HazMat Tool — substance information

Metallic substance, water-reactive, self-heating, n.o.s

HMT May 2026

UN / ID: UN 3209
Hazard class: 4.3
Packing group: I (multiple — see tabs)
ERG guide: ERG 138
Special provisions: SP A7, SP W31
Source: 49 CFR §172 (2026/05)

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Metallic substance, water-reactive, self-heating, n.o.s

Emergency Response Guide No. 138

Hazardous Materials Table

Source: 49 CFR §172 (2026/05)

Packing group I
Packing group II
Packing group III

(3) Hazard Class

4.3
Dangerous when wet materials

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.

A7	Steel packagings must be corrosion-resistant or have protection against corrosion. Browse special provision A7
W31	Non-bulk packagings must be hermetically sealed. Browse special provision W31

(8) Packing Authorizations (§173.***)

(8A) Exceptions	None
(8B) Non-bulk	211	see 49 CFR §173.211
(8C) Bulk	242	see 49 CFR §173.242

(9) Quantity Limits

(9A) Passenger aircraft/rail	Forbidden
(9B) Cargo aircraft only	15 kg

(10) Vessel stowage

(10A) Location

Stowage category “E” means the material may be stowed “on deck” or “under deck” 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 is prohibited from carriage on a passenger vessel in which the limiting number of passengers is exceeded.

Source: 49 CFR §172.101(k)

(10B) Other

13	see 49 CFR §176.84
40	see 49 CFR §176.84
148	see 49 CFR §176.84

Source: 49 CFR §176.84

(3) Hazard Class

4.3
Dangerous when wet materials

(4) Identification number

UN 3209

(5) Packing Group

Comparison View of PG

(6) Labels

Spontaneously combustible materials (4.2)

(1) Symbols

(7) Special Provisions (§172.102)

Steel packagings must be corrosion-resistant or have protection against corrosion.

Browse special provision A7

IB5

Authorized IBCs: Metal (11A, 11B, 11N, 21A, 21B, 21N, 31A, 31B and 31N); Rigid plastics (11H1, 11H2, 21H1, 21H2, 31H1 and 31H2); Composite (11HZ1, 21HZ1 and 31HZ1).

Browse special provision IB5

IP2

When IBCs other than metal or rigid plastics IBCs are used, they must be offered for transportation in a closed freight container or a closed transport vehicle.

Browse special provision IP2

Minimum test pressure (bar)	2.65
Minimum shell thickness	§ 178.274(d)(2)
Pressure-relief requirements	Normal
Bottom opening requirements	§ 178.275(d)(2)

Browse special provision T3

TP33

The portable tank instruction assigned for this substance applies for granular and powdered solids and for solids which are filled and discharged at temperatures above their melting point which are cooled and transported as a solid mass. Solid substances transported or offered for transport above their melting point are authorized for transportation in portable tanks conforming to the provisions of portable tank instruction T4 for solid substances of packing group III or T7 for solid substances of packing group II, unless a tank with more stringent requirements for minimum shell thickness, maximum allowable working pressure, pressure-relief devices or bottom outlets are assigned in which case the more stringent tank instruction and special provisions shall apply. Filling limits must be in accordance with portable tank special provision TP3. Solids meeting the definition of an elevated temperature material must be transported in accordance with the applicable requirements of this subchapter.

Browse special provision TP33

W31

Non-bulk packagings must be hermetically sealed.

Browse special provision W31

W40

Non-bulk bags are not allowed.

Browse special provision W40

(8) Packing Authorizations (§173.***)

(8A) Exceptions	None
(8B) Non-bulk	212	see 49 CFR §173.212
(8C) Bulk	242	see 49 CFR §173.242

(9) Quantity Limits

(9A) Passenger aircraft/rail	15 kg
(9B) Cargo aircraft only	50 kg

(10) Vessel stowage

(10A) Location

Source: 49 CFR §172.101(k)

(10B) Other

13	see 49 CFR §176.84
40	see 49 CFR §176.84
148	see 49 CFR §176.84

Source: 49 CFR §176.84

(3) Hazard Class

4.3
Dangerous when wet materials

(4) Identification number

UN 3209

(5) Packing Group

III

Comparison View of PG

(6) Labels

(1) Symbols

(7) Special Provisions (§172.102)

Steel packagings must be corrosion-resistant or have protection against corrosion.

Browse special provision A7

IB8

Authorized IBCs: Metal (11A, 11B, 11N, 21A, 21B, 21N, 31A, 31B and 31N); Rigid plastics (11H1, 11H2, 21H1, 21H2, 31H1 and 31H2 ); Composite (11HZ1, 11HZ2, 21HZ1, 21HZ2 and 31HZ1); Fiberboard (11G); Wooden (11C, 11D and 11F); Flexible (13H1, 13H2, 13H3, 13H4, 13H5, 13L1, 13L2, 13L3, 13L4, 13M1 or 13M2).

