Labeling and Placarding, Marking and Shipping Papers

Hazard communication forms the backbone of emergency response, and response begins with identification. The primary mission of DOT hazard communication is to alert the public and transportation workers of the presence of hazardous materials, and to insure that incompatible materials are segregated when placed in the same transport vehicle, storage area (or lab!). The distinctive DOT system of labeling and placarding provides another visual clue for responders to a hazardous material incident.

Hazard markings, labels and placards are a common approach to warning the public of hazards that may be encountered. The DOT uses labels, defined as 4" x 4" colored diamond with warning words and graphics, affixed to the outside of the shipping container or box. Labels are required on the outside of the package regardless of the quantity shipped. The DOT requires placards, a much larger version of the labels, to be displayed on tank cars, cargo tanks, portable tanks and bulk packaging. Requirements for placarding are dependent upon the identity and quantity shipped. "Markings" are required to convey specific information about the enclosed hazard and the person responsible.

Placards and Labels

Placards are used to represent the hazard classes of materials contained within freight containers, motor vehicles or train car. Labels communicate the same hazards for smaller containers and packages offered for transport. Examples of the placards and labels used for the various hazard classes follow.

Class 1 This placard or label is used to designate explosive materials, specifically Class 1.1, 1.2 and 1.3 explosives. Explosives that belong to classes 1.4, 1.5 and 1.6 will have that specified, with the class designation replacing the exploding ball.
This placard is required when transporting ANY quantity of a Class 1.1, 1.2 or 1.3 explosive, or over 1001 lbs of a Class 1.4 or 1.5 explosive.

These placards and labels are used to designate compressed gases. Given the diverse chemical properties of compressed gases, this class is subdivided into flammable gases (Class 2.1), nonflammable gases or oxygen (Class 2.2) and poisonous gases (Class 2.3).
This placard is required when transporting over 1001 lbs of Class 2.1 or 2.2, or when transporting ANY quantity of poisonous (Class 2.3) gas.

Class 2.1 Class 2.2 Class 2.3

Class 3 This is the label or placard used to designate flammable liquids. Certain common flammable liquids have their own placards, where the name of the material (such as gasoline and fuel oil) replaces the word "FLAMMABLE". Also, materials that fit the definition of a combustible material, have the word "COMBUSTIBLE" replacing the word "FLAMMABLE".
This placard is required when transporting over 1001 lbs of flammable materials.

The below placards and labels are used to indicate the cargo contains flammable solids (Class 4.1), materials that are pyrophoric (i.e., ignite in the presence of oxygen) (Class 4.2), and those that react adversely when exposed to water (or humidity!) (Class 4.3). These placards are required when transporting over 1001 lbs of Class 4.1 or 4.2 materials, or when transporting ANY quantity of a water reactive material (Class 4.3).

Class 4.1 Class 4.2 Class 4.3

Class 5.1 This placard or label is used to designate a cargo that contains oxidizing materials (Class 5.1). In addition, this class contains materials that are classified as organic peroxides (Class 5.2), and in that case the label would read "ORGANIC PEROXIDES" rather than "OXIDIZER".
Placards are required when transporting over 1001 lbs of oxidizers or organic peroxides.

Class 6.1 This class contains poisonous liquids that are designated as inhalation hazards. If the material is toxic, but not an inhalation hazard it is placed in Class 6.1. Materials in these classes may NOT be transported in the same cargo as foodstuffs, feed, or any other edible substances intended for humans or animals.
In addition to the POISON label, packages of 110 gallon capacity or less, and that are recognized as "inhalation hazards", must also be marked "INHALATION HAZARD".
Placarding is required when transporting ANY quantity of Class 6 material, and when transporting over 1001 lbs of a Class 6.1 material.

Class 7 This label is required on all radioactive materials and equipment. Packages containing radioactive species must be clearly labeled with 2 labels on opposite sides of the package. This class is divided into 3 divisions - I, II and III.
Placarding is required on ANY quantity of radioactive material rated as III; it is not required on materials rated as I or II.

