You'd have to pepper a lot of squirrels with a lot of lead and then not retrieve it while cleaning them, before you would even have to worry about it. I think your friend has swallowed (pun intended) the poison of the more radical environmentalists. The regs requiring steel shot for waterfowl have been a Pyrrhic victory for the environmentalists, or at least surely were the first few years, as many time more ducks and geese were wounded and lost from the less effective steel shot than were saved from death by ingesting lead contaminated food. For land dwelling animals where leaching into the food source doesn't happen, it's self-defeating to use steel shot where not required. Lead injected into the meat by gunfire isn't inside the meat long enough to cause leaching, and I will personally attest that accidentally eating a lead pellet or two while eating game meat is potentially more harmful to your teeth than your body as a whole from lead poisoning. Steel pellets are even worse on teeth, btw.
