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Hazardous materials and freight class

02.01.2019 | By AJ Todd | 4 min. read

Your guide to stress-free hazmat shipping

Table of contents

  1. Classes of hazardous materials
  2. Is it hazardous?
  3. Reportable quantities and small quantities
  4. Packing groups
  5. DOT hazard classes
    1. Class 1: explosives
    2. Class 2: gases
    3. Class 3: flammable liquids
    4. Class 4: flammable solids
    5. Class 5: organic peroxides and oxidizers
    6. Class 6: etiologic materials and poisons
    7. Class 7: radioactive materials
    8. Class 8: corrosives
    9. Class 9: miscellaneous substances
  6. Labeling
  7. Transportation of hazardous materials
  8. Calculating freight class
    1. Density and value
    2. Handling
    3. Liability
    4. Stow-ability
  9. Freight classes
  10. Moving hazardous materials via shared truckload
  11. Conclusion

People ship goods across the country every day, but what happens when that freight involves hazardous materials? Most people don’t realize that common, everyday items like batteries qualify as hazardous materials (or “hazmat”), and they end up incurring penalties for failing to properly identify the contents of their shipment.

Knowing how to properly classify a shipment is not only useful to business owners, but also to individuals who need to ship hazardous materials for non-professional reasons. If you’re armed with a comprehensive understanding of how shipping these materials affect your final statement, you’ll avoid overcharges and penalty tags.

As a rule of thumb, hazardous materials are more expensive to ship than non-hazmat goods; hazardous materials push shippers into a higher freight-shipping class. It’s not hard to understand why. Shipping hazardous materials without proper security and packaging involves a great deal of risk that can affect other freight in a truck and even harm or kill drivers. For this reason, the Department of Transportation (DOT) has carefully classified hazmat goods and made clear the penalties of violating precautions. 

Classes of hazardous materials

For safety reasons, the government heavily regulates the shipment of hazardous materials. The associated government organization is the Department of Transportation. The DOT has carefully identified hazardous materials, what to do if you’re dealing with a gray-area case that might potentially qualify as “hazardous material”, and, of course, the penalties for failing to properly stow or identify hazardous material. 

Is it hazardous?

Before shipping, it’s important to determine whether your goods are actually hazardous or qualify as “hazardous,” according to the DOT. You can find the terms of qualification as well as a list of items that qualify as “hazardous” under Title 49 of the Code of Federal Regulations.

In almost all cases, if you scan the list and discover that the item you’re attempting to ship does not appear, then it is likely not a hazardous material. However, there is one exception: If you’ve created a new material, the responsibility falls on you to properly describe and identify the potential hazards of the creation. If you’re having trouble determining if new material is potentially hazardous, contact the DOT for help with the identification process. 

Reportable quantities and small quantities

Hazardous materials can qualify as “reportable quantities” or “small quantities.” When a hazmat is “reportable,” there’s enough of it to justify reporting the shipment. In these cases, the amount of hazardous material is great enough to potentially cause harm if someone improperly handles or packages it. For this reason, it’s vital to properly identify and report the material.

However, other cases in which you’re only shipping “small quantities” may qualify for an exception. In these instances, while the material is certifiably hazardous, there just isn’t enough of it in the shipment to pose a real threat. If the shipper can prove that there isn’t enough of the hazardous material to justify a “reportable quantity”, then he or she is potentially eligible for a fee reduction. 

Packing groups

When you ship hazardous materials, various classifications apply. One of these classifications is the “packing group”. The purpose of this classification is to help carriers identify the potential risk of the package and thus the way they should handle it. The DOT outlines three categories of these groups:

  • Package Group I: If a hazardous material qualifies as Package Group I, it poses the highest possible risk. This means the materials within the package, given improper handling, might cause the greatest amount of damage to the surrounding environment.
  • Package Group II: Hazardous materials that qualify for Package Group II are moderately dangerous. They aren’t benign, but they also aren’t going to cause a massive amount of damage if a carrier improperly handles them.
  • Package Group III: The third package group represents materials that pose the least risk to their environment. While they are still hazardous and require cautious handling, they pose the smallest possible risk given the inherent danger of the material. 

