Loading, Unloading, and Bulk Liquid Transfer Safety
Most tanker incidents happen at the rack, not on the highway. The exam tests the sequence: secure the vehicle, control ignition sources, bond and ground, transfer, then close up.
Before transfer
- Park so the vehicle cannot roll: parking brake set, wheels chocked, engine shut down unless the pump requires it.
- Know where the emergency shutoff is and confirm it works.
- No smoking, no open flames, no running engines near the transfer point.
- Confirm the tank has enough outage space; never fill above the outage line or the marked 95 percent level.
Grounding and bonding
Static electricity can ignite flammable vapors. Ground the vehicle to a clean metal ground, bond the cargo tank to the storage tank or piping, and only then open the tank or connect product hoses. At the end, break the product connection first, then remove the bond, then the ground.
During and after
- Stay with the transfer; never leave the controls unattended.
- Watch the liquid level and shut off before the tank is full.
- Close internal and emergency valves, cap the lines, and drain hoses so you do not drive off with wet lines.
- Secure dome covers and check for drips before moving; record the amount transferred.
Worked example
A driver connects the product hose first, then the ground cable, because the hose fitting is easier to reach. The order is wrong: static charge built up during connection has no path to earth. The correct sequence is ground, bond, then hose - and reverse it when finished.
Traps that cost marks
- Believing a tank truck is "grounded by its tires" - tires insulate.
- Leaving the vehicle during transfer to do paperwork.
- Overfilling because the gauge lags the actual level.
- Driving off with caps off or hoses still full.