Washington state’s Department of Ecology said it has reached a settlement with the Department of Energy over access to data the state described as “critical” to the cleanup of the Hanford Site near Richland, Wash.

After nearly three years of discussions and more than 60 mediation sessions, the Department of Energy, Washington State Department of Ecology, and the Environmental Protection Agency announced that they have reached a conceptual agreement on revising plans for managing millions of gallons of waste stored in tanks at the Hanford Site near Richland, Wash.