Dichlorodimethylsilane

Avoid contact with skin, eyes, or clothing. Wear acid-vapor respirator, rubber gloves, chemical worker's goggles, other protective and corrosive-resistant equipment as needed. Runoff from fire control or dilution water may cause pollution. Isolate for one-half mile in all directions if tank car or truck involved in fire.

Use AFFF, carbon dioxide, dry sand, special powder. NO hydrous agents. NO water. In case of fire: keep drums, etc., cool by spraying with water. NO direct contact with water.

Fresh air, rest. Half-upright position. Artificial respiration may be needed. Refer for medical attention.

Remove contaminated clothes. Rinse skin with plenty of water or shower. Refer for medical attention .

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Rinse mouth. Do NOT induce vomiting. Give nothing to drink. Refer for medical attention .

· CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.

· ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area.

Signs and Symptoms of Acute Dimethyldichlorosilane Exposure: Signs and symptoms of acute ingestion of dimethyldichlorosilane may be severe and include increased salivation, intense thirst, difficulty 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 dimethyldichlorosilane. Acute inhalation exposure may result in sneezing, choking, laryngitis, dyspnea (shortness of breath), respiratory tract irritation, and chest pain. Bleeding of nose and gums, ulceration of the nasal and oral mucosa, pulmonary edema, chronic bronchitis, and pneumonia may also occur. If the eyes have come in contact with dimethyldichlorosilane, irritation, pain, swelling, corneal erosion, and blindness may result. Dermatitis (red, inflamed skin), severe burns, pain, and shock generally follow dermal exposure.

General First Aid:

· Wear positive pressure self-contained breathing apparatus (SCBA).

TIH (Toxic Inhalation Hazard) - Term used to describe gases and volatile liquids that are toxic when inhaled. Some are TIH materials themselves, e.g., chlorine, and some release TIH gases when spilled in water, e.g., chlorosilanes. [ERG 2016].

If material on fire or involved in fire: Do not extinguish fire unless flow can be stopped. Use alcohol foam, dry chemical, or carbon dioxide. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. Do not use water on material itself. If large quantities of combustibles are involved, use water in flooding quantities as spray and fog. Use water spray to knock-down vapors.

... Wear positive pressure self-contained breathing apparatus ... Wear appropriate chemical protective clothing ...

Approach fire from upwind to avoid hazardous vapors and toxic decomposition products. Use water spray to keep fire-exposed containers cool.

Isolate for one-half mile in all directions if tank car or truck involved in fire. Vapors are heavier than air and will collect in low areas. Vapors may travel long distances to ignition sources and flashback. Vapors in confined areas may explode when exposed to fire. Containers may explode in fire. Storage containers and parts of containers may rocket great distances, in many directions ... From a secure, explosion-proof location, use water spray to cool exposed containers. If cooling streams are ineffective (venting sound increases in volume and pitch, tank discolors, or shows any signs of deforming), withdraw immediately to a secure position.

SRP: Operations involving entry into tanks or closed vessels, and emergency situations, require consideration of potentially oxygen deficient, or "immediately dangerous to life and health" IDLH environments. This may necessitate use of a self-contained breathing apparatus (SCBA), or a positive pressure supplied air respirator.

Dimethyldichlorosilane must be stored to avoid contact with oxidizers (such as perchlorates, peroxides, permanganates, chlorates, and nitrates) since violent reactions occur. Before entering confined space where this chemical may be present, check to make sure that an explosive concentration does not exist. Store in tightly closed containers in a cool, well-ventilated area away from water, steam, or moisture because toxic and corrosive hydrogen chloride gas can be produced. Do not store at temperatures above 122 °F/50 °C. Sources of ignition, such as smoking and open flames, are prohibited where dimethyldichlorosilane is handled, used, or stored. Metal containers involving the transfer of 5 gallons or more of dimethyl dichlorosilane should be grounded and bonded. Drums must be equipped with self-closing valves, pressure vacuum bungs, and flame arresters. Use only nonsparking tools and equipment, especially when opening and closing containers of dimethyldichlorosilane.

