Transportation of Hazardous Materials (DOT)
This domain covers 49 CFR 171–180: how a material is classified, packaged, marked, labeled, described on a shipping paper, and placarded. Most items are straightforward once you separate shipper duties from carrier duties.
Classes and packing groups
Nine classes: 1 explosives, 2 gases, 3 flammable liquids, 4 flammable solids, 5 oxidizers and organic peroxides, 6 toxic and infectious substances, 7 radioactive, 8 corrosives, 9 miscellaneous. Packing group reflects degree of danger: I great, II medium, III minor. For Class 3, PG I is an initial boiling point at or below 35 °C; PG II is a flash point below 23 °C with boiling point above 35 °C; PG III is a flash point of 23–60 °C.
The shipping paper
Required entries: proper shipping name, hazard class or division, UN or NA identification number, packing group, total quantity, number and type of packages, a 24-hour emergency response telephone number, and the shipper's certification. Add "RQ" when a reportable quantity of a hazardous substance is in one package, and the marine pollutant notation where applicable.
Packaging and placards
UN packaging codes state what a package may carry: a 4G fiberboard box marked X is rated for PG I–III, Y for II–III, Z for III only. Placards are required for Table 1 materials in any quantity, Table 2 materials at 1,001 lb or more aggregate gross weight, and bulk packages regardless of quantity.
Worked example
A shipper offers 1,500 lb of a Class 8, PG II liquid in 55-gallon non-bulk drums. Aggregate gross weight exceeds 1,001 lb, so the vehicle needs CORROSIVE placards. The shipping paper shows the proper shipping name, "8," the UN number, "II," 1,500 lb, and the package count, and each drum carries the proper shipping name, UN number, and Class 8 label.
Traps
Using 1,000 kg rather than 1,001 lb as the placarding threshold; skipping placards for 900 lb shipped in bulk; omitting the packing group; letting recurrent training lapse, which DOT requires every three years including security awareness.