Tetramethylsilane

· 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.

Excerpt from ERG Guide 130 [Flammable Liquids (Water-Immiscible / Noxious)]:

General First Aid:

If material on fire or involved in fire: Do not extinguish fire unless flow can be stopped. Use water in flooding quantities as fog. Solid streams of water may spread fire. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. Use foam, dry chemical, or carbon dioxide.

Wear positive pressure self-contained breathing apparatus when fighting fires involving this material.

Suitable extinguishing media: For small (incipient) fires, use media such as "alcohol" foam, dry chemical, or carbon dioxide. For large fires, apply water from as far as possible. Use very large quantities (flooding) of water applied as a mist or spray; solid streams of water may be ineffective. Cool all affected containers with flooding quantities of water. ... Use water spray to cool unopened containers.

Special protective equipment for fire-fighters: Wear self contained breathing apparatus for fire fighting if necessary.

Store in cool place. Keep container tightly closed in a dry and well-ventilated place. Containers which are opened must be carefully resealed and kept upright to prevent leakage. Recommended storage temperature: 2 - 8 °C Over time, pressure may increase causing containers to burst. Handle and open container with care.

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.

Methods for cleaning up: Contain spillage, and then collect with non-combustible absorbent material, (e.g. sand, earth, diatomaceous earth, vermiculite) and place in container for disposal according to local / national regulations. Personal precautions: Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Remove all sources of ignition. Evacuate personnel to safe areas. Beware of vapors accumulating to form explosive concentrations. Vapors can accumulate in low areas.

Environmental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains.

Burn in a chemical incinerator equipped with an afterburner and scrubber but exert extra care in igniting as this material is highly flammable. Observe all federal, state, and local environmental regulations. Contact a licensed professional waste disposal service to dispose of this material.

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.

SRP: The scientific literature for the use of contact lenses by industrial workers is inconsistent. The benefits or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.

SRP: Contaminated protective clothing should be segregated in a manner that results in no direct personal contact by personnel who handle, dispose of, or clean the clothing. Quality assurance procedures to confirm the efficacy of the cleaning procedures should be implemented prior to the decontaminated protective clothing being returned for reuse by the workers. Contaminated clothing (including shoes/socks) should not be taken home at end of shift, but should remain at employee's place of work for cleaning.

If material not on fire and not involved in fire: Keep sparks, flames, and other sources of ignition away. Keep material out of water sources and sewers. Build dikes to contain flow as necessary. Attempt to stop leak if without undue personnel hazard. Use water spray to knock-down vapors.

Avoid breathing vapors. Keep upwind. Avoid bodily contact with the material. Do not handle broken packages unless wearing appropriate personal protective equipment. Wash away any material which may have contacted the body with copious amounts of water or soap and water.

For more Preventive Measures (Complete) data for Tetramethylsilane (7 total), please visit the HSDB record page.

Excerpt from ERG Guide 130 [Flammable Liquids (Water-Immiscible / Noxious)]:

Immediate precautionary measure

100 [ppm]

130 [ppm]

270 [ppm]

Samples collected and analyzed during the period from July to December 1980 detected tetramethylsilane on 4 of 12 subjects' exhaled breath in Bayonne and Elizabeth, New Jersey (nine subjects) and Research Triangle Park, North Carolina (3 subjects). The subjects were workers in the chemical and oil industries as well as a sewage treatment plant worker(1).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 44(SRC), determined from a structure estimation method(2), indicates that tetramethylsilane is expected to have very high mobility in soil(SRC). Volatilization of tetramethylsilane from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 4.25 atm-cu m/mole(SRC), based upon its vapor pressure, 718 mm Hg(3), and water solubility, 19.6 mg/L(4). Tetramethylsilane is expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(3). Biodegradation data were not available(SRC, 2009).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 44(SRC), determined from a structure estimation method(2), indicates that tetramethylsilane is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 4.25 atm-cu m/mole(SRC), derived from its vapor pressure, 718 mm Hg(4), and water solubility, 19.6 mg/L(5). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 2.7 hours and 3.7 days, respectively(SRC). According to a classification scheme(6), an estimated BCF of 64(SRC), from a log Kow of 3.24(7) and a regression-derived equation(8), suggests the potential for bioconcentration in aquatic organisms is moderate(SRC). Biodegradation data were not available(SRC, 2009).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), tetramethylsilane, which has a vapor pressure of 718 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase tetramethylsilane is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 16 days(SRC), calculated from its rate constant of 1.00X10-12 cu cm/molecule-sec at 25 °C(3). Tetramethylsilane does not contain chromophores that absorb at wavelengths >290 nm(4) and therefore is not expected to be susceptible to direct photolysis by sunlight(SRC).

Using a structure estimation method based on molecular connectivity indices(1), the Koc of tetramethylsilane can be estimated to be 44(SRC). According to a classification scheme(2), this estimated Koc value suggests that tetramethylsilane is expected to have very high mobility in soil.