DOT hazard classes

In a highly comprehensive fashion, the DOT has outlined all of the potentially hazardous materials (except for new materials) that shippers must report before shipment. The DOT has broken the different materials down into nine classes, which contain divisions. These divisions help identify the specific nature of the hazardous material.

These classes not only help identify the type of material that you’re going to ship, but also help determine the class. In general, the more dangerous the material, the higher the freight class. If freight requires extra-cautious handling or separate handling from other goods within the same truck, extra fees are common.c 

Class 1: explosives

The DOT defines “explosives” as “items that are capable of or designed to shatter or burst apart” and breaks down this class into six divisions:

  • 1: Mass explosion hazard
  • 2: Projection hazard
  • 3: Explosives with fire hazard
  • 4: Explosives without significant blast hazard
  • 5: Insensitive explosives
  • 6: Extremely insensitive explosives 
Class 2: gases

The DOT defines a “gas” as an “air-like liquid substance that can fill the area it occupies.”

  • 1: Flammable gases
  • 2: Non-flammable gases
  • 3: Poison gases
  • 4: Corrosive gases 
Class 3: flammable liquids

The DOT defines “flammable liquids” as “liquids that can catch on fire.”

  • 1: Flammable below -18°C (0°F)
  • 2: Flammable between -18°C (0°F) and 23°C (73°F)
  • 3: Flammable between 23°C (73°F) and 61°C (141°F) 
Class 4: flammable solids

This category consists of solid materials that can catch fire, materials that can spontaneously combust, and materials that are dangerous when wet.

  • 1: Flammable solids
  • 2: Spontaneously combustible material
  • 3: Materials that become dangerous when wet 
Class 5: organic peroxides and oxidizers

These are hazardous materials that react when they come into contact with oxygen.

  • 1: Oxidizers
  • 2: Organic peroxides 
Class 6: etiologic materials and poisons

These materials can cause infection or poison a person that comes into contact with them. They are the last class that the DOT divides into subdivisions.

  • 1: Poisonous materials
  • 2: Etiologic materials 
Class 7: radioactive materials

These are materials that alone, or in combination with other materials, can emit ionizing radiation. They can cause harm to goods or to people who come into contact with them. They are defined as “radioactive” if they are active at more than 0.002 microcuries per gram. 

Class 8: corrosives

Class 8 describes materials that are capable of causing irreversible, corrosive damage to skin or other materials. Class 8 material can damage steel and aluminum. 

Class 9: miscellaneous substances

These are materials that do not fall within Classes 1-8, but still pose a hazard during transport. 


In almost all cases, shippers must properly label hazmat packaging. The DOT has created labels specifically for the different classes. Shippers must officially print them and can’t make them by hand without qualifying for penalty fees. The DOT differentiates these labels by size, shape, and color. 

Transportation of hazardous materials

There’s a right way to ship hazardous materials, and there’s a wrong way. Often, the right way prevents serious harm from befalling people who are involved in the shipment process and damage to other goods within the truck. If you’re trying to figure out the correct steps to take leading up to shipping hazardous material, consider the following:

  • Check for regulation updates. It doesn’t happen often, but the DOT will occasionally change the regulations regarding the shipment of hazardous materials. Before sending out a shipment, check if anything has changed.
  • Make sure that you’ve filled out shipping forms correctly. This is a very important step – perhaps the most important next to packaging. The shipping form alerts the carrier to the contents of the package and the nature of the hazardous material. It also dictates the way the carrier should handle the package. For both your sake and the sake of the carrier, be scrupulous to avoid mishandling that can damage all goods in the truck and cause serious harm to transportation workers.
  • Choose the right packaging. If you choose incorrect packaging, the hazardous material might incur damage. 

Calculating freight class

Calculating freight class is a way for carriers to categorize your shipment and determine the amount to charge. These classes apply to less-than truckload shipments (LTL) in which the freight takes up less than a full truck and shares trailer space with other goods. There are 18 freight classes, which differ by weight and the nature of the shipment material.

