A quick skim of the Wikipedia article (which is a little lacking in references, but has a few) reveals that CFCs have been found in the stratosphere since at least the 1970's and demonstrated to be harmful to the ozone layer. Their widespread use is decreasing, but it seems the montreal protocol allows developing countries to make them until 2030 (which I was pretty surprised by).
Dupont was certainly involved in lobbying around the time their patents were expiring, but the CFC story is much bigger than them.
PG
On 28/12/2011, at 6:31 AM, Roland Harriston wrote:
> Robert:
>
> The much-repeated story about the banning of Dupont's Freon was that the
> patent was about to expire and that the material would become "generic" and
> anyone would be able of manufacture it. So Dupont lobbied intensely (and
> successfully) to get the compound outlawed because of the "damage" it did to
> the environment. The feds went for the story, and Freon became highly
> restricted in the States, although it is still made and sold freely
> elsewhere.
> Dupont had another compound that the feds immediately approved, and
> everyone went to using the new material.
>
> I think that Freon is a lot heavier than atmosphere, and thus, when
> released into the atmosphere, it immediately drops to the ground where
> it is
> absorbed. At least this is what a lot of people who worked with the
> stuff claimed.
>
> So, the question is: was Dupont's claim about Freon being very dangerous
> to the environment really valid?
> The stuff had been around for decades, and suddenly it was so bad it had
> to be restricted.
>
> Roland F. Harriston, P.D.
> ∗∗∗∗∗∗∗∗∗∗∗∗∗∗∗∗∗∗∗
>
> Robert wrote:
> >
> >
> > Interesting...
> >
> > I can recall reading something about Dupont having been reported as
> > lobbying to ban hemp (not forming any opinions here, just saying I
> > read this) farming in the US during the 30s just as they had patented
> > then new wood pulp processing chemicals. we pretty much have all nylon
> > or cotton rope now, I don't know the specifics or if there may be any
> > similarity to the banning of resist chemical (in favor of Riston dry
> > film resists by Dupont), it might be stretching beyond I mean, but
> > then there are circumstances I am sure not at all uncommon where a
> > company has many pronged efforts to secure it's place, beyond just
> > making a really good product.
> >
>
> [Non-text portions of this message have been removed]
>
>