On that Saturday morning in 1962, the men whose bodies formed the radiological front lines of the Cold War knew what it meant to see the eerie blue flash known as Cerenkov radiation.
"He saw the blue flash two times, and he knew that nobody had ever lived after seeing the blue flash. So in his mind he knew he was dead. He told me that," said Dorothy Aardal of her husband, Harold.
A worker in a plutonium plant in southeastern Washington's Hanford Nuclear Reservation, Harold Aardal was just a few feet away from a vat in which a nuclear chain reaction had accidentally started.
By the time Aardal was out of there, the buttons on his coveralls, the gold fillings in his teeth and even the blood in his body had become radioactive.
But Aardal didn't die, then or later, from the radiation's known effects.
Neither did the two other men who in a few dozen seconds received radiation doses that were several times what a person normally receives in an entire lifetime.
Nor did Harold R. McCluskey, the Hanford worker who was known as "The Atomic Man" after another accident, in 1976, embedded radioactive americium in his skull. Like Aardal, "The Atomic Man" died of cardiovascular problems, more than a decade after the accident.
Indeed, even as the federal government is opening up its records on numerous, and often secret, incidents of radiation exposure to workers and the public from the nuclear weapons industry, these men's lives bear witness to the difficulties in blaming radiation for health problems that appear many years later.
There are no definitive studies linking cardiovascular disease to acute radiation, although there are enough hints in animal studies to suggest a possible connection. No one can be sure because neither these general hints nor the specific problems of the men in the 1962 accident have been pursued at Hanford.
But the U.S. Department of Energy's new openness about past radiation releases is raising such issues as never before.
For example, a federally financed research panel reported in July that Hanford's massive releases of radioactive iodine into the air from 1945-47 were likely to have given area children high radiation doses to their thyroid glands.
Spewing invisibly from stacks above plutonium factories, the radioactive iodine concentrated in the thyroids of people who drank milk that came from local cows. Children's doses are estimated as high as 2,500 rem to the thyroid, more than 30,000 times greater than is considered acceptable today for a member of the public to receive in a year.
A separate study will look for health problems caused by the radioactive iodine. Already, though, the preliminary report has led to several lawsuits by people convinced that Hanford is to blame for health problems ranging from cancer to heart disease. And the prospect of additional revelations about other radiation releases is likely to result in even more litigation.
Such is the context for that 1962 accident at Hanford. Like a radioactive marker, the story of the accident points to the uncertainty of life at and near the plant where America made its nuclear weapons.
Most of the details have never been published in the non-scientific press. Newspaper reports at the time relied on the upbeat and very limited information provided by the Atomic Energy Commission, which then ran Hanford.
But a review of obscure scientific papers and talks with the survivors and their relatives paint a portrait of an Atomic Energy Commission institution that created its own definitions of radiation safety under a protective shroud of Cold War secrecy.
The crew in the 234-5 building at Hanford's Z-Plant knew enough to fear the blue flash on that Saturday, April 7, 1962.
By both mistake and malfunction, a valve allowed a plutonium solution to be sucked into an 18-gallon Pyrex tank. With a loud hiss at 10:59 a.m., the liquid reached a "critical mass"--the volume of material necessary for a nuclear chain reaction to spontaneously begin.
Inside a nuclear reactor, intense radiation emitted by this cascade of splitting, or fissioning, atoms is confined by lead shielding and thick concrete. But, because fission wasn't supposed to happen in the vats of Z-Plant, there were no such barriers to protect Aardal and co-workers Frank R. Lohdefinck and James R. Williamson.
The blue flash was the optical equivalent of a sonic boom. The fissioning material launched high-energy particles at such speed that it set up an optical rebound, a blue light.
Williamson is now 56 and looking forward to retirement from Hanford in four years. He shared his memories of the accident reluctantly. When a reporter approached, he shut off the lawn mower in his mother-in-law's back yard here and recalled a day that "I'd just as soon forget."
Williamson was in the same room with Aardal and Lohdefinck, but about 23 feet away.
