VoteWater Deep Dive: What’s the state’s game plan for the next toxic algae crisis?

If this summer brings toxic algae blooms to the St. Lucie and Caloosahatchee estuaries, are state agencies ready, willing and able to find the toxins and quickly warn the public?

The need for early detection of and warnings for toxic blue-green algae blooms is paramount to the health and welfare of Floridians and our millions of visitors. Microcystin, the most common toxin in blue-green algae, can cause rashes if touched and hay fever symptoms, nausea and vomiting if inhaled. Long-term contact has been linked to liver disease; and some research has linked breathing toxic fumes to neurological diseases including Parkinson’s and Lou Gehrig’s disease.

During the 2016 blooms in the St. Lucie Estuary, Martin Medical Health Systems (now Cleveland Clinic Martin Health) emergency rooms reported increases in patients with skin rashes, coughing, shortness of breath and aching limbs and joints

It’s easy to see why. The federal Environmental Protection Agency considers water with microcystin in concentrations of 8 parts per billion or more to be too harmful to touch. In 2018, toxin levels in St. Lucie Estuary algal blooms topped that mark 12 times, including two times when microcystin levels were over 100 parts per billion (110 ppb on Aug. 2 and 154.38 ppb on July 5).

And in 2016, a bloom at Central Marine on the north shore of the St. Lucie River in Stuart recorded a microcystin level at a whopping 33,000 parts per billion.

Where’s the warning?

In 2018, WPBF covered the illegal placement of homemade signs signs that read “Danger,” “Lake O Discharges” and “Swim at your own risk” along the City of Stuart’s waterfront Healthy Trail.

But prompt official warnings were hard to come by during the toxic blooms in 2016 and 2018.

“Years ago the (Florida) Department of Health fought a battle against putting up these (warning) signs,” Walter Bradley, chairman of the neurology department at the University of Miami said at the 2021 Everglades Coalition Conference. “They said there was no evidence there was neurological damage from exposure to these toxins, and I think there’s been a change of direction.”

Tom Frazer, then the state’s chief scientist and coordinator of the Florida Blue-Green Algae Task Force, said at the same conference – held online because of the COVID pandemic – that the state was working on signs to be used during future blooms. 

“We’re working with the Department of Health to think about how we’re going to provide information about these types of warning signs,” Frazer said. “We are working on some signage that lets people know blue-green algae is in the water and people need to take precautions.”

At a July 2020 meeting of the Blue-Green Algae Task Force, member James Sullivan, executive director of Florida Atlantic University’s Harbor Branch Oceanographic Institute at Fort Pierce, said, “There’s no safe exposure to toxins. If there’s a reliable detection (of toxins in the water), the number doesn’t mean anything. To be the most cautious for the public, if you detect toxins, you put out an advisory”

Here’s the plan

Dense blue-green algal mats clump up at the gates of Lake Okeechobee’s Port Mayaca on May 4, 2023, in Martin County.

A bevy of state and federal agencies are now involved with identifying algal blooms, collecting algae samples, notifying the public of any toxic danger and taking action to minimize damage.

The first indication of algal blooms are often starts satellite views of Lake Okeechobee provided by the National Oceanic and Atmospheric Administration. The images show the location and density of blooms on the lake but can’t determine the types of algae or whether it’s toxic.

For that, you need hand-collected samples.

The Florida Department of Environmental Protection and the South Florida Water Management District collect samples when algal blooms are seen during regular water quality surveys and when blooms are reported by the public. (You can report blooms by calling 855-305-3903 or online at

The Florida Fish and Wildlife Conservation Commission samples nearshore marine waters, typically for both blue-green algae and red tide. The SFWMD also collaborates with the Army Corps of Engineers for daily visual updates at structures staffed by the Corps, particularly Port Mayaca Lock and Dam on the east side of Lake O, Moore Haven Lock and Dam on the west side, St. Lucie Lock and Dam on the C-44 Canal leading to the St. Lucie River and the Franklin Lock and Dam on the C-43 Canal leading to the Caloosahatchee River.

Samples must be sent to the DEP lab in Tallahassee for a full screening to identify the type of algae, determine whether it contains toxins and, if so, at what levels. The lab takes two to five days to test samples and post results on the DEP harmful algal bloom dashboard.

DEP’s process is approved by the National Environmental Laboratory Accreditation Conference, so it’s the measurement the state health department uses to decide when to issue toxin warnings. However, the SFWMD staff also screens algae samples for microcystin, the most common toxin found in blue-green algae, and get results in 24 hours to 48 hours. And so far, the district’s test results have closely matched the DEP’s.

Generally, samples are split, with one portion going to the DEP lab for a full analysis and the other tested by the SFWMD for a quick check for microcystin. Any detectable level of microcystin will trigger and alert by the DEP, which then coordinates with the state health department for local alerts and warning signs. When the system works properly, the coordination continues with local health department officials working with county and municipal agencies for public notification and consistent messaging.

Here’s how it works

Dense blue-green algal mats clump up at the gates of Lake Okeechobee’s Port Mayaca on May 4, 2023, in Martin County.

Recently, we saw an example of the need for sampling and testing algal blooms, as well as proper action and collaboration by agencies.

On Feb. 24, the state Department of Health in Martin County issued an alert for a harmful algal bloom on the Lake O side of the Port Mayaca Lock and Dam, which separates the lake from the St. Lucie (C-44) Canal leading to the St. Lucie Estuary.

A DEP sample taken two days earlier had found microcystin at a concentration of 0.62 parts per billion. That’s well below the EPA’s too-harmful-to-touch threshold, but it’s unusual to find toxic algal blooms so early in the year.

The Corps, which controls the structure, closed the discharge gates from the lake to the canal on Feb. 28 – six days after the algae was reported and four days after the health department’s warning. The gates were reopened two days later after no algae was visible and tests by the water district showed microcystin below the detection limit of 0.2 parts per billion.

Quicker, but quick enough?

Fishermen seen just beyond a haphazardly-placed blue-green algae advisory at Port Mayaca in 2018 show the need for more public education and robust signage.

A two-day delay is significantly faster than the sloth-like pace of health department warnings during the 2016 and 2018 blooms. So, kudos to the health department for stepping up its game.

But should health department officials have to wait for DEP lab results before issuing warnings to avoid toxic water?

Test results in the case just mentioned came back quickly, but that might not always be the case. Tests by the SFWMD may not show all the toxins in the water; but if they’re available before the DEP’s, and they reveal microcystin-tainted water, it’s time to start sounding the alarm and putting up signs.

Also, the DEP had a bad habit (hopefully broken now) of under-reporting microcystin toxicity by sampling water around the edges of blooms rather than in the thickest parts where levels are likely to be the highest.

The Corps’ six-day delay between the algae report and the dam closure is not so laudable. Corps officials have admitted they knowingly discharged toxic algae from Lake O in the past. The Corps swings the big hammer here: Warning people about toxic water is paramount.

But ultimately, stopping its flow at the source (Lake Okeechobee), is infinitely better.