Loading, Unloading, Segregation, and Cargo Securement
Loading and securement questions test whether you protect the cargo, the vehicle, and the public. The core rules are in 49 CFR 177.848 for segregation and 49 CFR 393.100 for cargo securement.
Segregation and loading
- Do not load incompatible materials together. The segregation table in 177.848 uses hazard classes; for example, cyanides or cyanide mixtures must not be loaded with acids if contact could release hydrogen cyanide.
- Do not load leaking packages, and do not use hooks, ropes, or bars that could damage packaging.
- Keep food, food additives, and animal feed away from poisons and infectious substances.
- Set the parking brake, chock wheels where needed, and have a trained person attend the transfer.
Securement
- Cargo must be secured against shifting, sliding, and falling. Use tiedowns rated for the load; the working load limit and number of tiedowns must meet the rules.
- Close and secure valves, hatches, and domes before moving. Check that placards and labels remain visible.
Worked example
A warehouse asks you to load 40 boxes of sodium cyanide and 20 carboys of hydrochloric acid in the same trailer. The segregation table and the specific incompatibility of cyanides with acids mean you must refuse the mixed load unless they are separated by an approved method that prevents contact. If the acid leaked onto the cyanide, toxic hydrogen cyanide gas could form.
Traps that cost marks
"Compatible" in the segregation table does not mean every pair is safe; the specific material can be more restrictive. Segregation rules apply to both loading and unloading. Cargo securement is not optional for short hauls, and a closed valve is not the same as a secured valve.