Generator obligations and transporter obligations are not the same set
A terminal that changes oil is a generator. A carrier that moves hazardous waste for anyone — including itself, between its own sites — is also a transporter, and that is a separate role in the rules with its own identification number, its own manifest responsibilities and its own requirements when a shipment cannot be delivered. Layered over both is the transport regulation that governs how the material is classified, packaged, marked and placarded on the road, which is administered by a different agency and does not care what the waste rules call it. Most carriers meet all this through a contracted transporter, which is the straightforward answer. The ones that get caught out are those that quietly move drums between their own terminals on their own trucks, on the reasonable-sounding assumption that moving your own waste is an internal matter. It is not.