While I claim no expertise on the topic, any number of sources I read agree. If you (or anyone else) searched the issue you’d find that no reasonable authority considers there to be a safe amount of lead exposure. In other words according to those who consider themselves authorities on the topic, there is no amount of lead that is too small to cause the body harm.

Is something that causes the body harm a reasonable definition of poisoning? That is probably a good question and I don’t know the answer.

That said, accordingly, the CDC defines elevated blood level for lead for adults to be 10 (µg/dl) of whole blood. For children, the number is set at 5 (µg/dl) (by the way, “µg/dl” = micrograms per deciliter). It seems that children have a greater sensitivity to brain and other anomalies resulting from lead pollution/poisoning than do adults, and that’s the reasoning for the differing lead levels to be considered “elevated.”

This will provide you with an overview of lead toxicity. Lead poisoning - Wikipedia, the free encyclopedia There are many other sources that go into more or less detail.

So draw your own conclusion, but i conclude that what the CDC calls an elevated level of lead to safely demonstrate the owner of said blood is experiencing lead poisoning.

If you review my post above you’ll find a reference to a significant number of people with elevated lead levels who live near airports which use avgas. One of the articles I read indicated that at some airports which sell avgas can deliver up to 500 or 1000 lbs. of lead a day (iirc) into the air proximate to the airport. Lead doesn’t float very long and that’s likely why people tested up to a mile away the subject airports showed elevated blood levels of lead.

BTW, I’m most impressed by your ability to type in caps.