The term “hazardous materials” (HAZMAT) refers to any substances or materials which, if released in an uncontrolled manner (spilled, for example), can be harmful to people, animals, crops, water systems or other elements of the environment. The list is long and includes explosives, gases, flammable and combustible liquids, flammable solids or substances, oxidizing substances, poisonous and infectious substances, radioactive materials and corrosives.
One of the major problems is to determine what chemicals are where and in what quantities. Various organizations in the US have established or defined classes or lists of hazardous materials for regulatory purposes or for the purpose of providing rapid indication of the hazards associated with individual substances. As the primary regulatory agency concerned with the safe transportation of such materials in interstate commerce, the US Department of Transportation (DOT) has established definitions of various classes of hazardous materials, established placarding and marking requirements for containers and packages, and adopted an international cargo commodity numbering system.
The DOT requires that all freight containers, trucks and rail cars transporting these materials display placards identifying the hazard class or classes of the materials they are carrying. The placards are diamond-shaped, 10 inches on a side, color-coded and show an icon or graphic symbol depicting the hazard class. They are displayed on the ends and sides of transport vehicles. A four-digit identification number may be displayed on the placard or on an adjacent rectangular orange panel.
If you have spent time on the roads you have undoubtedly seen these placards or panels displayed on trucks and railroad tank cars. You may recognize some of the more common ones, such as 1993, which covers a multitude of chemicals including road tar, cosmetics, diesel fuel and home heating oil. Or you may have seen tankers placarded 1203 filling the underground tanks at the local gasoline station.
In addition to the placards, warning labels must be displayed on most packages containing hazardous materials. The labels are smaller versions of the placards (4 inches on a side). In some cases, more than one label must be displayed, in which case the labels must be placed next to each other. In addition to labels for each of the DOT hazard classes, other labels with specific warning messages may be required. Individual containers also have to be accompanied by shipping papers (if you can safely get close enough!) which contain the proper shipping name, the four-digit ID number and other important information about the hazards of the material.
HAZMAT Incident Guidelines
Approach the scene cautiously—from uphill and upwind. If you have binoculars, use them!
Try to identify the material by any one of the following:
- The four-digit number on a placard or orange panel
- The four-digit number (preceded by the initials “UN/NA”) on a shipping paper or package
- The name of the material on the shipping paper, placard or package.
Call for help immediately and let the experts handle the situation. Do not attempt to take any action beyond your level of training. Know what you are capable of doing.