Assertion: asbestos | /r/HasProperty | recognized carcinogen
Facets:
value: by at least the 1940s
type: TEMPORAL
Source sentences:
text: that occur in nature as crystalline fibers known as asbestos, a recognized carcinogen.
text: Despite asbestos being recognized as a carcinogen by at least the 1940s, the mineral was widely used throughout many industries through the 1970s.