UN 2936 — Thiolactic acid
Placard: Toxic. ERG Guide 153. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
Thiolactic acid is a corrosive organic acid assigned to ERG 153. It can burn skin and eyes, produce irritating vapors or mists and create acidic runoff during spills or fire control.
Hazard overview: The primary hazard is corrosive contact with liquid or mist. Heating can release irritating sulfur-containing and acidic gases, while incompatible oxidizers or bases may intensify the reaction.
Response guidance: Isolate the release, stay upwind and avoid direct contact. Use dry chemical, CO2, alcohol-resistant foam or water spray for surrounding fire and container cooling, while preventing acidic runoff from entering drains.
Firefighter training notes: Train responders to handle corrosive organic acid spills with splash control, vapor awareness, decontamination planning and runoff containment.
Regulatory context: UN 2936 is a regulated corrosive hazardous material. Verify concentration, packing group and emergency response contact from the SDS and shipping papers.
Storage & handling: Store in corrosion-resistant containers in a cool, ventilated area away from oxidizers, bases, metals and ignition sources.
UN 2936 Quick Details
Common Hazards of UN 2936
- Thiolactic acid is corrosive and can cause burns to skin and eyes.
- Vapor or mist may irritate the respiratory tract and may be harmful if inhaled.
- Combustible liquid; may burn when heated though it does not ignite as readily as low-flash liquids.
- Fire may produce sulfur oxides, carbon oxides and irritating acidic gases.
- Reaction with strong oxidizers or bases may generate heat.
- Runoff may be acidic and harmful to waterways.
- Containers may rupture when heated.
Chemical Identity & Physical Properties
Thiolactic acid is generally a liquid organic acid with a strong, unpleasant sulfur-like odor. It should be treated as corrosive even when appearance seems ordinary.
| Also known as | 2-Mercaptopropionic acidalpha-Mercaptopropionic acidThiolatic acid2-Sulfanylpropanoic acid |
| CAS Number | 79-42-5 |
| Appearance | Colorless to pale yellow liquid with a strong unpleasant mercaptan odor. Corrosive and toxic. |
| Flash Point | 107°C (225°F) |
| Boiling Point | 116°C (241°F) at 15 mmHg |
| Vapor Density | 3.7 (heavier than air) |
| Water Reactivity | No violent reaction expected, but dilution can generate heat and acidic runoff |
Fireground Response Guidance — UN 2936
Extinguishing Media
PPE Requirements
Use chemical-resistant gloves, boots, eye and face protection and protective clothing. SCBA is recommended for fire, mist, vapor or confined-space conditions.
Isolation & Evacuation
First Actions for a UN 2936 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; avoid low areas where vapors may collect.
- Avoid breathing vapors, dust, mist, smoke or fire gases.
- Do not touch damaged containers or spilled material without proper PPE.
- Ventilate confined spaces only if trained, equipped and authorized.
- Use ERG, SDS, shipping papers, labels and monitoring results for final tactical decisions.
📋 Copy & Share Field Card
UN 2936 — Thiolactic 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.