It's getting late and my brain is a little fuzzy. A cubic inch of lead weighs approximately .4 pounds (6.4 ounces). A casino chip has a volume of approximately .23 cubic inches. By the stated examples in those articles, for a chip to contain almost 50% lead content, it would have to weigh about 1.47 ounces, which would be about 42 grams. Since most casino chips weigh between 7 and 12 grams, either my math is way off, or the lead alarm articles' math is way off.

Like I said, it's late, and my math skills tend to be just as tired as me when it's this late, so I could be wrong.