The Hazardous Materials Table, commonly called the hazmat table, is a federally regulated reference chart that tells anyone shipping dangerous goods exactly how to classify, name, label, and package those materials for transportation. Codified under 49 CFR § 172.101 and maintained by the Pipeline and Hazardous Materials Safety Administration (PHMSA), the table is the single authoritative source that designates which materials count as hazardous for transportation purposes and spells out the rules for moving them safely by road, rail, air, or water.
What the Hazmat Table Actually Does
At its core, the table serves two functions. First, it officially classifies a material as hazardous. If a substance appears in the table, it is legally considered a hazardous material when offered for transport. Second, the table consolidates every key shipping requirement for that material into one row, so a shipper, carrier, or freight handler can look up a single entry and find the proper shipping name, hazard class, identification number, packing group, required labels, packaging instructions, aircraft quantity limits, and vessel stowage rules. Without the table, each of those requirements would live in a different section of the federal regulations, making compliance slow and error-prone.
Some entries in the table carry the designation “Forbidden” in the hazard class column. That means the material cannot be offered for transportation or transported at all under current federal rules.
How the Table Is Organized
The hazmat table is arranged alphabetically by proper shipping name and broken into several numbered columns. Each column provides a specific piece of information you need to ship the material correctly.
- Column 1 (Symbols): Special symbols flag important distinctions. A plus sign (+) locks in the proper shipping name, hazard class, and packing group for that entry, meaning you must use them exactly as listed regardless of whether the material might also fit another classification. The plus sign also signals that the material is known to pose a risk to humans. The letter “G” means you need to include one or more technical names in parentheses alongside the basic shipping description.
- Column 2 (Proper Shipping Name): The standardized name you are required to use on shipping papers, labels, and placards. You cannot substitute a trade name or abbreviation.
- Column 3 (Hazard Class or Division): The numeric hazard class or division that corresponds to the material’s primary danger, such as flammable liquid, corrosive, or oxidizer. If the entry reads “Forbidden,” the material cannot be shipped.
- Column 4 (Identification Number): A four-digit code preceded by either “UN” or “NA.” UN numbers are recognized internationally and domestically. NA numbers apply only within the United States and are not valid for international shipments.
- Column 5 (Packing Group): Indicates how dangerous the material is within its hazard class. Packing Group I means the danger level is great, Group II is medium, and Group III is minor. This classification directly affects which packaging standards apply.
- Column 6 (Labels): Codes that specify which hazard warning labels must appear on each package. The first code represents the primary hazard. Any additional codes indicate subsidiary hazards, meaning the material poses more than one type of danger.
- Column 7 (Special Provisions): Numeric codes that point to additional rules found in a separate section of the regulations (§ 172.102). These provisions can modify packaging requirements, exempt certain quantities, or impose extra conditions specific to that material.
Beyond these core columns, the table also references or specifies packaging authorizations, quantity limits for aircraft, and stowage requirements for vessels. These additional columns let you determine, from a single table lookup, whether your material can fly on a passenger aircraft, how much of it can go on a cargo-only plane, and where it must be stored on a ship.
Who Uses the Hazmat Table
Shippers are the most obvious users. If you manufacture, distribute, or sell a chemical, fuel, battery, aerosol, or any other regulated substance, you are legally required to consult the hazmat table before handing it off to a carrier. The table tells you how to fill out shipping papers, which packaging to buy, and what labels to affix. Getting any of these wrong can result in federal fines, shipment refusals, or, in serious cases, criminal penalties.
Carriers and freight handlers rely on the table to verify that shipments are properly classified and labeled before loading them onto trucks, railcars, aircraft, or vessels. Dispatchers and logistics coordinators use it to determine whether two hazardous materials can be loaded in the same vehicle or compartment. Emergency responders use the identification numbers and hazard classes from the table to quickly assess what they are dealing with at an accident scene, since those numbers appear on shipping documents and placards attached to vehicles. The classification system feeds directly into the Emergency Response Guidebook that firefighters and hazmat teams carry.
How the UN and NA Numbers Work
Every hazardous material in the table receives a four-digit identification number. If it starts with “UN,” the number is part of an international system maintained by the United Nations, and it is valid for both domestic and cross-border shipments. If it starts with “NA,” the number is specific to the United States and is not recognized abroad. This distinction matters if you ship internationally: using an NA number on a shipment headed overseas will cause it to be rejected at the border or by the receiving carrier.
These identification numbers appear on the diamond-shaped placards you see on the sides of tanker trucks and railcars. They allow anyone, from a highway patrol officer to a hazmat response team, to identify the contents without opening the container.
Packing Groups and Why They Matter
The packing group assignment in Column 5 is more than an academic ranking. It determines the type and strength of packaging you must use. A Packing Group I material (great danger) requires the most robust containers, tested to the highest performance standards. A Packing Group III material (minor danger) can often ship in lighter, less expensive packaging. Choosing packaging rated for the wrong packing group is a common compliance failure that can lead to leaks, spills, and regulatory violations.
Reading the Table in Practice
Say you need to ship acetone. You would look up “Acetone” alphabetically in the table and find its proper shipping name, hazard class (3, for flammable liquid), UN number (UN1090), and packing group (II, meaning medium danger). Column 6 tells you to apply a flammable liquid label. The packaging columns point you to the specific sections of the regulations that list approved container types and sizes for that combination of hazard class and packing group. If you are shipping by air, the table tells you the maximum quantity allowed per package on both passenger and cargo aircraft.
Every entry works this way. You start with the material’s name, read across the row, and each column gives you a concrete instruction or requirement. The table is designed so that a single horizontal reading produces a complete compliance picture for that substance.
Where to Access the Table
The full Hazardous Materials Table is published in the Electronic Code of Federal Regulations (eCFR) under Title 49, Section 172.101. It is freely available online through the eCFR website and through PHMSA’s own regulatory pages. Printed copies also appear in the Code of Federal Regulations volumes updated annually. Because materials are occasionally added, reclassified, or removed through federal rulemaking, always work from the most current version rather than an older printed copy.