Hexamethyldisilazane (HMDS)

1. Identification

Product Identifiers

Product Name

Hexamethyldisilazane (HMDS)

Other Names

HMDS

Product Number(s)

C108

CAS Number

999-97-3

Recommended use of the chemical and restriction on use

Company Details

Emergency Contact Details

2. Hazards Identification

Classification of the substance or mixture

Label Elements

Signal Words

None

Hazard Statement(s)

• Highly flammable liquid and vapour.
• Toxic if swallowed.
• Causes skin irritation.
• Causes serious eye irritation.
• May cause respiratory irritation.

Precautionary Statement(s)

• Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
• Ground / bond container and receiving equipment.
• Use explosion-proof [electrical/ventilating/lighting] equipment.
• Use non-sparking tools.
• Take action to prevent static discharge.
• Avoid breathing dust/fume/gas/mist/vapours/spray
• Wash thoroughly after handling.
• Do not eat, drink or smoke when using this product.
• Use only outdoors or in a well-ventilated area.
• Wear protective gloves/protective clothing/eye protection/face protection/hearing protection.

Primary route(s) of entry

Human Health

Inhalation

• In case of irregular breathing or respiratory arrest provide artificial respiration.
• In case of unconsciousness place patient stably in side position for transportation.

Ingestion

Do not induce vomiting; call for medical help immediately. Rinse mouth.

Eyes

Rinse opened eye for several minutes under running water. If symptoms persist, consult a doctor.

Skin

• Immediately remove any clothing soiled by the product.
• Immediately wash with water and soap and rinse thoroughly.

Environment

3. Composition / Information on Ingredients

4. First Aid Measures

Ingestion

Do not induce vomiting; call for medical help immediately.

Inhalation

In case of unconsciousness place patient stably in side position for transportation.

Skin Contact

Immediately wash with water and soap and rinse thoroughly.

Eye Contact

Rinse opened eye for several minutes under running water. If symptoms persist,

Other Information

• Immediately remove any clothing soiled by the product.
• In case of irregular breathing or respiratory arrest provide artificial respiration.

5. Firefighting Measures

Suitable extinguishing equipment

Fire

CO₂, sand, extinguishing powder. Do not use water.For safety reasons unsuitable extinguishing agents: Water with full jet

HAZCHEM

Not available.

Special protective equipment and precautions for fire fighters

6. Accidental Release Measures

Personal precautions, protective equipment and emergency procedures

Wear protective equipment. Keep unprotected persons away.

Environmental precautions

Do not allow to enter sewers/ surface or ground water. Dilute with plenty of water

Methods and materials for containment and clean up

• Absorb with liquid-binding material (sand, diatomite, acid binders, universal binders, sawdust).
• Dispose contaminated material as waste according to item 13.
• Ensure adequate ventilation.
• Do not flush with water or aqueous cleansing agents

7. Handling and Storage

Precautions for safe handling

• Advice on safe handling
• Work under hood. Do not inhale substance/mixture. Avoid generation of vapours/aerosols.
• Advice on protection against fire and explosion
• Flash back possible over considerable distance.Container explosion may occur under fire
• conditions.Keep away from open flames, hot surfaces and sources of ignition.Take
• precautionary measures against static discharge.
• Hygiene measures
• Immediately change contaminated clothing. Apply preventive skin protection. Wash hands
• and face after working with substance.

Conditions for safe storage

• Handle under nitrogen, protect from moisture. Store under nitrogen.
• Keep container tightly closed in a dry and well-ventilated place. Keep away from heat and
• sources of ignition. Keep locked up or in an area accessible only to qualified or authorised
• persons.
• Hydrolyzes readily.
• Storage class
• Storage class (TRGS 510): 3: Flammable liquids

8. Exposure Controls / Personal Protection

Exposure Standards

Engineering controls

Contains no substances with occupational exposure limit values.

Personal protective equipment

Eye and face protection

• Avoid contact with the eyes.
• Wear tightly sealed goggles.

