Robert, given the fact Mantle died fairly young--although he outlived his father--you might not want to use him as your poster boy for lead pollution issues.
Those that think indoor ranges are safe from being shut down . . . think again. I was the senior officer at an Army Reserve Center. We had a 50 foot indoor range, on which we could fire M-16's with subcaliber devices (.22's) or handguns. Local cops--city, county, etc--also used our range. Along came OSHA and shut it down. Insufficient ventilation, lead dust in the air, etc.
The original lead restrictions came about because of studies of toxicity in waterfowl that had consumed lead shot, and a lawsuit filed because some eagles died after eating shot but unrecovered gamebirds, thus ingesting lead. Since that time, the eagle population has exploded--which means the lead ban folks either need to find another poster bird (condor only works in CA), or else talk about the environment in general. They seem to be focusing on the latter, because there are virtually no studies showing that ingesting lead is causing any problems for upland gamebirds, except doves. If they want to ban lead for dove hunting, or especially on public areas where doves are regularly shot, they can probably make a decent case. For other upland game, there certainly isn't any significant concentration of lead shot (as there can be for waterfowl or doves in heavily hunted areas). But they're planning on coming after lead anyhow.
