The U.S. has millions of old gas and oil wells. Here's what it takes to plug them up

A crew with the company CSR Services works on plugging an orphan well on a homeowner

There was a circle in Maria Burns' yard where grass wouldn't grow and trees died. She knew what it was: An old natural gas well, plugged when she was a little girl, starting to leak again.

(Image credit: Maddie McGarvey for NPR)