New York CDL HazMat key terms

Any substance or material that the Secretary of Transportation has determined can pose an unreasonable risk to health, safety, or property when transported in commerce. Placarded loads and most bulk shipments of these materials require a CDL with a hazardous materials endorsement.

The letter H added to a Class A, B, or C commercial license after the driver passes a knowledge test and a TSA security threat assessment. It is required before driving any vehicle carrying a placarded amount of hazardous material.

One of nine numbered categories into which regulated materials are grouped by their dominant hazard, such as Class 3 flammable liquids or Class 8 corrosives. The class number drives placarding, loading rules, and emergency response information.

A subdivision of a hazard class that narrows the hazard, such as Division 1.1 for mass-explosive materials or Division 6.1 for toxic substances. Divisions matter because compatibility and segregation rules often depend on the specific division, not just the class.

A diamond-shaped warning sign, at least 10.75 inches on each side, affixed to a vehicle to show the hazard class of its cargo. Placards warn emergency responders and the public and are required above certain weight thresholds.

The quantity of a material at or above which placards must be displayed, generally 1,001 pounds aggregate gross weight for Table 2 materials. Table 1 materials must be placarded in any quantity, and bulk packages are placarded regardless of weight.

A hazardous material listed in the placarding table that must be placarded in any quantity, however small. Examples include certain explosives, poison gases, and dangerous-when-wet substances. Drivers must recognize these as always requiring placards.

A hazardous material that requires placards only when the aggregate gross weight of all Table 2 cargo in the load reaches 1,001 pounds or more. Below that threshold, no placard is required for those materials.

The combined weight of all packages of a given hazard class plus their packaging, used to decide whether the 1,001-pound placarding threshold is met. Non-placarded materials and the vehicle itself are not counted.

A placard bearing the word DANGEROUS instead of a specific hazard class, used for materials that meet the definition of two or more hazard classes. It may be used only when the shipper provides it and the rules allow.

The shipping document, such as a bill of lading, that describes hazardous materials in the required sequence and includes the basic description, emergency response phone number, and shipper certification. It must accompany the shipment and be readily accessible to responders.

The required sequence on a shipping paper: UN or NA identification number, proper shipping name, hazard class or division, and packing group, in that order. Getting the order wrong is a common citation and can confuse responders.

A four-digit number, preceded by UN or NA, assigned to a specific hazardous material and shown on the shipping paper and in the placard's lower corner. It lets responders look up the exact substance quickly.

The name of the hazardous material as listed in the hazardous materials table, which must appear on the shipping paper. Generic or trade names alone are not acceptable for regulated shipments.

A Roman numeral I, II, or III assigned to a material to indicate its degree of danger within its class, with I being the greatest hazard. It affects packaging and segregation requirements and appears on the shipping paper.

The regulatory listing that gives each material's proper shipping name, hazard class, identification number, packing group, label codes, and special provisions. It is the reference behind every shipping paper entry and placard decision.

A reference carried by hazmat drivers that organizes materials by guide number, showing initial isolation distances, protective clothing, and first-aid actions. Responders use the identification number and guide number from the shipping paper to find the right page.

A three-digit number in the emergency response guidebook that groups materials with similar hazards and prescribes initial response actions. It is often written on the shipping paper next to the basic description for quick reference.

The written or printed information that must accompany a hazardous materials shipment so responders can act safely, such as the guidebook page or a telephone number reachable at all times. It must be immediately available during transport.

A 24-hour telephone number, listed on the shipping paper, that responders can call for product-specific emergency instructions. It must be monitored at all times the shipment is in transit.

The principle that only materials that can safely share a space may be loaded together, based on their hazard classes and divisions. Incompatible materials must be separated or carried in different vehicles.

The required physical separation of incompatible hazardous materials during loading and transport, such as keeping oxidizers away from flammables. Segregation tables and the shipper's instructions determine what may share a vehicle.

A container with a capacity over 119 gallons for liquids, over 882 pounds for solids, or over 1,000 pounds of water capacity for gases. Bulk shipments are placarded regardless of weight and have special loading and unloading rules.

A packaging with a capacity at or below the bulk thresholds, such as drums, boxes, and cylinders. Non-bulk packages are counted by aggregate weight when deciding whether placards are required.

A bulk container permanently attached to a vehicle, such as a tank trailer or tank truck, used for liquids or gases. Cargo tanks require placards, specialized training, and attention to surge and rollover risks.

The forward or backward movement of liquid inside a partly filled tank caused by acceleration, braking, or turning. Surge can push a vehicle through a stop or tip it in a curve, so tank drivers brake and turn gently.

The empty space left above a liquid in a tank to allow for expansion as temperature rises. Overfilling a tank leaves too little outage and can cause the tank to rupture or overflow.

A crash in which a vehicle tips onto its side or roof, a leading hazard for tank vehicles because of their high center of gravity. Speed, load surge, and sharp steering are common causes that drivers must control.

Any spilling, leaking, pumping, pouring, emitting, or dumping of a hazardous material from its packaging. Drivers must stop, secure the area, notify authorities, and follow the emergency response information.

The amount of a hazardous substance released that triggers mandatory notification to the National Response Center and other authorities. Releases at or above this quantity must be reported immediately by the person in charge.

The requirement to notify authorities after certain hazmat incidents, such as a release, fire, or injury, and to file a written report when required. Prompt reporting protects responders and documents what happened.

The TSA background check a driver must pass before receiving or renewing a hazardous materials endorsement. It screens for criminal history and terrorism-related concerns and must be completed before the endorsement is issued.

A written plan required for certain high-risk hazmat shipments that describes how the carrier will protect the material from theft or attack. Drivers must follow its procedures, such as route restrictions and communication checks.

The N endorsement required to drive a tank vehicle, which is any vehicle carrying a tank with a capacity of 1,000 gallons or more. It covers the special handling skills needed for liquid loads.

A rule limiting where hazmat vehicles may travel, such as bans on tunnels, bridges, or densely populated areas. Drivers must plan routes that comply with federal, state, and local restrictions.

The requirement to park a placarded vehicle away from populated areas, bridges, tunnels, and places where people gather, and to attend it or secure it. Parking safely reduces theft and exposure risks.

A person who stays with a parked placarded vehicle to watch it and respond to problems. When no attendant is present, the vehicle must be locked and secured according to the rules.

To treat a spilled corrosive or other material so it is no longer hazardous, using an appropriate agent. Only trained personnel with proper equipment should attempt neutralization; drivers generally contain and report instead.

Clothing and gear such as gloves, goggles, and respirators that shield a driver from contact with hazardous materials. Drivers use it only within their training and must not enter a hazardous atmosphere without proper protection.