49 CFR 177.848: Hazmat Segregation Table, Bans, and Penalties

49 CFR 177.848 sets the hazmat segregation rules for highway transportation: a grid called the Segregation Table for Hazardous Materials tells you which hazard classes can share a vehicle or storage space and which cannot, backed by outright bans on a handful of especially dangerous pairings and a separate compatibility system for explosives. Getting it wrong exposes a carrier to civil penalties of up to $102,348 per violation and, for willful or reckless conduct, up to five years in federal prison.¹²

What Shipments the Rule Covers

The section reaches three kinds of hazmat loads. Any package that requires a hazard label or placard under Part 172. Any compartment within a multi-compartmented cargo tank. And any portable tank loaded inside a transport vehicle or freight container.³ Bulk liquid shipments in tanker compartments and large portable tanks are bound by the same segregation logic as small labeled boxes.

One boundary worth flagging: when a transport vehicle will be loaded onto a vessel other than a ferry, the maritime stowage rules at 49 CFR 176.83(b) apply instead of the highway table.³

How to Read the Segregation Table

The table is a grid with hazard classes and divisions listed across the top and down the left side. Locate the class of one material along the top row, find the class of the second along the left column, and read the cell where they meet. That cell governs whether the two can share a vehicle or a transit storage facility.³

The grid covers Divisions 1.1 through 1.6 (explosives), 2.1 (flammable gas), 2.2 (non-flammable gas), 2.3 (poison gas, split into Zone A and Zone B), Class 3 (flammable liquids), Divisions 4.1 through 4.3, 5.1 and 5.2 (oxidizers and organic peroxides), Division 6.1 liquids in Packing Group I Zone A, Class 7 (radioactive), and Class 8 liquids (corrosives).

Four symbols appear in the cells, and each carries a distinct consequence.

X means do not load, transport, or store the two materials together at any point during transportation. Full physical separation into different vehicles or storage areas is required.³

O means the two materials may travel together only if separated well enough that a leak under normal transport conditions could not allow them to mix. Even with adequate separation, Class 8 corrosive liquids may never be loaded above or next to Class 4 or Class 5 materials. The regulation includes one narrow exception for full truckload shipments where the shipper knows the mixture would not cause a fire, dangerous heat, or gas.³ The “O” designation is where carriers get tripped up most often. Inspectors ask whether a realistic leak scenario could allow contact, so stacking a corrosive above an oxidizer with only a wooden pallet between them fails the test even if every package is intact.

A blank cell means no specific segregation restriction applies. The two materials can share a vehicle, though every other packaging integrity rule still applies.

An asterisk appears in cells involving Class 1 explosives and directs you off the general table and into the separate Class 1 compatibility system.³

Combinations Banned Regardless of the Table

Some pairings are so dangerous that paragraph (c) of the rule bans them outright, independent of what the grid shows.

Cyanides, cyanide mixtures, or cyanide solutions may not be stored, loaded, or transported with acids if mixing them could produce hydrogen cyanide gas.³
Division 4.2 spontaneously combustible materials may not share space with Class 8 liquids.
Division 6.1, Packing Group I, Hazard Zone A materials (the most toxic liquids) may not be loaded with Class 3, Class 8 liquids, or Division 4.1, 4.2, 4.3, 5.1, or 5.2 materials.³

Forbidden materials listed under 49 CFR 173.21 may never be loaded into any motor vehicle or placed in any transit storage facility, regardless of trip length or package size.⁴

Class 1 Explosives Use a Separate Compatibility System

Explosives do not use the general segregation table. Class 1 materials are assigned to one of 13 compatibility groups identified by letter: A, B, C, D, E, F, G, H, J, K, L, N, and S. Some letters are omitted to avoid confusion with numerals. Each group reflects the physical and chemical characteristics of the explosive: Group A covers primary explosive substances like lead azide; Group B covers articles containing a primary explosive without two or more protective features, such as detonators and blasting caps; Groups C, D, and E cover propellants and secondary explosives that are frequently intermixed under specific conditions; and Group S covers items designed to contain any accidental functioning inside the package.⁵

The Class 1 compatibility table uses numbered footnotes rather than X or O symbols, and those footnotes carry instructions that override the general rules:

Footnote 1: Group L explosives may only share a vehicle with an identical explosive.
Footnote 2: Combining Groups C, D, or E assigns the entire load to Group E.
Footnote 4: Refers carriers to 49 CFR 177.835(g) for special rules covering detonators.
Footnote 5: Division 1.4S fireworks may not share a vehicle with Division 1.1 or 1.2 explosives.
Footnote 6: Group G explosive articles (other than fireworks and items needing special handling) may share space with Groups C, D, and E articles, provided no loose explosive substances travel in the same vehicle.³

Responsibility at Loading, Storage, and on the Road

The segregation requirements apply at every phase of the shipment: loading at the origin, interim storage at any transfer facility, and the highway leg itself.⁴ Storage facilities used for freight transfer follow the same standards that apply inside vehicles, so floor plans need to account for segregation distances and incompatible pairings. An unannounced DOT inspection can happen at any transfer point along the route.

The driver is the last checkpoint before the load moves. Before leaving a terminal, the driver is expected to review the shipping papers and check the physical labels on every piece of freight against the segregation table. If a warehouse worker has staged two incompatible loads on the same dock, the driver has to catch it. Roadside inspectors compare the manifest against the actual labels on the freight, and a mismatch is one of the fastest paths to an out-of-service order.⁶

Penalties for Segregation Violations

Federal hazmat penalties are structured to make non-compliance more expensive than doing the job right.

Civil Penalties

A knowing violation of the hazardous materials transportation regulations carries a maximum civil penalty of $102,348 per violation. If the violation results in death, serious illness, severe injury, or substantial property destruction, the cap rises to $238,809 per violation. There is no general minimum, but training-related violations carry a floor of $617. Each day a continuing violation persists counts as a separate offense, so costs compound quickly.¹

Criminal Penalties

Willful or reckless violations of the federal hazmat transportation law can bring criminal fines under Title 18 and imprisonment of up to five years. If the violation involves a hazardous material release that causes death or bodily injury, the maximum prison term doubles to ten years. A person acts recklessly under this statute when they show deliberate indifference or conscious disregard for the consequences of their conduct, which puts a carrier who knows the rules and ignores them squarely in scope.²

Operational Consequences

Beyond fines and prison time, a segregation violation caught at a roadside inspection typically triggers an immediate out-of-service order for the vehicle. The truck stays put until the violation is corrected, which often means dispatching a second vehicle to the scene and reloading freight on the shoulder. The carrier absorbs towing, storage, missed delivery penalties, and a recorded DOT violation that follows the operating authority.

1
eCFR. 49 CFR 107.329 – Maximum Penalties
2
Office of the Law Revision Counsel. 49 USC 5124 – Criminal Penalty
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eCFR. 49 CFR 177.848 – Segregation of Hazardous Materials
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GovInfo. 49 CFR 177.848 – Segregation of Hazardous Materials
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eCFR. 49 CFR 173.52 – Classification Codes and Compatibility Groups of Explosives
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Commercial Vehicle Safety Alliance. CVSA’s 2025 Out-of-Service Criteria Now in Effect