It is the responsibility of a carrier to refuse improper shipments of hazardous materials.

When marking hazardous materials in an "HM" column on a shipping paper, the letters "RQ" may be used instead of an "X" if a reportable quantity of the material must be identified.

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.

Hazardous materials warning placards are diamond-shaped.

Keep liquid discharge valves on a compressed gas tank closed except when loading and unloading.

Before transporting hazardous materials, you should research any restrictions that may apply to the routes you plan to take.

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

Hazardous materials placards must be positioned so any words or numbers can be read from left to right. They must be at least three inches away from any other markings.

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.

Hazardous materials packages with containers of liquid inside must have orientation markings with arrows pointing in the direction that should be upright.

Shippers must place diamond-shaped hazard warning labels on most packages of hazardous materials. If the label won't fit on the package, it can be placed on a tag that is securely attached to the package.

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

Many hazardous materials become more dangerous when exposed to heat. Hazardous materials should be loaded and unloaded away from heat sources.

For all shipments of hazardous materials, the shipper must use shipping papers to inform drivers and dockworkers of the risks presented by the cargo.

Flammable liquids should not be transferred from one vehicle to another on a public roadway, unless being moved due to an emergency. Always warn others of the hazards presented by the materials.

If you discover a leak in a cargo of hazardous materials, identify the materials in question by using the shipping papers, labels, or package location. Do not touch the leaking material.

The United States Department of Transportation (DOT)’s Emergency Response Guidebook (ERG) lists all hazardous chemicals and their assigned identification numbers.

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.

A shipping paper describes hazardous materials being transported. Shipping orders, bills of lading, and manifests are all shipping papers.

Containers of corrosive materials should be kept in their correct upright positions. They should not be dropped or rolled.

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

The loading of a tank with hazardous materials must always be watched by a qualified person. This person must be alert; have a clear view of the tank; stay within 25 feet of the tank; 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.

The shipper of hazardous materials is responsible for packaging, marking, and labeling the materials. They must supply any necessary placards.

Unless a package is clearly unsafe or does not comply with the Hazardous Materials Regulations, you may accept the shipper's certification that it was properly packaged.

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.

To obtain an original or renewed hazardous materials endorsement, you must pass a Transportation Security Administration (TSA) background check.

The use of cargo heaters is not always permitted. When transporting materials that are categorized as Class 1 (Explosives), Class 2.1 (Flammable Gases), or Class 3 (Flammable Liquids), the use of heaters in the same space is generally prohibited.

If you are driving a vehicle that is transporting Class 1 explosives and it is involved in an accident, you should warn others of the danger, keep bystanders away, and not allow smoking or open fires near the vehicle. Before separating the vehicles involved in the collision, remove all explosives and place them at least 200 feet away from the vehicles and any occupied buildings.

You must have a commercial driver license with a hazardous materials endorsement before driving a vehicle of any size that is used to transport hazardous materials, even if the vehicle is not transporting hazardous materials at the time of operation.

Diamond-shaped warning signs, called "placards," are placed on the outside of a vehicle carrying hazardous materials to serve as a warning.