I think it is a federal law that any business that sells motor oil and/or batteries has to take the old used product back for proper disposal in accordance with EPA requirements.
I may be wrong about it being a federal requirement but it is required in Texas and I cannot believe Texas would do anything to protect the environment without being forced to by the US gov.
I owned and ran an auto repair shop for well over twenty years. There is no law in CA. that states, if you sell oil you must take used oil. The reason most don't take used oil is because you have to pay by the gallon to have it picked up and disposed of. In addition to that, the oil recycler tests each drum of used oil, if it exceeds a certain of amount of hydrocarbons it is considered a "hot load" and they charge you more per gallon to dispose of it. The kicker to the last statement is; they just mix it in with the rest of the oil in the tanker and take your money. Quite a racket huh?
used oil has to be taken back by anyone that sells it. take mine to Canadian tire. They have the best price on oil around here. which reminds me time for a new thread