Officials also lifted an advisory about Culton Creek, saying the levels of the toxic chemical used in making plastics are too low to impact aquatic life.
The latest advisory warns residents in the area between Mount Tabor and Old Glory roads, West Lamar Alexander Parkway and Robert C. Jackson Drive to not use well water.
“Nobody is in any kind of danger at this point,” said Maryville City Manager Greg McClain.
Officials said they are working to alert the public as they know information as well as to identify and test wells in the restricted area. So far, about 13 wells have been identified.
As of Tuesday afternoon, there were 46 requests to test wells, and results were in from a little more than half of the wells with one well testing positive for low levels of acrylonitrile, said CSX spokesman Craig Camuso.
He said the rest of the results should be in by Wednesday.
The contaminated well serves American Foundation & Basement Repairs. Officials notified the business, which has stopped using the well, and CSX is running a temporary waterline to the company.
Camuso said well water testing is ongoing, and CSX is bringing in equipment to drill deeper and test the ground water.
Renée Hoyos, executive director of the Tennessee Clean Water Network, said she was glad to see CSX providing water and reimbursement to residents and hopes the company takes responsibility for the continued impact of the derailment.
“CSX should test those wells for a long period of time,” she said, adding that ground water is more difficult to predict than surface water, so testing should be ongoing for at least a year.
So far, no wells have been re-tested, but Camuso said it is possible that wells in the newly restricted area will be tested a second time.
For residents with questions about well water testing, call GHD — Environmental Consultants at 866-812-9565 or visit the Community Outreach Center at Heritage Middle School.