In the early 1970s there were reports of talc-dusting of rice. Asbestos is a common contaminant of talc. Google talc/rice/asbestos:
http://www.ncbi.nlm.nih.gov/pubmed/5098957?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=1&log$=relatedarticles&logdbfrom=pubmed