Loading, Unloading, Segregation, and Cargo Security
Segregation and compatibility
Hazardous materials must be loaded so that incompatible materials cannot contact each other if a leak occurs. The segregation table in the regulations identifies which hazard classes may not be loaded together, and the shipping paper and labels tell you what is aboard. A common exam trap is a question that asks whether two materials may share a trailer when they are in separate packages; the answer depends on the compatibility rules, not on whether the packages are closed.
Loading and securement
Packages must be loaded so they are secure against shifting, and so that labels and markings remain visible. Heavy packages should not crush lighter ones, and packages must not be loaded where they can be damaged by the vehicle's equipment. Cylinders must be loaded upright and secured. During unloading, the vehicle must be attended, and the parking brake set and wheels chocked where required.
Cargo security and theft deterrence
Hazardous materials are attractive targets for theft and misuse. The driver should keep the vehicle locked, park in a secure area, avoid leaving the load unattended, and report suspicious activity. High-consequence materials, such as certain toxic gases and explosives, require additional security planning by the shipper and carrier.
Worked example
You are asked to load a corrosive and an oxidizer in the same trailer. The segregation table shows they must not be loaded together, so the answer is to refuse the combination and request separate transport, not to separate them with a barrier.
Rule of thumb
If two materials could react dangerously when they leak, they are incompatible regardless of packaging, and they must not be loaded together.