UN/NA Number Reference
DOT Class 6.1 Toxic Substance placard

UN 1611: Hexaethyl tetraphosphate

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 1611 is assigned the proper shipping name Hexaethyl tetraphosphate 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 II. Required label(s): 6.1.

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 151)

Hazards: TOXIC. May be fatal if inhaled, ingested, or absorbed through skin. Contact may cause burns.

Fire: Use agent appropriate for surrounding fire. Cool containers with water.

Spill: Do not touch. Avoid inhalation. Use water spray to reduce dust/vapor. Ventilate.

Chemical and Physical Properties

Hexaethyl tetraphosphate is a yellow liquid which is miscible in water. It is difficult to burn. It is toxic by skin absorption and inhalation. It is a mixture of ethyl phosphates and ethyl pyrophosphate. It decomposes at high temperatures. May be found in the form of a dry mixture where the liquid is absorbed onto a dry carrier.

CAS Number: 757-58-4
Molecular Formula: C12H30O13P4
Molecular Weight: 506.25 g/mol
Color / Form: Yellow liquid
Odor: Odorless
Boiling Point: 150 C (decomposes)
Melting Point: -40 °C
Specific Gravity: 1.26 to 1.28
Vapor Pressure: 0.00000002 [mmHg]
Water Solubility: Miscible with water and many organic solvents except kerosene

Regulatory Data

CERCLA RQ (40 CFR 302.4)
100 lb
RCRA Waste Code(s)
[object Object], [object Object]

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: IB8, IP2, IP4, N76. 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 1611 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.