As I said in my previous post. The Doe Run smelter that is closing has been in trouble with the EPA for about a decade due to lead emission levels. The company that operates it made the decision to close the facility rather than upgrade it.
Now it is true that this happens to be the last primary smelter in operation in the US, which processes raw lead ore straight from the ground it is far from the last lead smelter in operation in the united states as there are many secondary smelters that process lead into lead products.
Sierra bullets has already made a statement that they don't believe the closure of the doe run primary smelting facility will have any impact on their ability to make and sell their product.
This facility was old and in need of an upgrade. If there was a nuclear power plant down the road from your house spewing radiation into the air I bet you would want scrubber on their exhaust pipes too. Unfortunately their does not seem to be enough profit involved for the company to upgrade or build a new facility, and profit is what all private companies operate on if you can believe that....