Skin protection

• This recommendation applies only to the product stated in the safety data sheet, supplied by us and for the designated use. When dissolving in or mixing with other substances and under conditions deviating from those stated in EN 16523-1 please contact the supplier of CE-approved gloves (e.g. KCL GmbH, D-36124 Eichenzell, Internet: www.kcl.de).
• Full contact
• Material: Nitrile rubber
• Minimum layer thickness: 0.4 mm
• Break through time: 480 min
• Material tested:Camatril® (KCL 730 / Aldrich Z677442, Size M)
• This recommendation applies only to the product stated in the safety data sheet, supplied by us and for the designated use. When dissolving in or mixing with other substances and under conditions deviating from those stated in EN 16523-1 please contact the supplier of CE-approved gloves (e.g. KCL GmbH, D-36124 Eichenzell, Internet: www.kcl.de).
• Splash contact
• Material: Chloroprene
• Minimum layer thickness: 0.65 mm
• Break through time: 240 min
• Material tested:KCL 720 Camapren®

Body protection

• Keep away from foodstuffs, beverages and feed.
• Immediately remove all soiled and contaminated clothing
• Flame retardant antistatic protective clothing.

Respiratory protection

required when vapours/aerosols are generated. Our recommendations on filtering respiratory protection are based on the following standards: DIN EN 143, DIN 14387 and other accompanying standards relating to the used respiratory protection system.

9. Physical and Chemical Properties

General information

Appearance

Colourless liquid

Odour

Ammonia-like

pH

8.5

Vapour Pressure

0.774 g/cm³

Density

0.774 g/mL at 25 °C

Boiling Point

126 °C

Melting Point

-82 °C

Solubility

insoluble

Specific Gravity of Density

0.774 g/cm³

Flash Point

11 °C

Flammable (Explosive) Limits

• Not applicable.
• Product is not explosive. However, formation of explosive air/vapour mixtures are possible.

Ignition Temperature

380.0 °C

Formula

Not available.

10. Stability and Reactivity

Reactivity

Vapors may form explosive mixture with air.

Chemical stability

The product is chemically stable under standard ambient conditions (room temperature). Hydrolyzes readily.

Possibility of hazardous reactions

No further relevant information available.

Conditions to avoid

Ammonia is formed upon contact with water or humid air. Warming.

Incompatible materials

No further relevant information available.

11. Toxicological Information

Acute effects

• Acute toxicity
• LD50 Oral - Rat - male and female - 851 mg/kg
• (OECD Test Guideline 401)
• LC50 Inhalation - Rat - male and female - 6 h - 10 mg/l
• (OECD Test Guideline 403)
• LD50 Dermal - Rabbit - male and female - 547 - 589 mg/kg
• (OECD Test Guideline 402)

Eye contact

Irritating effect.

Skin contact

Irritant to skin and mucous membranes.

Ingestion

No further relevant information available.

Inhalation

No further relevant information available.

Toxicity and irritation

• Repeated dose toxicity - Rat - male and female - inhalation (vapour)
• RTECS: JM9230000
• Material is extremely destructive to tissue of the mucous membranes and upper respiratorytract, eyes, and skin., spasm, inflammation and edema of the larynx, spasm, inflammation and edema of the bronchi, pneumonitis, pulmonary edema, burning sensation, Cough, wheezing, laryngitis, Shortness of breath, Headache, Nausea, Vomiting, To the best of our knowledge, the chemical, physical, and toxicological properties have not been thoroughly investigated.

12. Ecological Information

Ecotoxicity

• Toxicity to fish semi-static test LC50 - Danio rerio (zebra fish) - 88 mg/l - 96 h (Directive 67/548/EEC, Annex V, C.1.)
• Toxicity to daphnia and other aquatic invertebrates static test EC50 - Daphnia magna (Water flea) - 80 mg/l - 48 h (Directive 67/548/EEC, Annex V, C.2.)
• Toxicity to algae EC50 - Desmodesmus subspicatus (green algae) - 19.00 mg/l - 72 h

Persistence and degradability

• Biodegradability aerobic - Exposure time 28 d
• Result: 15.3 % - Not readily biodegradable.
• (Directive 67/548/EEC Annex V, C.4.E.)