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.

Use water spray to cool and disperse vapors and protect personnel. Control runoff and isolate discharged material for proper disposal.

Evacuate and restrict persons not wearing protective equipment from area of spill or leak until cleanup is complete. Remove all ignition sources. Establish forced ventilation to keep levels below explosive limit. Use water spary to reduce vapors; however do not get water inside containers. Small spills: absorb liquids in vermiculite, dry sand, earth, peat, carbon, or a similar material and deposit in sealed containers. Large spills: dike far ahead of spill for later disposal. Use effective fume removal device. Keep this chemical out of a confined space, such as a sewer, because of the possibility of an explosion, unless the sewer is designed to prevent the build-up of explosive concentrations. It may be necessary to contain and dispose of this chemical as a hazardous waste. If material or contaminated runoff enters waterways, notify downstream users of potentially contaminated waters.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal and plant life; and conformance with environmental and public health regulations.

AQUATIC FATE: In water, chlorosilanes are hydrolyzed rapidly, releasing hydrochloric acid. /Chlorosilane/

ATMOSPHERIC FATE: In the trophosphere, the ultimate fate of chlorosilane is probably determined by hydrolysis of the silicon-chlorine bonds in water droplets. /Chlorosilanes/

ATMOSPHERIC FATE: In arid regions, some transport of chlorosilanes to the stratosphere might occur. In the stratosphere, photolysis by short wavelength light is expected. /Chlorosilanes/

Burning sensation. Cough. Sore throat. Laboured breathing. Shortness of breath. Symptoms may be delayed.

Redness. Pain. Blisters. Skin burns.

Redness. Pain. Severe deep burns.

Burning sensation. Abdominal pain. Shock or collapse.

/SIGNS AND SYMPTOMS/ Acute inhalation exposure may result in sneezing, choking, laryngitis, dyspnea (shortness of breath), respiratory tract irritation, and chest pain. Higher exposure can cause pulmonary edema, a medical emergency that can be delayed for several hours. This can cause death. Bleeding of nose and gums, ulceration of the nasal and oral mucosa, pulmonary edema, chronic bronchitis, and pneumonia may also occur. If the eyes have come in contact with dimethyldichlorosilane, irritation, pain, swelling, corneal erosion, and blindness may result. Dermatitis (red, inflamed skin), severe burns, pain, and shock generally follow dermal exposure. Inhalation irritates mucous membranes. Severe gastrointestinal damage may occur. Vapors cause severe eye and lung injury. Upon short contact, second and third degree burns may occur. Signs and symptoms of acute ingestion of dimethyldichlorosilane may be severe and include increased salivation, intense thirst, difficulty swallowing, chills, pain, and shock. Oral, esophageal, and stomach burns are common. /Dimethyldichlorosilane/

/SIGNS AND SYMPTOMS/ Causes severe eye and skin burns. Serious health hazard. May be harmful if inhaled. Irritating to eye, skin, and respiratory system.

/SIGNS AND SYMPTOMS/ Inhalation irritates mucous membranes. Contact with liq causes severe burns of eyes and skin ... Vapors cause severe irritation of eyes and throat and can cause eye and lung injury. They cannot be tolerated even at low concn. Causes second- and third-degree burns on short contact ...

/SIGNS AND SYMPTOMS/ Dichlorodimethylsilane causes severe burns. Vapor is harmful.

For more Human Toxicity Excerpts (Complete) data for Dimethyldichlorosilane (7 total), please visit the HSDB record page.

