HazMat Tool — substance information

Selenium compound, liquid, n.o.s

HMT 15 June 2026

UN / ID: UN 3440
Hazard class: 6.1
Packing group: I (multiple — see tabs)
ERG guide: ERG 151
Special provisions: SP T14, SP TP2, SP TP27
Source: 49 CFR §172 (15 June 2026)

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Selenium compound, liquid, n.o.s

Selenium is a chemical element; it has symbol Se and atomic number 34. It has various physical appearances, including a brick-red powder, a vitreous black solid, and a grey metallic-looking form. It seldom occurs in this elemental state or as pure ore compounds in Earth's crust. Selenium (from σελήνη 'moon') was discovered in 1817 by Jöns Jacob Berzelius, who noted the similarity of the new element to the previously discovered tellurium (named for the Earth) Wikipedia

Emergency Response Guide No. 151

Hazardous Materials Table

Source: 49 CFR §172 (15 June 2026)

Packing group I
Packing group II
Packing group III

(3) Hazard Class

6.1
Poisonous Material

(4) Identification number

UN 3440

(5) Packing Group

Comparison View of PG

(6) Labels

(1) Symbols

This entry is signed with "G". The letter "G" identifies proper shipping names for which one or more technical names of the hazardous material must be entered in parentheses, in association with the basic description. (See §172.203(k)).

(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.

T14

Minimum test pressure (bar)	6
Minimum shell thickness	6 mm
Pressure-relief requirements	§ 178.275(g)(3)
Bottom opening requirements	Prohibited

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TP2

a. The maximum degree of filling must not exceed the degree of filling determined by the following:
TP2a

Where:
t_r is the maximum mean bulk temperature during transport,
t_f is the temperature in degrees celsius of the liquid during filling, and
α is the mean coefficient of cubical expansion of the liquid between the mean temperature of the liquid during filling (t_f) and the maximum mean bulk temperature during transportation (t_r) both in degrees celsius.
b. For liquids transported under ambient conditions α may be calculated using the formula:
TP2b

Where:
d₁₅ and d₅₀ are the densities (in units of mass per unit volume) of the liquid at 15 °C (59 °F) and 50 °C (122 °F), respectively.

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TP27

A portable tank having a minimum test pressure of 4 bar (400 kPa) may be used provided the calculated test pressure is 4 bar or less based on the MAWP of the hazardous material, as defined in § 178.275 of this subchapter, where the test pressure is 1.5 times the MAWP.

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(8) Packing Authorizations (§173.***)

(8A) Exceptions	None
(8B) Non-bulk	201	see 49 CFR §173.201
(8C) Bulk	243	see 49 CFR §173.243

(9) Quantity Limits

(9A) Passenger aircraft/rail	1 L
(9B) Cargo aircraft only	30 L

(10) Vessel stowage

(10A) Location	B Stowage category “B” means (i) The material may be stowed “on deck” or “under deck” on a cargo vessel and 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; and (ii) “On deck only” on passenger vessels in which the number of passengers specified in paragraph (k)(2)(i) of this section is exceeded. Source: 49 CFR §172.101(k)
(10B) Other	n/a