Public concerns about oil and natural gas extraction these days inevitably turn to hydraulic fracturing, where millions of gallons of water, sand, and chemicals are pumped underground at high pressures to crack open rocks. Hydraulic fracturing often occurs a mile or more down, far from the water we drink or the air we breathe. The focus for safety and environmental stewardship should often be somewhere else—nearer the surface—emphasizing risks from spills, wastewater disposal, and the integrity of oil and natural gas wells passing through drinking-water aquifers (1–4). In PNAS, Ingraffea et al. (5) examine one of these factors, well integrity, across the Marcellus region of Pennsylvania, using inspection records from the state Department of Environmental Protection (DEP).