Hill to sample air in buildings

HILL AIR FORCE BASE — Environmental scientists at Hill Air Force Base will begin an air-sampling program in some of the oldest buildings on base.

The program is designed to determine if chemical vapors from contaminated groundwater are evaporating from the groundwater and into the buildings.

It's a similar program the base has performed 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.

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

Cleanup efforts have been in force for years, and the U.S. 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.

During the coming week, Hill scientists will place six basketball-size sampling canisters in seven World War II-era buildings, know as the 1200 Area.

With coming development in the next 15 years, those buildings are slated to be demolished and replaced with new ones, but because they are currently in use, it's important to test the air, said project manager Shannon Smith.

Most of the buildings, which are converted warehouses, house administrative staff, but some are used for vehicle maintenance.

Groundwater models show a potential to have action levels of TCE and PCE in the buildings. Action levels determine when corrective action must be taken.

For industrial buildings, the action level is 11 parts per billion for TCE and 3 parts per billion for PCE, Smith said.

But the level that would affect people and cause watering eyes and headaches would be around 25,000 parts per million. That's for people working directly with the chemicals, Smith said.

If action is required at the end of the investigation, which will be complete by the first week in December, officials will decide whether any changes to the buildings' ventilation systems are needed or if vapor removal devices should be installed.

Vapor removal devices, which have been installed in some Roy homes, use a low-wattage fan below a building's foundation to draw any gases from the soil and vent them outside to dissipate.

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E-mail: jdougherty@desnews.com