

How would you know that no animal had ever crapped over the clay deposit and had rain drift in durable, long-lasting bacterial spores from the waste whiøe the rain was on its way through the clay to join the groundwater? That a burrowing critter didn’t die just upstream in the ground of where you’re digging? It’s not terribly likely that those would get you sick maybe but ‘absolutely no risk’ is a high bar to clear.
Also there can be other sorts of non-obvious contamination like if there are trace amounts of heavy metals. Kaopectate got sued by California because the clay contained in their popular anti-diarrhea pills had traces of lead, such that the adult version pills would have fifty micrograms of lead a pop or six to twelve micrograms for children. For reference California currently mandates a warning slapped on if a product exposes you to half a microgram of lead per day. It’s difficult to know the provenance and full risks of stuff dug from a hole for a regular person. Even trained people with a lot on the line sometimes screw up and get people hurt.









Clay swells when wet and shrinks when dry, the latter can open up deep fissures in it that act as channels for unfiltered water to flow down deeper than you may expect, leaving aside tectonic activity or other reasons that could cause such penetrations in the ground. The native plants also have impressively deep root systems that can provide similar gaps, and you may never know if it was there or not if the clay got wet again and sealed up the voids along with any presents washed down and absorbed into the clay matrix. It puts a lot of faith in Bo Taylor to break his back digging way way deep beyond the reaches of this above plus the necessary amount for scrubbing whatever waste may have gotten down that far… I agree it’s not especialy likely as far as bacterial infection alone, I just protest at the absolutely no risk formulation. There’s a reason bags of this stuff are sold as ‘novelty items’ rather than going through FDA approval.