This study contributes to the field of environmental justice by addressing two key questions: (1) To what extent are racial and ethnic composition, socio-demographic characteristics, and housing-related factors associated with the siting of hydraulic fracturing wells in the U.S.? and (2) How have these associations evolved over time, and have demographic changes contributed to increased environmental justice concerns? Using a panel dataset from FracFocus and the American Community Survey at the census-tract level between 2011 and 2023, the findings reveal that hydraulic fracturing wells are disproportionately located near census tracts with higher percentages of Black and Hispanic populations, indicating environmental injustice towards racial minorities. These findings remain consistent across alternative proximity measures, including different distance buffers and population exposure estimates using area interpolation. Moreover, the longitudinal analysis suggests a growing trend in well placement near marginalized communities in recent years. This pattern may be attributed to post-siting demographic change, where minority populations, particularly Hispanic residents, are increasingly concentrated in areas near fracking sites, while White populations gradually relocate farther away. These findings underscore our contribution to new empirical evidence that can inform communities and policymakers about the distributional impacts of fracking activities.