The algae can cause rashes, stomach cramps, nausea, vomiting and diarrhea.
Across a long stretch of the Mississippi gulf coast, beaches are closed because of a harmful algae covering the water. The blue-green algae bloom has closed nine beaches along about a 25 mile long stretch of coast.
"I've never seen it happen like this before," said Julie Macuick, who lives in Waveland. "We can't fish, we can't shrimp, we can't crab and it's killing the seafood industry."
The Mississippi Department of Environmental Quality sampled waters and closed beaches in Hancock and Harrison county including Bay St. Louis, Waveland, Pass Christian and Gulfport.
The algae can be harmful. It can cause rashes, stomach cramps, nausea, vomiting and diarrhea.
So, while you can enjoy the sand, avoid the water.