HazMat Tool — substance information

Organometallic substance, liquid, water-reactive, flammable

HMT May 2026

UN / ID: UN 3399
Hazard class: 4.3
Packing group: I (multiple — see tabs)
ERG guide: ERG 138
Special provisions: SP T13, SP TP2, SP TP7, SP TP36, SP TP47, SP W31
Source: 49 CFR §172 (2026/05)

Spot an error in this entry?

On this page

Organometallic substance, liquid, water-reactive, flammable

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.

T13

Minimum test pressure (bar)	6
Minimum shell thickness	6 mm
Pressure-relief requirements	Normal
Bottom opening requirements	Prohibited

Browse special provision T13

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.

Browse special provision TP2

TP7

The vapor space must be purged of air by nitrogen or other means.

Browse special provision TP7

TP36

For material assigned this portable tank special provision, portable tanks used to transport such material may be equipped with fusible elements in the vapor space of the portable tank.

Browse special provision TP36

TP47

The 2.5 year internal examination may be waived or substituted by other test methods or inspection procedures specified by the competent authority or its authorized body, provided that the portable tank is dedicated to the transport of the organometallic substances to which this tank special provision is assigned. However this examination is required when the conditions of §180.605 are met.

Browse special provision TP47

W31

Non-bulk packagings must be hermetically sealed.

Browse special provision W31

(8) Packing Authorizations (§173.***)

(8A) Exceptions	None
(8B) Non-bulk	201	see 49 CFR §173.201
(8C) Bulk	244	see 49 CFR §173.244

(9) Quantity Limits

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

(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

13	see 49 CFR §176.84
40	see 49 CFR §176.84
52	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 3399

(5) Packing Group

Comparison View of PG

(6) Labels

(1) Symbols

(7) Special Provisions (§172.102)

IB1

Authorized IBCs: Metal (31A, 31B and 31N).
Additional Requirement: Only liquids with a vapor pressure less than or equal to 110 kPa at 50 °C (1.1 bar at 122 °F), or 130 kPa at 55 °C (1.3 bar at 131 °F) are authorized.

Browse special provision IB1

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)	4
Minimum shell thickness	§ 178.274(d)(2)
Pressure-relief requirements	Normal
Bottom opening requirements	§ 178.275(d)(3)

Browse special provision T7

TP2

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

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.

Browse special provision TP2

TP7

The vapor space must be purged of air by nitrogen or other means.

Browse special provision TP7

TP36

For material assigned this portable tank special provision, portable tanks used to transport such material may be equipped with fusible elements in the vapor space of the portable tank.

Browse special provision TP36

TP47

Browse special provision TP47

W31

Non-bulk packagings must be hermetically sealed.

Browse special provision W31

(8) Packing Authorizations (§173.***)

(8A) Exceptions	151	see 49 CFR §173.151
(8B) Non-bulk	202	see 49 CFR §173.202
(8C) Bulk	243	see 49 CFR §173.243

(9) Quantity Limits

(9A) Passenger aircraft/rail	1 L
(9B) Cargo aircraft only	5 L

(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
52	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 3399

(5) Packing Group

III

Comparison View of PG

(6) Labels

(1) Symbols

(7) Special Provisions (§172.102)

IB2

Authorized IBCs: Metal (31A, 31B and 31N); Rigid plastics (31H1 and 31H2); Composite (31HZ1).
Additional Requirement: Only liquids with a vapor pressure less than or equal to 110 kPa at 50 °C (1.1 bar at 122 °F), or 130 kPa at 55 °C (1.3 bar at 131 °F) are authorized.

Browse special provision IB2

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)	4
Minimum shell thickness	§ 178.274(d)(2)
Pressure-relief requirements	Normal
Bottom opening requirements	§ 178.275(d)(3)

Browse special provision T7

TP2

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

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.

Browse special provision TP2

TP7

The vapor space must be purged of air by nitrogen or other means.

Browse special provision TP7

TP36

For material assigned this portable tank special provision, portable tanks used to transport such material may be equipped with fusible elements in the vapor space of the portable tank.

Browse special provision TP36

TP47

Browse special provision TP47

W31

Non-bulk packagings must be hermetically sealed.

Browse special provision W31

(8) Packing Authorizations (§173.***)

(8A) Exceptions	151	see 49 CFR §173.151
(8B) Non-bulk	203	see 49 CFR §173.203
(8C) Bulk	242	see 49 CFR §173.242

(9) Quantity Limits

(9A) Passenger aircraft/rail	5 L
(9B) Cargo aircraft only	60 L

(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
52	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	Organometallic substance, liquid, water-reactive, flammable	Organometallic substance, liquid, water-reactive, flammable	Organometallic substance, liquid, water-reactive, flammable
3	4.3	4.3	4.3
4	UN 3399	UN 3399	UN 3399
5	I	II	III
6	4.3, 3	4.3, 3	4.3, 3
7	T13, TP2, TP7, TP36, TP47, W31	IB1, IP2, T7, TP2, TP7, TP36, TP47, W31	IB2, IP4, T7, TP2, TP7, TP36, TP47, W31
8A	None	151	151
8B	201	202	203
8C	244	243	242
9A	Forbidden	1 L	5 L
9B	1 L	5 L	60 L
10A	D	D	E
10B	13, 40, 52, 148	13, 40, 52, 148	13, 40, 52, 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 3394	Organometallic substance, liquid, pyrophoric, water-reactive	4.2
UN 3396	Organometallic substance, solid, water-reactive, flammable	4.3
UN 3393	Organometallic substance, solid, pyrophoric, water-reactive	4.2
UN 3398	Organometallic substance, liquid, water-reactive	4.3
UN 3395	Organometallic substance, solid, water-reactive	4.3
UN 3397	Organometallic substance, solid, water-reactive, self-heating	4.3
UN 3392	Organometallic substance, liquid, pyrophoric	4.2
UN 3282	Organometallic compound, liquid, toxic, n.o.s	6.1
UN 3391	Organometallic substance, solid, pyrophoric	4.2
UN 3400	Organometallic substance, solid, self-heating	4.2
UN 3467	Organometallic compound, solid, toxic, n.o.s	6.1