Sept. 26, 1944, was the Tuesday it all came together at Hanford.

That's when the task that had engaged 150,000 construction workers and thousands of scientists and engineers for more than two years was to be tested: The world's first full-scale nuclear plant was ready to start.

"We arrived in the control room as the DuPont brass began to assemble," physicist John Marshall recalled in Making of the Atom Bomb, by Richard Rhoades.

"The operators were all in place, well-rehearsed, with their start-up manuals on their desks," Marshall said. "Some of the observers had celebrated with good whiskey; their exhalations braced the air."

Marshall and Enrico Fermi, the Italian physicist instrumental in the development of nuclear technology, strolled the control room checking readings.

"The operators withdrew the control rods in stages just as Fermi directed. Gradually, gauges showed the cooling water warm, flowing in at 50 degrees and out at 140 degrees. And there it was, the first plutonium-production reactor operating smoothly, steadily and quietly. In the control room could be heard the steady roaring sound of the high-pressure water rushing through the cooling tubes," Rhoades wrote.

One of those operators was Bill McCue of Richland, then a 35-year- old chemical engineer, who was among 40 people crowded into the control room that night.

McCue, now 85, was one of the few who fully understood what was about to happen.

He doesn't remember being particularly nervous that night as they began to pull the control rods from the reactor's core, unleashing the uranium fuel's incredible power. "We had been working on it a year and this was what we expected. Basically, this was our whole purpose in being, our contribution, and I had complete faith it would work."

It was a Tuesday night, uneventful elsewhere in the Tri-Cities. Thirty miles away in Richland, folks were still talking about the high school football team's 19-0 victory over Prosser a few days earlier.

All but a handful of people in the Tri-Cities were blissfully unaware that out on the mysterious federal site operators were starting to power up the world's first full-scale nuclear plant, uncertain whether a runaway chain reaction might blow it up.

There was a sense of excitement and an urgency to the work. Everyone knew the plant had been built at an incredible pace and they knew most of the big shots associated with the project were gathered in the control room.

Col. Franklin T. Matthias, the young Army officer hand-picked by Gen. Leslie Groves to oversee Hanford's construction, dwelt on little else in the hours leading up to the reactor's start. Groves had advised him to jump in with both feet if anything went wrong. A quick death would be preferable to the years of investigations and hearings that surely would follow.

The reactor was humming by 11 p.m. and went critical a few minutes past midnight; by 2 a.m. it was operating at a higher level of power than any previous chain reaction.

For an hour, things ran well. Then Marshall remembers the operating engineers whispering to each other, adjusting control rods, whispering more urgently. "Something was wrong. The pile (reactor) reactivity was steadily decreasing with time; the control rods had to be withdrawn continuously from the pile to hold it at 100 megawatts. The time came when the rods were completely withdrawn. The reactor power began to drop, down and down."

Finally, by early evening Sept. 27, it stopped altogether.

Scientists on that September night went to an office next to the control room. McCue and other puzzled operators watched through windows that ran from about waist high to the ceiling.

The group included Fermi; Eugene Wigner, head of the reactor's design team; Marshall; and others key to the project.

"They were sort of in a huddle," McCue recalled.

Later, McCue pulled a supervisor aside and asked for information about the conference. "It turns out they were in there making up a pool on when it would come back to life," McCue recalled.

Marshall and Fermi talked over the mystery with engineers, who first suspected a leaking tube, or that boron in the river water somehow plated out on the cladding, causing the reactor to stop.

Fermi remained confident, Rhoades wrote. But throughout that Wednesday, Sept. 27, the reactor was quiet.

Early on Sept. 28, the reactor restarted. It was a critical clue in solving the mystery. Some byproduct of the chain reaction was creating a substance that absorbed the neutrons, bringing an effective end to the reaction.

The fact it restarted indicated the substance was a short-lived isotope. By studying the power fluctuations, Princeton theoretician John Wheeler, then stationed at Hanford, was able to pinpoint the source, a radioactive gas called xenon.

"Wheeler and the Italian (Fermi) did a tremendous job of scientific detective work," Matthias recalled shortly before his death last December. "The cure they specified was absolutely perfect. Once they figured it out, they were confident that the reactor would work.

"In fact, they left. They just outlined exactly what to do. They had no part of it after that. They were done for the reactor."

The xenon problem put the project behind schedule, creating even more pressure to produce, but by the summer of 1945, Hanford had delivered enough plutonium for three bombs.

A portion went into the Trinity blast, a test that produced the world's first nuclear explosion. More went into the bomb dropped on Nagasaki, Japan, the last nuclear weapon used in war. About 44 percent of that city was destroyed, 35,000 people were killed and another 60,000 injured.

Out of that unimaginable destruction came the end of World War II and recognition of the contribution to peace made by men and women at Hanford.

The rest of the Hanford-produced plutonium went into a third bomb. But plans for dropping it on Japan were scrapped when Emperor Hirohito announced his nation's surrender Aug. 15, 1945.

Matthias would say years later, "We didn't think much beyond the general consciousness it would contribute to the end of the war.

"There was a lot of discussion about the moral side of it, but we were firebombing Japan and many more were killed by that than those two nuclear explosions. By and large, knowing about the forecast that a million Americans and 2 million Japanese would be lost in an invasion, that was the overwhelming thing to consider in the environment of the time. If the Manhattan Project hadn't done it, by now someone else would have."