The mode-specific parts of the Hazardous Material Regulations (HMR), Parts 174 to 177, contain instructions primarily for highway, rail, air, and vessel carriers and those who perform “carrier functions” like loading, moving, and unloading hazmat.
One particular “carrier function” shippers should be familiar with is the segregation of hazardous materials—which may influence not just the loading of shipments, but also the consolidation of packages in overpacks, and even how hazardous materials are packaged to begin with.
If you determine that different materials “may not be loaded, transported, or stored together” in a truck or CTU, it follows that those materials may not be consolidated in the same overpack or combined into the same package for shipping. Being familiar with the regulations of hazmat segregation and how to use the segregation table at 49 CFR can save shippers from unnecessary delays, rejected packages, and rising fines.
Domestic and International Hazmat Segregation Rules
The domestic and international regulations commonly used to ship hazmat by air (49 CFR 175, IATA DGR,
ICAO Technical Instructions
) and Vessel (49 CFR 176 and the IMDG Code
) have similar regulations for segregation and “stowage.” We’ll cover the basics here by discussing segregation regulations for shipping hazmat by highway and rail. [49 CFR 177.848 and 174.81]
Most shipments that involve the consolidation of different hazardous materials for transport will be subject to the segregation regulations, specifically the transport of packages that require hazard or handling labels and/or placards, or multi-compartment cargo tanks, or portable tanks inside a CTU.
Why Is Hazmat Segregated During Transport?
Packages and materials are segregated for transport based on their hazard classes and divisions, including any subsidiary hazards present. When shippers consolidate materials with different hazard classes or divisions for shipment, all
of the hazards of each material must be compared using the Segregation Table for Hazardous Materials located at 49 CFR 177.848(d).
When incompatible materials are shipped together, they may comingle and react in ways that pose serious hazards during transport, like fires, violent chemical reactions, creation of toxic gas, dangerous evolution of heat, and more.
How to Use the 49 CFR Hazmat Segregation Table
As you can see in our recreated hazmat segregation table above, the DOT hazmat hazard classes and divisions (1–8) are listed in numerical order down the left edge and
across the top of the table. You may notice that Class 9 is not found on the table, which means the segregation rules do not apply to Class 9 hazardous materials.
When consulting the Segregation Table for compatibility, we compare materials’ hazards two at a time. The lower-numbered hazard is located on the left-hand side of the table (“L” for Lower. “L” for Left).
The second material’s hazard is located along the top of the table. Use a straight-edge scan right along the row of the lower-numbered hazards until it crosses the column of the other hazard. Where the row and column meet, you will find any restrictions that apply regarding your materials’ compatibility:
- An “X” indicates that those two hazards CANNOT be consolidated or transported together.
- An “O” indicates that those two hazards CANNOT be consolidated or transported together UNLESS the materials can be kept from combining should they BOTH get out of their packaging.
- An empty box indicates that those two hazards CAN be consolidated and/or transported together.
- An asterisk (*) indicates that the shipper should refer to a separate compatibility table for Class 1 explosives, found at 49 CFR 177.848(f).
Remember, if there are subsidiary hazards associated with either material, the comparison must be run again for each subsidiary hazard present. The most restrictive result from all comparisons is the instruction to follow.
(click on the Table for a bigger version)
Hazmat Segregation Example
Now, let’s use the table above to determine if the following two materials can be loaded into the same tractor trailer.
Material 1: A drum of UN 3274—Alcoholates solution, nos
The hazards: A primary hazard of Class 3, flammable liquid
A subsidiary hazard of Class 8, corrosive
Material 2: A drum of UN 2002—Celluloid, scrap
The hazards: Class 4.2, spontaneously combustible materials
Can we ship these two materials together?
Step 1: Compare the Primary Hazards
- First, we’ll compare the materials’ primary hazards: Hazard Class 3 and Division 4.2. To do this, locate the row for Hazard Class 3 on the left-hand side of the table and the column for Division 4.2 across the top.
- In the box where the row and column meet, we find no code, which allows these hazards to be transported together.
Step 2: Compare the Subsidiary Hazards
- We are not done yet! Because Material 1 has a subsidiary hazard of corrosivity (Class 8), we must run the comparison again to include the subsidiary hazard.
- This time, we locate the row for Division 4.2 on the left side of the table as it is the lower hazard class/division and the column for Class 8 across the top.
- In the box where the row and column meet, we find an “X,” which indicates that these two hazards cannot be shipped together.
- The bottom line: We can NOT put these two barrels on the same vehicle or put them in the same overpack because spontaneously combustible materials cannot be shipped with corrosives.
Any hazard class or division not represented on the table is exempt from the segregation regulations along with certain types of packages. For example, packages assembled according to the regulations for limited quantity (LTD QTY) shipments are exempt from segregation concerns.
Also, there are special regulations for certain cyanide and cyanide mixtures at 49 CFR 177.848(c).
Before you combine materials in the same package or consolidate them in the same overpack, you must know whether any restrictions apply. Knowing ahead of time that certain materials cannot be shipped together or will require special protective measures to do so, can minimize losses resulting from unnecessary delays, rejected packages, and possible fines.
Meet DOT, IATA, and IMDG Hazmat Training Mandates
Don’t miss expert-led 49 CFR, IATA DGR,
and IMDG Code
training when it comes to your area in April. Build a step-by-step process for keeping your hazmat shipments in compliance with the latest requirements. Whether you ship hazmat every day or just once in a while, knowing your responsibilities is crucial to avoid rejection, costly customs delays, and DOT fines now as high as $77,114 per day, per violation. The Complete Multimodal Hazmat Shipper Certification Workshops will be presented in Kansas City on April 25-28, Chicago on May 2-5, and St. Louis on May 8-11.