UN/NA Number Reference
DOT Class 2.3 Toxic Gas placard

UN 3525: Phosphorus pentafluoride, adsorbed

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 3525 is assigned the proper shipping name Phosphorus pentafluoride, adsorbed in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 2.3 Toxic Gas material. Required label(s): 2.3, 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 125)

Hazards: TOXIC. Corrosive. Causes burns. May be fatal if inhaled. Vapors heavier than air.

Fire: Use water spray or fog. Do not get water inside containers.

Spill: Fully encapsulating suit required. Stop leak if safe. Use water spray.

Chemical and Physical Properties

Phosphine appears as a colorless gas with a disagreeable odor of fish or garlic. Boiling point -126 °F; freezing point -209 °F. Very toxic by inhalation at extremely low concentrations. Prolonged heating may cause containers to rupture violently and rocket. Rate of onset: Immediate & Delayed (Lungs) Persistence: Minutes - hours Odor threshold: 0.9 ppm Source/use/other hazard: Insecticide; used in manufacture of flame retardants and incendiaries.

CAS Number: 7647-19-0
Molecular Formula: H3P
Molecular Weight: 125.9657778 g/mol
Color / Form: Colorless gas; flammable
Odor: Disagreeable, garlic-like odor.
Boiling Point: -120 F
Melting Point: -207 °F (EPA, 1998)
Flash Point: Flammable gas
Autoignition: 212 °F (100 °C)
Specific Gravity: 5.805 (sinks in water)
Vapor Pressure: 760 mmHg at -125.5 °F (EPA, 1998)
Vapor Density: 1.17 (EPA, 1998) - Heavier than air; will sink (Relative to Air)
Water Solubility: Slight (NIOSH, 2024)
pH: SOLN ARE NEUTRAL

Regulatory Data

CERCLA RQ (40 CFR 302.4)
100 lb
EPCRA TPQ (40 CFR 355)
500 lb
OSHA PEL
0.3 0.4 0.3 ppm (ST) 1 ppm
NIOSH REL
TWA 0.3 ppm (0.4 mg/m 3 ) ST 1 ppm (1 mg/m 3 )
IDLH
50 ppm

A release of this material at or above its CERCLA reportable quantity (100 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: 1. 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 3525 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.