Hill Air Force Base » Hill Air Force Base officials say recent monitoring shows no health risk to the Layton city drinking water supply from contaminants found in groundwater plumes.

The contamination of groundwater, which ranges in depth from 10 to 150 feet, was caused by the disposal of degreaser solvents used on military planes.

Layton is one of seven cities who use the water supply. Hill is trying to clean up the contamination by extracting groundwater from the soil.

Water levels in some areas of the plume show the system is working and containing contaminated groundwater.

Hill's Operable Unit 8 site manager Barbara Hall last week told the Layton City Council that January tests show the plumes are not expanding. She said officials hope monitoring will better define the size of the plumes within the next 18 to 24 months, however, not much change is expected.

"We're going to be here for awhile," said Hall.

The base has been on the U.S. Environmental Protection Agency's list of Superfund cleanup sites since 1987 and restoration efforts have been under way since 1990.

In 2008 officials installed eight new monitor wells in Layton. Well sampling is done on a regular basis, but some wells will be tested more often to evaluated new sampling techniques, Hall said. Indoor air sampling also continues in Layton homes located over shallow plumes.

Base officials have contacted 855 Layton homeowners near the plume are since October 2008. Of those, 160 agreed to sampling and 107 samples have been taken so far, Hall said.

Few problems have been detected.

Base officials are providing air mitigation systems to the effected homes, said Bob Elliott, chief of the Environmental Restoration Branch.