UN/NA Number Reference
DOT Class 6.1 Toxic Substance placard

UN 1809: Phosphorus trichloride

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 1809 is assigned the proper shipping name Phosphorus trichloride in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 6.1 Toxic Substance material, Packing Group I. Required label(s): 6.1, 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 137)

Hazards: Produce flammable gases on contact with water. May ignite on contact with water. Some react violently with water.

Fire: DO NOT use water or foam. Use dry chemical, dry sand, or soda ash.

Spill: Do not touch. Keep material dry. Move containers from water. Dike to prevent water contact.

Chemical and Physical Properties

Phosphorus trichloride appears as a colorless or slightly yellow fuming liquid with a pungent and irritating odor resembling that of hydrochloric acid. Causes severe burns to skin, eyes and mucous membranes. Very toxic by inhalation, ingestion and skin absorption. Reacts with water to evolve hydrochloric acid, an irritating and corrosive gas apparent as white fumes. Used during electrodeposition of metal on rubber and for making pesticides, surfactants, gasoline additives, plasticizers, dyestuffs, textile finishing agents, germicides, medicinal products, and other chemicals.

CAS Number: 7719-12-2
Molecular Formula: Cl3P
Molecular Weight: 137.33 g/mol
Color / Form: Clear colorless, fuming liquid
Odor: Pungent
Boiling Point: 169 F
Melting Point: -170 °F (EPA, 1998)
Autoignition: Not flammable (USCG, 1999)
Specific Gravity: 1.574 (sinks in water)
Vapor Pressure: 100 mmHg at 69.8 F
Vapor Density: 4.75 (heavier than air)
Water Solubility: Reacts with water

Regulatory Data

CERCLA RQ (40 CFR 302.4)
1000 lb
EPCRA TPQ (40 CFR 355)
1000 lb
OSHA PEL
0.5 3 0.2 ppm (ST) 0.5 ppm
NIOSH REL
TWA 0.2 ppm (1.5 mg/m 3 ) ST 0.5 ppm (3 mg/m 3 )
IDLH
25 ppm

A release of this material at or above its CERCLA reportable quantity (1000 lb) requires immediate notification to the National Response Center at 800-424-8802.

Special Provisions

49 CFR 172.102 special provision codes for this entry: 2, B9, B14, B15, B32, B77, N34, T20, TP2, TP13, TP38, TP45. 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 1809 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.