By way of explanation, because clay is the base of all Redmond Clay products (including Redmond Earthpaste) and clay is from the earth, there are trace amounts of earth based elements, including lead. Because of this, for the state of CA we put a Prop 65 statement on the product that says it may not be appropriate for some women and children. We talk a little more about that here: http://www.earthpaste.com/prop65/.
That said, when it comes to elements and the body, the FORM of the element is key. Specifically, the clay particle is structured in such a way that it is not absorbed by the body. According to the FDA, "Apparently, very little, if any, bentonite is absorbed after oral administration and as much as 3 percent in the diet has no observable adverse effects on experimental animals. No adverse effects have been observed at dietary levels as high as 12 percent in experimental animals. The human therapeutic dose for diarrhea is about 250 to 1,000 mg per kg.” http://www.accessdata.fda.gov/scripts/fcn/fcnDetailNavigation.cfm?rpt=scogslisting&id=35.
Note: Natural dentists also use clay to remove mercury after amalgam extractions: http://www.winaturaldentist.com/amalgam_safety.asp
There are actually many studies showing that the consumption of the type of clay used in Earthpaste (bentonite/montmorillonite) has been found to "significantly reduce lead concentration of tissues in blood, brain, liver, bone, kidney and hair." For example, http://www.ncbi.nlm.nih.gov/pubmed/18568297 is a full peer-reviewed study published by PubMed (United States National Library of Medicine Search Engine).
Additionally, there are many other PubMed studies you might be interested in showing this type of clay's ability to remove toxins such as lead, cadmium, aflatoxin and others from the body. This is why many concerned with lead and other environmental toxins seek out bentonite/montmorillonite clay and clay containing products, even though in nature there is a small amount that is bound tightly to the clay.
We are not saying that clay or clay based products are the right answer for everyone, just that there are many peer reviewed studies linking clay consumption to reduced levels of lead and other toxins in the body, tissues, blood and liver. We don't want anyone to use any of our products if they don't good about using them. We have used them for ourselves and our families for many years and love what we see, but that does not mean it is the right answer for everyone.