UN/NA Number Reference
DOT Class 4.3 Dangerous When Wet placard

UN 1295: Trichlorosilane

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 1295 is assigned the proper shipping name Trichlorosilane in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 4.3 Dangerous When Wet material, Packing Group I. Required label(s): 4.3, 3, 8.

Packing group indicates the degree of danger within a hazard class: PG I is high danger, PG II medium, PG III low. The proper shipping name, hazard class, UN number, and packing group together form the basic shipping description that must appear on shipping papers and, where required, on the package and placard.

Emergency Response (ERG Guide 139)

Hazards: Produces toxic and flammable gases on water contact. TOXIC. May be fatal.

Fire: DO NOT use water. Dry chemical, dry sand.

Spill: Fully encapsulating suit. Keep material dry. Cover with dry earth.

Chemical and Physical Properties

Trichlorosilane appears as a colorless fuming liquid with a pungent odor. Flash point 7 °F. Vapor and liquid cause burns. More dense than water. Vapors are heavier than air.

CAS Number: 10025-78-2
Molecular Formula: Cl3HSi
Molecular Weight: 135.45 g/mol
Color / Form: Colorless liquid
Odor: ACRID ODOR
Boiling Point: 90 F
Melting Point: -197 °F (USCG, 1999)
Flash Point: greater than -58 F
Autoignition: 220 °F (USCG, 1999)
Specific Gravity: 1.344 (sinks in water)
Vapor Pressure: 594.0 [mmHg]
Vapor Density: 4.67 (heavier than air)
Water Solubility: Sol in benzene, carbon disulfide, chloroform, carbon tetrachloride

Special Provisions

49 CFR 172.102 special provision codes for this entry: N34, T14, TP2, TP7, TP13, W31. These codes modify the general requirements (packaging, quantity limits, exceptions) for this specific material. Look up each code in 49 CFR 172.102 for the full text.

Need the full interactive record? Open UN 1295 in the SpillNerd lookup tool for the live database entry with placard graphics, GHS pictograms, full segregation tables, and synonym search. For another material, use the UN number and chemical lookup.

Reference data compiled from the DOT Hazardous Materials Table (49 CFR 172.101), the 2024 Emergency Response Guidebook, and public chemical databases (PubChem, NIOSH, EPA). Always verify the correct shipping description against the current regulation and the manufacturer's SDS Section 14 before shipping.