Understanding Hazard Terms and Symbols

Core Regulatory Definitions and Documentation Terms

Federal Hazardous Materials Rules in 49 CFR 171.8 contain a complete glossary of regulatory terms. The manual recommends keeping an up-to-date copy of the hazardous materials rules for reference, but says you will not be tested on this glossary. Hazardous materials are substances or materials designated by the Secretary of Transportation as capable of posing an unreasonable risk to health, safety, and property when transported in commerce. This broad designation includes hazardous substances, hazardous wastes, marine pollutants, and elevated temperature materials.

When handling shipments, you must recognize key industry roles and basic documentation terms. A carrier is a person who transports passengers or property in commerce by rail car, aircraft, motor vehicle, or vessel. The consignee is the business or person to whom a shipment is delivered. A shipping paper is a shipping order, bill of lading, manifest, or similar shipping document prepared in accordance with subpart C of Part 172. A shipper's certification is a signed statement on a shipping paper certifying that the shipment was prepared properly according to law.

Hazard classification follows a structured system. A hazard class is the category of hazard assigned to a hazardous material under Part 173 and Sec. 172.101. A division is a subdivision of a hazard class. When a material meets the criteria for more than one hazard class, it is assigned to only one hazard class. The proper shipping name is the name of contents specified in Sec. 172.101, where it is shown in Roman print rather than italics. If a chemical has a recognized scientific designation, it may carry a technical name, which is a recognized chemical or microbiological name used in scientific and technical publications. N.O.S. stands for 'not otherwise specified.'

Drivers must also understand basic physical units and equipment terminology. Markings refer to descriptive names, identification numbers, instructions, cautions, weight, specifications, or UN marks on outer packaging. A mixture is a material composed of more than one chemical compound or element. Pressure measurements may be given as psi (pounds per square inch) or psia (pounds per square inch absolute). A fuel tank is defined specifically as a tank, other than a cargo tank, used to carry flammable or combustible liquid or compressed gas to fuel the vehicle to which it is attached or equipment on that vehicle. A transport vehicle is a cargo-carrying vehicle used to transport cargo by any mode, and each separate cargo-carrying body, such as a trailer or rail car, is considered an individual transport vehicle.

Distinguishing Bulk from Non-Bulk Packaging

The Federal Hazardous Materials Rules strictly define packaging sizes based on capacity thresholds. Bulk packaging is packaging, other than a vessel or barge, in which hazardous materials are loaded with no intermediate form of containment. Bulk packaging can include a transport vehicle or a freight container. A freight container is a reusable container having a volume of 64 cubic feet or more, designed and constructed to permit being lifted with its contents intact, and intended primarily for containing packages in unit form during transportation.

The exact dividing lines between bulk and non-bulk depend on the state of the material. For liquids, bulk packaging has a maximum capacity greater than 450 liters (119 gallons), while non-bulk packaging has a maximum capacity of 450 liters (119 gallons). Non-bulk packaging for solids has a maximum net mass less than 400 kilograms (882 pounds) and a maximum capacity of 450 liters (119 gallons) or less. However, a bag or box with a maximum net mass of 400 kilograms (882 pounds) or less can be classified as non-bulk packaging regardless of the bulk-packaging definition if it meets the applicable specification-packaging requirements, including maximum net mass limits. For gases, bulk packaging has a water capacity greater than 454 kilograms (1,000 pounds).

Gross weight or gross mass is the weight of the packaging plus the weight of its contents. Specification packaging that conforms to international standards is known as UN standard packaging, based on United Nations recommendations. Outage or ullage is the amount by which a packaging falls short of being liquid full, and it is usually expressed in percent by volume.

Specialized Containers: Cargo Tanks, Portable Tanks, and IBCs

Commercial drivers must know how the regulations distinguish among various large containers that travel over the road. A cargo tank is intended primarily for the carriage of liquids or gases and includes appurtenances, reinforcements, fittings, and closures. A cargo tank is permanently attached to or forms part of a motor vehicle, or, if not permanently attached, is loaded or unloaded without being removed because of its size, construction, or attachment. It is not fabricated under a specification for cylinders, portable tanks, tank cars, or multi-unit tank car tanks.

In contrast, a portable tank is bulk packaging equipped with skids, mountings, or accessories to facilitate mechanical handling. A portable tank is designed primarily to be loaded onto or temporarily attached to a transport vehicle or ship. The glossary excludes from its portable-tank definition a cylinder with a water capacity of 1,000 pounds or less, a cargo tank, a tank car, a multi-unit tank car tank, and a trailer carrying 3AX, 3AAX, or 3T cylinders.

Another common mechanical container is the intermediate bulk container, commonly abbreviated as IBC. An intermediate bulk container is a rigid or flexible portable packaging other than a cylinder or portable tank. Like portable tanks, an intermediate bulk container is designed for mechanical handling. Drivers may also encounter shipments designated as a limited quantity, which is the maximum amount of a hazardous material for which there may be specific labeling or packaging exceptions.

Hazardous Substances, Hazardous Wastes, and Concentration Rules

Not all hazardous materials carry the exact same regulatory responsibilities. Drivers must recognize the specific definitions of hazardous substances and hazardous wastes. Hazardous waste is any material subject to EPA Hazardous Waste Manifest Requirements in 40 CFR Part 262. Here, EPA stands for the U.S. Environmental Protection Agency. FMCSR stands for the Federal Motor Carrier Safety Regulations; PHMSA stands for the Pipeline and Hazardous Materials Safety Administration.

A hazardous substance must be listed in Appendix A to Sec. 172.101 and equal or exceed its reportable quantity in one package; mixtures and solutions must also meet the applicable requirements in that appendix. For a listed material to meet the glossary’s definition of a hazardous substance, the amount in one package must equal or exceed its reportable quantity (RQ). A reportable quantity is the quantity specified in Column 2 of the Appendix to Sec. 172.101 for a listed material. It is vital to note that the definition of a hazardous substance does not apply to petroleum products that are lubricants or fuels.

For mixtures and solutions, non-radionuclides must meet the concentration-by-weight requirement corresponding to their RQ; radionuclides must conform to paragraph 7 of Appendix A to Sec. 172.101. For a non-radionuclide in a mixture or solution, meeting the concentration corresponding to its RQ is one requirement for classification as a hazardous substance; the material must also be listed and meet the RQ in one package. The concentration thresholds vary directly with the assigned RQ. For an RQ of 5,000 pounds (2,270 kilograms), the concentration by weight threshold is 10 percent (100,000 PPM). For an RQ of 1,000 pounds (454 kilograms), the concentration threshold is 2 percent (20,000 PPM). For an RQ of 100 pounds (45.4 kilograms), the concentration threshold is 0.2 percent (2,000 PPM). For an RQ of 10 pounds (4.54 kilograms), the concentration threshold is 0.02 percent (200 PPM). For an RQ of 1 pound (0.454 kilograms), the concentration threshold is 0.002 percent (20 PPM).