Hazardous materials require more attention than non-hazardous materials and pose a greater risk to other goods in the truck. For these reasons, carriers bump hazmat shipments into the more expensive freight classes.

There are four main factors that affect freight class: 

Density and value

You can determine the density of a package by measuring its weight, length, and height. Somewhat counterintuitively, the lower the density, the higher the freight class. Measure the density by dividing the weight of a given item by its volume. 


In most cases, mechanical equipment handles freight. Machines that alleviate workers of extra effort load freight onto trucks. However, in some cases (especially those that involve hazardous materials), the freight requires careful or specialized handling. This often increases the freight class and makes the shipment more expensive. 


This factor calculates the risk of shipping freight. If the hazardous material that you’re shipping has the possibility of spontaneously combusting and therefore damaging other goods within the truck, it will have a higher liability. We calculate this number by determining a value per pound. 


Often, carriers cannot easily stow hazardous materials. They must place them in carefully managed compartments away from the rest of the goods in the truck. This kind of special treatment means that the price will increase. 

Freight classes

There are 18 different freight classes. To determine yours, carries combine the above factors to produce a number. Hazardous materials often have a higher categorization because they are more difficult to stow, are a bigger liability, and require special handling.

The purpose of freight class is to help shippers get unbiased pricing on their freight. It also helps carriers figure out the best way to organize goods before loading them onto a truck. If carriers have incorrect information, they may accidentally stack goods that shouldn’t be stacked or create a hazard by destroying or unleashing hazardous materials.

The final calculation is simple: the lower your freight class, the lower the cost. Below, the measurement in pounds refers to the weight per cubic foot. Remember, it’s important to have the correct freight class because you’ll most likely incur a penalty if you’ve used the wrong one.

  • Class 50 – Over 50 lbs.
  • Class 55 – 35-50 lbs.
  • Class 60 – 30-35 lbs.
  • Class 65 – 22.5-30 lbs.
  • Class 70 – 13.5-15 lbs.
  • Class 77.5 – 13.5-15 lbs.
  • Class 85 – 12-13.5 lbs.
  • Class 92.5 – 10.5-12 lbs.
  • Class 100 – 9-10.5 lbs.
  • Class 110 – 8-9 lbs.
  • Class 125 – 7-8 lbs.
  • Class 150 – 6-7 lbs.
  • Class 175 – 5-6 lbs.
  • Class 200 – 4-5 lbs.
  • Class 250 – 3-4 lbs.
  • Class 300 – 2-3 lbs.
  • Class 400 – 1-2 lbs.
  • Class 500 – Less than 1 lb. 

Moving hazardous materials via shared truckload

Flock Freight® offers shared truckload solution, FlockDirect™️, that makes hazmat transportation a breeze. Because shippers and organizations like the Federal Motor Carrier Safety Administration require shared truckload carriers to meet certain commodity-related demands, Flock Freight verifies the following items to ensure compliance:

  • Food: Because non-food products (especially hazardous materials) can contaminate food, Flock Freight gives shippers the option to select “Food Grade” in the quote and Vehicle Preferences settings. Flock Freight does the rest, ensuring food shipments don’t travel with potentially harmful substances and finding clean vehicles that are free of leaks and holes.
  • Plastics: Many plastics and packaging manufacturers don’t want their freight to develop a residual smell during transit. Flock Freight eliminates this concern by preventing plastics from shipping with freight that has a strong odor.
  • Hazardous materials: Flock Freight transports hazardous materials separately to comply with all applicable laws.

Learn more about our shared truckload solution by downloading our shared truckload guide. 


If you mislabel or incorrectly identify hazardous materials, you risk putting all of the surrounding goods in the truck in harm’s way and may injure the driver. For these reasons, it is vitally important that you make sure to correctly identify the hazardous material that you’re going to ship. If you have any questions regarding the way to package or ship hazardous material, contact the carrier or the Department of Transportation for clarification. Lastly, shared truckload service can be a solution for shipping your hazardous materials with ease.

Learn more about our shared truckload solution by downloading our STL white paper.