The Oklahoma Department of Environmental Quality recommends avoiding contact with the water at Bernice State Park on Grand Lake this summer.
This comes after the GRDA's lab confirmed the discovery of blue green algae in the water near the park.
The algae, commonly referred to as BGA, can release toxins in the water.
According to information from a DEQ fact sheet, BGA may look like thick pea soup, green paint, or bluish, brownish, or reddish-green paint. When it washes up on shore, it may appear to look like a thick green mat. BGA are made up of extremely small organisms that are difficult to pick up and hold. Consumption or inhalation of BGA can be unsafe.
Test results of the water will not be available until next week.
"It's nasty, way nastier than I've ever seen it," says local fisherman Steve Hulvey.
It's the stuff you would expect to see in an abandoned swamp, not at a popular destination spot like Grand Lake.
"They say it is toxic and can be toxic to humans," says Park Ranger John Chinn.
Blue Green Algae is a dangerous form of regular green algae. It's hard to detect but can be deadly.
"They contacted the Center for Disease Control and they have confirmed that she has been affected by this green toxin," says Chinn.
Just today Chinn he found out that his wife has been infected.
"We were in it about a week ago for about ten minutes," says Chinn."It started out itching we thought it might be poison ivy she swelled up underneath her eyes yesterday."
Friday the GRDA put out an alert cautioning people to look out.
"It's usually you can see 10-12 inches down and you can't even see 3-4 inches here, it's real greenish murky stuff," says Hulvey.
Chinn says it's the heat and shallow waters that makes the algae thrive, but it's never happened in his career as a Park Ranger.
"It's the first year that we know of, in 20 some years and first time we've known of the problem," says Chinn.
So far Chinn's wife is the only confirmed case in the Grand Lake area.