The City of Toledo has warned its residents not to drink the water.

An “Urgent Water Notice!” posted on Saturday revealed that water testing at the city’s Collins Park Water Treatment Plant had uncovered microcystin levels above the “do not drink” one microgram per liter standard.

The notice advised residents to avoid both drinking and boiling water. In fact, boiling the water will increase the concentration of the toxins. The notice also said that pets should not be allowed to drink the water.

The City of Toledo has asked residents to use alternative sources of water (bottled water) for drinking, making infant formula, making ice, brushing teeth hand making food.

According to the Environmental Protection Agency’s Drinking Water Treatability Database, microcystins are toxins generated by cyanobacteria, also known as blue-green algae. Cyanobacteria release toxins upon cell death or lysis. Most microcystins are hepatotoxins. While the liver is the primary target of microcystins, it is also a skin, eye and throat irritant.

The notice warns that if you drink water containing algal toxins, you may experience diarrhea, vomiting, nausea, numbness or dizziness. Consult a physician immediately if you think you have been exposed to microcystins.

City officials believe that Lake Erie, a source of potable water for Toledo resident, may have been affected by a harmful algal bloom. Additional testing is being conducted and the city reports that it is ensuring that water supplies are restocked.