Water tests after a chemical spill in West Virginia are encouraging, the governor said, but it's unclear when people might be able to use their taps again.
About 300,000 residents in nine counties in the southwest section of the state can't use tap water.
"Our team has been diligent in testing samples from throughout the affected area. The numbers look good and, like last night, they are very encouraging. I believe that we're at a point where we can say that we see light at the end of the tunnel," West Virginia Gov. Earl Ray Tomblin told reporters Sunday.
Jeff McIntyre, president of West Virginia American Water - a company affected by the spill - said that officials will begin lifting the water bans by zone. Certain areas will be prioritized, including downtown Charleston, but decisions will also depend on test results.
He declined to put a timeline on when the do-not-use orders will be lifted.
"I don't believe we're several days from starting to lift, but I'm not saying today," McIntyre said.
Officials have warned water customers to watch for symptoms of exposure to the chemical, which is used to clean coal, such as skin irritation, nausea, vomiting or wheezing.
Karen Bowling, secretary of the state's Department of Health and Human Resources, said Sunday that more than 1,000 people had called the West Virginia Poison Center, concerned about their exposure to contaminated water. There have also been more than 60 animal exposures reported.
A total of 10 people have been admitted to three hospitals, none in serious or critical condition, and 169 patients have been treated and released from emergency rooms, Bowling said.
Water restrictions were imposed Thursday after it was discovered that about 7,500 gallons of a chemical used to clean coal - 4-methylcyclohexane methanol - had leaked out of a storage tank a mile upriver from the West Virginia American Water plant.
Residents were told to use bottled water to wash hands, brush teeth or take showers.
The federal Department of Homeland Security sent 16 tractor-trailer loads of bottled water to help and the water company also provided truckloads.
The medical impact was hard to assess.
"We've had a lot of worried-well calls," Dr. Rahul Gupta of the Kanawha-Charleston Health Department said over the weekend. He cited complaints of irritation of the skin, throat, chest and stomach that some residents have linked to possible exposure.
The unknowns made residents anxious.
"They don't even know what the health risks are," Stacy Kirk of Culloden told CNN affiliate WSAZ. "We had bathed, cooked and everything right before the news came on yesterday."
"I don't know anything about the chemical to say too much good or bad about it, so we're all up in the air," said Arthur Taylor. "We're common folks - we're not chemists."