Cast iron isn’t completely without risk. The iron from the pan can leach into food which can be a problem for people with high iron issues. On the flip side people with anemia could see some benefit. My personal favorite as someone with hemachromatosis is enameled cast iron.

I definitely thought it looked like a microscopic cat walked all over the sample.

That’s a good point. My understanding of how results are provided to employers was incorrect.

Pre-employment drug screens test for amphetamines so it will come up on that screening if the company does them.