Then I heard that the soapstone itself was toxic, because it contains talc. California soapstone, for instance, is notorious for asbestos contamination. While one can take samples to a testing lab to make sure, this would probably only be worthwhile if one was quarrying one's own. Most stone dealers are aware of this problem, and only carry stone that is known to be asbestos-free.
Some soapstone contains silica, which can cause silicosis when inhaled.
This should likewise be avoided, but is not as serious a hazard as asbestos. Granite, for instance, contains a lot of silica, but it may be carved safely if proper precautions are followed. Lung scarring is, however, associated with chronic exposure to respirable talc - to be safe, wear a dust mask when appropriate, and clean up after carving.