# NIOSH Pocket Guide to Chemical Hazards
Methyl silicate | CAS 681-84-5
(CH3O)4Si | RTECS VV9800000
Synonyms & Trade Names Methyl orthosilicate, Tetramethoxysilane, Tetramethyl ester of silicic acid, Tetramethyl silicate | DOT ID & Guide 2606 155
Exposure Limits | NIOSH REL: TWA 1 ppm (6 mg/m3)
OSHA PEL†: none
IDLH N.D. | Conversion 1 ppm = 6.23 mg/m3
Physical Description Clear, colorless liquid. [Note: A solid below 28°F.]
MW: 152.3 | BP: 250°F | FRZ: 28°F | Sol: Soluble
VP(77°F): 12 mmHg | IP: ? |  | Sp.Gr: 1.02
Fl.P: 205°F | UEL: ? | LEL: ? |
Class IIIB Combustible Liquid: Fl.P. at or above 200°F.
Incompatibilities & Reactivities Oxidizers; hexafluorides of rhenium, molybdenum & tungsten
Measurement Methods None available
Personal Protection & Sanitation Skin: Prevent skin contact Eyes: Prevent eye contact Wash skin: Daily Remove: When wet or contaminated Change: No recommendation Provide: Eyewash | First Aid (See procedures) Eye: Irrigate immediately Skin: Soap wash Breathing: Respiratory support Swallow: Medical attention immediately
Respirator Recommendations To be added later
Exposure Routes inhalation, ingestion, skin and/or eye contact
Symptoms Irritation eyes, corneal damage (following even short-term exposure to the vapor); lung, kidney injury; pulmonary edema
Target Organs Eyes, respiratory system, kidneys
See also: INTRODUCTION