A water ban that had hundreds of thousands of people in Ohio and Michigan scrambling for drinking water has been lifted, Toledo's mayor announced on Monday.
Ohio's fourth-largest city had warned residents not to use city water early on Saturday after tests at one treatment plant showed readings for microcystin, a toxic peptide, above the standard for consumption. The contamination was most likely precipitated by fertilizer and manure runoff into Lake Erie that caused harmful algae buildup.
Drinking the microcystin-contaminated water could cause vomiting, cramps and rashes, but no serious illnesses had been reported by late on Sunday. Health officials advised children and those with weak immune systems to avoid showering or bathing in the water.
Ohio Gov. John Kasich had declared a state of emergency and called in the state's National Guard to help deliver water to residents.
Mayor D. Michael Collins lifted the ban at a Monday morning news conference, saying the city's drinking water is safe. In announcing the end to the ban, the mayor took a drink of water to show he thought it was safe enough to drink.
The toxins that contaminated the region's drinking water supply didn't just suddenly appear.
Water plant operators along western Lake Erie have long been worried about this very scenario as a growing number of algae blooms have turned the water into a pea soup color in recent summers, leaving behind toxins that can sicken people and kill pets.
In fact, the problems on the shallowest of the five Great Lakes brought on by farm runoff and sludge from sewage treatment plants have been building for more than a decade.
The National Oceanic and Atmospheric Administration released a satellite image showing a small but concentrated algae bloom centered right where Toledo draws its water supply, said Jeff Reutter, head of the Ohio Sea Grant research lab.
The bloom was much smaller than in past years and isn't expected to peak until early September. But instead of being pushed out to the middle of the lake, winds and waves drove the algae toward the shore, he said.
"Weather conditions made it such that bloom was going right into the water intakes," said Reutter, who has been studying the lake since the 1970s, when it was severely polluted.
The amount of phosphorus going into the lake has risen every year since the mid-1990s. "We're right back to where we were in the '70s," Reutter said.
Almost a year ago, one township just east of Toledo told its 2,000 residents not to drink or use the water coming from their taps. That was believed to be the first time a city has banned residents from using the water because of toxins from algae in the lake.
Researchers largely blame the algae's resurgence on manure and chemical fertilizer from farms that wash into the lake along with sewage treatment plants. Leaky septic tanks and stormwater drains have contributed, too. Combined, they flush huge amounts of phosphorus into the lake.
Environmental groups and water researchers have been calling on Ohio and other states in the Great Lakes region to drastically reduce the amount of phosphorus flowing into the lake.
Ohio lawmakers this past spring took a step toward tackling the algae problem when they enacted a law requiring most farmers to undergo training before they use commercial fertilizers on their fields. But they have stopped short of mandating restrictions on farmers.
The International Joint Commission, an advisory agency made up of Canadian and U.S. officials, said last year urgent steps are needed to reduce phosphorus applied to fields, suggesting among other things that states ban the spread of manure on frozen or snow-covered ground.
That report came after a state task force in Ohio called for a 40 percent reduction in all forms of phosphorus going into the lake.
Agriculture industry groups have been asking farmers for more than a year to reduce phosphorus runoff before government regulators step in and impose their own restrictions.
"We're clearly showing progress," Reutter said. "You have to decide for yourself whether you think it's fast enough."
Al Jazeera and The Associated Press