Hazardous Materials (Hazmat) Endorsement Knowledge
Domain scope and legal basis
The Missouri CDL Hazmat endorsement knowledge test draws on 49 CFR Parts 171–180 and Part 397, plus Missouri CDL issuance rules. It tests whether you can read the Hazardous Materials Table, check shipping papers, select placards, load and segregate safely, park and attend a placarded vehicle, stop at railroad crossings, and use emergency response information. Missouri will not issue the H endorsement until TSA completes a Security Threat Assessment.
Core rules
- Nine hazard classes: 1 explosives, 2 gases, 3 flammable liquids, 4 flammable solids, 5 oxidizers/organic peroxides, 6 toxic/infectious, 7 radioactive, 8 corrosive, 9 miscellaneous.
- Placards: Table 1 materials require placards in any quantity. Table 2 materials require placards at 1,001 lbs or more aggregate gross weight. Bulk packages are placarded based on the material, not the weight threshold.
- Shipping papers: proper shipping name, hazard class/division, UN/NA number, packing group, quantity, and a monitored emergency response telephone number. Keep them within reach.
- Railroad crossings: placarded loads stop within 50 feet but not less than 15 feet of the nearest rail.
- Attendance: never leave a placarded load unattended; Division 1.1, 1.2, and 1.3 explosives have the strictest attendance and parking limits.
Worked example
A driver loads 1,200 lbs of UN1263, Paint, Class 3, PG II. Because Paint is a Table 2 material and the aggregate weight exceeds 1,001 lbs, the vehicle needs FLAMMABLE LIQUID placards. The shipping paper must show UN1263, Paint, 3, PG II, 1,200 lbs, and an emergency phone. At a grade crossing the driver stops 15–50 feet from the rail.
Traps
Do not apply the 1,001-lb rule to Table 1; any amount needs a placard. Do not placard a bulk tank only because of weight. Do not accept a shipping paper without emergency response information. Do not park under a bridge or leave a placarded load unattended.