Hazardous Materials
What this domain tests
Hazardous materials questions test placarding, shipping papers, emergency response information, parking, smoking, routes, and the nine hazard classes. The exam expects you to know when a placard is required.
Core rules
- The nine classes are explosives (1), gases (2), flammable liquids (3), flammable solids (4), oxidizers (5), toxic substances (6), radioactive materials (7), corrosives (8), and miscellaneous (9).
- Placard any amount of Table 1 material. Placard Table 2 materials when the aggregate gross weight is 1,001 pounds or more.
- Shipping papers must accompany the load and include an emergency response telephone number.
- Keep shipping papers within reach and emergency response information available.
- Do not smoke near hazardous materials. Follow parking, tunnel, route, and railroad-crossing rules.
- Secure the load and check for leaks, damaged packages, and incompatible materials.
Worked example
A truck carries 1,200 pounds of a Class 3 flammable liquid. Class 3 is a Table 2 material, and 1,200 pounds exceeds the 1,001-pound threshold, so the vehicle must be placarded. If the load were 500 pounds of the same material, no placard would be required under the Table 2 threshold, assuming no other material triggers placarding. The aggregate weight, not the number of packages, controls.
Traps that cost marks
Placarding by package count instead of aggregate weight; forgetting Table 1 materials require placards at any amount; lacking a 24-hour emergency number; and ignoring parking or smoking restrictions.