Originally Posted by scocar
A few years ago the EPA was testing in El Dorado Hills (up Highway 50 in the Sierra Foothills) for asbestos because they were bulldozing the heck out of the place to build McMansions during the housing boom. Well, there's a ton of serpentinite up there. Pictures of hazmat suited and masked EPA folks riding bikes through kid's parks made the front page. Lots of hysteria ensued.
Samples from Marin Headlands and Mt. Tamalpais:
Been to the Marin Headlands many times.
If they had just asked a geologist they wouldn't have needed hazmat stuff. The dangerous typeof serpentinite is alled Crysotile Serpentinite, which I can tell from the picture that that is not.
Crysotile is the fibrous form of serpentinite, pictured below.