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Chemical name: Hexamethyldisilazane
Synonyms: HMDS, 1,1,1,3,3,3-hexamethyldisilazane
Chemical formula: C6H19NSi2
CAS number: 999-97-3
Appearance: Clear, colorless liquid with strong ammonia-like odor
Common uses: Surface modifier in semiconductor manufacturing, water repellent applications, organic synthesis
Route of exposure: Inhalation, skin contact, eye contact, ingestion
Classification: Flammable liquid, irritant
Physical hazards: Can ignite easily and forms explosive mixtures with air
Health risks: May cause irritation to skin, eyes, respiratory tract
Environmental impact: Harmful to aquatic life, may persist in the environment
Specific symptoms: Exposure can trigger coughing, sore throat, redness; vapors may cause headaches, dizziness
Pictogram indicators: Flammable, harmful, irritant
Main ingredient: Hexamethyldisilazane (approx. 100 percent)
Impurities: Trace amounts of ammonia and organic siloxanes sometimes detected in manufacturing environments
Nature of mixture: Pure compound, not a blend
Skin contact: Rinse affected area thoroughly with soap and water, remove contaminated clothing
Eye contact: Flush eyes with plenty of water for several minutes, seek medical advice
Inhalation: Move person to fresh air, keep at rest; if breathing problems arise, consult medical professionals
Ingestion: Do not induce vomiting, rinse mouth and seek immediate medical attention
Immediate medical attention: Advisable for significant exposure, especially if symptoms persist
Suitable extinguishing media: Alcohol-resistant foam, dry chemical, carbon dioxide
Hazardous combustion products: May emit ammonia, nitrogen oxides, silicon oxides upon burning
Firefighting precautions: Use full protective gear, self-contained breathing apparatus
Special fire risks: Vapors may travel, flashbacks possible
Cooling measures: Water spray to cool containers not yet ignited
Personal precautions: Evacuate area, ensure proper ventilation, keep away from ignition sources
Protective equipment: Chemical-resistant gloves, eye protection, flame-resistant clothing
Spill containment: Absorb spills using inert material; avoid direct drainage into waterways
Cleanup methods: Collect contaminated material in tightly sealed containers for safe disposal
Evacuation: Necessary for large releases, or in case of fire
Handling advice: Use in well-ventilated workspaces, prevent static discharge, ground all equipment
Incompatible materials: Strong oxidizers, acids, moisture
Storage requirements: Store in cool, dry area, out of direct sunlight, in containers tightly closed
Segregation: Keep away from food, feed, and incompatible substances
Special storage notes: Regular container checks, spill trays recommended
Exposure limits: No established US OSHA PEL; recommendations suggest minimizing contact by practical means
Ventilation: Local exhaust systems preferred
Personal protection: Wear chemical splash goggles, gloves (nitrile or neoprene), flame-resistant clothing, face shield for splash risk
Hygiene measures: Wash hands after use, prevent contact with face while working
Respiratory protection: Organic vapor respirators fit for the task
Physical state: Liquid
Color: Colorless
Odor: Ammonia-like
Melting point: -60°C
Boiling point: 126°C
Flash point: 41°C (closed cup)
Solubility: Slightly soluble in water, readily soluble in organic solvents
Vapor pressure: Notably high at room temperature, presents inhalation hazard
Density: 0.77 g/cm³
Chemical stability: Stable under recommended conditions
Reactivity: Reacts with water, alcohols, acids, oxidizing agents
Hazardous decomposition: Ammonia, silicon oxides may form in fire
Polymerization: Not anticipated under normal handling
Acute toxicity: Vapors and liquid irritate mucous membranes, eyes, skin
Inhalation effects: Respiratory discomfort, coughing, drowsiness with high exposure
Dermal impacts: Redness, dryness, potential irritation
Chronic exposure: Data limited; prolonged contact may raise skin and respiratory issues
Carcinogenicity: Not listed as carcinogenic by NTP, IARC, or OSHA.
Aquatic toxicity: Harmful to aquatic organisms, possible long-term effects on bodies of water
Persistence: Resistant to biodegradation under normal environmental conditions
Bioaccumulation: Low potential expected, yet due to persistence caution is wise
Waste treatment: Dispose as hazardous organic chemical waste, incineration preferred method in licensed facilities
Precautions: Avoid dumping into sewers or public waterways
Special regulations: Consult local and regional authority for specific disposal rules
UN number: UN 1993
Transport hazard class: 3 (Flammable liquid)
Packaging: Use adequate leak-proof, chemical-resistant containers designed for flammable liquids
Shipping advice: Keep away from heat, secure upright during transit
Regulations: Subject to IATA, ADR, IMDG transport requirements for hazardous materials
Safety labeling: Required by OSHA GHS, European REACH
Restrictions: Use limited by flammable liquid and toxic chemical rules in many regions
Workplace requirements: Mandates safety training, emergency response preparation
Reporting obligations: May apply based on volume, region, and industrial use case
