HILL AIR FORCE BASE — The air inside aging buildings on the west side of Hill Air Force Base is still OK to breathe, according to results from an air-sampling survey recently completed at the base.

Officials didn't expect anything to be wrong, but they were prepared to take action if certain chemicals had been found in high enough concentrations.

The sampling was done because of the buildings' proximity to contaminated groundwater.

Base scientists have performed similar sampling for homes in Clearfield, Roy, South Weber, Sunset, Layton, Clinton and Riverdale — the seven cities affected by various contaminated groundwater plumes originating on base.

The chemicals trichloroethylene, or TCE; and tetrachloroethylene, or PCE, both potential carcinogens, began finding their way into the groundwater beneath the base beginning in the 1930s. For 40 years, the chemicals were disposed of directly onto the ground or into unlined chemical pits — procedures that are now unacceptable.

Both chemicals tend to evaporate out of the groundwater in the form of vapors.

The U.S. Air Force has paid for some homes to install a low-wattage vapor-removal system that vents gases from the soil beneath homes directly to the outside, where they can dissipate.

The groundwater contamination landed Hill on the National Priorities List as a Superfund site in 1987, and the base will likely remain on the list for at least 60 years.

Cleanup efforts have been in force for years, and the Air Force spends millions of dollars a year at Hill and in the surrounding communities.

No contamination has been found in drinking water, which comes from wells hundreds of feet below the contaminated groundwater plumes, which tend to flow just feet underground.

On base, some of the 47 air samples, which were collected during the first week of November, showed traces of chemicals, but nothing that would warrant action, according to the base.

Air sampling results show that though PCE and TCE were both detected below the buildings floors, PCE was detected in the indoor air in only one building, but in concentrations so low that the level had to be estimated. TCE wasn't found in any indoor air.

Col. Linda Medler, commander of the 75th Air Base Wing, said in a news release that she's happy to report positive news.

"We plan to do additional monitoring to ensure conditions do not change," Medler said.

The results can be viewed online at www.hillrab.org/1200area.

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E-mail: jdougherty@desnews.com