Residents in northwestern Ohio remained unable to use tap water for a third day after testing showed toxins were still present in the city’s water supply, NBC News reported. Toledo Mayor D. Michael Collins said early Monday that while tests continued to show a positive trend, they "do not convince us of safety," NBC station WNWO reported. On Saturday, authorities announced that a toxin had been detected in the water supply and warned residents not to use the tap for drinking, bathing and even cooking.