(CNN) — Don't use, drink, cook with, or even boil any of the water in Toledo, Ohio. Restaurants should close up for the day.
That's the message from officials after two samples from a water treatment plant showed readings for microcystin, a toxin that is released by algae blooms.
More than 400,000 people in the Toledo area are affected by the water warning, and Ohio Gov. John Kasich issued a state of emergency for Lucas and Wood counties and other parts of Northwest Ohio. The National Guard is scheduled to set up water stations around town, according to CNN affiliate WTOL.
City officials say the alert is a precaution as they expect more detailed test results by Saturday evening.
"We hope the tests come back and that we are not in the dire strait we fear we might be in," said Toledo Mayor Michael Collins. "We are erring on the side of caution."
There are no reports of anyone getting sick from the water, officials said.
Toledo's drinking water comes from Lake Erie, where a harmful algae bloom, that causes microsystin has been growing, according to a city spokeswoman.
Water lines form
People had lined up at a water distribution site, but were told to return at 3 p.m. ET, WTOL reports. Many just remained in line. A city spokeswoman said they will give out one case per family once the water arrives.
A grocery store called "The Andersons" said it has just received two truckloads of water and is limiting water sales to four cases per customer.
"It's one of the busiest day I've had in my 28 years," store manager John Kowalski told CNN.
Kroger said all its stores in the Toledo have run out of water. Stores in the Columbus area, more than a two-hour drive away, are close to running out.
More bottled water is on the way to its 15 stores in the affected area, said Kroger spokeswoman Kacie Siedmann.
"As soon as the water shipments are in, they are going out the front door," she said.
Green leaf lettuce and other produce that is misted by water in Kroger stores will be thrown out as a precaution, Sieman said.
CNN's Ryan Sloane and Marisa Marcellino contributed to this report.
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