☣️ UN 1228 • CLASS 3
Mercaptan mixture, liquid, flammable, poisonous, n.o.s.
Placard: Flammable. 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 1228
Class: 3
Placard type: Flammable
ERG: Guide 131 (check current ERG)
Isolation: ERG 131: isolate spill 50m all directions; evacuate 300m downwind for large spills; isolate 800m all directions if tank/rail car involved in fire
Chemical & Response Details
| Also known as | Thiol mixtureSulfhydryl compound mixtureAlkyl mercaptan blendFlammable mercaptan solution |
| Appearance | Clear to pale yellow liquid with extremely strong, offensive, garlic-like or skunk-like odor. Mercaptans are sulfur-containing organic compounds detectable at very low concentrations. |
| Flash Point | Typically below 23°C (73°F), varies by specific mercaptan composition |
| Boiling Point | Variable, typically 35-150°C (95-302°F) depending on mercaptan components |
| Vapor Density | Heavier than air (typically 2-4), vapors accumulate in low areas |
| Water Reactivity | No significant reaction with water, but immiscible and will float on water surface |
| Extinguishing | Alcohol-resistant foam (AR-AFFF), CO2, dry chemical; regular foam may not be effective |
| PPE | ⚠️ Level A or B required; SCBA mandatory; full chemical-resistant suit due to extreme toxicity and skin absorption hazard; butyl rubber gloves recommended |
| Isolation | ERG 131: isolate spill 50m all directions; evacuate 300m downwind for large spills; isolate 800m all directions if tank/rail car involved in fire |
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, ingested or absorbed through skin.
- Inhalation or contact with some of these materials will irritate or burn skin and eyes.
- Methyl chloroacetate (UN2295) is an eye irritant/lachrymator (causes flow of tears).
- Fire will produce irritating, corrosive and/or toxic gases.
- Vapors may cause dizziness or asphyxiation, especially when in closed or confined areas.
- Runoff from fire control or dilution water may cause environmental contamination.
- HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames.
- Vapors may form explosive mixtures with air.
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 for at least 50 meters (150 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 1228 — Mercaptan mixture, liquid, flammable, po HAZMAT RADIO NOTE — UN 1228
Product: Mercaptan mixture, liquid, flammable, poisonous, n.o.s.
Class 3 / Flammable / ERG 131
PPE: Level A or B required; SCBA mandatory; full chemical-resistant suit due to extreme toxicity and skin absorption hazard; butyl rubber gloves recommended
ISOLATION: ERG 131: isolate spill 50m all directions; evacuate 300m downwind for large spills; isolate 800m all directions if tank/rail car involved in fire
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 1228 — Mercaptan mixture, liquid, flammable, poisonous, n.o.s.
Class: 3 | Placard: Flammable | ERG Guide: 131
Appearance: Clear to pale yellow liquid with extremely strong, offensive, garlic-like or skunk-like odor. Mercaptans are sulfur-containing organic compounds detectable at very low concentrations.
Water Reactivity: No significant reaction with water, but immiscible and will float on water surface
Extinguishing: Alcohol-resistant foam (AR-AFFF), CO2, dry chemical; regular foam may not be effective
PPE: Level A or B required; SCBA mandatory; full chemical-resistant suit due to extreme toxicity and skin absorption hazard; butyl rubber gloves recommended
Isolation: ERG 131: isolate spill 50m all directions; evacuate 300m downwind for large spills; isolate 800m all directions if tank/rail car involved in fire
— Key Hazards —
• TOXIC; may be fatal if inhaled, ingested or absorbed through skin.
• Inhalation or contact with some of these materials will irritate or burn skin and eyes.
• Methyl chloroacetate (UN2295) is an eye irritant/lachrymator (causes flow of tears).
— 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/1228 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1228 Mercaptan mixture, liquid, flammable, poisonous, n.o.s. Cls3 ERG131 | allfirefighter.com/hazmat/un/1228SMS / 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/1228
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FAQ
TOXIC; may be fatal if inhaled, ingested or absorbed through skin. Inhalation or contact with some of these materials will irritate or burn skin and eyes. Methyl chloroacetate (UN2295) is an eye irritant/lachrymator (causes flow of tears). Fire will produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or asphyxiation, especially when in closed or confined areas. Runoff from fire control or dilution water may cause environmental contamination. HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air.
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 A or B required; SCBA mandatory; full chemical-resistant suit due to extreme toxicity and skin absorption hazard; butyl rubber gloves recommended
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 131 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.