Nuke fallout found in Las Vegas attics

Thursday, March 2, 2000 | 11:32 a.m.

Traces of radiation and banned pesticides lie in the attic dust of older homes in Las Vegas -- undisturbed footprints of decades of nuclear bomb tests and use of poisons no longer allowed.

University of Nevada, Reno, graduate student James Cizdziel found the evidence of plutonium, lead and DDT after crawling across the wooden beams of attics in both Las Vegas and Southern Utah for more than a year looking for decades-old dust as part of his research for an environmental chemical health degree.

The study was not intended to measure how much radioactive exposure came from atomic bomb fallout in the 1950s and 1960s. But it could provide a method for scientists in the future to measure how much fallout descended on Las Vegas and other communities downwind from the Nevada Test Site.

Cizdziel found that the attic dust scraped from the homes 20 to 98 years old preserved the chemical substances better than the soils surrounding them.

Unlike house dust that is swept and swiped away or nearby soils that are dug or trampled, the attic dust stayed undisturbed for decades.

Cizdziel, working with UNLV chemistry professor Vernon Hodge, collected and analyzed 17 attic dust samples from Las Vegas, Toquerville, Utah, and Washington City, Utah.

He realized early in the study the advantage of collecting attic dust. He discovered 17 trace elements and other organic compounds in 10 samples of attic dust and three soil samples.

By gently sweeping the dust from the beams with a fine-haired brush onto a plastic dustpan, Cizdziel collected the pile of particles. He wore a filter mask to protect himself from exposure to other airborne hazards -- especially asbestos fibers, which can cause lung disease, and rodent droppings, which can contain hantavirus, a respiratory disease that can kill rapidly.

Of all of the elements Cizdziel discovered in attic dust, lead had higher concentrations than those in nearby soil samples.

The dust in older homes also contained the pesticides DDT and chlordane, both banned in the United States since the 1970s, in addition to the traces of radiation.

Cizdziel in the research published in February's Microchemical Journal laid out a method for scientists to track dust samples to reconstruct potential exposure to toxic materials in the air.

He is continuing his work in environmental chemistry at the U.S. Environmental Protection Agency laboratory in Las Vegas.

Originally, Cizdziel set out to help the Department of Energy determine radiation doses from the nuclear weapons fallout. Using his measurements, the DOE had hoped to reconstruct fallout doses to Las Vegas residents in the 1950s and 1960s. Above-ground atomic blasts ended in 1963, but the plutonium clinging to dust particles he found did not occur from early bomb experiments.

Instead, Cizdziel discovered that the nuclear remains were part of high explosives events called safety experiments.

The radiation in the attic dust was blown in from dirt that was contaminated in 1963 during a joint U.S.-United Kingdom operation called "Roller Coaster." The Atomic Energy Commission, now the DOE, tested the safety of nuclear materials such as plutonium in simulated accidents at the desert's surface. That is how the dust blew into attics.

The DOE has removed about 125,000 cubic feet of soil from part of the Nellis Air Force Range north of the Test Site that was contaminated during the experiments.

One site known as Clean Slate 1 was scraped down 6 inches in an effort to remove the contaminated soil, then the soil was placed inside special wrappers for trucking to Area 3, a disposal area on the Test Site.

The Clean Slate 1 test contained 3,269 pounds of explosives, including three pounds of plutonium.

Another site near the old mining town of Goldfield was known as Double Tracks. It had the smallest plutonium contamination, the DOE said.

The DOE is working to return all Operation Roller Coaster sites to the control of the U.S. Air Force, DOE spokeswoman Nancy Harkess said.

The two federal agencies are in negotiations on the most conservative scenario, which would allow troops to train on soils contaminated by up to 25 millirems per year of radiation, Harkess said.

A millirem is a measurement of radiation. The average exposure from all sources of natural and man-made radiation from sunlight, continental jet flights and cosmic rays is 360 millirems a year per person.

Mary Manning covers environmental issues for the Sun. She can be reached at (702) 259-4065 or by e-mail at manning@lasvegassun.com.