A study published in the Journal of Environmental Protection shows for the first time that contamination from fracking is related to increased infant mortality. The Marcellus shale area of Pennsylvania was one of the first regions where hydraulic fracturing of subsurface rock, or fracking, gained prominence. The epidemiological study by Christopher Busby and Joseph Mangano examines early infant deaths zero to twenty-eight days before and after the drilling of fracking wells, using official data from the US Center for Disease Control to compare the immediate post-fracking four-year period 2007–2010 with the pre-fracking four-year period 2003–2006.