reaction products.

No. This is a training/quick-reference aid only. Always consult the current ERG Guide 138 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.