When a shipper packages hazardous materials, they certify that the package has been prepared according to Hazardous Materials Regulations (HMR). Unless a package is clearly unsafe or noncomplying with HMR, you may accept the shipper’s certification concerning the proper packaging of a material.

If transporting chlorine in cargo tanks, a driver must have an approved gas mask in their vehicle.

Packaging can be an indicator of whether or not materials are hazardous. Cylinders and drums are often used to hold and transport hazardous materials.

Hazardous materials warning placards are diamond-shaped.

The marine pollutant symbol is the image of a fish in a white triangle with an X through through the fish.

When transporting hazardous materials, you may leave your vehicle unattended in a safe haven. A safe haven is a location that has been approved for parking unattended vehicles that are loaded with explosives.

If you discover a cargo leak while transporting hazardous materials, use the shipping papers, label, or package location to identify which materials are involved. Do not try to touch or smell the leaking materials to determine what they are because doing so could result in injury or death.

If you need to refuel a vehicle carrying hazardous materials, you must first turn off the engine. While refueling, someone must be at the nozzle and controlling the fuel flow at all times.

Shippers of hazardous materials are required to warn drivers and others about the risks of the materials by putting hazard warning labels on packages, putting placards on the transporting vehicles, and providing proper shipping papers and emergency response information.

When carrying Division 1.1, 1.2, or 1.3 explosives, you should not park within 300 feet of a bridge, tunnel, or building, unless you are parking for a short period of time while performing an operational necessity, like refueling.

To determine which placards need to be used, you must know the hazard class of the materials being shipped, the amount of hazardous materials being shipped, and the total weight of all hazardous materials in your vehicle.

It is a driver's responsibility to refuse packages or shipments of hazardous materials if they contain leaks.

It is always a good idea to compare package markings and labels to accompanying shipping papers. Always make sure the shipper has displayed the correct basic description on the shipping paper and has provided the proper labels on the packages.

If you are experiencing a truck fire, you should not attempt to open trailer doors without first feeling the doors to see if they are hot. If the doors are hot, there may be a cargo fire. Leave the doors closed if there is a cargo fire.

If a shipping paper describes both hazardous and non-hazardous materials, the hazardous materials must be distinguished in one of three ways. They must be entered first on the shipping paper, highlighted in a contrasting color, or properly marked with an "X" in a column titled "HM."

If a shipping paper includes information about both hazardous and non-hazardous materials, the hazardous items must be clearly identified on the paper. They may be entered first, highlighted in a contrasting color, or identified with an "X" placed before the shipping description.

You should not smoke within 25 feet of a placarded cargo tank used to transport materials that are categorized as Class 3 (flammable liquids) or Division 2.1 (gases). Do not smoke or carry a lit cigar, pipe, or cigarette near a vehicle containing flammable or explosive materials.

A placarded vehicle must have at least four identical placards: one on the front, one on the rear, and one on each side of the vehicle.

A person attending a parked placarded vehicle must be either awake inside the vehicle or they must be within 100 feet of it. If not inside the vehicle itself, the person must have a clear view of the vehicle. The person attending may not be inside the sleeper berth.

When required, hazardous materials placards must be placed on all four sides of a vehicle transporting hazardous materials.

If a driver stops and exits their vehicle, the hazardous materials shipping papers must be left on the driver's seat.

Hazardous materials warning placards are diamond-shaped.

A placard must be placed at least three inches away from any other markings. The placard should be kept clear of attachments or devices, such as doors and ladders. Placards should always be placed against a background of a contrasting color.

Information about hazardous chemicals is found in the Emergency Response Guide (ERG) provided by U.S. Department of Transportation (DOT). The ERG is indexed by the proper shipping names and identification numbers of substances.

Before loading or unloading a tank with flammable liquids, you should turn off the engine, unless running the engine is necessary to operate a pump. Ground the tank before opening the filling hole and maintain the ground until after closing the filling hole.

Always load hazardous materials away from heat sources. Be aware of regulations on explosive or flammable materials that prohibit them from being loaded in cargo spaces with heaters.

Except when parking briefly to perform necessary functions for vehicle operation (such as refueling), never park a vehicle carrying Division 1.1, 1.2, or 1.3 explosives within 300 feet of a bridge, tunnel, or building. Never park such a vehicle within five feet of the traveled portion of the road.

A person attending a placarded vehicle must be awake inside the vehicle or otherwise within 100 feet of the vehicle; know the hazards associated with the materials; know what to do in an emergency; and be able and authorized to move the tank if necessary.

Shippers of certain kinds of hazardous materials are required to display diamond-shaped warning signs, known as placards, on any transporting vehicles. Shippers are required to provide applicable placards, labels, shipping papers, and emergency response information.

When applying for an original or renewed HazMat endorsement, you must undergo a federal security threat assessment done by the Transportation Security Administration (TSA).