Class 8
This placard/label is used to designate any corrosive liquid.
Placarding is required whenever the quantity exceeds 1001 lbs of a corrosive liquid.

Class 9
Class 9 materials are those that have not been placed in a hazard class, but may still pose some degree of danger in transport. Placarding is not required for materials that are not classified. However, you may placard a material that presents a hazard during transport and weighs more than 1001 lbs.

This applies to placarding only and is required when 1001 lbs or more of material is transported and it is composed of 2 or more hazard categories. It will replace the specific placards for the individual classes. An exception is when one single class in a multiple class transport exceeds 5000 lbs, in which case the placard for the large load class must be displayed.


Each person offering for transport a hazardous material must ensure the package, container or vehicle carries the markings appropriate for the corresponding hazard. Specific rules and requirements are outlined in CFR 49 172.300. The following requirements are generally true, though exceptions are the rule!

  • the proper shipping name and the proper identification number (preceded by UN or NA as appropriate)
    Fire dot ID
  • the identification number, when required, may be displayed separately from the warning placard. If so it must consist of black writing on an orange background. If the identification number is displayed on the warning placard itself, it shall be black writing on a white background and will replace the warning wording on the placard, but not the graphic. The identification number must be affixed to each side and each end if the packaging has a capacity of 1,000 gallons or more. It must be affixed on opposite ends if the packaging capacity is less than 1,000 gallons.

  • The markings must be durable, in English and printed legibly.

  • They must be displayed on a background of sharply contrasting color.

  • They must be unobscured by labels or attachments.

  • The markings must be placed sufficiently far from other markings, such as advertising, so as not to detract from them or less their effectiveness.

In addition to the above general requirements, some materials require that specific markings be displayed on packages and on vehicles when offered for transport. The guidelines for these materials are as follows:

  • For radioactive materials, each package must have its weight clearly marked on the outside of the package. The packaging type (TYPE A or TYPE B) must be clearly marked on the outside of the package.
  • Liquid hazardous materials in non-bulk packaging must be packaged with the closures upward and be legibly marked with package orientation markings pointing in the correct upright direction. Markings that depict arrows for purposes other than to indicate the upward position may not be used on hazardous liquid materials. This requirement does not apply to packaging where the interior package is a metal cylinder.

  • Bulk packages which contain materials that are poisonous if inhaled must be marked with the warning "Inhalation Hazard" on two opposing sides. Non-bulk packages must be marked with the word "POISON" within 6 inches of the closure.

  • Non-bulk packages of materials classified as ORM-D must be marked on at least one side or end with the ORM-D designation directly below the proper shipping name of the material. This marking is certification by the person offering the material for transport that the description, classification, packaging, marking and labeling are all correct and appropriate for the material.

Shipping Papers

Whenever a hazardous material is offered for transport, it must be accompanied by proper shipping papers, which fully identify the hazards involved.

The description must fulfill the following requirements:

  1. If a hazardous material and a non-hazardous material are described on the same shipping papers, the hazardous material must be:
    • named first
    • shown in contrasting (highlighted) color on all copies of the form
    • identified with an "X" in the column marked "HM".
  2. The shipping description must furnish:
    • proper shipping name
    • hazard class or division (this from column 3 of the Hazardous Materials Table)
    • identification number (this from column 4 of the Hazardous Materials Table)
    • packing group (this from column 5 of the Hazardous Materials Table)
    • except for empty packages, the total quantity, including unit for measurement, of the hazardous material.
  3. Entry must be legible and in English.
  4. Unless specifically authorized or required, the description may not contain codes or abbreviations.
  5. Additional information must follow the basic description.
  6. Must contain the name of the shipper when transported by water.
  7. If more than one page is required, the first page must indicate multiple pages, i.e., "page 1 of 3".
  8. Shipping paper must show an emergency response telephone number.
  9. Shipping paper must contain shipper's certification. An example of the shipping paper entry is as follows:
Hazardous Material Shipping Papers
Destination Zip
Origin Zip

Vehicle Number

US DOT Hazmat Reg.No.

HM Kind of Packages, Description of Articles
(subject to
(or exemption)