The U.S. Department of Energy didn’t exhibit undue alarm a year ago when word came that an underground storage tank at the Hanford nuclear reservation was leaking radioactive waste. The agency blamed construction problems for the leak and said it “seems unlikely” that other tanks would spring a leak.

Now it seems very likely.

The Associated Press has reported that surveys for the Energy Department have found some sort of problem in 20 of the double-walled 28 tanks, including six that shared defects with the leaking tank that could lead to leaks in the future. Thirteen other tanks have flaws that could bring problems down the road. The AP reported that the leaking tank was the oldest of 28 doubled-walled tanks built from the 1960s to 1980s.

Recall that the 177 underground tanks, many of which are decades-old single-walled shells that also have leaked, are a stopgap solution for storing 53 million gallons of nuclear waste. The material is a legacy of plutonium production for the Manhattan Project, which built America’s atomic bomb during World War II. A vitrification plant is being built to convert the waste into glasslike logs for permanent storage, but the plan is years behind schedule and billions of dollars over budget. So now the waste sits in the tanks as a mudlike sludge, and officials hope most of it stays put and doesn’t leak into the ground.

Once in the ground, the waste would pose a danger to groundwater and the neighboring Columbia River, which forms the northern and eastern borders of the reservation. Nobody wants this to happen, and since the discovery of the leak a year ago, the Energy Department has started inspecting the tanks more frequently. But the agency needs to look at a more stable place to put the stuff until the vit plant comes on line, which won’t happen for another five years at the earliest.

The 1989 Tri-Party agreement signed by the Energy Department, federal Environmental Protection Agency and the state Department of Ecology stipulates that the federal government is responsible for the cleanup. A year ago, Washington Gov. Jay Inslee and Oregon Gov. John Kitzhaber called for building new tanks, a step that admittedly comes at a cost. But the short-term financial outlay is minimal compared to the long-term cost of contamination of the Columbia River, which holds immense economic and environmental importance to the Northwest.

The region’s politicians have worked across party and state lines to assure money for Hanford cleanup; Republican congressman Doc Hastings and Democratic Sens. Patty Murray and Maria Cantwell have an ally in Oregon Sen. Ron Wyden, a Democrat who chairs the Senate Energy and Natural Resources Committee. Our neighbor to the south shares our intense interest in making sure the Columbia River is free of nuclear contamination.

Hastings will step down from his congressional seat when his term expires early next year, and the open seat has attracted a host of candidates. The August primary and November election may seem far away, but now is the time for candidates to develop an understanding of the Hanford issue. Our next congressional representative must balance overall fiscal responsibility with appreciating Hanford’s critical economic role in Central Washington’s economy and exercising environmental stewardship of the nation’s most polluted nuclear waste site. Our new representative, along with the state’s other elected officials, must continue to hold the federal government accountable for its role at Hanford.

• Members of the Yakima Herald-Republic editorial board are Sharon J. Prill, Bob Crider, Frank Purdy and Karen Troianello.