JFC it's a boogie man. IF your indoor range is hazy and you smell like gunpowder you might might have elevated lead level. If its almost cool and you can't light a match and the air is pulled from the firing line to the backstop you'll never have a problem.
Owned a indoor range, we tested everyone even clerks who were never on the range. Saved one person, he had old lead pipes in his house, bad bad water leach. When we closed our outdoor range, guess where the old berm and lead went? On the new range as berms. All federally approved.
Lead free ammo has a shorter shelf life. Already seeing duds in 7 year old ammo. You have to eat a ton of lead paint chips or inhale lead powder to really be poisoned. There are other first hand lessons I won't speak to now but know it is a anti gun ploy. Lead bullets in the berm now will be there a million years from now causing no harm.