It wasn't clear that it was harmful. For example, there was a Radium health craze, after it apparently cured cancer in some patients: https://www.nyhistory.org/

It wasn't clear that it was harmful. For example, there was a Radium health craze, after it apparently cured cancer in some patients: https://www.nyhistory.org/blogs/get-me-a-radium-highball-new-york-and-the-radium-craze https://www.nyhistory.org/blogs/get-me-a-radium-highball-new... > After scientists successfully killed cancer cells with radium in early experiments in Europe, the demand for the element soared. And it's not like that approach was unusual. I'm old enough to remember folks used to just pour old paint and motor oil into the ground in their backyards.