I get my blood tested regularly since I started casting, and the only time my lead level spiked was just after I got stupid during a smelting session (melting raw wheel weights into clean ingots) and was drinking a cup of coffee while doing it. My level only spiked to 19 mg/dl, and my doctor told me that the normal range is 0 - 20. 6 months later it dropped to 3. During that time I continued casting and loading, but the difference was that I didn't eat or drink anything while doing it.
To be fair, the person posting about the danger of casting with wheel weights
, did not specify lead. He warned of heavy metals
(arsenic, antimony). I do not have any proof that is a problem, but he did not post the article with the study (so we could evaluate if the "study" had scientific merit), either.
If it is a problem, I do not care and will continue to cast using wheel weights...I have been exposed to every toxin known to man in my 67 years and am not going to worry about just wheel weights.