UN 1595 — Dimethyl sulphate
Placard: Toxic. ERG Guide 156. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1595 is Dimethyl sulphate, a highly toxic corrosive liquid assigned to ERG Guide 156. It can be absorbed through skin or inhaled as vapor, and exposure effects may be delayed.
Hazard overview: UN 1595 presents toxic inhalation, skin absorption, corrosive runoff and combustible vapor hazards. Water contact slowly forms acidic decomposition products, and fire may produce toxic sulfur-containing gases.
Response guidance: For a UN 1595 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 156. Establish incident command, isolate the area, stay upwind, prevent dust or vapor exposure, control runoff and choose entry or cleanup actions based on monitoring, SDS and local SOP.
Firefighter training notes: Training for UN 1595 should emphasize delayed toxic effects, skin absorption, corrosive runoff, vapor control, decontamination and strict entry control. Use ERG 156, SDS and hazmat SOP.
Regulatory context: Dimethyl sulphate is regulated as a hazardous material for transportation and emergency response purposes. Transportation, workplace exposure, spill reporting, waste handling, storage and environmental requirements may vary by formulation, concentration, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, facility documents and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Dimethyl sulphate should be stored in tightly closed compatible containers in a secure, cool, dry, well-ventilated toxic/corrosive area away from water contamination, bases, strong oxidizers, heat and unauthorized access. Secondary containment and decontamination planning should follow SDS.
UN 1595 Quick Details
Common Hazards of UN 1595
- HIGHLY TOXIC and corrosive alkylating liquid; inhalation, ingestion or skin contact may cause severe injury or death.
- Delayed symptoms may occur after inhalation or skin exposure.
- Combustible liquid; vapors may form ignitable mixtures when heated.
- Vapors are heavier than air and may collect in low or confined areas.
- Water contact slowly forms acidic and toxic decomposition products and can increase corrosive runoff.
- Fire may produce sulfur oxides, corrosive vapors and toxic gases.
- Containers may rupture or explode when heated.
Chemical Identity & Physical Properties
Colorless to pale yellow oily liquid with a faint onion-like odor. Denser than water and sinks.
| Also known as | DMSMethyl sulfateSulfuric acid dimethyl esterDimethylsulfatDMSO4 |
| CAS Number | 77-78-1 |
| Appearance | Colorless to pale yellow oily liquid with a faint onion-like odor. Denser than water and sinks. |
| Flash Point | 83°C (182°F) |
| Boiling Point | 188°C (370°F) |
| Vapor Density | 4.35 (heavier than air) |
| Water Reactivity | Reacts slowly with water forming sulfuric acid and methanol; reaction accelerates with heat producing corrosive and flammable decomposition products |
Fireground Response Guidance — UN 1595
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA and full chemical protective clothing selected by hazmat specialists. Level A may be needed for close entry or unknown vapor levels because inhalation and skin absorption can be severe and delayed.
Isolation & Evacuation
First Actions for a UN 1595 Incident
- CALL 911. Then call the emergency response telephone number on the shipping paper, if available.
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Avoid breathing vapors, fumes, dust or mist and avoid all skin or eye contact.
- Eliminate ignition sources if it is safe to do so and keep vapors out of drains, sewers and low areas.
- Do not touch or walk through spilled material unless properly trained and wearing appropriate protective equipment.
- Ventilate closed spaces before entering, but only if properly trained, equipped, monitored and authorized by incident command.
- Isolate the spill or leak area and expand the perimeter if vapor, dust, fire involvement or unknown concentration is present.
- Use ERG Guide 156, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1595 — Dimethyl sulphateUse 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.