On a compressed gas tank, liquid discharge valves must always be kept closed, except during loading and unloading.

Hazardous materials warning placards are usually diamond-shaped.

The person in charge of loading or unloading a hazardous materials cargo tank must ensure that a qualified person is always supervising the process. The supervisor must be alert; have a clear view of the tank; be within 25 feet of the tank; know the hazards of the involved materials; know the procedures to follow in the case of an emergency; and be authorized to and capable of moving the tank.

The shipper of hazardous materials is responsible for identifying the product's identification number; proper shipping name; hazard class; packing group; and correct packaging, labels, marking, and placards.

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.

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

One clue that a shipment may contain hazardous materials is that the shipper is in a line of business that involves such materials. Examples include paint dealers; chemical suppliers; scientific supply houses; pest control businesses; agricultural supply firms; and dealers in explosives, munitions, or fireworks.

While shippers of hazardous materials are responsible for providing necessary placards, it is the driver's responsibility to actually place them on the vehicle.

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.

A vehicle must be properly placarded before it can be driven. A vehicle that does not display the proper placards may not be moved unless doing so is necessary to protect life or property in an emergency.

Carriers and drivers must be able to quickly identify hazardous materials' shipping papers. Shipping papers for hazardous materials should be on the top of a stack of shipping papers.

In general, a shipper is required to list an emergency response telephone number on hazardous materials' shipping papers. There are some exceptions to this rule.

Column 2 of the Hazardous Materials Table lists the proper shipping names and descriptions of regulated materials.

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."

In general, vehicles carrying hazardous materials are required to display diamond-shaped warning signs on all four sides. These warning signs are called "placards."

When experiencing a cargo fire, it may be a bad idea to open the doors to the trailer. Doing so allows oxygen to enter the area, potentially causing the fire to flare up and expand.

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.

Diamond-shaped signs called placards are placed on bulk packages and on the outside of vehicles to warn drivers and others of the presence of hazardous materials. It is the responsibility of the shipper to place the placards, and it is the responsibility of the driver to verify that the correct placards have been placed.

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.

The power unit of a placarded vehicle must be equipped with a fire extinguisher with an Underwriters Laboratories (UL) rating of 10 B:C or more.

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

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

While hazardous materials are being transported, shipping papers should either be kept in a pouch in the driver's side door or in another location where the driver is able to easily reach them while their seat belt is fastened. The papers must be clearly visible to anyone who is entering the cab.

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.

Containers of hazardous materials should be braced so they will not fall, slide, or bounce around during transportation.

Radiation surrounds packages of radioactive materials and passes through to other nearby packages. To address this, the number of radioactive packages that can be loaded together is limited.

If transporting any amount of chlorine, a driver must always stop at a railroad crossing 15 to 50 feet from the nearest track, regardless of the presence of a train.

Transporting hazardous materials can be risky. The regulations are intended to protect you, those around you, and the environment.

You should use a floor lining when transporting Division 1.1, 1.2, or 1.3 materials. The floors must be tight and the liner must be made from either non-metallic material or non-ferrous metal. Non-ferrous metals are any metals that do not contain iron or iron alloys.

All drivers must be trained in the security risks of hazardous materials transportation. This training must include how to recognize and respond to possible security threats. Hazardous materials employees must be trained and tested at least once every three years.