EPA completes construction at Tucson Airport Superfund Site

The Environmental Protection Agency has finished building a $5.5 million soil and groundwater treatment facility at the Tucson Airport Superfund Site in Arizona.

The soil-and groundwater-treatment plant project includes 11 new groundwater-extraction wells, seven new soil vapor-extraction wells and one new well to re-inject treated water into the aquifer. Groundwater is treated using an air stripper and soil vapors are treated usinggranular-activated carbon.

EPA says the expected flow of groundwater treatment at the site is65 gallons per minute, with soil vapor extraction at 1,200 cubic-feet per minute. The exhaust stream from the air stripper also will be treated to minimize any discharges to the outside air.

Beginning in 1942, the Airport Three Hangars Area was occupied by defense contractors who disposed of volatile organic compounds on site, including trichloroethylene (TCE), methylene chloride, chloroform,carbon tetrachloride and benzene.

At least 20 separate facilities operated at the site since 1942, including aircraft and electronics facilities which discharged waste liquids directly into the soil; fire drill training areas, where wastes from training operations were left in unlined pits; and unlined landfills, which received various wastes from a number of sources. Large-scale waste disposal also occurred at the missile plant during the 1950s.

Missile Systems

The facility was a government-owned plant operated under contract by Raytheon Missile Systems Co., formerly known as Hughes Missile Systems Co. The plant was operated by Hughes or its subsidiaries from its construction in 1951 until it was purchased by Raytheon in 1997.

In 1981, EPA and Tucson investigators sampled groundwater from city wells within the airport property and found "unsafe levels" of TCE.Subsequent investigations identified a main plume of groundwater contamination about a half mile wide and five miles long linked to the site, and additional municipal and private water wells in the vicinitywere shut down.

In 1983, EPA declared the Tucson International Airport Area a Superfund site. The site covers some 10 square-miles, including the airport, portions of an Indian reservation, residential areas in Tucson and South Tucson and the site of Air Force Plant No. 44, Raytheon Missile Systems Co. EPA signed several consent decrees with potentially responsible parties during the agency's activities at the site.

Contact: Francisco Arcaute, EPA Region 9, (213) 244-1815.