Tetramethylsilane's production and use in chemical deposition of films of silicon carbide, as a 1H NMR primary reference standard(1), and as an additive to aviation fuel(2) may result in its release to the environment through various waste streams(SRC).

An estimated BCF of 64 was calculated for tetramethylsilane(SRC), using a log Kow of 3.24(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is moderate(SRC), provided the compound is not metabolized by the organism(SRC).

The Henry's Law constant for tetramethylsilane is estimated as 4.25 atm-cu m/mole(SRC) derived from its vapor pressure, 718 mm Hg(1), and water solubility, 19.6 mg/L(2). This Henry's Law constant indicates that tetramethylsilane is expected to volatilize rapidly from water surfaces(3). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(3) is estimated as 2.7 hours(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(3) is estimated as 3.7 days(SRC). The estimated Henry's Law constant for tetramethylsilane indicates that volatilization from moist soil surfaces is likely(SRC). The potential for volatilization of tetramethylsilane from dry soil surfaces may exist(SRC) based upon a vapor pressure of 718 mm Hg(1).

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ The potential toxicity of tetramethylsilane ... was evaluated in a combined repeated exposure toxicity study with a reproductive/ developmental toxicity screening test. The study design utilized an enhanced version of the protocol in accordance with the OECD and EPA test guidelines Nos. 422 and 870.3650, respectively. Developmental neurotoxicity endpoints including Functional Observational Battery (FOB) and Motor Activity were performed on male and female rats. The test substance was administered six hours a day, seven days a wk by inhalation to 10 rats/sex/group at 0, 200, 1000, and 5000 ppm. All animals survived to the scheduled necropsy. There were no clinical signs or effects on body weights and food consumption among the groups. No treatment-related changes were observed in any FOB or motor activity parameters. There were no alterations in hematology, serum chemistry, organ weights, organ to body weight ratios or macroscopic examination of organs/tissues among the groups. Histopathologic examination of tissues and organs for control and high exposure animals demonstrated no significant microscopic findings. No effects were observed in any of the reproductive parameters evaluated. One female in 200 ppm group was found non-gravid but the remaining females produced litters that were similar in all respects to control litters. Based on the results of this study, the NOAEL for tetramethylsilane in rats via inhalation route was considered to be 5000 ppm.

The rate constant for the vapor-phase reaction of tetramethylsilane with photochemically-produced hydroxyl radicals is 1.00X10-12 cu cm/molecule-sec at 25 °C(1). This corresponds to an atmospheric half-life of about 16 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(SRC). The rate constants for the vapor-phase reaction of tetramethylsilane with ozone and nitrate are <0.7X10-20 and <0.8X10-16 cu cm/molecule-sec at 25 °C, respectively(1). Tetramethylsilane is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(2). Tetramethylsilane does not contain chromophores that absorb at wavelengths >290 nm(2) and therefore is not expected to be susceptible to direct photolysis by sunlight(SRC).

NIOSH (NOES Survey 1981-1983) has statistically estimated that 1,822 workers (272 of these were female) were potentially exposed to tetramethylsilane in the US(1). Occupational exposure to tetramethylsilane may occur through inhalation and dermal contact with this compound at workplaces where it is produced or used. The general population is not likely to be exposed to tetramethylsilane as it is predominately used in a research and manufacturing setting(SRC).

DRINKING WATER: Samples collected and analyzed during the period from July to December 1980 detected tetramethylsilane in 1 of 1 drinking water sample; the sample was collected from a home of workers in the chemical and oil industries or a sewage treatment plant worker in Bayonne or Elizabeth, New Jersey or in Research Triangle Park, North Carolina(1).

Tetramethylsilane's production and use as a chemical deposition agent for films of silicon carbide, an 1H NMR primary reference standard, and an additive to aviation fuel may result in its release to the environment through various waste streams. If released to air, a vapor pressure of 718 mm Hg at 25 °C indicates tetramethylsilane will exist solely as a vapor in the atmosphere. Vapor-phase tetramethylsilane will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 16 days. Tetramethylsilane does not contain chromophores that absorb at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight. If released to soil, tetramethylsilane is expected to have very high mobility based upon an estimated Koc of 44. Volatilization from moist soil surfaces is expected to be an important fate process based upon an estimated Henry's Law constant of 4.25 atm-cu m/mole. Tetramethylsilane may volatilize from dry soil surfaces based upon its vapor pressure. Biodegradation data were not available. If released into water, tetramethylsilane is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is expected to be an important fate process based upon this compound's estimated Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 2.7 hours and 3.7 days, respectively. An estimated BCF of 64 suggests bioconcentration in aquatic organisms is moderate. Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions. Occupational exposure to tetramethylsilane may occur through inhalation and dermal contact with this compound at workplaces where it is produced or used. The general population is not likely to be exposed to tetramethylsilane as it is predominately used in a research and manufacturing setting. (SRC)

Tetramethylsilane

1

10000

Flammable chemical that can be released at a facility.