Identification numbers, shipping names and the Hazardous Materials Table

Once a material is classified, it needs an identity that everyone in the transport chain recognizes. That identity is its identification number and its proper shipping name, both taken from the Hazardous Materials Table in 49 CFR 172.101. The identification number is a four-digit number preceded by UN or NA, such as UN1203 for gasoline. The proper shipping name is the official name of the material as it appears in the table, such as Gasoline. Together with the hazard class and packing group, they form the basic description that appears on shipping papers, and the identification number often appears on the vehicle itself.

UN numbers

UN numbers are assigned by the UN Sub-Committee of Experts and run from UN0004 to above UN3500. Low numbers starting with 0 are explosives. Numbers in the 1000s include many common gases, liquids and solids; numbers in the 3000s and above tend to be newer entries, including many generic entries and lithium battery entries. A UN number can cover a single substance (UN1090 Acetone), a group of similar substances (UN1987 Alcohols, N.O.S.) or an article (UN3480 Lithium ion batteries). Responders use the UN number as their key to emergency information, so an incorrect number can send them to the wrong guidance.

A few numbers beginning with NA (North America) are used only in the United States and for shipments between the United States and Canada, for materials that have no UN number or that the United States classifies differently. For example, NA1993 covers combustible liquid, n.o.s., diesel fuel and fuel oil, and NA3082 covers some hazardous substances that are regulated domestically only because of their reportable quantity. NA numbers are not accepted for international air or sea shipments, which must use UN numbers.

Shipping names

In the Hazardous Materials Table, the proper shipping name is the part of column 2 printed in roman (upright) type. Words in italics are not part of the proper shipping name, although they help you choose the right entry; for example, Sulfuric acid with more than 51 percent acid tells you which concentration the entry covers. Some entries allow a choice of names. The proper shipping name may be written in upper or lower case on the shipping paper, but it must not be abbreviated or changed, apart from permitted variations such as singular and plural forms or the use of the word Waste or Residue in front of it.

Choosing the right entry

When more than one entry might fit, the rules give an order of preference. First, use an entry that names the substance exactly. Second, if there is no specific entry, use a generic entry that describes the chemical group, such as Alcohols, N.O.S. or Pesticide, liquid, toxic, flammable, N.O.S. Third, use the broadest generic entry for the hazard, such as Flammable liquid, N.O.S. or Toxic solid, organic, N.O.S. Generic and N.O.S. entries often require the technical name of the hazardous component, or of the two most hazardous components in a mixture, in brackets after the shipping name, for example FLAMMABLE LIQUID, N.O.S. (Toluene, Methanol). A trade name such as a brand name is never acceptable as a technical name.

Many entries carry special provisions, listed by code in column 7 and explained in 49 CFR 172.102. Codes with only numbers apply to all modes; codes starting with letters apply to particular situations, such as A for air, B for bulk packagings, IB and IP for intermediate bulk containers, N for non-bulk packagings, R for rail, T and TP for portable tanks and W for vessels. Special provisions can require extra information on the shipping paper, limit packaging, allow exceptions or forbid certain modes. Always read the special provisions listed for your entry before deciding how to ship.

Reading the list

Each row of the Hazardous Materials Table contains the information you need to start a shipment. The table below summarizes its columns. The values for a few entries are given later in the worked example; always check the current table for the actual values, which change from time to time.

Some materials are listed with the word Forbidden in column 3, meaning they may not be offered or transported at all, usually because they are too unstable. Others are forbidden only on passenger aircraft or on all aircraft, as shown in columns 9A and 9B. A forbidden material can be shipped only under a special permit or approval issued by PHMSA.

Additional descriptions

Some shipments need more than the basic description. A hazardous substance, listed in Appendix A to 172.101, must be identified with the letters RQ (reportable quantity) when one package contains at least the reportable quantity, and if the proper shipping name does not identify it, its name must be added in parentheses. Marine pollutants must be identified when shipped by vessel or in bulk. Hazardous wastes need the word Waste and a hazardous waste manifest. Materials shipped hot need the word HOT or Molten. Lesson 8 covers these additions. Note that the August 2026 rules replace Appendix A with a reference to the EPA's list of hazardous substances in 40 CFR Part 302, taking effect by December 2026.

# Building basic shipping descriptions from a small, simplified extract of the list (illustrative).
LIST = {
    "UN1203": ("GASOLINE", "3", None, "II"),
    "UN1075": ("PETROLEUM GASES, LIQUEFIED", "2.1", None, None),
    "UN1830": ("SULFURIC ACID", "8", None, "II"),
    "UN3480": ("LITHIUM ION BATTERIES", "9", None, None),
    "UN1005": ("AMMONIA, ANHYDROUS", "2.3", "8", None),
}

def description(un, technical=None):
    name, cls, sub, pg = LIST[un]
    parts = [un, name + (f" ({technical})" if technical else "")]
    parts.append(cls + (f" ({sub})" if sub else ""))
    if pg:
        parts.append("PG " + pg)
    return ", ".join(parts)

for un in LIST:
    print(description(un))

UN1203, GASOLINE, 3, PG II
UN1075, PETROLEUM GASES, LIQUEFIED, 2.1
UN1830, SULFURIC ACID, 8, PG II
UN3480, LITHIUM ION BATTERIES, 9
UN1005, AMMONIA, ANHYDROUS, 2.3 (8)

The order of the basic description is fixed: identification number, proper shipping name, hazard class, subsidiary hazards in parentheses, packing group. The output above uses the international classification of anhydrous ammonia, 2.3 with a subsidiary 8; for domestic US transport, the table classes it as 2.2 with an inhalation hazard. Checking the right column for your mode and destination matters.

Using the list in practice

Most people search the table by name, not by number. The Hazardous Materials Table is arranged alphabetically by proper shipping name, and the electronic CFR and many commercial tools let you search by name, identification number or keyword. Searching by keyword helps when the product name on a label is a trade name or a synonym; the safety data sheet's section 14 usually gives the identification number, which you can then confirm in the table.

Similar names cause many errors. Ammonia, anhydrous (UN1005), a gas, and ammonia solution (UN2672), a class 8 corrosive liquid, are very different products. Sodium hydroxide, solid (UN1823) and sodium hydroxide solution (UN1824) have different entries because a solid and a liquid need different packaging. Several products have entries that depend on concentration, such as hydrogen peroxide or nitric acid, where the descriptive text tells you which range the entry covers. Always read the whole entry, including the descriptive text, before choosing.

When a product could fit more than one entry and you are unsure, ask the manufacturer, a dangerous goods specialist or the regulator before shipping. Writing down why you chose an entry, with the source you used, makes the decision easier to defend and easier for the next person to check.

When the list changes

Entries are added, removed and rewritten as the UN Model Regulations evolve. PHMSA's harmonization rules periodically add new identification numbers, revise proper shipping names and change special provisions to match international text, and the August 2026 rules replaced the hazardous substances appendix with a reference to the EPA list. A shipper that copied descriptions into its order system years ago may now be using an entry that has changed. Reviewing your regular products against the current table after each amendment, and keeping a dated record of the review, avoids that drift.