How long does the rich broth really last though? If you make a big batch on Sunday and eat beans all week, the Instant Pot time saved is 35 minutes one time, not every meal. Your grandma's pot wins on taste but the electric one wins on Tuesday night when you forgot to soak anything.

Ever walk into an open house just to see how the other half stages their throw pillows? Honestly that was probably half my traffic too, and I do this for a living.

Air quality does not bounce back that fast in most places. I grew up near a smelter in Montana that closed in the 80s, and the soil is still toxic enough that they tell kids not to play in the dirt. Same deal with the rivers around old mining towns, the fish are still full of mercury 40 years later. What probably happened in your case is the plant was the only big source left, so once it stopped, the everyday soot cleared out quick. That is different from the stuff that soaks into the ground and stays there for decades. So yeah, you got lucky, but I would not count on it being that clean under the surface.