"What we know is there was some remediation done on this property," he said. "It's unclear exactly the extent of it."
The 2.8-acre site is by far the most controversial of four chosen by city leaders for 150-bed shelters that they hope will be more conducive to helping people escape homelessness and less convenient for preying drug dealers.
Commercial tenants at 653 E. Simpson include a popular day care, and the site abuts a neighborhood where homeowners have expressed fears of diminished safety and property values. Others have expressed sticker shock at the $7 million cost.
The city has the option to terminate the deal at any time during its due diligence period, which lasts until April. Reberg said Mayor Jackie Biskupski has requested an environmental review "to clean up the mystery" related to the uranium remediation.
Carcinogenic tailings, a byproduct of uranium milling, were sometimes used in construction during the heyday of the nuclear arms race. Millions of tons of the stuff were piled high at mills and — thought safe — made a handy backfill for nearby building foundations.
"It was a nice, uniform, fine-grain sand that was easy to deal with," said Rich White, a consulting civil and environmental engineer at Midvale-based EarthFax.
From 1951 to 1968, the Vitro Chemical Company, at 3300 South and about 600 West, processed uranium and vanadium ore for the U.S. Atomic Energy Commission.
A 1996 report from the U.S. Department of Energy found that by the time Vitro closed, it had produced nearly 5,000 tons of concentrated yellowcake and 4 million tons of tailings.
Among 100 area properties that used the tailings as backfill was a city fire station that was found to have seven times higher the exposure to hazardous radon particles than is allowed for uranium miners.
A 1978 act of Congress charged the Energy Department with cleaning up defunct mills and their associated tailings. The government finished its work nearly a decade later and, in 1996, found that all Environmental Protection Agency standards had been met in relation to the Vitro plant.
Disclosures from 653 E. Simpson seller Forest Company, obtained from the city in response to a Salt Lake Tribune records request, include an undated letter from the state's Department of Health that seeks consent to survey 2230 S. 700 East, which was then the Continental Beauty College and is now the site of the Sherman Kendall Academy of Beauty Arts and Sciences.
A 1981 letter from the Energy Department says the beauty school was designated for remediation in late 1980. Noted appendices are missing from the seller's record.
White worked on the Vitro cleanup during its latter stages for engineering firm Ford, Bacon and Davis. Generally, he said, such tailings were excavated and replaced with clean fill, and damage to the landscape was then repaired.
Forest Company's remediation documents "would probably indicate that it was cleaned up to levels that at least at that time were considered appropriate for whatever the activity was that was going on," White said.