UN 2381 — Dimethyl disulphide
Placard: Flammable. ERG Guide 131. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2381 At a Glance
UN 2381 (Dimethyl disulphide) is listed as DOT Class 3 Flammable and is assigned to ERG Guide 131. Use this page to review placard data, common hazards, PPE notes, isolation context, first actions, and related UN numbers.
UN 2381 is Dimethyl disulphide, a toxic flammable sulfur-containing liquid assigned to ERG Guide 131. Strong odor does not replace SCBA or air monitoring.
Hazard overview: TOXIC and FLAMMABLE sulfur-containing liquid; inhalation, ingestion or skin absorption may cause serious injury. Vapors may ignite and form explosive mixtures with air. Strong garlic/onion odor may be noticeable, but odor is not a reliable exposure-control method.
Response guidance: For UN 2381, isolate the area, eliminate ignition sources and use SCBA. Keep vapors out of drains, prevent toxic/corrosive runoff and select foam, dry chemical or CO2 using SDS and ERG 131.
Firefighter training notes: Training for UN 2381 should emphasize toxic/corrosive exposure, SCBA use, skin-contact prevention, sewer flashback, decontamination, runoff control and foam selection. Use ERG 131, SDS and local SOP.
Regulatory context: Dimethyl disulphide is regulated as a hazardous material for transport and emergency response. Storage, exposure, spill reporting, waste and fire-code duties depend on quantity, concentration and jurisdiction; verify shipping papers, SDS and local authority requirements.
Storage & handling: Dimethyl disulphide should be stored in approved flammable/toxic or corrosive-liquid containers with ventilation, secondary containment and separation from heat, ignition sources, oxidizers and incompatible materials.
UN 2381 Quick Details
Common Hazards of UN 2381
- TOXIC and FLAMMABLE sulfur-containing liquid; inhalation, ingestion or skin absorption may cause serious injury.
- Vapors may ignite and form explosive mixtures with air.
- Strong garlic/onion odor may be noticeable, but odor is not a reliable exposure-control method.
- Vapors are heavier than air and may travel to ignition sources and flash back.
- Fire may produce sulfur oxides, carbon monoxide and irritating/toxic smoke.
- Runoff may create fire, odor and toxic contamination hazards.
- Containers may rupture or explode when heated.
Chemical Identity & Physical Properties
Colorless to pale yellow liquid with a strong, disagreeable garlic-like or onion-like odor. Volatile and immiscible with water.
| Also known as | DMDSMethyl disulfide2,3-DithiabutaneDimethyl disulfide |
| CAS Number | 624-92-0 |
| Appearance | Colorless to pale yellow liquid with a strong, disagreeable garlic-like or onion-like odor. Volatile and immiscible with water. |
| Flash Point | -15°C (5°F) |
| Boiling Point | 109-110°C (228-230°F) |
| Vapor Density | 3.24 (heavier than air) |
| Water Reactivity | No significant reaction; insoluble in water |
Fireground Response Guidance — UN 2381
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for vapor, fire or confined-space exposure. Wear chemical-resistant gloves, boots, eye/face protection and protective clothing; avoid skin contact.
Isolation & Evacuation
First Actions for a UN 2381 Incident
- Call 911 and the emergency response number on the shipping paper, if available.
- Keep unauthorized personnel away and establish incident command.
- Stay upwind, uphill and upstream; keep responders out of low vapor areas.
- Eliminate ignition sources if this can be done safely.
- Avoid breathing vapor, mist or smoke and avoid skin or eye contact.
- Prevent toxic, alkaline or corrosive runoff from entering drains and waterways.
- Do not touch damaged containers or spilled material without proper training and PPE.
- Ventilate confined spaces only after monitoring and only if properly trained and equipped.
- Use ERG Guide 131, SDS, shipping papers and air monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 2381 — Dimethyl disulphideUse for: Quick radio or face-to-face size-up. Short, structured, field-ready.
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
Use for: Quick text to command or incoming units. Fits in a single SMS.