Michael Switzer Designwork / AP
Employees of the South Charleston Public Works Department assist residents in getting clean water Sunday after a chemical spill Jan. 9, 2014, in the Elk River in West Virginia.
West Virginia officials announced Monday they have begun to lift a tap-water ban — but strictly on a zone-by-zone basis — that has left 300,000 residents without safe drinking and bath water since a chemical spill five days ago.
“The numbers we have today look good, and we’re finally at a point where the do-no-use order has been lifted in certain areas,” Gov. Earl Ray Tomblin said at a news conference.
Residents and businesses in the first zone — described as downtown Charleston and the capital city’s East End district — can begin a flushing process to ensure their pipes are cleansed of any traces of the chemical 4-methylcyclohexane methanol. Also known as MCHM, the chemical had leaked out of a 40,000-gallon storage tank along the Elk River.
Residents in nine counties first reported a licorice-type smell in their water Thursday morning.
Restaurants, day-care centers and schools have closed during the emergency, and there were still questions about how the leak occurred and whether the company, Freedom Industries, took too long to tell state officials there was a problem.
Federal authorities, including the U.S. Chemical Safety Board, opened an investigation into the spill.
Jeff McIntyre, president of West Virginia American Water, which runs the region’s water treatment plant, said it could still be “days” before all customers in the system are given the clear based on test results.
The company is launching an online map at www.westvirginiaamwater.com and has a hotline to allow customers to find out if they are in a zone where the “do-not-use” ban has been lifted. West Virginia American Water is also auto-dialing customers who are in the safe “blue” zones.
McIntyre said the odor could still persist after flushing — but residents shouldn’t keep running their water. He added there's no need to boil the tap water.
Officials in neighboring states along the Ohio River where the chemical is flowing through are monitoring the amount of it in the water.
MCHM, because it's classified as an alcohol, will continue to be diluted and evaporate as it flows further downstream, said Don Siegel, chair of the Earth Sciences Department at Syracuse University.
“A lot of the chemicals we introduce into the environment degrade very quickly by natural process,” Siegel told NBC News.
He added that West Virginia officials were “very prudent” in ordering the ban but that residents shouldn’t have to worry about the chemical if testing shows the water is safe.
The Associated Press contributed to this report.