How to Ship Hazmat with No Packing Group

Updated 09/02/2025: Added video and details about additional Hazard Classes and Divisions. 

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Not all hazardous materials are equally hazardous. Even within the same hazard class or division, the severity of the hazard posed by different materials can vary greatly. For example: Some flammable liquids (Class 3) ignite at lower temperatures than others, making them more susceptible to an incident during transportation.

Packing Groups (PGs) address this by sorting hazardous materials within the same hazard class or division based on the “degree of danger” they present—great danger (PG I), moderate danger (PG II), or minor danger (PG III). The packing group for a hazardous material is shown in Column 5 of the Hazmat Table in 49 CFR 172.101. 

Shippers use hazardous material packing groups in two important ways: 

• To communicate the degree of danger the material poses on shipping papers; and
• To determine the strength of packaging required to contain the material in transportation. 

But not all types of hazardous materials are assigned to packing groups. Many classes and divisions treat severity of hazard differently, using more or fewer than three groups to denote severity of hazard (as needed). In other cases, materials in the class or division are not grouped in any way.

Hazmat with No Packing Group (PG)

What kinds of hazmat have no packing group? Division 2.1 and 2.2 hazardous materials comprise flammable and non-flammable gases, respectively. For these gases, there are no groupings based on severity of hazard. These gases are transported under pressure in UN specification cylinders that are engineered, tested, and regularly re-certified for use. This packaging eliminates the need for PG I, II, and III. 

Some, but not all, Class 9 materials are assigned to PG I, II, or III. Class 9 materials that are designated as "articles" are not assigned to a packing group, for example. This includes lithium-ion batteries without packing group assignments include lithium batteries and other articles in Class 9. When a Class 9 material is assigned a packing group, the PG will be listed in column 5 of the Hazmat Table in 49 CFR 172.101. 

For example: Articles that are classified as Class 9 hazmat, including lithium batteries, certain safety devices, and others, are not assigned to packing groups. Class 9 is the miscellaneous hazard class. Because there is no concrete criteria for assigning materials to Class 9 based on physical or chemical properties, comparing some Class 9 materials is like comparing apples to oranges. 

What Is a Hazmat Article?

Unfortunately for shippers, the hazmat regulations do not define the term "article." In regulatory and industry circles, a commonly-used definition comes from the OSHA Hazard Communication Standard (HCS), which defines "article" to mean—
 

"a manufactured item other than a fluid or particle: (i) which is formed to a specific shape or design during manufacture; (ii) which has end use function(s) dependent in whole or in part upon its shape or design during end use; …."

[29 CFR 1910.1200(c)]

Some article may contain a regulated hazardous materials. That said, an "article" has more purpose than a container, which is why articles are treated differently. 

Selecting Hazmat Packaging with No Packing Group (PG)

When hazmat is assigned to packing groups, the PG (I, II, or III) corresponds to a UN package rating of X, Y, or Z. Only X-rated packagings are authorized for PG I materials (great danger) or lower. Y-rated packagings may be used to ship PG II materials or lower, and Z-rated packagings may be used for PG III materials (minor danger) only. 

Without a packing group to go on, shippers must use other available info to determine the strength rating of packaging required for their hazmat. Luckily, the packing instructions for the material in Section 173 of the HMR and/or the Special Provisions associated with the material will specify the type and strength of packaging required. 

The cylinders built to contain Division 2.1 and 2.2 gases are meant to contain gas during transportation regardless of the exact chemical properties of the gas. So, severity of hazard does not factor into packaging selection in the same way it does with other classes and divisions.

Hazmat Shipping Papers with No Packing Group (PG) 

When filling out hazmat shipping papers, the Packing Group is a required element of the basic description (when applicable). When a material has no packing group, you simply don't include it. Materials with no packing group are excepted from requirement to include PG on shipping papers [see 49 CFR 172.202(a)(4)].

When a material does not have a PG, it is important that it is not included. Extraneous, inaccurate information included on shipping papers or package markings can create confusion in the supply chain, cause delays, and put shippers at risk of liability for violating the HMR.

Severity of Hazard with No Packing Group (PG)

These Classes and Divisions of hazardous materials address severity of hazard using groupings, "categories," "zones," etc. other than PG I, II, and III:

• Explosives (Divisions 1.1—1.6). Class 1 explosives are divided into thirteen separate “compatibility groups” that denote degree of hazard. So many groups are needed because Class 1 covers materials that range from firecrackers to weapons that pose a “mass explosion hazards.” Division into compatibility groups prevents certain explosives from being transported together or with other incompatible materials. 

• Flammable Gases (Division 2.1) and Non-flammable Gases (2.2). For these gases, there are no groupings based on severity of hazard. These gases are transported under pressure in UN specification cylinders that are engineered, tested, and regularly re-certified for use. These cylinders are intended to contain gas during transportation regardless of the exact chemical properties of the gas.  

• Poison Gases (Division 2.3). Division 2.3 gases are poison-by-inhalation (PIH) gases. Gases in this division are assigned to one of four Hazard Zones–A, B, C, or D–based on inhalation toxicity, judged by "lethal concentration" (LC50). As shown in the video above, having four zones allows for fast identification of the most acutely hazardous materials in the event of an emergency. 

• Self-reactive Materials in Division 4.1. Unlike other hazardous materials in Division 4.1, self-reactive materials are assigned not a PG but to one of seven "generic types," A through G, based on their likelihood to react dangerously during transportation and the potential severity of the incident that could occur. 

• Organic Peroxides (Division 5.2). Division 5.2 organic peroxides are categorized similarly to Division 4.1’s, utilizing generic types A through G. Organic peroxides and are judged by similar criteria as well. Type is assigned based on the likelihood of the material to react and the severity of the hazard posed. 

• Infectious Substances (Division 6.2). Infectious substances are divided into only two categories, Category A and Category B. Category A substances are those that are in a form capable of causing permanent disability or life-threatening or fatal disease in humans or animals. Category B covers all other infectious substances. 

• Radioactive Materials (Class 7). When dealing with materials that emit radiation, the "small, medium, and large" dynamic of PG I, II, and III is nowhere near precise enough to effectively communicate the hazard. In fact, the HMR spends a full Subpart (Subpart I) describing how to safely package radioactive materials for transportation based on the type of nuclides present (alpha, beta, gamma, etc.), radionuclide number(s) fissile vs. non-fissle, and more.   

• Some Class 9 (Miscellaneous) Hazardous Materials. Some Class 9 materials are assigned to PG I, II, or III, but not all are. Materials with no packing group include lithium batteries and other articles in Class 9. When a Class 9 material is assigned a packing group, the PG will be listed in column 5 of the Hazmat Table in 49 CFR 172.101. 

For those used to shipping flammable liquids or corrosive chemicals, encountering a material with no PG may be confusing or disorienting at first. By paying close attention to details elsewhere in the HMR, though, shippers can still find the details needed to select the right package and offer any hazmat for transportation in full compliance with the HMR—with or without a packing group.