Minnesota CDL HazMat key terms

Any substance or material capable of posing an unreasonable risk to health, safety, or property when transported in commerce, as designated by the U.S. DOT. This includes items in packaging, waste, and empty containers that held such material.

One of nine numbered categories DOT uses to group materials by their dominant risk, such as flammable liquid or corrosive. The class number appears on the placard and shipping paper and drives packaging, loading, and driving rules.

A subdivision within a hazard class that narrows the type or degree of danger, such as 2.1 flammable gas versus 2.2 non-flammable gas. Division numbers appear in the hazard class column of shipping papers.

A Roman numeral (I, II, or III) assigned to a hazardous material showing its degree of danger within a class, with I being the greatest danger. It influences packaging strength and quantity limits.

A large diamond-shaped warning sign affixed to the exterior of a vehicle, bulk package, or freight container showing the hazard class and often the specific material. Placards warn emergency responders and the public what is on board.

A table in the DOT regulations listing which materials require placards, at what quantities, and which placard to use. Drivers and shippers consult it to decide whether a load must be placarded.

The threshold requiring placards when the total gross weight of all hazardous materials in a class on the vehicle equals or exceeds 1,001 pounds. It applies to classes 1.4, 1.5, 1.6, 2, 3, 4, 5, 6.1, 8, and 9.

A four-digit number, sometimes preceded by UN or NA, that identifies a specific hazardous material on shipping papers, placards, and packages. Emergency responders use it to look up the material's hazards and response guidance.

The transport document that accompanies a hazardous materials shipment and gives the proper shipping name, hazard class, identification number, quantity, and shipper information. It must be kept where it is readily accessible during transport.

The required sequence on a shipping paper: proper shipping name, hazard class or division, identification number, and packing group, in that order. It must be easy to find and read, often printed in a distinct color or highlighted.

The exact name DOT assigns to a hazardous material, which must appear on shipping papers and packages rather than a brand or common name. Using the correct name helps responders identify the hazard quickly.

Written guidance that must accompany a hazardous materials shipment, describing immediate hazards, first aid, and fire or spill response. It may be a DOT guide page or the carrier's own equivalent document.

A reference book, often carried in the cab, that pairs identification numbers and material names with numbered guide pages describing hazards, protective actions, and evacuation distances. It is used before and during an emergency response.

Material that is hazardous and has been discarded or is being accumulated, stored, or treated before disposal. Shipments require a hazardous waste manifest and often use the placard for the underlying hazard class.

A multi-copy tracking document required for hazardous waste shipments that follows the waste from generator to disposal facility. Each party signs it, and it must be kept in the vehicle's paperwork.

The amount of a hazardous substance that, if released, must be reported to federal authorities. Spills above this amount trigger notification requirements and may require the shipper to mark the material on shipping papers.

A material listed by the EPA as dangerous to the environment when released, such as certain chemicals and heavy metals. Shipments above reportable quantities carry special marking and documentation requirements.

Packaging built and tested to withstand specified conditions such as dropping, stacking, and pressure, rather than to a fixed design. The UN code on the package shows what it was tested for.

A marking stamped on packaging that identifies the package type, performance level, and tests it passed, such as a box rated for packing group II. Drivers can use it to confirm the package matches the shipment.

Keeping incompatible hazardous materials apart during loading and transport so a leak or fire in one does not worsen the other. The segregation table in the regulations shows which class combinations must be separated.

Two or more hazardous materials that could react dangerously if they mix, such as an oxidizer and a flammable liquid. They must be separated by distance or a barrier during transport.

A material in hazard class 5.1 that can supply oxygen and cause other materials to burn faster or ignite. Oxidizers must be kept away from fuels and combustible materials during loading and transport.

A class 5.2 material that is thermally unstable and may decompose, burn, or explode if heated or contaminated. Some require temperature control, and they must be kept away from heat and incompatible materials.

A hazardous materials load that must be kept within a specified temperature range to prevent dangerous reaction, decomposition, or pressure buildup. The driver must monitor conditions and act if the range is exceeded.

A liquid in hazard class 3 with a low flash point that gives off vapors able to ignite at normal temperatures. These loads require placards above the threshold and careful handling around heat and sparks.

The lowest temperature at which a liquid gives off enough vapor to form an ignitable mixture near its surface. A lower flash point means a greater fire hazard and stricter handling requirements.

A liquid with a higher flash point than a flammable liquid, so it ignites less easily at ordinary temperatures but still burns. Some combustible liquids require placards when shipped in bulk or above quantity limits.

A class 4.1 material that ignites readily and burns vigorously, such as certain powders and matches. It must be protected from moisture, heat, and friction during loading and transport.

A class 4.2 material that can heat and ignite on its own when exposed to air, without an ignition source. It requires packaging that excludes air and careful monitoring during transport.

A class 4.3 material that reacts with water to release flammable or toxic gas. It must be kept dry, loaded away from moisture sources, and never washed down or sprayed with water in a spill.

A class 8 material that can destroy skin or metal on contact, such as strong acids and bases. It requires leak-resistant packaging and care to avoid contact with people, vehicles, and other cargo.

A toxic material that poses a special danger when its vapors are breathed, requiring a special hazard marking and often a toxic gas placard. These loads carry stricter routing, parking, and emergency response rules.

A class 6.1 substance that can cause serious injury or death if swallowed, inhaled, or absorbed through skin. It requires secure packaging and caution to avoid spills and exposure.

A class 6.2 material known or reasonably expected to contain a pathogen that can cause disease in humans or animals. It requires specialized packaging and handling to prevent release and exposure.

A class 7 material that emits ionizing radiation above defined limits. Shipments require specific packaging, labeling, and sometimes exclusive-use vehicle rules, and drivers must avoid unnecessary exposure.

A class 9 category for materials that pose a hazard in transport but do not fit the other eight classes, such as certain lithium batteries and dry ice. Many class 9 loads require placards above the quantity threshold.

The process of placing and removing hazardous cargo, which requires checking compatibility, securing packages, and using proper equipment. The driver must ensure the load is blocked, braced, and not leaking before departure.

The methods used to keep hazardous materials from shifting, tipping, or falling during transport, such as blocking, bracing, and tiedowns. Secure cargo prevents leaks, spills, and crashes that could release the material.

The requirement to notify authorities after certain hazardous materials incidents, such as a spill, fire, or release above a reportable quantity. The driver must report promptly and follow the emergency response information.