UN 2436 — Thioacetic acid
Placard: Flammable. ERG Guide 129. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2436 is Thioacetic acid, a flammable sulfur-containing acid assigned to ERG Guide 129. Vapor flashback and sulfur/acid decomposition products are key concerns.
Hazard overview: FLAMMABLE sulfur-containing acid liquid; vapors may ignite and form explosive mixtures with air. Vapors are heavier than air and may travel to ignition sources and flash back. Hydrolysis may form acetic acid and hydrogen sulfide-type odor/toxic concerns.
Response guidance: For UN 2436, isolate the area, eliminate ignition sources, keep vapors out of drains and use SCBA. Use foam, dry chemical or CO2 as compatible and contain sulfur/acid contaminated runoff.
Firefighter training notes: Training for UN 2436 should emphasize toxic/corrosive exposure routes, skin absorption, SCBA use, decontamination, runoff containment and SDS verification. Use ERG 129, SDS and local SOP.
Regulatory context: Thioacetic acid 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: Thioacetic acid should be stored in tightly closed compatible containers in a secure toxic/corrosive-material area with ventilation, secondary containment, restricted access and SDS-based segregation.
UN 2436 Quick Details
Common Hazards of UN 2436
- FLAMMABLE sulfur-containing acid liquid; vapors may ignite and form explosive mixtures with air.
- Vapors are heavier than air and may travel to ignition sources and flash back.
- Hydrolysis may form acetic acid and hydrogen sulfide-type odor/toxic concerns.
- Liquid or vapor may irritate or burn eyes, skin and respiratory tissue.
- Fire may produce sulfur oxides, carbon monoxide and irritating/toxic smoke.
- Runoff to sewers may create fire, odor and toxic/corrosive contamination hazards.
- Containers may rupture or explode when heated.
Chemical Identity & Physical Properties
Clear to pale yellow liquid with a strong, unpleasant sulfur or rotten cabbage odor. Liquid at room temperature.
| Also known as | Ethanethioic acidThioacetic acidMercaptoacetic acidThiolacetic acid |
| CAS Number | 507-09-5 |
| Appearance | Clear to pale yellow liquid with a strong, unpleasant sulfur or rotten cabbage odor. Liquid at room temperature. |
| Flash Point | 18°C (64°F) |
| Boiling Point | 93°C (199°F) |
| Vapor Density | 2.6 (heavier than air) |
| Water Reactivity | Hydrolyzes slowly in water forming acetic acid and hydrogen sulfide; no violent reaction |
Fireground Response Guidance — UN 2436
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for vapor, fire or confined-space exposure. Wear chemical-resistant gloves, boots, eye/face protection and flame-resistant protection as appropriate.
Isolation & Evacuation
First Actions for a UN 2436 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.
- Eliminate ignition sources if this can be done safely.
- Avoid breathing vapor, dust, mist, smoke or fumes and avoid skin or eye contact.
- 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 129, SDS, shipping papers and monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 2436 — Thioacetic acidUse 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.