I use to haul fuel last summer to Quick trip on a dedicated account.I learned a few things about fuel,before going back to dry van driving.
All fuel is piped in through the same lines,and split up to different loading racks.
Drivers are sent to load up,and they enter different access codes that recieve the particular blends for each station they drive for.
The probability for contaminated fuel was shocking.If for instance you hauled diesel on your last load,you ran your premium load through those hoses,and tanks on your trailer on the following load.This is how the tank,and hoses get cleaned of diesel.
Each drop spot(premium,regular,mid grade) also has a pull chain that we pull that dumps excess water/trash/cigarette butts from drop spots on top of the gas,when rain fills it.
Drivers are required to apply a paste that detects water,and stick each tank,before dropping fuel.Anything over 3 inches of water was "supposed" to be pumped out.
Cross drops did occour.When a driver hooks up 87 to a 93 grade tank for instance,and starts dumping,thats is whats known as a cross drop.
Tanks are also cleaned twice a year.By cleaned,I mean they are ran almost empty.All water and trash are sitting on the bottom,and we get whatever the tanks filters miss.(Memorial day weekend)
One last one I remembered that disturbed me most..
Example>>You start your 12 hr shift,and the driver before you may have been in a hurry.He fails to completely empty all diesel from last load.Your sent to load up,and dump regular,or premium on top of this,and deliver it to your customer.
Drivers are supposed to check that all compartments are empty,before loading,but when you get paid ( poorly) by the load guys sometimes overlook it.
Saw that one happen^^
I also stay faar away from mom and pop stations that sale minimal fuel..