# NIOSH Pocket Guide to Chemical Hazards
Ethyl silicate | CAS 78-10-4
(C2H5)4SiO4 | RTECS VV9450000
Synonyms & Trade Names Ethyl orthosilicate, Ethyl silicate (condensed), Tetraethoxysilane, Tetraethyl orthosilicate, Tetraethyl silicate | DOT ID & Guide 1292 132
Exposure Limits | NIOSH REL: TWA 10 ppm (85 mg/m3)
OSHA PEL†: TWA 100 ppm (850 mg/m3)
IDLH 700 ppm | Conversion 1 ppm = 8.52 mg/m3
Physical Description Colorless liquid with a sharp, alcohol-like odor.
MW: 208.3 | BP: 336°F | FRZ: -117°F | Sol: Reacts
VP: 1 mmHg | IP: 9.77 eV |  | Sp.Gr: 0.93
Fl.P: 99°F | UEL: ? | LEL: ? |
Class IC Flammable Liquid: Fl.P. at or above 73°F and below 100°F.
Incompatibilities & Reactivities Strong oxidizers, water [Note: Reacts with water to form a silicone adhesive (a milky-white mass).]
Measurement Methods NIOSH S264 (II-3)
Personal Protection & Sanitation Skin: Prevent skin contact Eyes: Prevent eye contact Wash skin: When contaminated Remove: When wet (flammable) Change: No recommendation | First Aid (See procedures) Eye: Irrigate immediately Skin: Soap wash promptly Breathing: Respiratory support Swallow: Medical attention immediately
Respirator Recommendations NIOSH Up to 100 ppm: (APF = 10) Any supplied-air respirator* Up to 250 ppm: (APF = 25) Any supplied-air respirator operated in a continuous-flow mode* Up to 500 ppm: (APF = 50) Any self-contained breathing apparatus with a full facepiece/(APF = 50) Any supplied-air respirator with a full facepiece Up to 700 ppm: (APF = 2000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode Emergency or planned entry into unknown concentrations or IDLH conditions: (APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode/(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus Escape: (APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister/Any appropriate escape-type, self-contained breathing apparatus
Exposure Routes inhalation, ingestion skin, and/or eye contact
Symptoms Irritation eyes, nose; in animals: lacrimation (discharge of tears); dyspnea (breathing difficulty), pulmonary edema; tremor, narcosis; liver, kidney damage; anemia
Target Organs Eyes, respiratory system, liver, kidneys, blood, skin
See also: INTRODUCTION