Even so, residents have watched anxiously as test wells were driven in their neighborhood just south of the Schuylkill Expressway.
``We are concerned,'' Myrtle Carter, head of the Passyunk Homes Tenant Council, said yesterday.
Last week, Carter's organization asked representatives of the Sun refinery and the Defense Personnel Support Center what they planned to do about the 180,000 to 240,000 gallons of oil beneath the base.
The answer so far is the agreement in which neither Sun nor the supply center admitted causing the plume. Since both have pools of petroleum on their properties, they agreed to split the cost of cleaning up neighborhood contamination.
Meanwhile, the DEP and city Water Department are checking out the sewers around Passyunk Homes, where residents periodically report petroleum odors.
The sewer is the only potential exposure pathway, DEP spokesman Rob Goldberg said.
Petroleum vapors can cause respiratory irritation or other health risks and can pose an explosion hazard in excavations. A risk assessment required under the agreement will examine potential health impacts.
The most recent map of the plume, drawn by consultants to Sun, shows petroleum underground on both sides of the expressway, in the south end of the supply center and the north end of Passyunk Homes.
Nearest the expressway, a maximum thickness of about 18 inches of oil lies on top of the groundwater. At Passyunk Homes, the thickest oil is under grass and a parking area immediately south of the expressway. But lesser depths extend under some of the homes, tapering off to about 1/8 inch south of Homestead Terrace.
The pact gives the companies 28 months to set up a complete oil recovery system. Meanwhile, the supply center has begun an interim cleanup that has skimmed off about 700 gallons of oil. That work will continue while the bigtime operation is set up.
While neighborhood concerns center on health risks and odors, another concern plagues the supply center, to close in 1999.
The city plans to take over the property for light industrial and office development. However, if the place isn't cleaned up, the city doesn't want it.
The city's defense conversion chief, Terry Gillen, said yesterday the project appears to be moving ahead. ``I don't see any reason that they couldn't get it cleaned up by '99'' if the city can keep the federal funding for the center's share of the cleanup, she said.