Absestos was a particularly unfortunate case. The negative effects of it would not been seen for decades after it was put into good use. Then again, coal dust

Absestos was a particularly unfortunate case. The negative effects of it would not been seen for decades after it was put into good use. Then again, coal dust and cigarette smoke were also not particularly known to be a problem until about the same part of the 20th century, so maybe it was a focus on diseases of a cardiopulmonary nature as people were living longer that contributed awareness on all such issues... The more we know, the more fragile our lives seem, and the more dangerous the world looks.