Asbestosis lung cancer cases were first diagnosed in 1935
The first cases of asbestosis and lung cancer attributable to asbestos exposure were diagnosed in the United States in 1935.
Commercial production of asbestos insulation began in 1879, and the first case of asbestos-related disease, described as "curious bodies" in the lungs, was detected in 1899.
The Congressional Library of Congress has had a book on the harmful effects of asbestos and its link to cancer causation as it discusses the analysis of workplace illnesses on its shelves since it was published in 1939.
Courtesy of the EPA

No safe asbestos exposure levels: all levels hazardous to health.