ASHLAND, Mass. -- The Environmental Protection Agency is expanding the test area near an old dye plant in Ashland in an effort to learn more about hazardous chemicals in the groundwater.

NewsCenter 5's Jack Harper reported Wednesday that the Nyanza plant has been linked to elevated cancer levels.

Homeowner Ron Philbrick said that his basement has a dirt floor, and he was worried that the fumes could be leaking into his home. The EPA said that they plan to test homes on and around Pleasant Street.

"Groundwater is coming down from the former Nyanza site in this area," EPA spokesman Jim Murphy said.

The stream, carrying wastewater from the plant, used to be a running joke.

"We used to call it the colored creek. Every day it would be a different color," Philbrick said.

"The groundwater has been contaminated a long time. It is moving, to some degree. We have been trying to get a handle on exactly where the worst areas of the contamination are. We know some of them. We don't have complete information yet. We need to be coming back, and we are looking for more answers," Murphy said.

The EPA said its study on the Sudbury River is complete, and mercury was found in some of the sediment below the surface. Officials are trying to determine if they should dig it up. The report on the river will be delivered to affected communities in October.

Homeowner Don Rushford was waiting to find out if his basement would be done over with a new ventilation system.

"If they go through what they say they are going to do, I think it’s a positive thing for everybody in this neighborhood," Rushford said.