Ohio’s governor called out the National Guard on Saturday to deliver bottled water to people around Toledo after a toxin contaminated the drinking water supply. About 400,000 people were told not to drink tap water after tests at a treatment plant showed above-standard readings for microsystin, which can cause liver problems, diarrhea and vomiting. After the warning came about 2 a.m. local time, people ran to stores and emptied the shelves of bottled drinking water and police were called in to keep order. "It looked like Black Friday," Aundrea Simmons told The Associated Press. Groceries and other stores were trucking in extra supplies to help meet the need.

Residents were warned not to drink tap water even after boiling because that could increase the toxin's concentration. Residents can use tap water to flush toilets but were warned that children shouldn't bathe in it and pets shouldn't drink it. Restaurants were forced to close, and grocers were tossing produce that was washed in the water, NBC station WNWO of Toledo reported. The toxin, the city said, was likely borne from algal blooms in Lake Erie. Officials in Chicago were testing their own water supply after the news from Toledo.

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UPDATE: Additional water sample being sent for federal testing. City hoping for answers by mid-day Sunday. #ToledoWaterWarning — NBC 24 (@nbc24wnwo) August 3, 2014

Just got this map of affected #toledo areas from health dept, which promised next update at 11:30. #emptyglasscity pic.twitter.com/zJhLugtyC4 — Vanessa McCray (@vanmccray) August 2, 2014

— Gil Aegerter andJacob Passy