Edisto Court residents watched quietly Tuesday as government workers drilled holes in their yards to verify evidence of long-buried toxic pollution.

The U.S. Environmental Protection Agency and the S.C. Department of Health and Environmental Control returned to Edisto Court to continue an investigation of industrial contamination in the small neighborhood off Rosewood Drive in south Columbia.

Much of the work occurred on Easy Street and relied on drilling equipment to collect deeper soil samples for analysis in a laboratory. Easy Street has had some of the highest lead and arsenic levels discovered so far during the investigation.

The contamination is believed to have come from an industrial corridor nearby, perhaps dating as far back as the early 1900s, but no one knew about it until recently, state regulators say.

“I’d describe this as scary,” said 28-year-old Mike Robinson, who had his blood tested Tuesday for lead. “You don’t know how long this has been down here or what it is going to do, or what the effects of it are. I’ve stayed here all my life.”

Lead and arsenic provide a variety of health hazards. Exposure to lead can hurt children’s ability to learn, while also contributing to high blood pressure or strokes in adults. Arsenic is an ancient poison that has been linked to certain cancers.

Rick Jardine, the EPA’s on-scene coordinator, said some yards where DHEC found pollution near the surface did not have contamination much past 2 feet below ground. But Jardine said the agency still has numerous homes to look at, so it was difficult Tuesday to make a complete assessment. The area has about four dozen yards that would conceivably be checked with drilling equipment.

If the EPA verifies the contamination, it could launch a cleanup that includes digging up tainted dirt and replacing it with clean soil. Jardine said it is unlikely homes would be demolished as part of a cleanup. Contamination levels are not nearly as high in Edisto Court as at some sites he has worked on in the Southeast, but the issue also needs resolution, he said.

“These folks need some attention,” he said.

As the soil testing resumed Tuesday, DHEC continued a second day of health screenings for Edisto Court residents. For the two day testing period that ended Tuesday, 68 people, including 15 children, had sought health screenings from DHEC at a local community center.