Toxic bacteria are keeping swimmers out of the water on the Mississippi Gulf Coast, and it will be weeks before financial information shows whether beach closures are hurting the local economy.

The communications director for the tourism agency Coastal Mississippi, Erin Rosetti, says she’s seeing fewer people hanging out on the sand.

“We do see people on the beach. However, we don’t see them en masse as we are used to during this month,” Rosetti told The Associated Press on Monday.

The Mississippi Department of Environmental Quality is warning that people and pets should stay out of saltwater near the mainland beaches. The agency started closing some beaches June 22 and on Sunday closed the last two sections near the Alabama line. While the water is off limits, people can still be on the sand.

Polluted Midwest floodwaters have fed an outbreak of cyanobacterium. Commonly known as blue-green algae, it can cause rashes, diarrhea and vomiting. It is spreading eastward as water from the Mississippi River pours into the Gulf of Mexico.

Rosetti said beach closures are a “hindrance,” but keeping people safe is the priority.

Rosetti said other water activities remain available, such as river kayaking. Beaches remain open on Mississippi’s barrier islands miles offshore.