HazMat Tool — substance information

Maleic anhydride

HMT May 2026

UN / ID: UN 2215
Hazard class: 8
Packing group: III (multiple — see tabs)
ERG guide: ERG 156
Special provisions: SP IB8, SP IP3, SP T1, SP TP33
Source: 49 CFR §172 (2026/05)

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Maleic anhydride

Maleic anhydride is an organic compound with the formula C2H2(CO)2O. It is the acid anhydride of maleic acid. It is a colorless or white solid with an acrid odor. It is produced industrially on a large scale for applications in coatings and polymers. Wikipedia

Substance Data

Source: PubChem (HSDB, 13.12.2019)

CAS-Number

108-31-6

Flash Point

n/a

Boiling Point

n/a

Emergency Response Guide No. 156

Hazardous Materials Table

Source: 49 CFR §172 (2026/05)

Packing group III
Packing group

(3) Hazard Class

8
Corrosive liquids

(4) Identification number

UN 2215

(5) Packing Group

III

Comparison View of PG

(6) Labels

(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.

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

IP3

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

Browse special provision IP3

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

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

(8) Packing Authorizations (§173.***)

(8A) Exceptions	154	see 49 CFR §173.154
(8B) Non-bulk	213	see 49 CFR §173.213
(8C) Bulk	240	see 49 CFR §173.240

(9) Quantity Limits

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

(10) Vessel stowage

(10A) Location

Stowage category “A” means the material may be stowed “on deck” or “under deck” on a cargo vessel or on a passenger vessel.

Source: 49 CFR §172.101(k)

(10B) Other

53	see 49 CFR §176.84
58	see 49 CFR §176.84
95	see 49 CFR §176.84
102	see 49 CFR §176.84

Source: 49 CFR §176.84

(3) Hazard Class

8
Corrosive liquids

(4) Identification number

UN 2215

(5) Packing Group

III

Comparison View of PG

(6) Labels

(7) Special Provisions (§172.102)

Minimum test pressure (bar)	2.65
Minimum shell thickness	§ 178.274(d)(2)
Pressure-relief requirements	Normal
Bottom opening requirements	§ 178.275(d)(3)

Browse special provision T4

TP3

The maximum degree of filling (in %) for solids transported above their melting points and for elevated temperature liquids shall be determined by the following:
TP3

Where: d_f and d_r are the mean densities of the liquid at the mean temperature of the liquid during filling and the maximum mean bulk temperature during transport respectively.

Browse special provision TP3

(8) Packing Authorizations (§173.***)

(8A) Exceptions	None
(8B) Non-bulk	213	see 49 CFR §173.213
(8C) Bulk	240	see 49 CFR §173.240

(9) Quantity Limits

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

(10) Vessel stowage

(10A) Location

Stowage category “A” means the material may be stowed “on deck” or “under deck” on a cargo vessel or on a passenger vessel.

Source: 49 CFR §172.101(k)

(10B) Other

53	see 49 CFR §176.84
58	see 49 CFR §176.84
95	see 49 CFR §176.84
102	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 III	PG III
1
2	Maleic anhydride	Maleic anhydride, molten
3	8	8
4	UN 2215	UN 2215
5	III	III
6	8	8
7	IB8, IP3, T1, TP33	T4, TP3
8A	154	None
8B	213	213
8C	240	240
9A	25 kg	Forbidden
9B	100 kg	Forbidden
10A	A	A
10B	53, 58, 95, 102	53, 58, 95, 102

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 8 considered depending if there are liquid. Currently HazMat Tool is not able to to check if a HazMat is liquid or not. Therefore it is assumed as liquid. See PHMSA Interpretation #09-0252.

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 2698	Tetrahydrophthalic anhydrides with more than 0.05 percent of maleic anhydride	8
UN 2214	Phthalic anhydride with more than .05 percent maleic anhydride	8
UN 2215	Maleic anhydride	8
UN 1715	Acetic anhydride	8
UN 2739	Butyric anhydride	8
UN 2496	Propionic anhydride	8