Yeah, I’ve seen this cropping up over the last few days and was wondering.
A quick look through a few news sources suggests that it is related to an artificial ground mulch made from recycled materials. This mulch was used in a bunch of parks. It came from a recycling company that claims all its mulch has tested negative for asbestos. Again, although it is referred to as ‘bonded asbestos’ which means it has been combined with another building material, it doesn’t say what. Up until the 90s asbestos was used in concrete, under lino, and in drywall.
… I don’t know who the fuck would use ground up construction materials for playgrounds mulch. Pretty sure the school near me (in Canada) users ground up tires, so I’m not walking too tall here. I suspect that’s going to be it’s own thing in a few years. (Tires are pretty fucking toxic. They very optimistically thought they could make artificial reefs from them in the 80s. No. Nothing will grow on them.)