SMITHFIELD — Environmental workers who have been working since May to clean up contaminated soil at the site of the former Providence Barrel Co. are now turning their attention to surrounding properties, which are residential, according to the U.S. Environmental Protection Agency.

The EPA reported that testing of 10 neighboring properties in December identified “elevated levels” of trichloroethylene (TCE) and perchloroethelene (PCE). The agency said that workers would begin to remove tainted soil from the residential properties this week, and added that it was possible that groundwater could have been contaminated. The site lies near the Woonasquatucket River.

The EPA has been working with town officials and the state Department of Environmental Management,

Ted Bazenas, on-scene coordinator for the EPA, said in May that none of the surrounding houses relied on wells for their drinking water. He said the agency had sunk two test wells to monitor the situation.

The federal agency said that there was a “potential” for gases to pass through soil and affect the air in surrounding houses. “Low levels of organic vapors” were detected in some basements, the agency said, adding that the data thus far show such contamination not to have reached a level of concern for health.

Providence Barrel reclaimed barrels on the 2½-acre lot on Oak Street from 1972 to 1980.

The EPA said on Monday that “potentially hazardous” soil that had been excavated in the first phase of the cleanup is being trucked away in an operation that began last week.

An early investigation of the soil in the barrel reclamation site showed “elevated levels” of lead, arsenic and semivolatile organic compounds.

Cynthia Gianfrancesco, principal environmental scientist for the DEM, said in May that contaminated soil would go to a landfill that is approved to accept it. She said it has been many years since the site was used for business. She said the town demolished the buildings there because they were unsafe.

She said that the operation, which had been in the works for years, was made more difficult because the land had been abandoned.

“In most cases where there is a property owner we require the property owner do an investigation and cleanup. But the owner that caused the problem, as far as we know, is no longer alive. The site has shuffled from owner to owner. Once they realized they had a contaminated site, they would unload it on the next unknowing owner.”

Bazenas has estimated the cost of the cleanup at $500,000.

tmorgan@projo.com