Not very long for companies mass producing things to figure out what they're going to do.
Unless they have an easy fix, maybe Red4-40
Prolly take 2 years to get some companies current inventory cleaned out, the big bois.
It gives big petroleum enough time to figure out (was already figured out before the ban was even a consideration) what to do with the by-products.
And definitely yes, it gives them more than enough time to use the surplus already in the warehouses.