Hazmat reference

Hazmat classes chart: the 9 DOT hazard classes, divisions and placards

By Mike Shelton, truck dispatcher, 15 years in trucking · Reviewed and updated October 2026 · How we check facts

Prints the chart and rules without the site menus.

The hazmat classes chart

Classes and divisions from 49 CFR 173.2; placards from 49 CFR 172.519 to 172.560; placarding table from 172.504(e). Checked October 2026.
Class	Division	Name	Placard	Placard table	Common examples
1	1.1, 1.2, 1.3	Explosives: mass explosion, projection, predominately fire	EXPLOSIVES 1.1 / 1.2 / 1.3, orange	Table 1	Dynamite, detonators, some fireworks
1	1.4, 1.5, 1.6	Explosives: no significant blast, very insensitive, extremely insensitive	EXPLOSIVES 1.4 / 1.5 / 1.6, orange	Table 2	Small arms ammunition, blasting agents
2	2.1	Flammable gas	FLAMMABLE GAS, red	Table 2	Propane, butane
2	2.2	Non-flammable compressed gas	NON-FLAMMABLE GAS, green	Table 2	Nitrogen, carbon dioxide, argon
2	2.3	Poisonous gas	POISON GAS, white	Table 1	Chlorine, anhydrous ammonia (inhalation hazard)
3	None	Flammable and combustible liquid	FLAMMABLE or COMBUSTIBLE, red	Table 2	Gasoline, diesel (combustible), paint
4	4.1	Flammable solid	FLAMMABLE SOLID, white with 7 red stripes	Table 2	Matches, sulfur
4	4.2	Spontaneously combustible	SPONTANEOUSLY COMBUSTIBLE, white over red	Table 2	Oily rags, some metal powders
4	4.3	Dangerous when wet	DANGEROUS WHEN WET, blue	Table 1	Calcium carbide, sodium
5	5.1	Oxidizer	OXIDIZER, yellow	Table 2	Ammonium nitrate, hydrogen peroxide
5	5.2	Organic peroxide	ORGANIC PEROXIDE, red over yellow	Table 1 (Type B, temperature controlled); otherwise Table 2	Benzoyl peroxide, MEK peroxide
6	6.1	Poisonous materials	POISON, white (POISON INHALATION HAZARD for inhalation hazards)	Table 1 (inhalation hazard); otherwise Table 2	Pesticides, cyanides
6	6.2	Infectious substance	No placard	Table 2 (no placard)	Medical waste, cultures
7	None	Radioactive material	RADIOACTIVE, yellow over white	Table 1 (Radioactive Yellow III label)	Medical isotopes, gauges
8	None	Corrosive material	CORROSIVE, white over black	Table 2	Sulfuric acid, sodium hydroxide, batteries
9	None	Miscellaneous hazardous material	CLASS 9, white with 7 black stripes on top half	Table 2 (not required domestically)	Lithium batteries, dry ice, hot asphalt

The classes and divisions come from 49 CFR 173.2. Placard colors follow the section for each placard; for example, flammable solid is white with seven red stripes, spontaneously combustible is white over red, organic peroxide is red over yellow and Class 9 has seven black stripes on its top half. The swatches above show colors only; real placards carry the symbol and words set out in each section. Examples are common products in each class; the shipper's classification on the shipping paper is what counts for any load.

What each class means on the road

Class 1, explosives: the strictest class. Divisions 1.1 to 1.3 are placarded in any amount, larger shipments need a safety permit, and parking and routing rules are tight.
Class 2, gases: carried in cylinders or pressure tanks. Poison gases (2.3) are placarded in any amount; propane and other flammable gases (2.1) are the most common in trucking.
Class 3, flammable liquids: the biggest volume in trucking, led by gasoline and fuel blends in cargo tanks.
Class 4, flammable solids: three very different hazards. Dangerous when wet materials (4.3) react with water and are placarded in any amount.
Class 5, oxidizers and organic peroxides: they feed a fire. Some organic peroxides must travel temperature controlled.
Class 6, poisons and infectious substances: inhalation hazards are placarded in any amount and segregated from food.
Class 7, radioactive: labels decide the placard; Yellow III packages need it in any amount.
Class 8, corrosives: acids and caustics, common in chemical tankers and battery loads.
Class 9, miscellaneous: lithium batteries, dry ice, elevated-temperature materials; no placard required domestically, but the paperwork still applies.

How to read the chart

The class is the broad hazard. The division narrows it: Division 2.1 flammable gas and 2.3 poison gas are both gases, but carry very different risks and rules. The placard is the 250 mm diamond on each side and end of the vehicle, with the class or division number in its lower corner. The placard table tells you when the placard is required.

