There are an estimated 200,000 abandoned oil and gas wells in Pennsylvania but officials only know where the exact boundaries of about four percent of them. The information gap is a problem, because abandoned wells are dangerous, especially when drillers start to sink new wells into the countryside.
Abandoned wells provide pathways for methane gas to seep to the surface or to other voids, and under the right settings it can trigger explosions. In June, the intersection between a Shell fracking operation and a forgotten well drilled in 1932 likely led to a 30-foot geyser of methane and gas.
You can read the entire series at the website of our partner StateImpact Pennsylvania.