We've found that the biggest contributor to lead contamination (or lead poisoning, a term I hate) is that the average shooter just doesn't really know it's there, and if they do, they don't know how simple it is to take care of it. There is a lot of false information floating around on the internet (gee, who da thunk!). By dumping the hyperbole, and sticking to the scientific facts, the mystery is peeled away and good knowledge replaces it.
I often see people post that it's absolutely forbidden to have a vibratory tumbler indoors. I've got three of them in my shop, and they're running most of the time. I do use the Berry's covered separators for sifting the brass from the media, and that does help keep the dust down. My tumblers are two Thumler's Ultra-vibe 18's and a Berry's tumbler, all of which have covers. When common sense is injected into the conversation, it becomes much easier to deal with.
In working with the EPA, Edward Guster, their range expert, told us that the EPA's official position is that lead on ranges is a recyclable metal, as long as the range is active, and the lead is not leaving the property. The lead is being used for it's intended purpose, and is easily recycled. Once a range is closed permanently, the lead then becomes a hazardous substance, and will have to be removed. That's why when a land developer eyes the open space of a range that has been in existence for a long period of time, they don't try to force the range to close so they can build shopping centers or houses on the land. It's expensive to remove all traces of lead that's been deposited over a long period of time, and the cost of cleanup sometimes exceeds the value of the land. The argument is usually over who is responsible for the cleanup, and since a lot of ranges are incorporated as 501(c)3's or 501(c)7's, they don't have any real assets, other than the land they sit on. That would leave the burden of cleanup with the buyer.
Hope this helps.
Fred