President Obama is sending federal assistance to West Virginia after chemicals spilled into a river near Charleston on Thursday, threatening the water supply for thousands of residents.

“The President today declared an emergency exists in the State of West Virginia and ordered federal aid to supplement state and local response efforts due to the emergency conditions resulting from a chemical spill beginning on January 9, 2014, and continuing,” the White House announced Friday morning in a statement.

Obama authorized the Department of Homeland Security and the Federal Emergency Management Agency “to coordinate all disaster relief efforts” with local authorities.

Reports said a storage tank on the Elk River began leaking 4-methylcyclohexane methanol, a compound used in coal mining.

The spill occurred in an area one mile north of a water treatment plant. Nearly 200,000 residents in Charleston and surrounding counties were without drinking water, the state’s governor said, according to a report in the New York Times.

Residents stocked up on bottled water and businesses and schools remained closed for the day.

Officials said they were uncertain how much of the chemical had spilled into the river. Although it is not toxic, it can cause headaches and irritation after exposure.

CNN reported Friday that a U.S. attorney was launching an investigation into the release of the chemicals into the water supply.

Democratic West Virginia Gov. Earl Ray Tomblin declared a state of emergency in nine counties, and warned residents to “refrain from using the water for drinking, cooking, cleaning, bathing and washing.”

This story was published at 11:36 a.m. and has been updated.