Environment Canada’s testing found it ‘acutely lethal’. I’d consider composting an acutely lethal substance that is extremely high in salt to be the dumb idea.
Canada actually has scientists. From reading through these comments, I know that’s a shock but we do, they test things and they follow the evidence before making recommendations. In fact, those test results from back in 2016 are even public.
Just because this is news to you doesn’t mean it’s a new thing. Other cheaper solutions were looked into and they weren’t safe enough. It’s remarkably simple if you make yourself aware of everything involved. Salt in a compost though? How does that work?
It could simply be diluted with lots of river water and disposed into the sea, like the waste product of saltwater desalination plants.
Another solution would be to test it in a lab and then bottle it up and sell it, like it was originally intended to be done. But that's a non-starter for the same reason the producer went out of business back then.
They’re going zip it up, as if that won’t break eventually and then leak into the environment. I don’t need to be an environmental scientist to know that is a monumentally stupid solution.
A little salt in compost is fine. Too much is an issue. They actually sell salt based soil amendments for areas that have been depleted of minerals. (Sea-90 is one brand). It's very lightly applied.
It could be composted and that would kill the smell, it's just getting the ratios right and you might need an additional nitrogen source, but Canada has a lot of wood chips for the carbon.