On the morning of July 14, 1959, Sodium Reactor Experiment trainee John Pace received the bad news from a group of supervisors who had, he recalled, "terribly worried expressions on their faces."
A reactor at the Atomics International field laboratory in the Santa Susana Mountains had experienced a power surge the night before and spewed radioactive gases into the atmosphere.
For The Record
Los Angeles Times Tuesday, July 14, 2009 Home Edition Main News Part A Page 4 National Desk 1 inches; 43 words Type of Material: Correction
1959 nuclear meltdown: A headline on an article in Monday's Section A about the first nuclear meltdown in the U.S. said the reactor was in Chatsworth. The reactor was in Ventura County in the Santa Susana Mountains overlooking Los Angeles County, including Chatsworth.
"They were terrified that some of the gas had blown over their own San Fernando Valley homes," recalled Pace, who was 20 at the time. "My job was to keep radiation out of the control room."
Pace set to work sealing doors and windows with clear packing tape and scrubbing the walls with sanitary napkins soaked with special chemicals because, he said, "soap and water wouldn't do the trick."
Today, on the 50th anniversary of America's first nuclear meltdown accident, Pace will join federal regulators and former lab workers in a commemorative gathering at the Aerospace Cancer Museum of Education in Chatsworth.
The group will provide an update of recent developments, including the Environmental Protection Agency's plans to spend $40 million in stimulus funds on a comprehensive radioactive survey of the nuclear site.
"It's about time," said Holly Huff, who was 8 years old when the meltdown occurred a mile from her home.
Standing on a bluff overlooking the 2,850-acre facility, which is now owned by Boeing Co. and NASA, Huff said, "They say it will be cleaned up by 2017 -- I doubt it. We'll wait and see."
In December, Huff was diagnosed with leukemia and thyroid problems, ailments she believes are connected to having been exposed to radioactive gases as a child.
"I find it fascinating," she said, shaking her head, "that a lot of people still don't know what happened here."
In August 1959, about five weeks after the accident, the Atomic Energy Commission published a press release indicating that "a parted fuel element had been observed," a reference to damage. But it added that there was no evidence of radioactive releases or unsafe operating conditions.
"They wanted to keep it secret," Pace said.
Lab officials kept switching the reactor off and on until July 26, when it was shut down and dismantled. There was evidence of melting in a third of the reactor's fuel elements.
For about two weeks, the facility, which employed several thousand people, had been venting colorless and odorless radioactive gas into the environment.
"Radioactivity levels during the accident went off-scale," said Dan Hirsch, a spokesman for the antinuclear group Committee to Bridge the Gap. "We thus do not know to this day how much radioactivity was released."
Details of the incident were not disclosed until 1979, when a group of UCLA students discovered documents and photographs that referred to a problem at the site involving a "melted blob."
Ever since, residents have worried about downstream health risks associated with soil contaminated by years of rocket and nuclear testing.
Radioactive emissions from the accident could have resulted in 260 to 1,800 cases of cancer within 62 miles of the site over a "period of many decades," according to a study released in 2006.
Boeing officials disputed the findings, saying the study was based on miscalculations and faulty information. They cited a Boeing-commissioned study released in 2005 that found overall cancer deaths among employees at the field lab and at Canoga Park facilities between 1949 and 1999 were lower than in the general population.
A Boeing official said the company was committed to a timely and thorough cleanup of the site in a way that protects public health.
Half a century after the accident, nuclear cleanup operations and chemical decontamination remain incomplete.
The lab was opened on a craggy plateau in easternmost Ventura County in 1948 as the nearby San Fernando and Simi valleys were on the cusp of a postwar population boom.
Scientists at the site, originally operated by North American Rockwell, conducted nuclear research for the federal government for more than four decades before ceasing those operations in the late 1980s.
Home to 10 nuclear reactors and plutonium- and uranium carbide-fabrication plants, it has also been the site of more than 30,000 rocket engine tests, the thunderous explosions serving as a Cold War-era hallmark for nearby residents.
Old-timers still talk about being alarmed by experiments that lighted up the night sky, shook the ground and cracked windows.
Under a court order, the Department of Energy is preparing an environmental impact statement on a proposed cleanup operation.
Senate Bill 990, which took effect last year, requires Boeing, the U.S. Department of Energy and NASA to clean the property to levels suitable for residential and agricultural use.
"I have wasted three decades of my life trying to get them to clean up the mess they made," Hirsch said, "and we are still at least a decade away."
"That tells us," he added, "that a nuclear reactor can become a radioactive mess in minutes and can take decades to clean up.
"We should approach this technology with substantial trepidation."