The Florida Department of Health in Martin County issued a health alert on June 19 for the presence of harmful blue-green algae toxins in Lake Okeechobee.
Health officials are urging people to stay out of the water at several sampling points and to keep pets away from any visible scum or discolored water.
The blue-green algae in Lake Okeechobee is not unlike the algae bloom that formed in the Lincoln Memorial Reflecting Pool. The reflecting pool — a centerpiece of Trump’s highly touted Washington, D.C., makeover — has turned into a spectacle of green water, peeling blue coating and political blame‑shifting. A massive algae bloom has turned the water lime green.
Blue-green algae in Lake Okeechobee is not uncommon.
The Florida Department of Health in Palm Beach County has issued multiple health alerts and cautions since spring, most recently after a June 10 sampling at site L007 and a June 17 sampling at S352 showed harmful cyanobacteria or visible blooms, triggering signs around the lake and standard guidance: don’t swim, don’t drink the water, and avoid spraying it on lawns or crops.
Past summers saw massive algae blooms on Lake Okeechobee
Those alerts follow a familiar pattern over the past few summers.
In June 2024, the state Department of Heath in Palm Beach County warned of toxins at Lake Okeechobee’s S351 and S352 structures; in July 2025, state health officials issued repeated alerts and cautions for Lake Okeechobee in Palm Beach and Martin counties as cyanotoxins turned up in samples near discharge points and marinas, with residents reporting odors and irritation from the water. State and federal briefings note that these blooms, typically driven by warm, slow‑moving, nutrient‑rich water, are now a seasonal fact of life, forcing regular advisories that can last weeks at a time.
Blue-green algae peaked during the years 2013, 2016 and 2018, when satellite images showed huge mats of Microcystis cyanobacteria spreading across much of the surface and into the St. Lucie and Caloosahatchee estuaries.
In 2016, NASA and state scientists estimated a bloom covering roughly 85 square kilometers in early summer; by late June, toxins were high enough downstream that Gov. Ron DeSantis declared a state of emergency in Martin and St. Lucie counties as thick, paint‑like algae fouled canals and marinas.
A similar pattern in 2018 saw cyanobacteria cover up to about 90 percent of Lake Okeechobee at the July peak, according to satellite analyses, prompting widespread health advisories and national attention to the threat of airborne toxins and the fallout from lake discharges.
The June 19 alert was in response to a water sample taken on June 16.
What is blue-green algae?
It is a type of bacteria that is common in Florida’s freshwater environments. A bloom occurs when rapid growth of algae leads to an accumulation of individual cells that discolor water and often produce floating mats that emit unpleasant odors.
Blue-green algae blooms can also appear as scum, foam, or paint on the surface of the water in various colors. The Department of Health urges those who want to know more about the appearance of algae blooms to visit Protecting Florida Together.
Some environmental factors that contribute to blue-green algae blooms are sunny days, warm water temperatures, still water conditions, and excess nutrients. Blooms can appear year-round but are more frequent in summer and fall. Many types of blue-green algae can produce toxins. Blue-green algae may not always be visible as a bloom, but it can still be present in the water.
The health department urges people to take these precautions
Is blue-green algae harmful?
Blue-green algae can produce toxins, which can be harmful to human and pets as well as ecosystems, including fish and other aquatic animals. Sensitive individuals (e.g., children, the elderly, and those who are immunocompromised) may still be at risk even at low concentrations and should avoid any exposure.
For additional information on potential health effects of algae blooms, visit the Florida Department of Health’s harmful algae blooms webpage.
Where you can report issues related to algae blooms
If you have other health questions or concerns about blue-green algae, call DOH-Martin at 772-221-4090.
John Bisognano is Executive Editor of The Palm Beach Post. He can be reached at jbisognano@pbpost.com.
This article originally appeared on Palm Beach Post: Health alert issued for Lake Okeechobee after blue-green algae tested
Reporting by John Bisognano, Palm Beach Post / Palm Beach Post
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By John Bisognano, Palm Beach Post | USA TODAY Network
