Based on the hazard classes, hazmat placards are of the following types:
1. Hazard Class 1 Placard — Explosives
These are for explosives such as TNT, ammunition, fireworks, and airbag inflators. Orange in color, these placards have one of six sub-categories:
1: Mass Explosion Hazard
2: Mass Projection Hazard
3: Fire/Minor Blast/Minor Projection Hazard
4: Minor Explosion Hazard
5: Blasting Agent
6: Very Insensitive Materials
2. Hazard Class 2 Placard — Gases
These are for fire extinguishers, aerosols, propane tanks, and gas cartridges. Placards colors signify the following:
- Green: Non-Flammable Gas
- Red: Flammable Gas
- White: Toxic Gas
- Yellow: Oxygen Gas
- White with Black Skull Inset: Inhalation Hazard
3. Hazard Class 3 Placard — Flammable and combustible liquids
These are for flammable liquids like gasoline, paint, acetone, and kerosene. Red in color, these placards identify liquid substances having a flashpoint less than 60 °Celcius (140 °F), or any material in a liquid phase with a flashpoint at or above 37.8 °Celcius (100 °F).
4. Hazard Class 4 Placard — Flammable materials
These are for flammable solids such as matches, powdered metals, and activated carbon. Different color schemes mean the following:
- Red and White Stripes: Flammable Solids
- Upper Half White, Lower Half Red: Spontaneously Combustible Solids
- Blue: Water-Reactive Solids
5. Hazard Class 5 Placard — Oxidizer and organic peroxide
These are for oxidizing substances and organic peroxides such as ammonium nitrate fertilizer and chemical oxygen generators. They have two different categories:
- Yellow: Oxidizer
- Red Top, Yellow Bottom: Organic Peroxide
6. Hazard Class 6 Placard — Poisons
These are for toxic and/or infectious substances like regulated medical waste, tear gas, and strong poisons such as cyanides and neonicotinoids. They have two design schemes:
- White: Toxic
- White with Black Skull Inset: Inhalation Hazard
7. Hazard Class 7 Placard — Radioactive
These are for radioactive substances such as medical isotopes and radioactive ore. They have a yellow top that features the international symbol for radiation and a white bottom.
8. Hazard Class 8 Placard — Corrosive
These are for corrosive chemicals such as strong acids, lye, and certain dyes and paints. They have a white top with an illustration of a chemical burning a human hand and a black bottom.
9. Hazard Class 9 Placard — Miscellaneous
These are for other hazardous substances such as dry ice and lithium-ion batteries. These placards have a black and white striped top half and a white bottom.
NFPA placard system uses a color-coded diamond with four quadrants:
Blue indicating Health Hazard
Red indicating Flammability Hazard
Yellow indicating Reactivity Hazard
White section is used to display other special hazards
Numbers are displayed in the upper three quadrants to signal the degree of the hazard.
No, placarding is not necessary for the following situations:
Hazardous material placards warn firefighters who might have to handle or approach the cargo if there is an accident like a spill or a leak. Having your vehicle properly placarded ensures that first responders and emergency personnel can identify the hazardous materials and know exactly what they are dealing with. Placards are designed to provide information at a glance in time-restricted situations and help firefighters create the necessary action plan to control the damage.
Using a “Dangerous” placard is an option, not a requirement. 49 CFR section 172.504(b) permits a transport vehicle hauling non-bulk packages in two or more classes listed in Table 2 to be placarded with DANGEROUS placards. However, this is an option and may be used instead of separate placards for each of the materials in Table 2.
While using the Dangerous placard, it should be noted that:
Remember to always consider basic placarding first and then figure out whether or not you want to use a Dangerous placard. This is because there is a loss of clarity about the hazards in the vehicle.
The DOT requires displaying placards on each side and end of the freight container, unit load device, transport vehicle, or rail car carrying hazardous materials. Placards must be displayed on all 4 sides of a transport vehicle. Some carriers also place two extra signs on either side of the truck cab for additional visibility.
Each placard on a motor vehicle and rail car must be clearly visible from the direction it faces, except the direction of another transport vehicle or rail car to which it is coupled. Placards must be located clear of appurtenances and devices such as ladders, pipes, doors, and tarpaulins and away from any marking (such as advertising) that could substantially reduce its effectiveness, and in any case, at least 3 inches (76.0 mm.) away from such marking. DOT placards must be located where dirt or water from the wheels is not directed.
Any lettering or numbers on the placard (when required) must read horizontally, left to right. DOT placards have to be on the background to contrast the color or must have a dotted line or solid line border.
Proper classification may be obtained through a variety of sources. These include, but are not limited to, the manufacturer of the material, laboratory testing, and Safety Data Sheets. SDS of products includes a transportation hazard classification for the product. This classification provides a four-digit ID number, a proper shipping name, the hazard class, and the packing group for the product. Use this information to identify the correct entry on the Hazardous Materials Table.
The Hazardous Materials Table contains label codes and basic descriptions for the hazmat, references to the appropriate packaging sections, certain quantity limitations, and any special provisions or exceptions.
For inhalation hazard load, a Class 6 placard (Division 6.1) must be used.
Material can either be poisonous by inhalation or toxic by inhalation. Such materials can be:
(1) A gas meeting the defining criteria in § 173.115(c)
(2) A liquid (other than as a mist) meeting the defining criteria in § 173.132(a)(1)(iii)
(3) Any material identified as an inhalation hazard by a special provision in column 7 of the § 172.101 table.