More tests are needed to ensure that toxins are out of Toledo's water supply, the Ohio city's mayor said Sunday, instructing the 400,000 people in the region to avoid drinking tap water for a second day.
Mayor D. Michael Collins said that new samples showing decreased levels of toxins in the water are a positive sign.
Toledo officials issued the warning early Saturday after tests at one treatment plant showed two sample readings for microsystin above the standard for consumption, possibly because of algae on Lake Erie, the shallowest of the five Great Lakes.
The city also said not to boil the water because that would only increase the toxin's concentration. The mayor also warned that children should not shower or bathe in the water and that it shouldn't be given to pets.
Algae blooms during the summer have become more frequent and troublesome around the western end of Lake Erie. The algae growth is fed by phosphorus mainly from farm fertilizer runoff and sewage treatment plants, leaving behind toxins that have contributed to oxygen-deprived dead zones where fish can't survive.
The toxins can kill animals and sicken humans.
Long lines quickly formed at water distribution centers and store shelves were emptied of bottled water. The warning effectively cut off the water supply to Toledo, most of its suburbs and a few areas in southeastern Michigan.
City and state officials monitoring the water were waiting for a new set of samples to be analyzed Sunday at a federal lab in Cincinnati, Collins said.
Residents waited hours for deliveries of bottled water from across Ohio as the governor declared a state of emergency.
Gov. John Kasich said it was too early to say how long the water advisory will last or what caused toxins to spike suddenly in the drinking water.
Families toting empty coolers, milk jugs and even cookie jars topped them off with well water funneled out of the back of a pickup truck.
Late Saturday, Kasich ordered the state's National Guard to deliver water purification systems, pallets of bottled water and ready-to-eat meals to residents in several counties.
There were no reports yet of people becoming sick from drinking the water, Collins said.