☣️ UN 1023 • CLASS 2
Coal gas, compressed
Placard: Toxic Gas. 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 1023
Class: 2
Placard type: Toxic Gas
ERG: Guide 119 (check current ERG)
Isolation: ERG 119: Isolate spill/leak area 100m in all directions. If tank/rail car involved in fire, isolate 800m in all directions and evacuate initial 800m radius.
Chemical & Response Details
| Also known as | Town gasIlluminating gasManufactured gasCoal distillation gasRetort gas |
| Appearance | Colorless to pale yellow gas with a characteristic coal tar or aromatic odor. Lighter than air. Typically a mixture of hydrogen, methane, carbon monoxide, and other hydrocarbons produced by coal distillation. |
| Flash Point | Not applicable (flammable gas) |
| Boiling Point | Not applicable (gas mixture, components vary) |
| Vapor Density | 0.4-0.6 (lighter than air) |
| Water Reactivity | No significant reaction with water |
| Extinguishing | Do not use water or foam on gas leak. Use dry chemical or CO2 for small fires. Stop gas flow if safe to do so. |
| PPE | ⚠️ Level B minimum with SCBA required. Full protective clothing for liquid contact. Gas is highly toxic - respiratory protection mandatory. |
| Isolation | ERG 119: Isolate spill/leak area 100m in all directions. If tank/rail car involved in fire, isolate 800m in all directions and evacuate initial 800m radius. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- TOXIC; may be fatal if inhaled or absorbed through skin. Some may cause severe skin burns and
- Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite.
- Fire will produce irritating, corrosive and/or toxic gases.
- Runoff from fire control or dilution water may cause environmental contamination.
- Flammable; may be ignited by heat, sparks or flames.
- May form explosive mixtures with air. Ethylene oxide (UN1040) may react explosively even in the
- Those substances designated with a (P) may polymerize explosively when heated or involved in a fire.
- Vapors from liquefied gas are initially heavier than air and spread along ground.
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.
- Many gases are heavier than air and will spread along the ground and collect in low or confined areas
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area for at least 100 meters (330 feet) in all directions.
- 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 1023 — Coal gas, compressed HAZMAT RADIO NOTE — UN 1023
Product: Coal gas, compressed
Class 2 / Toxic Gas / ERG 119
PPE: Level B minimum with SCBA required. Full protective clothing for liquid contact. Gas is highly toxic - respiratory protection mandatory.
ISOLATION: ERG 119: Isolate spill/leak area 100m in all directions. If tank/rail car involved in fire, isolate 800m in all directions and evacuate initial 800m radius.
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 1023 — Coal gas, compressed
Class: 2 | Placard: Toxic Gas | ERG Guide: 119
Appearance: Colorless to pale yellow gas with a characteristic coal tar or aromatic odor. Lighter than air. Typically a mixture of hydrogen, methane, carbon monoxide, and other hydrocarbons produced by coal distillation.
Water Reactivity: No significant reaction with water
Extinguishing: Do not use water or foam on gas leak. Use dry chemical or CO2 for small fires. Stop gas flow if safe to do so.
PPE: Level B minimum with SCBA required. Full protective clothing for liquid contact. Gas is highly toxic - respiratory protection mandatory.
Isolation: ERG 119: Isolate spill/leak area 100m in all directions. If tank/rail car involved in fire, isolate 800m in all directions and evacuate initial 800m radius.
— Key Hazards —
• TOXIC; may be fatal if inhaled or absorbed through skin. Some may cause severe skin burns and
• Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite.
• Fire will produce irritating, corrosive and/or toxic gases.
— 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.
• Many gases are heavier than air and will spread along the ground and collect in low or confined areas
SOURCE: allfirefighter.com/hazmat/un/1023 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1023 Coal gas, compressed Cls2 ERG119 | ERG 119: Isolate spill/leak area 100m in all directions. If tank/rail car involv | allfirefighter.com/hazmat/un/1023SMS / 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/1023
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FAQ
TOXIC; may be fatal if inhaled or absorbed through skin. Some may cause severe skin burns and Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite. Fire will produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may cause environmental contamination. Flammable; may be ignited by heat, sparks or flames. May form explosive mixtures with air. Ethylene oxide (UN1040) may react explosively even in the Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. Vapors from liquefied gas are initially heavier than air and spread along ground.
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. Full protective clothing for liquid contact. Gas is highly toxic - respiratory protection mandatory.
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 119 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.