There is more to this smelter closure than was discussed at the link. That plant has a sordid history of lead pollution. A jury awarded citizens a multi- hundred million dollar judgement against that plant.
The issue has been discussed on this site.
http://thefiringline.com/forums/showthread.php?t=535414
Another good discussion of the issue:
http://www.thehighroad.org/showthread.php?t=732805