Are Generic and N.O.S. Hazmat Names the Same Thing?

Posted on 8/27/2018 by Philip "Flip" De Rea

The US DOT’s Hazardous Materials Regulations (HMR) require shippers to identify all hazardous materials using a proper shipping name (PSN) from column (2) of the 49 CFR 172.101 table. Shippers must choose a PSN that:

  • Appears on the 172.101 Hazmat Table.
  • Accurately describes the material being shipped, and
  • Is the most specific name available.

Selecting the right PSN is one of the most important steps in the shipping process: The name assigned to your material provides accurate and specific information about the material and its hazards to First Responders, supply chain personnel, or anyone else who encounters your shipment in transport. Choosing an incorrect PSN can cause further mistakes in how the material is packaged, marked, labeled, handled, and segregated—and even impact emergency response in a worst-case scenario.

While the 172.101 Hazmat Table lists about three-thousand hazmat shipping names, it does not cover every possible hazardous material. So, what do shippers do when a specific name for their material cannot be found on the table? The DOT provides two tools to use to solve this problem; the placement of the letters “n.o.s.” at the end of a PSN, and the designation of certain PSNs as “generic.”

Because these two Proper Shipping Name designations often overlap, a common misconception in the shipping industry is that all PSNs ending with “n.o.s.” are “generic,” and vice versa. This is not the case!

The “n.o.s.” and “generic” designations are in fact distinct from each other and have different implications for hazmat transport safety.

How & When to Use an N.O.S. PSN

Shippers may use Proper Shipping Names (PSN) that end in the abbreviation “n.o.s.”—short for “not otherwise specified”— to identify a hazardous material that is not specifically listed by name in the Hazmat Table at 49 CFR 172.101. N.O.S. shipping names cover groups of similar chemicals, materials with particular end-uses, and hazard class names.

Some examples of n.o.s. entries are:

  • Flammable solid, toxic, inorganic n.o.s.
  • Ketones, liquid n.o.s.
  • Medicine, liquid, toxic n.o.s.
  • Nitriles, inorganic, aqueous solution n.o.s.

The abbreviation “n.o.s.” located at the end of a PSN it is a tool used in the “identification” step to help shippers choose the best, most accurate PSN to identify their material.

For example:

Your Hazard Class 3, PG II material is accurately described by BOTH the PSN “Acetone” and the PSN “Ketones, liquid, n.o.s.” So, which PSN should you use?

At 49 CFR 172.101(c)(12)(ii) the DOT advise us that, given a choice, an accurate PSN that does NOT end in “n.o.s.” is better than one that does. This makes Acetone the best choice for the PSN.

Similarly, given a choice between the PSN “Flammable liquids, n.o.s.” and the PSN “Compounds, cleaning liquid”; the better choice will be, and is, “Compounds, cleaning liquid.”

You can ship hazmat using an n.o.s. name only when no more specific and accurate option is available. When a non-n.o.s. shipping name is available, it is always a more descriptive and accurate option—and therefore the right choice for HMR compliance.

When & How to Use a “Generic” (G) PSN

A “generic” PSN is indicated by the presence of a “G” (for Generic) in column (1) of the 172.101 table.

Other examples of generic PSNs are:

  • Compounds, cleaning liquid
  • Ketones, liquid n.o.s.
  • Metal catalyst, dry
  • Nitriles, inorganic, aqueous solution n.o.s.

When a PSN is designated as “generic” it means that the PSN, as listed, is too vague for use in transport.

When you (the shipper) use a generic PSN to mark packages and complete shipping papers, you must add technical name(s) (in parenthesis) to identify the source of the hazard. For example:

  • Corrosive liquid n.o.s (Sodium Carbonate, Potassium Carbonate)
  • Dyes, solid, toxic n.o.s. (Methyl Orange)
  • Pesticides, liquid, flammable, toxic (Acetone, 4-Nitrophenol)

G vs. N.O.S.: What's The Difference?

The extremely high co-occurrence between generic (G) PSNs and PSNs that end in “n.o.s.” is what causes confusion here. “Ketones, liquid n.o.s.” for example, or “Fluorosilicates, n.o.s.” are both generic shipping names that also end in n.o.s. This frequent overlap gives the impression that “generic” and “n.o.s.” are synonymous, but really it’s just an overlap; a common co-occurrence. Some generic (G) shipping names do not end in n.o.s., and some n.o.s. shipping names are not generic.

While shipping names that end in n.o.s. cover multiple materials with the same hazard class, chemical family, or use-group; those n.o.s. names do not necessarily require the addition of more information—only a “G” in column (1) of the 172.101 table tells you that.

If and only if your n.o.s. name is also “generic”—i.e. there is a “G” in Column 1--will you need to supplement it with technical names on your package markings or shipping papers.

So, even though a “G” often appears in column (1) for a PSN that ends in “n.o.s.”, they are distinct pieces of advice and are used by hazmat handlers at different points in the shipping process. By understanding the difference between these two similar tools, you are better prepared to select the right shipping name for any material—and keep your shipments in full compliance.

Online Training to Simplify Hazmat Shipping Compliance

Develop a step-by-step approach to ship hazardous materials in full compliance with current US and international regulations! The Hazmat Ground Shipper Certification (DOT) online course prepares new or experienced shippers to properly classify, name, package, mark, label, handle, and document hazardous materials shipments for highway transportation.

The course is designed to help satisfy US DOT PHMSA's hazmat training mandate for hazmat employees at 49 CFR 172.704. US DOT requires training every 3 years for hazmat employees. For hazmat air and vessel shippers, Lion offers courses that cover the additional IATA DGR and IMDG Code requirements.

Hazmat Air Shipper Certification (IATA)
Hazmat Vessel Shipper Certification (IMDG)

Find hazmat training for managers and employees with any experience level or job description at

Tags: DOT, hazardous materials,, hazmat shipping, PHMSA, proper shipping names

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