Bioaccumulative potential

No further relevant information available.

Other adverse effects

No further relevant information available.

13. Disposal Considerations

General information

14. Transport Information

ADG label required

HAZCHEM

Not available.

UN Number

UN3286

Proper shipping name

• DOT Flammable liquid, toxic, corrosive, n.o.s.
• ADR 3286 FLAMMABLE LIQUID, TOXIC, CORROSIVE, N.O.S.
• IMDG, IATA FLAMMABLE LIQUID, TOXIC, CORROSIVE, N.O.S.

Transport hazard class

3 Flammable liquids

Packing group

PG II

Environmental hazard

Marine pollutant

Special precautions for users

• Special precautions for user Warning: Flammable liquids
• Hazard identification number (Kemler code): 33
• EMS Number: F-E,S-E

Additional information

None

15. Regulatory Information

Poisons Schedule Number

• Therapeutic Goods (Poisons Standard) : No poison schedule number
• Instrument allocated

Other Information

• Sara
• Section 355 (extremely hazardous substances):
• Substance is not listed.
• Section 313 (Specific toxic chemical listings):
• Substance is not listed.
• TSCA (Toxic Substances Control Act):
• ACTIVE
• Hazardous Air Pollutants
• Substance is not listed.
• Proposition 65
• Chemicals known to cause cancer:
• Substance is not listed.
• Chemicals known to cause reproductive toxicity for females:
• Substance is not listed.
• Chemicals known to cause reproductive toxicity for males:
• Substance is not listed.
• Chemicals known to cause developmental toxicity:
• Substance is not listed.
• Carcinogenic categories
• EPA (Environmental Protection Agency)
• Substance is not listed.
• TLV (Threshold Limit Value)
• Substance is not listed.
• NIOSH-Ca (National Institute for Occupational Safety and Health)
• Substance is not listed.

16. Other Information

SDS preparation date

24 February 2026

Comments

• Abbreviations and acronyms:
• ADR: Accord relatif au transport international des marchandises dangereuses par route (European Agreement Concerning the International
• Carriage of Dangerous Goods by Road)
• IMDG: International Maritime Code for Dangerous Goods
• DOT: US Department of Transportation
• IATA: International Air Transport Association
• EINECS: European Inventory of Existing Commercial Chemical Substances
• CAS: Chemical Abstracts Service (division of the American Chemical Society)
• NFPA: National Fire Protection Association (USA)
• HMIS: Hazardous Materials Identification System (USA)
• VOC: Volatile Organic Compounds (USA, EU)
• PBT: Persistent, Bioaccumulative and Toxic
• vPvB: very Persistent and very Bioaccumulative
• NIOSH: National Institute for Occupational Safety
• OSHA: Occupational Safety Health
• TLV: Threshold Limit Value
• PEL: Permissible Exposure Limit
• REL: Recommended Exposure Limit
• Flammable liquids 2: Flammable liquids - Category 2
• Acute toxicity - oral 3: Acute toxicity - Category 3
• Skin irritation 2: Skin corrosion/irritation - Category 2
• Eye irritation 2A: Serious eye damage/eye irritation - Category 2A
• Specific target organ toxicity (single exposure) 3: Specific target organ toxicity (single exposure) - Category 3

References

• SDS EMS (HMDS) HEXAMETHYLDISILAZANE, REAGENT 20/04/2022 https://www.emsdiasum.com/docs/technical/msds/16700.pdf
• Merk SDS Hexamethyldisilazane 18.12.2024 https://www.sigmaaldrich.com/AU/en/sds/sial/52619-userType=anonymous