CDL Hazardous Materials Endorsement (HME)Communication RulesMedium
A driver is transporting a mixed load of hazardous materials. The vehicle contains 300 pounds of UN1789, Hydrochloric acid, Class 8, PG II, and 200 pounds of UN1219, Isopropanol, Class 3, PG II. Neither material individually meets the placarding threshold. What placarding rule applies to determine if placards are needed?
- ATable 1 placarding rules, as both are Class 8 and Class 3.
- BThe aggregate placarding rule for Table 2 materials.
- CThe subsidiary hazard placarding rule for Class 8.
- DNo placards are required since each material is below 1,001 pounds.
Show answer & explanationAnswer & explanation
Correct answer: B. The aggregate placarding rule for Table 2 materials.
Both Hydrochloric acid (Class 8) and Isopropanol (Class 3) are Table 2 materials. When individual quantities are below 1,001 pounds, but their aggregate gross weight exceeds 1,001 pounds, the aggregate placarding rule for Table 2 materials applies, requiring a 'DANGEROUS' placard or specific placards for each class if desired.
Why the other options are wrong
- A. Table 1 materials are typically placarded regardless of quantity (e.g., explosives, PIH), which is not the case here.
- C. Subsidiary hazard placarding is for specific subsidiary risks, not the primary rule for mixed loads below individual thresholds.
- D. This is the correct answer. The aggregate weight of the two Table 2 materials is 300 lbs + 200 lbs = 500 lbs. Since 500 lbs is less than the 1,001-pound aggregate placarding threshold for Table 2 materials, no placards are required (49 CFR 172.504(c)).
Aggregate Placarding (Table 2)
For Table 2 hazardous materials, placards are required only if the aggregate gross weight of all Table 2 materials in the vehicle exceeds 1,001 pounds.
- Applies to materials listed in HM Table 2.
- Threshold is 1,001 pounds aggregate gross weight.
- Below this threshold, no placards are required for Table 2 materials.
- Above this, a 'DANGEROUS' placard or specific placards are needed.
Memory trick: One thousand and one pounds, for Table 2, sets the placard bounds.