R.J.
- Water supply
- Air (near a firing range? Downwind from factories?)
- Art supplies (especially older oil paints)
- Ceramic (a lot of low fire glazes are lead based. They aren't food safe, even if sold "for" food. I do a bit of ceramic, it drives me nuts that no matter how many stickers you put on non-foodsafe items, people STILL use them for food. I actually inscribe in wet clay if they're not foodsafe, but most don't.).
- Clothes (many clothes, ESP newer ones from china are contaminated with a plethora of heavy metals, toxins, etc. most wash out, they're "just" from being in the air in china, which is a noxious stew)
- Vintage ________ (toys, cookware, furniture, etc.)
- Environmental spills (it can hours or YEARS for contamination to spread. Check the soil... Because govt records of EPA spills & violations are a pain. We were on a well with an arsenic spill that contaminated the groundwater... So we knew... But everyone growing veggies in their garden had contaminated food and DIDN'T know.
- Construction (demo or building) upwind or through an area you drive through.
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Check @ home first
Then extend your search pattern.