So this is private property and it was created with private money, jobs were paid for, taxes were paid, these THINGS belong to the people (company) who created it. None of it is government's business how they want to use it but now government says: these things you own, you cannot destroy it, you must keep it? For how long do these things need to be stored and where, who is going to be paying to store it?
It is the same thing is the government came to your house and said: you cannot throw away this garbage, though you paid for it, you paid the taxes, you don't need it. Now you must keep it in your house even though you paid the waste disposal fees.
This entire thing is as insane as anything any government does on any given day.
I imagine a company can run a 'sale' of these unsold items for a price of 1 cent per ton of goods sold, 'sell' it to a company that will then dispose of it. Freaking nuts, but it is not even the inconvenience of this that is bothersome, it is the fact that people think it is perfectly acceptable to tell anyone what to do with their own THINGS they made, their property they made.
If the question is how the items are destroyed, some environmental impacts, that would be one thing (some costs added to disposing of THINGS, there are always costs). But fundamentally this is so much worse, it is some authority commanding your life in a way that shouldn't be possible.