Lead, and other heavy metals are still used today in steel production (and other industries), and have been used for so long, that trace amounts can be found in

Lead, and other heavy metals are still used today in steel production (and other industries), and have been used for so long, that trace amounts can be found in the road sediment, such as in Gary, Indiana (and most of Northwest Indiana). https://www.sciencedirect.com/science/article/pii/S0160412019301941 https://www.sciencedirect.com/science/article/pii/S016041201...