The states of Oregon and Washington, having filed suit against the US Department of Energy in 2008, have negotiated a court-enforceable settlement agreement regarding continuing cleanup activities at Hanford nuclear reservation. Hanford is the most heavily contaminated facility in the western hemisphere with 53 million gallons of radioactive waste at 194 million Curies, the measure of radioactive potency.
The core of the settlement agreement focuses on languishing federal efforts to empty 140 remaining single shell storage tanks of radioactive sludge, and the severely delayed construction of the largest radioactive waste treatment facility in the US. Almost half of the single shell storage tanks are known to be leaking into the soil and to have infiltrated the groundwater in the Hanford plateau. This radioactive spill is moving toward the Columbia River and will reach the shoreline within 20-50 years according to current estimates. A seismic event could increase the speed of travel.