Three days after Republican Ohio Gov. John Kasich declared a state of emergency across three counties due to contaminated tap water, Toledo Mayor D. Michael Collins has lifted the ban against drinking or using water. Although recent tests on water from Lake Erie revealed it was probably safe, Collins chose to err on the side of caution by extending his advisory into Monday morning while health officials assessed the extent of the damage caused by the toxin, microcystin.

Satellite imaging released by the National Oceanic and Atmospheric Administration showed “a small but concentrated" algae bloom located in the area where Toledo gets its tap water from, Jeff Reutter, head of the Ohio Sea Grant research lab told The Associated Press. Water samples taken from the Collins Water Treatment Plant were sent to three different labs for testing. Two of the earlier tests were considered “too close for comfort," but further tests that were reviewed at Monday’s city council meeting revealed the contaminatin had dissipated. 

Following the state of emergency declared by Gov. Kasich, residents of Lucas, Wood, and Fulton counties were advised to avoid drinking tap water or using it to bathe, brush their teeth, or wash dishes and home appliances. The ban has left over 400,000 residents of northwestern Ohio and southwestern Michigan scrambling to find a safe source of water. Truckloads of bottled water were distributed across the state and the Ohio National Guard has brought in a water purification system to produce uncontaminated water.

Lake Erie water plant operators said this is not a recent problem, but one that has been developing over the past few summers as a string of algae blooms have turned water from one of the five Great Lakes a murky, green color. This year’s bloom was not expected to peak until September and was estimated to be much smaller than past years. However, due to inclement weather the algae was pushed from the center of the lake into the shore.

While algae blooms do not usually leave behind byproducts harmful to humans and pets, this recent contamination was especially concerning after a large concentration of microcystin produced by cyanobacteria was discovered. According to the Environmental Protection Agency (EPA), microcystins are algae-induced toxins that target the liver and can also cause irritation on the skin, eyes, and throat. Ingesting large amounts of microcystins can lead to symptoms that include diarrhea, nausea, and dizziness.

Health complications experienced by humans who are exposed to microcystins are rarely life-threatening, but microcystin poisoning often kills local wildlife. There is no treatment for microcystin poisoning, so symptoms must be handled individually. Symptoms tend to show up hours after exposure; however, they can sometimes be delayed by up to a couple of days.