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Seven additional homes near East High School are in the clear as the search continues for a harmful pollutant that may infiltrate residents' basements.

The houses were tested this spring for a chemical called tetrachloroethylene, or PCE, that has been detected in wells and springs in the area. Scientists are working to identify the exact location of the contaminated groundwater, but they said Wednesday that they were relieved to see that the data collected indicate that the problem is not widespread.

PCE is a synthetic chemical used by dry cleaners and other industrial operations. When groundwater becomes contaminated by PCE, the chemical can be released as a gas and accumulate in nearby basements.

In high concentrations, PCE is linked to eye and respiratory irritation, kidney dysfunction and neurological effects such as behavioral changes, impaired coordination, dizziness, headaches and fatigue, according to the Environmental Protection Agency.

PCE also is a likely carcinogen, the EPA warns.

Federal officials believe the contaminated groundwater near East High originated from a Department of Veterans Affairs dry cleaning operation at the George E. Wahlen VA Medical Center in the 1970s.

PCE was detected in irrigation wells in that area in the 1990s. In the early 2000s, it was found in a municipal drinking water well, prompting Salt Lake City to remove that well from service as a precautionary measure. Then, in 2010, PCE was discovered in several surface-level springs during the aftermath of the Chevron oil spill. The site was listed as a Superfund project in 2013.

Since the VA began testing houses in 2015, Lynne Welsh, who is supervising the project, said one home contained enough PCE to warrant action. Four were slated for further testing. But none of the seven homes checked this spring exceeded the PCE screening level.

Two nearby parochial schools, Judge Memorial Catholic High School and Our Lady of Lourdes Catholic School, have tested positive for PCE gas, though neither topped the screening level. East High itself had a negative test result.

As a precautionary measure, the VA has offered air-purifying units to homeowners whose tests come back above the screening level while the agency monitors the site and crafts a permanent plan for PCE removal.

The U.S. Geological Survey has been tapped to determine where the PCE is located and how it might be moving underground. So far, groundwater data in the area have been too limited to identify the exact location of the contaminated water, which is thought to be concentrated in the vicinity of 700 South and 1600 East.

Wells used to gather data about groundwater levels and movements are too far apart to get specific insight into the 300 to 400 acres in question, Welsh said. So while general information about the aquifer is available, the location of the PCE is difficult to pin down.

Welsh said the VA plans to install more test wells next summer.

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