West Virginia residents line up to get water at West Virginia State University, in Institute, West Virginia, Friday, Jan. 10, 2014. Lisa Hechesky/Reuters

West Virginia schools and restaurants closed, grocery stores sold out of bottled water, and state legislators who had just started their session canceled the day’s business Friday after a chemical spill in the Elk River in Charleston shut down much of the city and surrounding counties even as the cause and extent of the incident remained unclear.

The warnings affect about 300,000 people. There have been no reports of sickness or death, although residents have expressed frustration and anger at authorities and the chemical plant for not informing them of the spill earlier.

“About time you issued this! Communication failure to the public on your part!” a Charleston resident tweeted Thursday at West Virginia American Water, the water company that services the city.

“The water has been contaminated,” West Virginia Gov. Earl Ray Tomblin said Thursday evening. The governor didn't know how long the emergency declaration would last. Federal authorities have also declared a disaster in the area, which includes West Virginia American Water customers in Boone, Cabell, Clay, Jackson, Kanawha, Lincoln, Logan, Putnam and Roane counties.

The state's Department of Environmental Protection has ordered the company responsible for the chemical, Freedom Industries — a producer of chemicals for the mining, steel and cement industries — to shut down operations.

No more than six people have been brought into emergency rooms with symptoms that may stem from the chemical, and none were in serious or critical condition, said Department of Health & Human Resources Secretary Karen L. Bowling.

Several lawsuits have already been filed against American Water and Freedom Industries by local businesses and individuals. The Kanawha County Circuit Clerk's office reports that two lawsuits were filed Friday against Freedom Industries. Four other suits named Freedom Industries and West Virginia American Water as defendants.

Tomblin told residents of the affected area that tap water should be used only for flushing toilets, saying the advisory extends to restaurants, hospitals, nursing homes and other establishments.

Officials are not sure what threat the chemical spill poses to humans. Jimmy Glanato, director of the state Division of Homeland Security and Emergency Management, said the chemical — a coal-refining agent called MCHM — isn't lethal.

However, according to the Toxicology Data Network, high exposures to the chemical can cause death.

On Friday it remained unclear how long it would take before life returns to normal in the region.

"This could be a matter of hours for some communities, and for other it could be a matter of days," Al Jazeera correspondent Jonathan Martin reported from Charleston.

Federal authorities on Friday began investigating how the chemical escaped the plant and seeped into the Elk River.