He said he recalls hearing a short, loud hiss like the sound of an arc welder and seeing two quick blue flashes that lit up the entire 30-by-40-foot room.
"Once Harold saw it he said: 'Let's get out of here!' Lohdefinck was saying: 'Are you sure?' and Harold said: 'Yeah!' "
The weekend skeleton crew of 22 scrambled to get out of the 480-foot-long building and as far away from the radiation as possible.
Even 75 yards away from the building, though, detectors showed that penetrating radiation levels were increasing. Standing in that spot for an hour would subject a person to 200 millirem of gamma radiation per hour, a little more than half the radiation dose an American receives in a year from natural sources such as cosmic rays. The fission reaction continued for another 37 hours.
Glen Thoennes, a pipe-fitter who was working behind a partial wall about 40 feet from the fissioning material, says that when he saw the flashes and heard the alarms he thought a routine radioactive contamination incident had occurred.
Now 73 and retired, Thoennes was the fourth man hospitalized because of the accident, although his radiation dose was later determined to be relatively small, about three times the annual dose from background radiation.
Thoennes reminisced about the accident in an interview at the condominium he shares with his wife in central Richland.
"When I heard the alarm I thought a bag or a glove had broken and it was contamination," he said. "We hadn't had that much experience with (penetrating external) radiation. It was just all new. But we knew we were supposed to move out, so we did--I did anyway!"
The men were taken to a first-aid station away from the immediate vicinity. Thoennes recalled radiation technicians arriving at the station within an hour and embarking on a hunt for all metal. Neutrons shooting from the fission reaction make metals radioactive.
"We had coveralls then with metal buttons. When they finally got a crew out from town and they checked us, those buttons were so 'hot' they cut them off, and they took all of our keys and rings, and our watches, and everything else that was metal because they were all really emitting some radiation."
His wife, Bernadine, also remembers an Atomic Energy Commission official who "told me not to say anything" to the press about the accident. She hid out for days with the wife of a Hanford safety official.
The men had been taken to the first-aid station in private cars and a bus--which, ironically, was driven by Harold R. McCluskey. McCluskey had narrowly missed being directly involved in the criticality accident: Aardal had just taken over to allow McCluskey a break when the accident happened.
Fourteen years later, though, on Aug. 30, 1976, McCluskey earned the label "The Atomic Man" when he was nearly blinded and made permanently radioactive by a chemical explosion in another plutonium processing plant at Hanford.
His skull and upper body were peppered with americium-241, which remains significantly radioactive for 4,580 years. McCluskey sued the government and received $275,000 for his injuries. Still, until his death in 1987, he remained a booster of the nuclear industry, using his evocative nickname.
For Aardal, Lohdefinck, Williamson and Thoennes in 1962, their accident was followed with a trip to a special radiation-accident unit at a Richland hospital.
But treatment wasn't the only objective; so was research. In one of the more chilling paradoxes of the nuclear industry, it is only through such accidents that scientists get their best information on what radiation does to the human body.
Hanford doctors took blood samples hourly for days and continued regular blood tests for more than a year after that. They used various counting techniques to try to figure out how much radiation the men had received. They tracked the radioactive decay in their bodies. They trimmed their fingernails close, shaved off all their radioactive body hair and considered pulling out their gold-filled teeth.
"They flew in doctors from all over. They would take the blood and then they would freeze it, and then they would have a plane waiting to fly it wherever they took it--I can't remember where it was," Dorothy Aardal said.
It wasn't until three years later that clear calculations of the men's total radiation doses appeared in scientific papers. Herbert W. Parker, the respected health physicist who was at Hanford from its beginning in the mid-1940s, listed them in a paper for the International Atomic Energy Agency.
Aardal received 109 to 123 rem of "whole-body" radiation overall, with 510 to 630 rem to his eyes. For Lohdefinck, the whole-body dose was 41 to 47 rem, and 138 to 168 rem to the eyes. Williamson received 19 rem of whole-body radiation and 43 rem of retinal radiation. Radiation to the testicles was about 245 rem for Aardal and 110 rem for Lohdefinck.
