By Joe Holden

NORWOOD, Pa. (CBS) — Next month marks four years since a federal investigation began into a spike in illnesses like cancer and other autoimmune illnesses in Delaware County. It concluded nothing in the environment was to blame.

But Eyewitness News learned an EPA contractor has been spotted in Delaware County.

Public pressure changed everything last November. Tempers went through the roof at a town meeting because the investigation been conducted quietly up until then.

Now, the EPA is back in Norwood, taking a more exhaustive look at what lies beneath the surface.

The wait for answers continues. But for Mark Gonzalez, who with his wife Peggy, buried their 8-year-old daughter Sarah in June, he’s relieved to see work happening.

“Every day’s a struggle but we just gotta keep her memory alive,” Mark Gonzalez said.

Sarah died from complications of brain cancer.

The Gonzalez family and so many others are convinced dumping from decades ago in old town landfills has created a toxic environment in Norwood.

Hundreds of cases of cancer and other autoimmune diseases have been charged, and there’s no explanation why the number is so high in such a concentrated area.

“There’s definitely gotta be something going on here. You can tell, people are moving out of here and the people who are buying, I don’t know if they’re telling these people what’s going on here,” Gonzalez said.

Council President Bill Gavin says the EPA has recently bored and drilled, taking soil and water samples. It’s a renewed round of testing after fierce public backlash last year once knowledge of a previously quiet three-year-long investigation was broken wide open through a series of CBS3 reports.

This time around, the ground around dozens of homes will be sampled.

“We’ve had an open relationship with them and trying to work and get them to do this. And finally this time they’re really going through and doing it right,” Gavin said.

The EPA has bored all over the place in Norwood — deep in the woods, down hills, water samples, soil samples. It will take some time to process all of that.

The EPA will also test private properties and residential areas, something Norwood residents have mentioned time and time again.