#### § 175.78 Stowage compatibility of cargo.

(a) For stowage on an aircraft, in a cargo facility, or in any other area at an airport designated for the stowage of hazardous materials, packages containing hazardous materials which might react dangerously with one another may not be placed next to each other or in a position that would allow a dangerous interaction in the event of leakage.

(b)

(1) At a minimum, the segregation instructions prescribed in the following Segregation Table must be followed to maintain acceptable segregation between packages containing hazardous materials with different hazards. The Segregation Table instructions apply whether or not the class or division is the primary or subsidiary risk.

(2) Packages and overpacks containing articles of Identification Numbers UN3090 and UN3480 prepared in accordance with [§ 173.185(b)(3)](/on/2024-09-24/title-49/section-173.185#p-173.185(b)(3)) and [(c)(4)(vi)](/on/2024-09-24/title-49/section-173.185#p-173.185(c)(4)(vi)) must not be stowed on an aircraft next to, in contact with, or in a position that would allow interaction with packages or overpacks containing hazardous materials that bear a Class 1 (other than Division 1.4S), Division 2.1, Class 3, Division 4.1, or Division 5.1 hazard label. To maintain acceptable segregation between packages and overpacks, the segregation requirements shown in the Segregation Table must be followed. The segregation requirements apply based on all hazard labels applied to the package or overpack, irrespective of whether the hazard is the primary or subsidiary hazard.

Table to Paragraph (b): Segregation Table

| Hazard label | Class or division | | | | | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | 2.1 | 2.2, 2.3 | 3 | 4.1 | 4.2 | 4.3 | 5.1 | 5.2 | 8 | 9 see (b)(2) |
| 1 | Note 1 | Note 2 | Note 2 | Note 2 | Note 2 | Note 2 | Note 2 | Note 2 | Note 2 | Note 2 | Note 2 |
| 2.1 | Note 2 | | | | | | | | | | X |
| 2.2, 2.3 | Note 2 | | | | | | | | | | |
| 3 | Note 2 | | | | | | | X (Note 3) | | | X |
| 4.1 | Note 2 | | | | | | | | | | X |
| 4.2 | Note 2 | | | | | | | X | | | |
| 4.3 | Note 2 | | | | | | | | | X | |
| 5.1 | Note 2 | | | X (Note 3) | | X | | | | | X |
| 5.2 | Note 2 | | | | | | | | | | |
| 8 | Note 2 | | | | | | X | | | | |
| 9 see (b)(2) | Note 2 | X | | X | X | | | X | | | |

(c) Instructions for using the Segregation Table are as follows:

(1) Hazard labels, classes or divisions not shown in the table are not subject to segregation requirements.

(2) Dots at the intersection of a row and column indicate that no restrictions apply.

(3) The letter “X” at the intersection of a row and column indicates that packages containing these classes of hazardous materials may not be stowed next to or in contact with each other, or in a position which would allow interaction in the event of leakage of the contents.

(4) Note 1. “Note 1” at the intersection of a row and column means the following:

(i) Only Division 1.4, Compatibility Group S, explosives are permitted to be transported aboard a passenger aircraft. Only certain Division 1.3, Compatibility Groups C and G, and Division 1.4, Compatibility Groups B, C, D, E, G and S, explosives may be transported aboard a cargo aircraft.

(ii) Division 1.4 explosives in Compatibility Group S may be stowed with Division 1.3 and 1.4 explosives in compatibility groups as permitted aboard aircraft under paragraph (c)(4)(i) above.

(iii) Except for Division 1.4B explosives and as otherwise provided in this Note, explosives of different compatibility groups may be stowed together whether or not they belong to the same division. Division 1.4B explosives must not be stowed together with any other explosive permitted aboard aircraft except Division 1.4S, unless segregated as prescribed in [paragraph (c)(4)(iv)](/on/2024-09-24/title-49/section-175.78#p-175.78(c)(4)(iv)) of this section (“Note 1”).

(iv) Division 1.4B and Division 1.3 explosives may not be stowed together. Division 1.4B explosives must be loaded into separate unit load devices and, when stowed aboard the aircraft, the unit load devices must be separated by other cargo with a minimum separation of 2 m (6.5 feet). When not loaded in unit load devices, Division 1.4B and Division 1.3 explosives must be loaded into different, non-adjacent loading positions and separated by other cargo with a minimum separation of 2 m (6.5 feet).

(5) Note 2. “Note 2” at the intersection of a row and column means that other than explosives of Division 1.4, Compatibility Group S, explosives may not be stowed together with that class.

(6) Packages containing hazardous materials with multiple hazards in the class or divisions, which require segregation in accordance with the Segregation Table, need not be segregated from other packages bearing the same UN number.

(7) A package labeled “BLASTING AGENT” may not be stowed next to or in a position that will allow contact with a package of special fireworks or railway torpedoes.

(8) Note 3. “Note 3” at the intersection of a row and column means that UN 3528, Engines, internal combustion, flammable liquid powered; Engines, fuel cell, flammable liquid powered; Machinery internal combustion, flammable liquid powered; and Machinery, fuel cell, flammable liquid powered need not be segregated from packages containing dangerous goods in Division 5.1.

[[71 FR 14604](https://www.federalregister.gov/citation/71-FR-14604), Mar. 22, 2006, as amended at [71 FR 54396](https://www.federalregister.gov/citation/71-FR-54396), Sept. 14, 2006; [71 FR 78634](https://www.federalregister.gov/citation/71-FR-78634), Dec. 29, 2006; [76 FR 3384](https://www.federalregister.gov/citation/76-FR-3384), Jan. 19, 2011; [85 FR 27899](https://www.federalregister.gov/citation/85-FR-27899), May 11, 2020]