I wrote this back in October of last year related to lead levels and lead exposure:
Lead levels in the human body, when measured via blood test are expressed as "micrograms per deciliter". That said, here are some factors to consider:
(BTW, all of the below comes from stuff I have read by the American Society of Law Enforcement Trainers, aka "ASLET". These guys are more likely to be exposed to lead in an indoor environment than are more other shooters, so they have done LOTS of research on the topic.)
Most of the issue with lead ingestion comes from shooting on INDOOR RANGES. The ones outdoors have enough ventilation and natural "cleaning" factors to reduce the lead ingestion levels pretty easily.
Lead ingestion by shooters comes from 4 major sources, not necessarily listed in order of significance:
1. molten airborne lead particles generated during firing, melting off the back of lead bullets, and inhaled
2. particulate lead absorbed when touching/handling lead bullets
3. lead primer byproducts inhaled as a result of shooting
4. molten lead particles inhaled during casting lead bullets
Most of us don't cast our own bullets, so we can ignore #4 above as a source of lead ingestion. However...source #3 above is by FAR the BIGGEST CONTRIBUTOR to lead ingestion by shooters. (It's something like 10 times greater than the next highest source!!)
The reason here is that, most "non-corrosive" primers contain lead styphnate or something similar. When lead primers ignite, the chemical reaction creates a lead salt that is airborne, and worse yet, it hydroscopic, like all salts. It picks up moisture easily.
Guess what's in your throat and lungs? Lots of moisture, waiting for the lead salt to combine with it. Instant absorbtion.
The solution---RIGOROUS cleanliness on the range, and care when shooting indoors:
1. Don't smoke, eat, or drink on the range. You are ingesting just that much more lead in doing so.
2. Don't shoot on an indoor range that does not ventilate by pulling combustion products AWAY from the shooting line. If you MUST shoot on a range with poor ventilation (Lord knows why), use an OSHA approved mask.
3. DON'T SWEEP with a broom on an indoor range. The floor is COVERED in lead salts, and brooming puts them back in the air.
4. Once you are done shooting on an indoor range, wash your hands immediately. If you can take a shower and change clothes ASAP, all the better.
5. Lastly, DON'T go to bed after shooting indoors until you take a shower and wash your hair. You hair traps lots of lead particles that will transfer to your pillow, and then to your mouth/nose while sleeping.
People I know who have followed the above rules can sucessfully shoot indoors A LOT (like IPSC practice multiple times per week) without having excessive lead levels.
Green ammo primarily concentrates on minimizing lead content in the primers, and secondarily minimizing vaporized lead due to backsplash and propellant gas melting.
All of this, of course, is MUCH more of an issue for shooters to inhabit INDOOR ranges than those of us who shoot out of doors.
And biting lead sinkers is NOT a significant health hazard.