Officials from the U.S. Environmental Protection Agency said Wednesday that they will continue to focus on chemical-cleanup efforts on the city’s South Side.

“It’s a process, but it’s an ongoing one,” the EPA’s Matthew Jefferson said Wednesday. That may include testing more sites to see if the so-called plume of trichloroethylene (TCE) and 1,4-dioxane has spread west of its current site, which extends roughly from the Tucson International Airport northwest to Interstate 19 and West Irvington Road.

The update was part of a quarterly meeting Wednesday night at the El Pueblo Neighborhood Center, 101 W. Irvington Road. During the past two decades, officials have been cleaning up the chemicals, which were dumped into the ground by Hughes in the early 1950s.

The Star’s Tony Davis reported in July that the EPA ordered Tucson-based Raytheon Co., Hughes’ successor, and the U.S. Air Force to build a new plant for better treatment of groundwater polluted by the industrial solvents, which are considered carcinogens.

An official from the U.S. Geological Survey said at Wednesday’s meeting that readings of trace chemicals from area water wells has remained the same. Dioxane levels moving north from the Air Force-owned Hughes site have been dropping over the years.