Browse special provision IB8

IP4

Flexible, fiberboard or wooden IBCs must be sift-proof and water-resistant or be fitted with a sift-proof and water-resistant liner.

Browse special provision IP4

Minimum test pressure (bar)	1.5
Minimum shell thickness	§ 178.274(d)(2)
Pressure-relief requirements	Normal
Bottom opening requirements	§ 178.275(d)(2)

Browse special provision T1

TP33

Browse special provision TP33

W31

Non-bulk packagings must be hermetically sealed.

Browse special provision W31

(8) Packing Authorizations (§173.***)

(8A) Exceptions	None
(8B) Non-bulk	213	see 49 CFR §173.213
(8C) Bulk	242	see 49 CFR §173.242

(9) Quantity Limits

(9A) Passenger aircraft/rail	25 kg
(9B) Cargo aircraft only	100 kg

(10) Vessel stowage

(10A) Location

Source: 49 CFR §172.101(k)

(10B) Other

13	see 49 CFR §176.84
40	see 49 CFR §176.84
148	see 49 CFR §176.84

Source: 49 CFR §176.84

Packing group comparison

Multiple packing groups apply to this entry. See assignment criteria in 49 CFR §173 Subpart D. Details are in the tabs above; differences are highlighted.

	PG I	PG II	PG III
1	G	G	G
2	Metallic substance, water-reactive, self-heating, n.o.s	Metallic substance, water-reactive, self-heating, n.o.s	Metallic substance, water-reactive, self-heating, n.o.s
3	4.3	4.3	4.3
4	UN 3209	UN 3209	UN 3209
5	I	II	III
6	4.3, 4.2	4.3, 4.2	4.3, 4.2
7	A7, W31	A7, IB5, IP2, T3, TP33, W31, W40	A7, IB8, IP4, T1, TP33, W31
8A	None	None	None
8B	211	212	213
8C	242	242	242
9A	Forbidden	15 kg	25 kg
9B	15 kg	50 kg	100 kg
10A	E	E	E
10B	13, 40, 148	13, 40, 148	13, 40, 148

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.

Hazard class	8	7	6.1	5.2	5.1	4.3	4.2	4.1	3	2.3B	2.3A	2.2	2.1	1.6	1.5	1.4	1.3	1.1/1.2
1.1/1.2
1.3
1.4
1.5
1.6
2.1
2.2
2.3A
2.3B
3
4.1
4.2
4.3
5.1
5.2
6.1
7
8

	Must not be loaded, transported, or stored together in the same vehicle or facility.
	May be loaded, transported, or stored together.
	May be loaded, transported, or stored together only with restrictions.

Similar substances

UN / ID	Proper shipping name	Hazard class
UN 0222	Ammonium nitrate, with more than 0.2 percent combustible substances, including any organic substance calculated as carbon, to the exclusion of any other added substance	1.1D
UN 1942	Ammonium nitrate, with not more than 0.2% combustible substances, including any organic substance calculated as carbon, to the exclusion of any other added substance	5.1
UN 3476	Fuel cell cartridges or Fuel cell cartridges contained in equipment or Fuel cell cartridges packed with equipment, containing water-reactive substances	4.3
UN 3477	Fuel cell cartridges or Fuel cell cartridges contained in equipment or Fuel cell cartridges packed with equipment, containing corrosive substances	8
UN 3543	Articles containing a substance which in contact with water emits flammable gases, n.o.s.	4.3
	Formaldehyde solutions (with not less than 10% and less than 25% formaldehyde), see Aviation regulated liquid, n.o.s. or Other regulated substances, liquid, n.o.s.
NA 1693	Tear gas devices with more than 2 percent tear gas substances, by mass	6.1
UN 0341	Nitrocellulose, unmodified or plasticized with less than 18 percent plasticizing substance, by mass	1.1D
UN 0343	Nitrocellulose, plasticized with not less than 18 percent plasticizing substance, by mass	1.3C
UN 3397	Organometallic substance, solid, water-reactive, self-heating	4.3
UN 3394	Organometallic substance, liquid, pyrophoric, water-reactive	4.2
UN 3393	Organometallic substance, solid, pyrophoric, water-reactive	4.2
UN 3542	Articles containing a substance liable to spontaneous combustion, n.o.s.	4.2
UN 0482	Substances, explosive, very insensitive, n.o.s. or Substances, EVI, n.o.s.	1.5D
UN 3398	Organometallic substance, liquid, water-reactive	4.3