Biological activity in vitro of chrysotile compared to its quarried parent rock (platy serpentine).

Crushed serpentine rock, quarried at Rockville, Maryland, has been used in large quantities for road and playground surfacing. The rock consists essentially of the fibrous serpentine mineral chrysotile (asbestos) and platy serpentines. In vitro bioassay in P338D1, a malignant mouse macrophage-like cell line, show that chrysotile is cytotoxic while the platy serpentines are not.