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Hazmat segregation chart
The DOT segregation table in 49 CFR 177.848 tells you which hazard classes may share a truck. An X means they may not be loaded, transported or stored together in the same vehicle; an O means they may only if separated so that leaking packages cannot mix; a blank means the table sets no restriction. Flammable liquids (Class 3) and oxidizers (5.1) are an O, for example, and flammable gases (2.1) and Zone A poison gases (2.3) are an X. Pick two classes below for the answer, or download the printable chart.
Updated October 12, 2026
Source: 49 CFR Parts 172, 173, 174 and 177 on eCFR, current to October 8, 2026. Fixed sites use a different system: see the NFPA 704 diamond maker.
Hazmat load and segregation chart, 49 CFR 177.848(d)
Need it on the wall or in the cab? The tool above downloads a free printable PDF of this chart, with the Class 1 compatibility table and the extra rules from 177.848(c) and (e), on two landscape pages in Letter or A4. No sign-up and no watermark.
| Class | 1.1, 1.2 | 1.3 | 1.4 | 1.5 | 1.6 | 2.1 | 2.2 | 2.3 A | 2.3 B | 3 | 4.1 | 4.2 | 4.3 | 5.1 | 5.2 | 6.1 A | 7 | 8 liq |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1.1 and 1.2 Explosives | * | * | * | * | * | X | X | X | X | X | X | X | X | X | X | X | X | X |
| 1.3 Explosives | * | * | * | * | * | X | X | X | X | X | X | X | X | X | X | |||
| 1.4 Explosives | * | * | * | * | * | O | O | O | O | O | O | O | ||||||
| 1.5 Very insensitive explosives | * | * | * | * | * | X | X | X | X | X | X | X | X | X | X | X | X | X |
| 1.6 Extremely insensitive explosives | * | * | * | * | * | |||||||||||||
| 2.1 Flammable gases | X | X | O | X | X | O | O | O | ||||||||||
| 2.2 Non-toxic, non-flammable gases | X | X | ||||||||||||||||
| 2.3 Poisonous gas, Zone A | X | X | O | X | X | X | X | X | X | X | X | X | ||||||
| 2.3 Poisonous gas, Zone B | X | X | O | X | O | O | O | O | O | O | O | O | ||||||
| 3 Flammable liquids | X | X | O | X | X | O | O | X | ||||||||||
| 4.1 Flammable solids | X | X | X | O | X | O | ||||||||||||
| 4.2 Spontaneously combustible | X | X | O | X | X | O | X | X | ||||||||||
| 4.3 Dangerous when wet | X | X | X | X | O | X | O | |||||||||||
| 5.1 Oxidizers | X | X | X | X | O | O | X | O | ||||||||||
| 5.2 Organic peroxides | X | X | X | X | O | X | O | |||||||||||
| 6.1 Poisonous liquids, PG I, Zone A | X | X | O | X | O | X | X | X | X | X | X | X | ||||||
| 7 Radioactive materials | X | X | O | |||||||||||||||
| 8 Corrosive liquids | X | X | O | X | X | O | O | X | O | O | O | X |
Transcribed from 49 CFR 177.848(d) as published on eCFR, current to October 8, 2026, and tested cell by cell against the saved regulation text. * means the Class 1 compatibility table decides. Notes column: Division 1.1 and 1.2, 1.5 and 5.1 carry note A (ammonium nitrate).
How to read it
Find the first material’s class or division in the left column and the second one along the top. The cell where they meet is the answer.
X: not in the same transport vehicle or storage facility during transportation (177.848(e)(2)).
O: together only if separated so that, if packages leak in normal transport, the materials cannot mix (177.848(e)(3)).
Blank, or a class that is not in the table at all: no restriction from the table (177.848(e)(1)).
*: both are explosives; use the compatibility groups below (177.848(e)(4)).
Some classes appear only in part. The 6.1 row and column cover only Packing Group I, Hazard Zone A poison liquids, and the Class 8 column covers corrosive liquids only. Other 6.1 materials, corrosive solids, 2.3 Zones C and D, 6.2 and Class 9 are not in the table, so the table puts no restriction on them.
Rules that apply on top of the table
Cyanides may not be loaded with acids that would release hydrogen cyanide (177.848(c)).
Division 4.2 materials may not be loaded with Class 8 liquids, and Packing Group I, Zone A poisons may not be loaded with Class 3, Class 8 liquids or Divisions 4.1, 4.2, 4.3, 5.1 or 5.2 (177.848(c)).
Even with separation, Class 8 liquids may not be loaded above or next to Class 4 or Class 5 materials, except in truckload shipments known not to react (177.848(e)(3)).
Subsidiary hazards count: if a package needs a subsidiary label, apply that hazard’s segregation when it is stricter (177.848(e)(6)).
Note A: ammonium nitrate (UN1942) and ammonium nitrate fertilizer may be loaded with Division 1.1 or 1.5 despite the X, unless 177.835(c) says otherwise (177.848(e)(5)).
Class 1 compatibility table, 49 CFR 177.848(f)
| 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 |
X: not on the same vehicle. 1: group L only with an identical explosive. 2: a mix of C, D or E is treated as group E. 3: C, D or E with N is treated as group D. 4: see 177.835(g) for detonators. 5: 1.4S fireworks not with 1.1 or 1.2. 6: group G articles with C, D and E articles if no explosive substances are on board.
Rail is almost the same
Rail cars follow 49 CFR 174.81, whose segregation table has the same cells as the highway table (this tool checks that against both regulations). The Class 1 notes differ slightly: on rail, an X between compatibility groups can be met by separate freight containers on the same car, and note 4 bars Division 1.4S detonators and detonating primers from a car carrying Division 1.1 or 1.2 materials.
Common questions
Does segregation apply to every hazmat package?
It applies to packages that must be labeled or placarded, to compartments of multi-compartment cargo tanks under 173.33, and to portable tanks on a vehicle (177.848(a)). A load going on a vessel follows 176.83 instead.
What counts as separated for an O?
The regulation sets an outcome, not a distance: if packages leak in conditions normal to transport, the materials must not mix (177.848(e)(3)). Agree the method of separation with your carrier before loading.
What about the placards for the same load?
Use the DOT hazard classes and placard lookup: it works out the placards, the 1,001 lb rule and the DANGEROUS option for a mixed load.
Limits
A reference aid, not training. 49 CFR governs, and your carrier’s rules can be stricter. Check each material’s class and subsidiary hazards in the Hazardous Materials Table, 49 CFR 172.101, before you load.
WHERE MORSA FITS
Shipping hazmat? Check the papers before the truck does.
Morsa checks the shipping papers against the order before the truck arrives, and asks your team or the supplier about anything that does not match while there is still time to fix it. It works in email, Teams, WhatsApp or whatever you already run on, and reads from your ERP.
