Fracking and indoor radon: Spurious correlation or cause for concern?

Unconventional gas development (fracking) is controversial in large part because of environmental and health concerns. We consider the concern that fracking leads to more carcinogenic radon gas in nearby buildings. Our empirical approach estimates treatment effects where treatment is continuous (number of wells) and varies in intensity (distance to the wells) and in duration of exposure (the time since wells were drilled). The approach allows...