I bought Zinc White paint from GOLDEN and the health warning on the container really surprised me. It says: "this product contains cadmium and lead…"
My question is: How can there be cadmium and lead in Zinc White?

The reason our Zinc White label states this is because the pigment contains trace amounts of these metals.    They occur in extremely low concentrations as impurities in the zinc ore.  We select our zinc oxide pigment with the lowest levels of these metals available, resulting in levels in finished product of less than 2.5 ppm lead and less than 12.5 ppm cadmium, much less than what Toxicologists deem significant under the Federal Labeling of Hazardous Art Materials Act.

To help put these levels in perspective, you should know that EPA has an established upper limit of .01 ppm lead and .005 ppm cadmium as safe for drinking water.  If you ate a dab of Zinc White about the size of a pea, you would consume about the same amount of lead and cadmium allowed by EPA in your daily drinking water intake. 

We are required to label for these under California's Proposition 65 because they are present in the product.  However, a recent agreement with California has established a threshold for lead-containing artist paints at 12 ppm.  Therefore, we have removed the lead portion of the label warning from all products containing zinc oxide pigment.