The Center for Public Integrity has won the National Press Foundation’s 2016 Thomas L. Stokes Award for Best Energy Writing for its investigation into the nation’s worst fossil fuel polluters.

The heart of the winning entry was a project titled “America’s Super Polluters.” NPF judges said of the project, which is part of CPI’s overall “Carbon Wars” coverage:

“CPI combined two databases to create a list of the worst of the worst polluters, producing a data-driven investigation exposing government laxity, coal industry indifference and the human toll on workers and communities. Methodically filing 50 state FOIA requests, the center also unmasked state-level regulatory cutbacks at a time many areas seek to rein in pollution.”

CPI’s exhaustive coverage of energy and environmental issues previously won the Stokes Award in 2011 and 2014.