[mrmargaritaville]

Honeywell has had a non cfc or hcfc blowing agent for polyurethane foams for about 5 years now. Fa245. Foams using their blowing agent have worked well in the old R11 and hcfc systems with minor changes to the formulations. The idea that the blowing agent is a problem is not true. (I have been working in polyurethanes for 25 years).

[alecqss]

...and old Mercuries were flying just fine, too.

It does not matter that there agents you are sure in (with minor modifications). EPA irresponsibility banned production of the foam and mandated to use a recycled one (now recycled foam use is prohibited).

They could mandate the phase out in 5 years or something like that - until a new agent is certified to be just as good as an old one. But they banned outright. And that lead to a catastrophe (they could get away with it if foam damaged the less critical parts of the shuttle, but no luck).

Asbestos ban caused changes that resulted in Challenger tragedy.

In both case EPA irresponsibility proved to cost human lives.