In hearings this week, environmental advocates and community members voiced concerns about the state’s many contaminated sites.
States banning coal — including Hawaii — had mostly already committed to reducing carbon emissions.
The utility will drop its legal fight with the state, dig up nearly 80 million tons of ash and move it to lined storage.
Amid federal uncertainty, two of the state’s most notorious coal ash storage sites will likely test new cleanup rules adopted this year.
Private well samples indicated possible contamination near the J.H. Campbell coal plant.