Table 1 vs Table 2: when placards are required

Table 1 materials need placards in any amount: Divisions 1.1, 1.2 and 1.3, 2.3, 4.3, 5.2 Type B temperature controlled, 6.1 inhalation hazards and Class 7 Radioactive Yellow III. Table 2 covers everything else, from 1.4 explosives and flammable gases through Class 3, 8 and 9. Table 2 materials need placards once the aggregate gross weight of all Table 2 materials on the vehicle reaches 1,001 lb, with listed exceptions.

Reading a mixed load

EXAMPLE

A van carries 600 lb of Class 8 batteries and 500 lb of Class 3 paint in non-bulk packages: 1,100 lb of Table 2 materials, so the truck needs placards. It can show CORROSIVE and FLAMMABLE placards, or one DANGEROUS placard for the mixed load, as long as no single category reaches 2,205 lb loaded at one facility. Add one drum of a Table 1 material and that class needs its own placard regardless of weight.

Labels vs placards

Labels and placards use the same colors and symbols, but they go in different places. Labels are the small diamonds on packages, put on by the shipper. Placards are the large diamonds on the vehicle, which the carrier displays when the load requires them. A box can carry a Class 8 label on a truck that needs no placard because the load is under 1,001 lb of Table 2 materials. The reverse never works: a vehicle that needs placards can't skip them because the packages are small.

Where the class appears on the shipping paper

The shipping paper lists each hazardous material in a set order: the UN or NA identification number, the proper shipping name, the hazard class or division, and the packing group where one applies, followed by the quantity and an emergency response phone number. Match each entry to the placards and to the packages before you leave the dock. If the paper says Class 3 and the drum is labeled Class 8, stop and call the shipper.

Placard exceptions drivers get wrong

Class 9 placards are not required in domestic transport, though bulk packages still show the ID number.
Division 6.2 infectious substances carry labels but no placard.
Combustible liquids in non-bulk packages have their own exceptions; in bulk they are placarded.
A placard on the truck must match what is on the shipping paper, not what you think the product is.

The license that comes with each class

Any driver hauling placarded hazmat needs the H endorsement on a CDL, or X when the vehicle is also a tank vehicle. The class decides much of the rest: the security plan, the route, the insurance tier and, for the most dangerous materials such as highway route-controlled radioactive loads, large explosive shipments and some poison inhalation hazards, a federal safety permit. See our hazmat segregation table explainer, the segregation and placard checker, and the full hazmat trucking guide.

Methodology

Class and division names are quoted from 49 CFR 173.2. Placard colors are summarized from the individual placard sections, 49 CFR 172.521 to 172.560, with sizes from 172.519. Table assignments follow 172.504(e). Example products are common shipping descriptions in each class, not a classification of any specific load. We review this chart every year and after any change to the Hazardous Materials Regulations.

GearLoads is a dispatch service; we don't book placarded hazmat. For the rigs and loads we do book, including hotshot dispatch, start at the GearLoads home page.

Hazmat classes chart FAQ

01What are the 9 hazmat classes?

Class 1 explosives, Class 2 gases, Class 3 flammable and combustible liquids, Class 4 flammable solids, Class 5 oxidizers and organic peroxides, Class 6 poisonous and infectious substances, Class 7 radioactive material, Class 8 corrosives and Class 9 miscellaneous hazardous materials. Classes 1, 2, 4, 5 and 6 are split into divisions, listed in 49 CFR 173.2.

02Which hazmat classes need placards in any amount?

Table 1 materials: Divisions 1.1, 1.2 and 1.3 explosives, 2.3 poisonous gas, 4.3 dangerous when wet, 5.2 organic peroxide Type B temperature controlled, 6.1 materials that are poisonous by inhalation, and Class 7 with a Radioactive Yellow III label. Everything on Table 2 is placarded at 1,001 lb or more aggregate gross weight, with listed exceptions.

03Is diesel fuel a hazmat class?

Diesel is usually shipped as a combustible liquid under Class 3, or as a flammable liquid depending on its flash point. In bulk, such as a cargo tank, it is regulated and placarded; in small non-bulk packages, combustible liquids have exceptions. The shipping paper tells you exactly how the shipper classed it, so read it before you load.

04What does the number at the bottom of a placard mean?

It is the hazard class or division number, printed in the lower corner of every diamond placard at least 1.6 inches tall. A 3 means flammable liquid; 2.1 means flammable gas. It is different from the four-digit UN identification number, which identifies the exact material and is shown on bulk packages and on orange panels or the placard itself.

Mike Shelton, Truck dispatcher

Mike Shelton is a truck dispatcher with 15 years of experience in trucking. He writes and reviews the GearLoads hauling guides, calculators, factoring and DOT compliance pages, and checks every rule against its official source.