MARTIN COUNTY — The Florida Department of Health in Martin County (DOH-Martin) has issued a health alert for harmful blue-green algae toxins in Lake Okeechobee-S308C.
The alert follows water samples taken on September 22, 2025, which confirmed the presence of algae toxins in the area. As a result, the public is being advised to exercise caution when in or around the water.
Residents and visitors are urged to avoid drinking, swimming, wading, or using personal watercrafts in waters where visible algae blooms are present.
In addition, anyone who comes into contact with discolored or odorous water should wash their skin and clothing with soap and water.
Pets and livestock should be kept away from the affected waters to prevent harmful exposure, and alternative water sources should be provided for animals in the area.
The health department also warns that water contaminated by algae blooms should not be used for cooking or cleaning, as boiling the water will not eliminate toxins.
However, eating fillets from healthy fish caught in freshwater lakes with blooms is safe, as long as the fish is thoroughly cooked and the guts are discarded. Shellfish from affected waters should not be consumed.
The Florida Department of Environmental Protection (DEP) and its partners are monitoring the situation, collecting algae samples from bloom locations.
Once the samples are analyzed, toxin levels will be available on the Protecting Florida Together website or the DEP’s Algal Bloom Dashboard.
Blue-green algae, a type of bacteria, is common in Florida’s freshwater environments. A bloom occurs when algae grow rapidly, causing an accumulation of cells that can discolor water and produce floating mats that emit unpleasant odors.
These blooms can appear as scum, foam, or paint-like patches on the water's surface. Environmental factors such as warm water temperatures, still water conditions, and excess nutrients can contribute to the development of blue-green algae blooms, which are most common in the summer and fall months.
Although algae blooms may not always be visible, the toxins they produce can still be present in the water.
Blue-green algae can produce toxins that pose risks to human health, as well as to pets and wildlife, including fish and other aquatic animals. Sensitive groups, including children, the elderly, and those with weakened immune systems, should avoid exposure even at low concentrations.
For more information on the health effects of algae blooms, individuals can visit the Florida Department of Health's harmful algae blooms webpage.