# J — Hazmat load segregation — which hazard classes may travel together, highway vs vessel

For J, second hazard class (table column) is H; row description is Compatibility group; transport mode is Carriage by Public Highway; segregation code is X; what the code requires is The letter “X” in the table indicates that explosives of different compatibility groups may not be carried on the same transport vehicle, verified against its source on 2026-08-10.

- **First hazard class (table row):** J _(verified: appears in the quote below)_
- **Second hazard class (table column):** H _(verified: appears in the quote below)_
- **Row description:** Compatibility group _(verified: appears in the quote below)_
- **Transport mode:** Carriage by Public Highway _(verified: appears in the quote below)_
- **Segregation code:** X _(verified: appears in the quote below)_
- **What the code requires:** The letter “X” in the table indicates that explosives of different compatibility groups may not be carried on the same transport vehicle. _(verified: appears in the quote below)_

## What the source says

> Compatibility Table For Class 1 (Explosive) Materials Compatibility group | A | B | C | D | E | F | G | H | J | K | L | N | S | A | | X | X | X | X | X | X | X | X | X | X | X | X | B | X | | X | X (4) | X | X | X | X | X | X | X | X | 4/5 | C | X | X | | 2 | 2 | X | 6 | X | X | X | X | 3 | 4/5 | D | X | X (4) | 2 | | 2 | X | 6 | X | X | X | X | 3 | 4/5 | E | X | X | 2 | 2 | | X | 6 | X | X | X | X | 3 | 4/5 | F | X | X | X | X | X | | X | X | X | X | X | X | 4/5 | G | X | X | 6 | 6 | 6 | X | | X | X | X | X | X | 4/5 | H | X | X | X | X | X | X | X | | X | X | X | X | 4/5 | J | X | X | X | X | X | X | X | X | | X | X | X | 4/5 | K | X | X | X | X | X | X | X | X | X | | X | X | 4/5 | L | X | X | X | X | X | X | X | X | X | X | 1 | X | X | N | X | X | 3 | 3 | 3 | X | X | X | X | X | X | | 4/5 | S | X | 4/5 | 4/5 | 4/5 | 4/5 | 4/5 | 4/5 | 4/5 | 4/5 | 4/5 | X | 4/5 | | ( g ) Instructions for using the compatibility table for Class 1 (explosive) materials are as follows: ( 1 ) A blank space in the table indicates that no restrictions apply. ( 2 ) The letter “X” in the table indicates that explosives of different compatibility groups may not be carried on the same transport vehicle. ( 3 ) The numbers in the table mean the following: ( i ) “1” means an explosive from compatibility group L shall only be carried on the same transport vehicle with an identical explosive. ( ii ) “2” means any combination of explosives from compatibility groups C, D, or E is assigned to compatibility group E. ( iii ) “3” means any combination of explosives from compatibility groups C, D, or E with those in compatibility group N is assigned to compatibility group D. ( iv ) “4” means see <https://www.ecfr.gov/current/title-49/section-177.835#p-177.835(g)> § 177.835(g) when transporting detonators. ( v ) “5” means Division 1.4S fireworks may not be loaded on the same transport vehicle with Division 1.1 or 1.2 (explosive) materials. ( vi ) “6” means explosive articles in compatibility group G, other than fireworks and those requiring special handling, may be loaded, transported and stored with other explosive articles of compatibility groups C, D and E, provided that explosive substances (such as those not contained in articles) are not carried in the same transport vehicle.

## Source

- https://www.ecfr.gov/current/title-49/subtitle-B/chapter-I/subchapter-C/part-177/subpart-C/section-177.848

Last verified: 2026-08-10. Review by: 2027-08-10.
Part of [Hazmat load segregation — which hazard classes may travel together, highway vs vessel](https://referencesource.org/hazmat-segregation-matrix/).