Temporary radiation sickness symptoms, such as vomiting, occur in about 5% of the people exposed to 50 to 100 rem of whole-body radiation. The threshold dose for cataracts caused by radiation is 60 rem.
It wasn't until two weeks later, Dorothy Aardal remembers, that doctors seemed confident of Aardal's survival.
However, Aardal was seriously anemic for a couple of years, his wife said. And their fourth child, a daughter born a month after the accident, was their last. The radiation had made him sterile.
A couple of years later, when Williamson met the woman who would be his wife, he informed her he was afraid to have any children with her because of the accident. Kathryn Williamson adds, though, that it wasn't much of an issue for them because she already had children from a previous marriage.
Aardal kept working in plutonium processing until retiring in 1987, but "his nerves were shot," his wife said. "He kept a lot to himself. Maybe he didn't want to worry me."
Psychological help was not part of the medical follow-up that Hanford offered the workers. Neither was there any follow-up at Hanford aimed specifically at linking long-term physical health effects to the radiation exposures.
Indeed, a longstanding criticism by outsiders of Hanford's worker health studies is that the studies recognize only one negative health outcome from radiation exposure--cancer. Annual worker health examinations and a small study of worker illnesses take note of problems only if they seriously compromise a person's ability to work.
"When one of our physicians is doing a medical exam on anybody out here, he has a record of that guy's radiation exposure," said Jerry Yesberger, a health physicist for the Energy Department. "This is one of the things that he would look at, and it would be a flag to him."
But there is no special effort at tracking something as subtle as incipient cataracts or atherosclerosis, or at correlating them to radiation exposure, Yesberger said.
Dorothy Aardal, Lohdefinck's son, Richard, and Williamson say the Hanford workers detected no vision problems as a result of the 1962 accident.
But McCluskey did have cataracts as well as atherosclerotic heart disease when he died three years ago of coronary and respiratory failure. He was 75. Lohdefinck and Aardal also died of cardiovascular problems, Lohdefinck in 1988 at the age of 77 and Aardal a year earlier at 65. Williamson and Thoennes say they have no symptoms of unusual health problems.
Cardiovascular problems have never been definitively related to external radiation in Japanese atom bomb survivors or elsewhere.
On the other hand, there are hints of a possible connection in past research, and there is recent evidence of molecular aspects of heart disease that might be affected by radiation.
A 1971 study found that large X-ray doses enhanced atherosclerosis in pigs that ate a high-fat, high-cholesterol diet. But not much research has been done on the hints about human health this offers, said Dr. Daniel Steinberg, a leading atherosclerosis researcher at UC San Diego.
Atherosclerosis is the obstruction of blood flow through fatty plaques inside blood vessels. Heart attack, high blood pressure and stroke are the results.
If the pig study findings apply to humans--which hasn't been shown--radiation might promote plaques in arteries by injuring the artery wall or by increasing oxidation of cholesterol, Steinberg suggested. Both are critical steps in cardiovascular disease.
But separating any of radiation's effects from those of diet and lifestyle would be just as difficult as the current task in Washington state of trying to find radiation effects in Hanford-area children of the mid-1940s.
"It just would be awfully hard, because coronary heart disease is so common," said Dr. William Hollingsworth, a member of the U.S. commission that studied radiation effects in Japanese atom bomb survivors after World War II. "People die mostly of heart (disease), cancer and strokes, and that's the whole problem with studying radiation effects in any population."
After an initial couple of years of intensive monitoring by Hanford, researchers stopped any special health monitoring of the men involved in the 1962 accident. McCluskey, however, received lifetime medical care under his lawsuit settlement with the government.
Dorothy Aardal notes the difference in the way the men were treated, but said that her husband just didn't feel he could sue the only employer he had had since leaving the Marine Corps after World War II.
"My husband said: 'Maybe I could end up with $5,000 or $10,000 and lose my job. And how are you going to raise a family on that?' " she recounted. "Nowadays maybe you would get more, and they couldn't fire you. But back then you didn't have a leg to stand on."