The water in Fremont has tested positive for nitrate contamination, leading the Fremont Water Treatment Plant to issue advisory warnings to residents.
Results from water samples collected Wednesday and yesterday showed nitrate levels of 13.2 milligrams per liter, exceeding the maximum contaminant level of 10 milligrams per liter.
Nitrate in drinking water is a serious health threat for pregnant or nursing women and infants under 6 months old, Stephen Lamale, assistant superintendent of the treatment plant, said. Nitrate stops infants from absorbing oxygen, causing a condition known as "blue-baby syndrome," Mr. Lamale said.
Symptoms include a bluish skin color and shortness of breath. The infant also may experience nausea, vomiting, and dizziness. If untreated, the syndrome can be fatal.
People should not boil the water because that increases nitrate levels and should not use tap water in preparing infant formula, Dina Pierce, an Ohio EPA spokesman, said.
Fremont water customers should continue to take precautions until the nitrate level is under control, she said.
Nitrate is not a general health concern for adults and children older than 6 months.
Information from the EPA has deemed the Fremont water safe to drink for everyone except infants and pregnant and nursing women, Mr. Lamale said.
The treatment plant is investigating the cause of the contamination, but Mr. Lamale said it is probably coming from lawn and farm fertilizers south of Fremont that enter drinking water sources by storm water.
"We're hoping that within a few days, the level will drop below the [maximum contaminant level] of 10," Mr. Lamale said.
Nitrate levels usually spike during spring and summer, Ms. Pierce said, because rain increases runoff from farms.
Cities like Fremont, which draw their water from surface sources instead of wells, are required to test the water monthly.
Now that Fremont has found the contamination, the city is required to test the water weekly until the nitrate level dips below 8 milligrams per liter, Ms. Pierce said, at which time the city will issue another public statement.