Plutonium for the first nuclear explosion left the Hanford Nuclear Reservation in February 1945. One century later — decades from today — remediation of the radioactive mess left behind will still be ongoing if a proposed agreement between the State of Washington and U.S. Department of Energy is approved.

The deal allows for a 17-year delay in vitrifying the nastiest waste sitting in tanks scattered around the 596-square-mile reservation bordering the Columbia River. That would push start-up to 2039, although the state is shooting for 2034.

The new deadlines recognize what has been painfully obvious in recent years: much of the technology for isolating nuclear waste in glass logs remains theoretical. Agreements with the state that set near-term deadlines for each stage of the cleanup were akin to pushing string.

Expensive string at that. But without continued pressure from the state, Hanford might slip off the radar in Washington, D.C.

The federal government has been spending $690 million each year for the last decade on the cleanup effort. There have been some successes _ removal of chromium-contaminated waste near the river was completed this this week — but the problems of how to safely pre-treat the stew of radioactive material as it is pumped from the tanks, and vitrifying the most dangerous, have defied the quick resolution called for in a 2010 pact with the state.

To hasten the work, contractors tried to build while design work continued. That was a fiasco.

Engineers last year found 362 “significant design vulnerabilities” in seals, ventilation and other components. Work stopped on everything but a low-level melter for vitrifying less deadly waste.

That plant might be operational by 2022. Might be.

Meanwhile, the need to replace weakened the subsurface tanks that continue to threaten the river becomes more urgent if their contents will not be treated for decades. Federal and state negotiators have not been able to reach terms on how many more, if any, double-hulled tanks must be built pending operation of the high-level melting plant for the worst waste.

At $85 million to $150 million per one million gallon tank, that’s no small issue.

And Tri-Cities officials must be concerned about the willingness of Congress to sustain such an expensive undertaking when deadlines skip not a year or two, but decades.

Although the Tri-Cities economy has diversified and thrived since the Hanford facilities rose above the area semi-desert in the 1940s, retaining and replacing the 8,000-plus skilled workers who toil on the waste treatment projects may be difficult.

The new negotiations add some irony to the establishment 10 days ago of the Manhattan Project National Historical Park, which memorialized Hanford’s contribution to the victory over Japan.

Turns out remediating all the damage done over decades of disregard for the byproducts of bomb production is about as easy as recompressing all the energy unleashed at Alamagordo back into the wirey sphere that was the Trinity test bomb.

To respond to this editorial online, go to www.spokesman.com and click on Opinion under the Topics menu.