After three days without safe drinking water, Ohio's fourth-largest city lifted its ban on Monday. Toledo Mayor D. Michael Collins said tests showed non-detectable levels of the toxin microcystin. "Our water is safe," he said at a press conference announcing the good news. Residents were told to flush their water systems if they hadn't used them since saturday when the ban went into effect. The city first issued an alert on Saturday when tests revealed a toxin, possibly from algae on Lake Erie, was in the city’s water supply. The city also advised against brushing one’s teeth with the water or boiling it, as that would only increase the toxin’s concentration. Ohio Governor John Kasich declared a state of emergency to allow state agencies and the Ohio National Guard to begin bringing in water. Water distribution centers were also set up around the city, limiting families to one case of bottled water.