FILE - Okeechobee

In this Friday, Oct. 25, 2019, photo, a sailboat starts down the St. Lucie Canal after leaving Lake Okeechobee, background, through the Port Mayaca, Fla., lock north of Belle Glade, Fla. The lock and dam was built in 1977 to raise the water level in the lake and provide flood control.

(The Center Square) – U.S. Rep. Brian Mast is threatening to sue the U.S. Army Corps of Engineers for “reckless decision-making” if it releases Lake Okeechobee water into the St. Lucie river system and a coalition of groups is calling on Gov. Ron DeSantis to declare a state of emergency “to protect the Caloosahatchee (river system) from harmful lake discharges.”

The agitation comes as the National Oceanic & Atmospheric Administration reported on May 12 that nearly two-thirds of the lake, or 500-square-miles, was covered with blue-green algae, threatening to befoul the St. Lucie and Caloosahatchee river systems, which drain the lake to the east and west, respectively.

The sprawling algae matt of is raising alarm across South Florida and Southwest Florida where memories of 2018-19’s toxic blue algae and red tide blooms, which shuttered beach economies, befouled the air and sickened many, remain vivid.

Blue-green algae blooms east of Lake Okeechobee have surfaced in the C-51 canal along Southern Boulevard in Palm Beach County.

West of Lake Okeechobee, blooms have been reported from the Moore Haven lock to the W.P Franklin Lock & Dam on the Caloosahatchee, where the Florida Department of Health in Lee County Thursday issued a health alert based on reports of algae toxins present in the water.

The fears are amplified by the lake’s unseasonably high water levels, warmer-than-usual water temperatures and the apparent suspension of a Trump administration policy that allowed more winter and spring releases south of the lake when cooler water is less algae-prone.

Gov. Ron DeSantis toured the lake on May 11 and called on the Corps to release water south of the lake rather than into the St. Lucie and Caloosahatchee rivers.

On Friday, the Corps announced it was reducing discharges into the Caloosahatchee to 1,500 cubic feet per second (cfs) from 2,000 cfs. Releases will come in pulses to “flush out” algae and timed for when tides push higher salinity levels upriver, it said.

The Corps said it is “continuing to maximize sending water to the south,” which constituted about 51% of all releases from the lake last week.

While the Corps maintains it is not releasing water into the St. Lucie system now, Mast says that temporary concession won’t last and "the U.S. Army Corps of Engineers is again threatening to discharge this toxic water" into the both systems.

In a Friday letter to Corps’ Commanding General Lt. Gen. Scott Spellmon, Mast said "algal blooms on Lake Okeechobee recently tested more than 100 times too toxic for human contact” and demanded he visit local communities to see for himself what the released do.

"If you are going to poison our community yet again you should first look in the eye the men, women and children whose lives you are putting at risk with your reckless decision making," Mast wrote.

A 15-group collation in a May 8 letter requested DeSantis declare a state of emergency to stop any releases into the Caloosahatchee and waive restrictions that stop water managers from moving more water south into conservation areas.

Multiple blue-green algae health alerts have already been issued along the Caloosahatchee and St. Lucie rivers, and in Lake Worth Lagoon, the letter states, and with the rainy season nearing, the situation is unlikely to get better.

“Compounding this crisis, an ongoing Gulf of Mexico red tide bloom occurring since November 2020, continues threatening public health at locations nearshore and in back bays of Southwest Florida causing fish and other marine life mortality,” the groups say. “These co-occurring toxic blooms present the potential for a calamitous event that are likely to cause lasting damage to local economies and ecosystems throughout much of south Florida, similar to what occurred during 2018 and 2019.”