IIRC, it has already been done here in Jersey, to save wildfowl from ingesting spent pellets and getting lead poisoning. I’m not sure, as I have not hunted in a number of years.
Actually, lead-free shot was mandated by the Feds. However, the greenies have yet to show that the ban on lead for waterfowling has had any effect on blood lead levels in waterfowl or hunters. Similarly, there has been no clearly demonstrated link between blood lead in condors and ammo. The “studies” presented claiming such a link have so many holes in them that they look like someone was patterning a shotgun with ‘em!