The Point of Generation refers to the time when a material becomes a waste. If you have a brew of corrosive material inside a manufacturing vat, RCRA has NO jurisdiction over it because the material is in a manufacturing process and no one has decided to discard it. Once someone takes it out from the vat (remove it from the manufacturing process) and decides to discard (then abandon) the corrosive material, it becomes a solid waste and hazardous waste – in that order.
What if the manufacturing process stops, can the corrosive material sits inside the vat indefinitely? The answer is NO. The reason is that 40 CFR 261.4(c) states that the material will be considered abandoned by the operator after 90 days. This is to prevent people from storing their wastes inside an idle manufacturing unit indefinitely.
Technically speaking, all that material sitting inside the vat is hazardous material (not hazardous waste) for 90 days before it becomes abandoned per 40 CFR 261.4 (c) or when someone decides to discard it – whichever comes first. But in reality, they are hauled off and disposed of as hazardous wastes (per DEA policy) by DEA – who will be the generator of those wastes.
A generator is a person that FIRST causes a material to be abandoned.