It shows up in chlorinated water, some foods and drugs in TRACE amounts. The gubment places a limit on how much each pill can contain of 96 nanograms. Here's the problem.
NDMA can form while sitting on store shelves, in your medicine cabinet or even after you have swallowed it. It is contaminatef during the manufacture but doesn't stop there. Whatever you test for at the manufacturing level isn't all there is or the end of it.
It is found most often in drugs for hypertension, diabetes and heartburn. Some such meds were recalled awhile ago for the high levels of NDMA at some point whose names I do not know.
So if it keeps increasing after manufacture it cannot be controlled.
How old are those pills in your medicine cabinet?
How long does it take for shelf-sitting to create a drug that may be harmful? I don't know and I don't know if those in the know know.
So now you know. SIGH.
If I find something else you can worry about I shall let you know. Meantime? Well good luck.