METHYLTRICHLOROSILANE

Diamond	Hazard	Value	Description
3 4 2 W	Health	4	Can be lethal.
	Flammability	3	Can be ignited under almost all ambient temperature conditions.
	Instability	2	Readily undergoes violent chemical changes at elevated temperatures and pressures.
	Special	W	Reacts violently or explosively with water.

A colorless fuming liquid with a pungent odor. Flash point 8°F. Vapor and liquid may cause burns. Denser than water. Vapors are heavier than air.

• Highly Flammable
• Water-Reactive
• Air-Reactive

Highly flammable. Fumes in air. Reacts violently with water, steam, moist air, alcohols, acetone, light metals with generation of heat and combustible (H2) and corrosive (HCl) gases. On contact with air it gives off HCl gas. [Handling Chemicals Safely 1980. p. 924].

Methyltrichlorosilane reacts vigorously with water to generate gaseous HCl. Based on a scenario where the chemical is spilled into an excess of water (at least 5 fold excess of water), half of the maximum theoretical yield of Hydrogen Chloride gas will be created in 1.4 minutes. Experimental details are in the following: "Development of the Table of Initial Isolation and Protective Distances for the 2008 Emergency Response Guidebook", ANL/DIS-09-2, D.F. Brown, H.M. Hartmann, W.A. Freeman, and W.D. Haney, Argonne National Laboratory, Argonne, Illinois, June 2009.

Toxic hydrogen chloride and phosgene gases may form in fires. Reacts with water or steam to form hydrochloric acid. Vapor forms flammable mixture with air. May form explosive mixture in air. Avoid contact with water or moist air. (EPA, 1998)

As with other chlorosilanes, acute exposures may be highly toxic and may cause death or permanent injury after very short exposures to small quantitites. Chronic exposures may be moderately toxic and involve irreversible and reversible changes. Skin contact may produce severe burns with pain and risk of secondary infections. Ingestion may produce oral, esophageal, and stomach burns, intensity will vary from mild to very severe, gastrointestinal damage is rare but may occur. (EPA, 1998)

Chlorosilanes, such as METHYLTRICHLOROSILANE, are compounds in which silicon is bonded to from one to four chlorine atoms with other bonds to hydrogen and/or alkyl groups. Chlorosilanes react with water, moist air, or steam to produce heat and toxic, corrosive fumes of hydrogen chloride. They may also produce flammable gaseous H2. They can serve as chlorination agents. Chlorosilanes react vigorously with both organic and inorganic acids and with bases to generate toxic or flammable gases.

• Chlorosilanes

Use caution: Liquids with this reactive group classification have been known to react with the absorbents listed below.

• Cellulose-Based Absorbents
• Mineral-Based & Clay-Based Absorbents
• Dirt/Earth

Excerpt from 155 [Substances - Toxic and/or Corrosive (Flammable / Water-Sensitive)]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

SPILL: See ERG Table 1 - Initial Isolation and Protective Action Distances on the UN/NA 1250 datasheet.

FIRE: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2020)

Self-contained breathing apparatus is required as combustion/decomposition yields acid gases/pulmonary irritants. Corrosion-resistant protective clothing, as well as appropriate foot, hand, arm, head, eye, and face protection are required where contact is possible.

Dry chemical or carbon dioxide may be used for small fires. Water may be used for large fires if firefighters are protected from violent reaction of methyltrichlorosilane with water. Water may be used to keep containers cool. (EPA, 1998)

Excerpt from 155 [Substances - Toxic and/or Corrosive (Flammable / Water-Sensitive)]:

ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. All equipment used when handling the product must be grounded. Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. A vapor-suppressing foam may be used to reduce vapors. FOR CHLOROSILANES, use AFFF alcohol-resistant medium-expansion foam to reduce vapors. DO NOT GET WATER on spilled substance or inside containers. Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material. Prevent entry into waterways, sewers, basements or confined areas.

SMALL SPILL: Cover with DRY earth, DRY sand or other non-combustible material followed with plastic sheet to minimize spreading or contact with rain. Use clean, non-sparking tools to collect material and place it into loosely covered plastic containers for later disposal. (ERG, 2020)

For emergency situations, wear a positive pressure, pressure-demand, full facepiece self-contained breathing apparatus (SCBA) or pressure- demand supplied air respirator with escape SCBA and a fully-encapsulating, chemical resistant suit. (EPA, 1998)

Normalized Breakthrough Times (in Minutes)

Chemical	CAS Number	State	QS	QC	SL	C3	TF	TP	RC	TK	RF
Methyl trichlorosilane	75-79-6	Liquid				>480	>480	>480	>480	>480	>480

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Warning: In the presence of water, methyltrichlorosilane liberates hydrochloric acid, which is extremely corrosive. Caution is advised.

Signs and Symptoms of Acute Methyltrichlorosilane Exposure: Signs and symptoms of acute ingestion of methyltrichlorosilane may include excessive salivation, intense thirst, difficulty in swallowing, chills, pain, and shock. Oral, esophageal, and stomach burns are common. Vomitus generally has a coffee-ground appearance. The potential for circulatory collapse is high following ingestion of methyltrichlorosilane. Acute inhalation exposure may result in hoarseness, laryngitis, a feeling of suffocation, dyspnea (shortness of breath), choking, respiratory tract irritation, chest pain, and pulmonary edema. Sneezing, bleeding of the nose and gums, and ulceration of the nasal and oral mucosa may also occur. Renal toxicity has been observed in animals. If the eyes have come in contact with methyltrichlorosilane, then irritation, pain, swelling, corneal erosion, and blindness may result. Dermatitis (red, inflamed skin), severe burns, pain, and shock generally follow dermal exposure.

Emergency Life-Support Procedures: Acute exposure to methyltrichlorosilane may require decontamination and life support for the victims. Emergency personnel should wear protective clothing appropriate to the type and degree of contamination. Air-purifying or supplied-air respiratory equipment should also be worn, as necessary. Rescue vehicles should carry supplies such as plastic sheeting and disposable plastic bags to assist in preventing spread of contamination.

Inhalation Exposure:
1. Move victims to fresh air. Emergency personnel should avoid self-exposure to methyltrichlorosilane.
2. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer oxygen or other respiratory support.
3. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.
4. RUSH to a health care facility.

Dermal/Eye Exposure:
1. Remove victims from exposure. Emergency personnel should avoid self- exposure to methyltrichlorosilane.
2. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer oxygen or other respiratory support.
3. Remove contaminated clothing as soon as possible.
4. If eye exposure has occurred, eyes must be flushed with lukewarm water for at least 15 minutes.
5. Wash exposed skin areas THOROUGHLY with soap and water.
6. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.
7. RUSH to a health care facility.

Ingestion Exposure:
1. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer oxygen or other respiratory support.
2. Rinse mouth with large amounts of water. Inform victims not to swallow this water.
3. DO NOT induce vomiting or attempt to neutralize!
4. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.
5. Activated charcoal is of no value.
6. Give the victims water or milk: children up to 1 year old, 125 mL (4 oz or 1/2 cup); children 1 to 12 years old, 200 mL (6 oz or 3/4 cup); adults, 250 mL (8 oz or 1 cup). Water or milk should be given only if victims are conscious and alert.
7. RUSH to a health care facility. (EPA, 1998)

• METHYLSILICON TRICHLORIDE
• METHYLSILYL TRICHLORIDE
• METHYLTRICHLOROSILANE
• SILANE, METHYLTRICHLORO-
• SILANE, TRICHLOROMETHYL-
• TRICHLOROMETHYLSILANE
• TRICHLOROMETHYLSILICON