In short: Nowhere.

Scotchgard ingredients belong to a family of fluorocarbon chemicals that degrade to form perfluorooctane sulfonate (PFOS). 3M has manufactured PFOS since 1948, and in 2000 was expected to produce more than 10 million pounds of the compound for use in Scotchgard products. It does not anymore. It's in the blood of every human being now. PFOS is in most fish. It's found in the Antarctic.

Eating too many fish is problematic. Many fish contain polychlorinated biphenyls (PCBs), toxic industrial compounds that were banned in 1979, but that persist in the environment. Mercury is in most fish now too - more than two servings a week of fish is considered dangerous.

All of the air in the world has contaminants, both from natural and man-made sources, and the USA's air, while much cleaner than, say China's, is often dirty.

Every single state in the US has advisories against drinking any form of untreated water. Now, I know of a spring right in New Jersey that emits clear, wonderful drinking water that needs no treatment - but they monitor it daily in case that changes.

30 years ago, my brother used to canoe the Hudson bay, and they would drink right out of it - but a few kids got bad bouts of Giardia and they stopped. I don't know about today.