HazMat Tool — substance information

Hexaethyl tetraphosphate and compressed gas mixtures

HMT May 2026

UN / ID: UN 1612
Hazard class: 2.3
Packing group: —
ERG guide: ERG 123
Special provisions: SP 3
Source: 49 CFR §172 (2026/05)

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Hexaethyl tetraphosphate and compressed gas mixtures

Emergency Response Guide No. 123

Hazardous Materials Table

Source: 49 CFR §172 (2026/05)

(3) Hazard Class

2.3
Poisonous gas

(7) Special Provisions (§172.102)

×Note:
Special provisions may be very complex. The extracts are taken from 49 CFR §172.102. Please be careful with the information, as necessary, additional conditions may be applied that are not written here. Please check the original source and report bugs.

3	This material is poisonous by inhalation (see §171.8) in Hazard Zone C (see §173.116), and must be described as an inhalation hazard under the provisions of this subchapter. Browse special provision 3

(8) Packing Authorizations (§173.***)

(8A) Exceptions	None
(8B) Non-bulk	334	see 49 CFR §173.334
(8C) Bulk	None

(9) Quantity Limits

(9A) Passenger aircraft/rail	Forbidden
(9B) Cargo aircraft only	Forbidden

(10) Vessel stowage

(10A) Location

Stowage category “D” means the material must be stowed “on deck only” on a cargo vessel or on a passenger vessel carrying a number of passengers limited to not more than the larger of 25 passengers or one passenger per each 3 m of overall vessel length, but the material is prohibited on a passenger vessel in which the limiting number of passengers is exceeded.

Source: 49 CFR §172.101(k)

(10B) Other

40	see 49 CFR §176.84

Source: 49 CFR §176.84

Segregation chart for load, transport, and storage

This chart shows whether loading, transport, or storage with other hazard classes is permitted, prohibited, or restricted. Based on 49 CFR §177.848.

Note: In this segregation and separation chart are HazMat of hazard class 2.3 considered depending on their poisonousness by inhalation (Hazard zone A/B). See PHMSA Interpretation #09-0252.

Scope & sources (important)Click to show CFR references

This check evaluates segregation per 49 CFR §177.848. Additional loading/unloading and handling requirements may still apply; see 49 CFR §177 Subpart B (Loading and Unloading):

§177.834 - General requirements
§177.835 - Class 1 materials
§177.837 - Class 3 materials
§177.838 - Class 4 (flammable solid) materials, Class 5 (oxidizing) materials, and Division 4.2 (pyroforic liquid) materials
§177.839 - Class 8 (corrosive) materials
§177.840 - Class 2 (gases) materials
§177.841 - Division 6.1 and Division 2.3 materials
§177.842 - Class 7 (radioactive) material
§177.843 - Contamination of vehicles

Similar substances

UN / ID	Proper shipping name	Hazard class
UN 1611	Hexaethyl tetraphosphate, liquid	6.1
UN 1611	Hexaethyl tetraphosphate, solid	6.1