The issue with lead in the context of how we use it is the formation of the white residue that forms with age. It’s lead carbonate formed by the lead complexing with carbon dioxide, as a result of decomposition over time. This white residue is highly toxic and can be absorbed through the mouth, lungs and skin. There is little doubt that this wouldn’t effect miners. As recent as the second half of the 20th century the white residue was used a paint pigment by mixing with various oils(ie linseed). This, as well as it being a primary ingredient of asbestos, plumbing materials, etc., is what brought much of the attention to lead. It was quickly picked up by the anti-gun nuts and propagandized.