The red-flag warnings at Grand Lake St. Marys pose significant health risks to swimmers, waders, and pets. Exposure to harmful algal toxins can lead to illnesses such as gastroenteritis, skin rashes, and even nervous system or liver damage. Vulnerable groups, including children, older adults, and individuals with weakened immune systems, are particularly at risk. The Ohio Environmental Council highlights the need for more aggressive measures to reduce phosphorus runoff, which fuels these blooms. While programs like H2Ohio have made progress, the current pace of nutrient reduction is insufficient to prevent recurring outbreaks.