/LABORATORY ANIMALS: Acute Exposure/ The Skin2 1350 and CORROSITEX assays were used to evaluate skin irritancy of hexamethyldisiloxane, aminofunctional siloxane polymer (Q2-8075), tetraethoxysilane, hexamethyldisilazane, trimethylchlorosilane, dimethyldichlorosilane, tetramethyloxysilane, ETS-900, ethyltriacetoxysilane, and phenyltriacetoxysilane to assess their ability to predict the skin corrosivity potential of these materials. ... The results obtained with the two assays were compared with those obtained previously with the standard in-vivo rabbit assay. CORROSITEX correctly identified trimethylchlorosilane, dimethyldichlorosilane, ethyltriacetoxysilane, ETS-900, and phenyltriacetoxysilane, the five corrosive compounds in the set, as corrosive. CORROSITEX classified hexamethyldisilazane as corrosive, whereas the in-vivo test indicated that it was only minimally irritating. CORROSITEX could not evaluate the other four compounds, all noncorrosive, because they did not react with the biobarrier. The Skin2 1350 assay correctly classified all ten materials as to their corrosivity and noncorrosivity, but underpredicted the corrosive potential of the five corrosive substances...

/LABORATORY ANIMALS: Acute Exposure/ Dichlorodimethylsilane is of moderate acute toxicity to rats when administered by stomach tube (oral LD50 595 mg/kg bw) and on inhalation exposure (4-hour LC50 4.91 mg/L, 1-hour LC50 12.5 mg/L or in the range of 16 to 25 mg/L, respectively). Signs of toxicity include ruffled fur, increased salivation, general malaise, breathing difficulties and sedation. The rats that died showed effects on the gastrointestinal tract, pancreas, liver and kidneys, and after inhalation exposure lung damage.

/LABORATORY ANIMALS: Acute Exposure/ The vapor is of high acute toxicity to mice (2-hour LC50 0.3 mg/L), these much lower concentrations resulting in mucosal irritation, breathlessness, agitated motor activity spreading of hind limbs and laying on the stomach; the mice that died showed various changes in the lungs, liver, kidneys, spleen, heart and brain.

/LABORATORY ANIMALS: Acute Exposure/ Application of dichlorodimethylsilane to the skin or eyes of rabbits produces severe irritation or corrosion, and the vapor is also irritating to the eyes of mice, rats and rabbits.

For more Non-Human Toxicity Excerpts (Complete) data for Dimethyldichlorosilane (10 total), please visit the HSDB record page.

Silane compounds decompose upon contact with water or steam to produce heat and toxic and corrosive fumes of hydrogen chloride(1,2). The complete hydrolysis of dimethyldichlorosilane leads to an oligomer mixture consisting of cyclic dimethylsiloxanes and hydroxyl-terminated dimethylsiloxanes(3). Silane ignites spontaneously in air(1,2). With a little ammonia, it forms a self-igniting product(1). /Chlorosilanes/

According to the 2006 TSCA Inventory Update Report, the number of persons reasonably likely to be exposed in the industrial manufacturing, processing, and use for dichlorodimethylsilane is 1000 or greater; the data may be greatly underestimated(1).

NIOSH (NOES Survey 1981-1983) has statistically estimated that 57 workers (none of these were female) were potentially exposed to dichlorodimethylsilane in the US(1).

Chlorosilane compounds' production and use as intermediates for silicone products may result in their release to the environment through various waste streams. However, these compounds decompose to release hydrogen chloride upon contact with water or steam. Therefore, volatilization, biodegradation, and bioconcentration are not expected to be important environmental fate processes. /Chlorosilanes/ (SRC)

Releases of CERCLA hazardous substances are subject to the release reporting requirement of CERCLA section 103, codified at 40 CFR part 302, in addition to the requirements of 40 CFR part 355. Dimethyldichlorosilane is an extremely hazardous substance (EHS) subject to reporting requirements when stored in amounts in excess of its threshold planning quantity (TPQ) of 500 lbs.

Dimethyldichlorosilane

1

10000

A Commercial Grade

A Placarded Amount

Flammable chemical that can be released at a facility.