&quot;Lead paint, tobacco, bloodletting [..] we ought to remember that the same sentence has been said, earnestly and confidently, about things that absolutely were hazardous.&quot;<p>I&#x27;ve heard this argument before but it sounds really wrong to me. Did anyone ever really say lead paint is absolutely safe? For all of these things I feel people just didn&#x27;t think about it. They never thought &#x27;hmm maybe if we put poisonous metal in paint (we knew lead was poisonous) it could go into the air and affect the brain development of our children&#x27; they just went to a hardware store and bought the paint that was good and cheap, assuming that since everyone else bought it, it would be good. Same for tobacco.