My great uncle talked about that when I was a kid. Said at the time Field and Stream published some research to the effect that a very large quantity of shot would have to be injested in a relatively short period of time to cause lead poisoning. He postulated that it was just to price out the average duck hunter.I was hunting waterfowl when we switched to steel. I promise you that more birds were lost to crippling than lead poisoning in the early years. The performance just wasn’t there.