As far as I know asbestos was often mixed with cement for insulating properties. And in this case was often deemed unharmful.

Maybe it'll find uses in locations that use cement that requires thermal insulation but isn't exposed to humans.

What about during demolition, including unplanned demolition such as what happened on 9/11? A lot of people got sick and died from breathing in that dust.

Electrolysis membranes.

One thought would be as a cement additive in marine applications.

What about asbestos and marine wild life?

Genuine question, if you do not have lungs does asbestos have any negative impact on you? Marine animals either hold their breath and come up for air or have gills.

If it becomes loose in the water it would get in their gills and bottom feeders would suck it up off the sea floor and harm them the same way it harms lungs. That said, im not sure there would be loose pieces of it leaving the cement. Plus if someone REALLY wanted the properties of asbestos, there are plenty of ceramic wools that are pretty much identical products (with the same risks of asbestos) that are comparable in price and not subject to the same kind of rules. However nobody that makes ceramic wool would be dumb enough to pretend that shit isn't harmful to be exposed to.

I would wager that most marine animals would be unaffected. Mammals would hold their breath, and any other animal with gills already deals with fine-grained sediment.

Might perforate the blood vessels in the gills and enter the blood stream? Later on we eat it?

Deep space probes?